e-Proceedings (WWSS21)

July 26 – 31, 2021

e-Proceedings

https://wastewater2021.eap.gr/

Editors: I. K. Kalavrouziotis and P. Kokkinos

6th distance education e-learning International Summer School and Workshop on “Wastewater and Biosolids Management” (WWSS21)

e-Book of Proceedings

Edited by: I. K. Kalavrouziotis and P. Kokkinos

HELLENIC OPEN UNIVERSITY Patras, Greece, July 2021

6th distance education e-learning International Summer School and Workshop on “Wastewater and Biosolids Management” (WWSS21)

e-Book of Proceedings Editors:

Professor Dr. Ioannis K. Kalavrouziotis (Dean of the School of Science and Technology) Dr. Petros Kokkinos

Asistants: Ms Ekavi Isari (PhD student) Mr Spyridon Kyritsis (MSc student) Copyright © 2021 6th distance education e-learning International Summer School and Workshop on “Wastewater and Biosolids Management” (WWSS21) Laboratory of Sustainable Waste Management Technologies School of Science & Technology Hellenic Open University Parodos Aristotelous 18, 26 335 Patras, Greece ISBN: 978-960-611-012-2

The authors are exclusively responsible for their work and not the editors of the proceedings.

Contents Preface ................................................................................................................................................. 5 Posters Session .................................................................................................................................... 7 A mathematical model for an optimum land use configuration with the least environmental impact: model development and application ...................................................... 8 Degradation of antibiotics and textile dyes in water by DBD plasma driven by high voltage nanopulses.................................................................................................................... 10 Photocatalytic treatment of landfill leachate under simulated solar irradiation using titanium dioxide as catalyst enhanced by oxidants ................................................................... 12 Anaerobic digestion of complex substrates: a proposed protocol for the process ratelimiting step determination ....................................................................................................... 16 Removal of pharmaceutical compound from wastewaters with adsorption onto activated carbons produced from orange peels, sucrose, tea stalks and kiwi peels ................................. 18 Monitoring microplastics in wastewater treatment plant of Thessaloniki: sampling, identification and quantiffication of particles........................................................................... 20 Recovery of N and P from municipal wastewater .................................................................... 24 Utilization of water treatment residual sludge for the improvement of barren soil ................. 26 Green houses for olive mill wastewater treatment ................................................................... 28 Evaluation of the adsorption of the antidepressant citalopram by graphene oxide (GO)......... 30 The potential of activated carbon from tea tree sawdust in efficient diesel oil removal .......... 32 Adsorption of Methylene blue from aqueous solutions by activated carbon in tubes: The effect of rotation in batch process ............................................................................................ 34 Effect of packed beds wettability on salt precipitation ............................................................ 36 Can we estimate the emitted N2O from constructed wetlands treating wastewater? ............... 38 Energy requirements by municipal wastewater treatment plants of Greece ............................ 40 Additional operational characteristics of the wastewater treatment plants for the estimation of their seismic vulnerability .................................................................................. 42 Non-structural characteristics of wastewater treatment plants as factors for estimating their seismic vulnerability ........................................................................................................ 44 A quantitative microbial risk assessment for COVID-19 infection from wastewater .............. 46 Knowledge & Attitudes of high Schools students in Greece, towards Waste Management .................................................................................................................................................. 48 Exploitation of by-products from biogas plants for greenhouse heating and production of high added-value agricultural products with reduced environmental footprint ....................... 52 Predicting biogas production from anaerobic wastewater treatment plants using a user friendly software platform ........................................................................................................ 54 Towards to a model of a “Smart City” using treated wastewater ............................................. 56 Biosolids usage in agriculture over the centuries ..................................................................... 58

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Preface Thank you for your interest in the 6th distance education e-learning International Summer School and Workshop on "Wastewater and Biosolids Management" (WWSS21), which took place in Patras, Greece, July 26 - 31, 2021. This scientific event was organized in the context of the Postgraduate Study Programme “Waste Management”, by the Hellenic Open University.

The Summer School started in 2015 and was successfully continued since then with tens of wastewater and biosolids experts from many different countries worldwide (USA, China, Greece, Germany, Jordan, Philippines, Spain, UK, Tunisia, etc.), as keynote speakers. Our aim is to establish the Summer School as an important and distinguished distance education e-learning educational scientific event, which will be organized annually.

The Summer School is intended for Public and private institutions, graduate students, postdoctoral researchers, and generally scientists interested in the field of wastewater and biosolids management issues.

The 2021 program followed the strategy of maintaining basic lectures enriched with new topics of interest on the new trends in wastewater and biosolids management technologies and representative case studies. As special features, the 2021 Summer School: 1) dedicated a session on wastewater management history, focused in China 2) included a session, as in 2019, on practical laboratory exercises and data analysis tools for measuring the basic wastewater parameters requested by regulations 3) offered the opportunity to postgraduate and doctoral students, as well as professionals of waste and biological solids, equipment suppliers, public bodies and organizations to present their work via eposter in a dedicated special session. This was particularly expected to allow young scientists to attend summer school, interact with each other and facilitate research synergies.

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Posters on water and wastewater treatment technologies, treatment of emerging contaminants of wastewater (e.g. pharmaceuticals, microplastics), mathematical model development and application, use of treated wastewater in the context of SMART CITIES, QMRA assessment for COVID-19 infection from wastewater, recovery of phosphorus and nitrogen, wastewater and sludge reuse in agriculture, pollution remediation technologies, energy requirements and seismic vulnerability of wastewater treatment plants, biogas production from wastewater treatment, and knowledge and attitudes of students on waste management issues, have been presented.

Closing this short preface, I would like to express my deep gratitude to all those who have supported this effort since 2015, and sincerely thank the keynote speakers from the Hellenic and foreign Universities and research institutes, for contributing to a programme of such high quality.

We would cordially like to invite all interested parties to disseminate this educational event.

We are confident that the participants of WWSS21 have benefited from, and enjoyed the programme.

Sincerely Yours

Professor Dr. Ioannis K. Kalavrouziotis Dean of the School of Science and Technology

Dr. Petros Kokkinos

Asistant: Ms Ekavi Issari (PhD student) Mr Spyros Kyritsis (MSc student)

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Posters Session

7

WWSS21: e-Book of Proceedings

Posters Session

A MATHEMATICAL MODEL FOR AN OPTIMUM LAND USE CONFIGURATION WITH THE LEAST ENVIRONMENTAL IMPACT: MODEL DEVELOPMENT AND APPLICATION

Francis Leomarie T. Conato and Alfonso B. Labao Abstract In this paper, we investigate the environmental impact of the future construction of a military base in the province of Bataan, Philippines. In particular, we assess the sensitivity to pollution of different areas, as measured by the proximity of the area to point sources of pollution - arising from various configurations of the military base. This is done by fixing the current base layout to a certain configuration, and then forecasting the most probable land use in the near term using spatial Markov chain predictions of land use classes. For simulation, we also implement a genetic algorithm to estimate the set of optimal base configurations that minimize sensitivity to pollution while respecting constraints arising from military base requirements.

Affiliations College of Engineering University of the Philippines Diliman Philippines

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A mathematical model for an optimum land use configuration with the least environmental impact: Model Development and Application Francis Conato, Alfonso Labao, and Florencio Ballesteros Jr. College of Engineering, University of the Philippines, Diliman

Abstract

Optimal Location Algorithm

We investigate the optimal spatial arrangement of a future building site construction in a simulated forested area. The objective is to minimize the diffusion of pollutants to nearby rivers from non-point sources, as well as minimize transforming existing forest land cover areas to non-forest.

The model that computes the optimal land location of buildings is described by the following algorithm:

Our method simulates the diffusion of pollutants from non-point sources by applying spatial filters to a raster map. Afterwards, future land use is predicted by means of a combination of Markov Chains and spatial filters to incorporate neighboring effects to land cover profiles. The pollution impact of a certain building location is measured by the amount of pollutants diffused to a water source, as well as by the amount of deforestation. We then perform an iterative grid search for the optimal configuration of building locations that minimizes pollution risk.

Introduction The construction of man-made structures in forested areas induces variation in the future land-use of the area. In addition, it diffuses pollutants in the surrounding neighborhood of a structure’s location. Thus, a structure’s location is an important variable in considering the environmental impact of construction projects.

In this paper, we propose a mathematical model that estimates the optimal location of three structures in a simulated area. Optimality is expressed in terms of minimization of environmental impact, which is measured as the additive sum of two factors: (1) the amount of pollutants from non-point sources diffused to nearby water areas, and (2) the amount of deforestation that will occur in the future Estimation of the first factor is done by applying a spatial filter to a binary raster map consisting of pixels that identify that mark the structure’s location. The spatial filter approximates the diffusion of pollutants. Pollutant diffusion is then measured by the amount of overlap of the diffused binary map with water sources..

Estimation of the second factor is done by means of a combined Markov chain and spatial filter to predict the future land use given a raster map of the land-cover (including the buildings). The amount of deforestation is measured by the number of predicted forest land-use that decreased.

Given these two factors, a grid of possible building locations is iteratively examined – computing the total pollution contributed by each building location. The optimal building location is then derived by retrieving the location with least environmental impact as measured by the sum of the two factors above.

Contact Francis Conato, Dr. Florencio Ballesteros Jr. Department of Environmental Engineering College of Engineering, UP Diliman Email: junconatz@gmail.com; fcballesteros@up.edu.ph

Function: Compute_Water_Pollutant Input 1 : forest land cover raster map Input 2 : array of building coordinates Steps: 1) Create a binary map where the building coordinates are labeled as 1, all others are zero 2) Apply a 200x200 spatial filter over the binary map to approximate pollutant diffusion 3) Set all nonzero values in filtered binary map to 1 4) Let ܹܲ denote the water pollution metric, where ‫ ݌ݎ‬is the land cover class in the forest raster map and ݀‫ ݌‬is the value of the filtered binarymap. ܹܲ ൌ

෍

Fig 1. Simulated Forest Land Cover Map, where blue pixels denote water cover, dark green pixels denote forest cover, black pixels denote inconstructible land (i.e. ravines), and light green pixels denote grassland

ሾ‫ ݌ݎ‬ൌ ‫ݎ݁ݐܽݓ‬ሿ Ƭ ሾ݀‫ ݌‬ൌ ͳሿ

௥௣ ௜௡ ௙௢௥௘௦௧ ௠௔௣

Function: Compute_Deforestation Input 1 : forest land cover raster map Input 2 : array of building coordinates Input 3 : Markov chain transition probabilities Steps: 1) Using the array of building coordinates, label the pixels in the forest raster map as building with 100% probability 2) Using the Markov chain transition matrix, compute the likelihood future land cover use per pixel in the raster map.

3) Apply a 5x5 2D spatial filter over the predicted future probabilities of land cover 4) Let ‫ ܨܦ‬denote the deforestation metric, and ‫݌ݎ‬ as the land cover class in the raster map prior to prediction and ‫ ݂݌ݎ‬as the predicted future land cover

‫ ܨܦ‬ൌ

෍

‫ ݌ݎ‬ൌ ݂‫ ݐݏ݁ݎ݋‬Ƭ ሾ‫ ݂݌ݎ‬Ǩ ൌ ݂‫ݐݏ݁ݎ݋‬ሿ

௥௣ ௜௡ ௠௔௣

Function: Minimize_Env_Impact Input 1: forest land cover raster map Input 2: building configuration Input 3: Markov chain transition probabilities Steps: 1) Divide the forest map into a grid 2) Compute all possible building locations over the grid 3) For each building location, do: 3a) compute ܹܲ = Compute_Water_Pollutant 3b) compute ‫ = ܨܦ‬Compute_Deforestation 3c) compute the impact: ‫ ܫ‬ൌ ܹܲ ൅ ‫ܨܦ‬ 4) Output the building location with the least ‫ܫ‬ The main routine of the algorithm is Minimize_Env_Impact, which calls the functions Compute_Water_Pollutant and Compute_ Deforestation iteratively – going through all the possible building locations in the grid. The algorithm may be inefficient if the size of a grid cell is too small. For our experiment, the simulated forest map is of size 1280x914, and is divided into a 4x4 grid.

The algorithm is implemented in Python.

Fig 2. Estimated best building location output by the algorithm. The white colored pixels denote the three buildings set at the computed optimal location by the algorithm.

ravine (r) water (w) Forest (f) grass (g) building (b)

(r) (w) (f) (g) (b) [0.90, 0.02, 0.03, 0.05, 0.00] [0.01, 0.80, 0.10, 0.09, 0.00] [0.00, 0.25, 0.70, 0.10, 0.00] [0.20, 0.10, 0.10, 0.60, 0.00] [0.00, 0.00, 0.00, 0.00, 1.00]

Tab. 1. Simulated Markov Chain transition probability matrix consisting of five classes – denoting the set of possible classes In the map.

Discussion of Results The simulated forest land cover map prior to building construction is shown in Fig. 1. The simulated Markov chain probability matrix is shown in Tab. 1. The algorithm is run using these two objects as input, and the computed optimal building locations is shown in Fig. 2.

From Fig. 2, the optimal building locations are set to be far from the water sources (shown as blue pixels). This follows from the observation that non-point pollutants are most likely to affect those that are near the surrounding area of the buildings. At the same time, it can be seen in Fig. 2 that the optimal building locations have minimal overlap with the forest. Here, only two forest “packets” are located near the building.

The algorithm can be made more accurate by minimizing the size of the grid cells, and perhaps by incorporating rotations or horizontal flips in the buildings. However, very small grid cells involve increasing computation time. For future work, the experiment can be implemented in actual GIS data, where land cover can be derived using supervised maximum likelihood (i.e. LULC).

WWSS21: e-Book of Proceedings

Posters Session

DEGRADATION OF ANTIBIOTICS AND TEXTILE DYES IN WATER BY DBD PLASMA DRIVEN BY HIGH VOLTAGE NANOPULSES

S. Meropoulis and C.A. Aggelopoulos* Abstract Textile dyes and antibiotics represent some of the most complicated environmental pollutants due to their variety and complex structure. Cold atmospheric plasma (CAP) is regarded as a highly competitive advanced oxidation process towards the removal of organic pollutants from wastewater.

In this study, a gas-liquid nanosecond pulsed dielectric barrier discharge (NSP-DBD) plasma reactor was used for the degradation/mineralization kinetics of popular dyes (Orange II, Methylene Blue, Methyl Orange, Methyl Violet and Sunset Yellow) as well as for the antibiotic enrofloxacin. The experimental setup used to treat polluted water samples consisted of a gas-liquid DBD reactor driven by nanosecond pulsed voltage supplied by means of a nanosecond pulse generator producing positive high-voltage pulses of rising time about 4 ns. The applied high voltage pulses and the circuit current were monitored on a digital oscilloscope and measured using a high voltage probe and a current transformer, respectively. The inter-electrode gap was fixed at about 10 mm. The distance between the dielectric surface and aqueous solution surface was about 3 mm and its gap was filled with dry air injected over the aqueous phase at a constant flow rate. The complete degradation of textile dyes and enrofloxacin in water at high-energy yield, suggests that the gas-liquid nsp-DBD system has the potential to be an extremely cost-effective technology for the treatment of polluted wastewater.CaO2 and H2O2 as promoting additives should be considered both as an extra source of the highly reactive H2O2 which is actively involved in pollutants degradation.

Affiliations Foundation for Research and Technology Hellas – Institute of Chemical Engineering Sciences, Stadiou str., Platani, 1

26504 Patras-Rio, Greece *email: caggelop@iceht.forth.gr

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“Degradation of antibiotics and textile dyes in water by DBD plasma driven by high voltage nanopulses” S. Meropoulis and C.A. Aggelopoulos* 1Foundation

for Research and Technology Hellas – Institute of Chemical Engineering Sciences, Stadiou str., Platani, 26504 Patras-Rio, Greece *email: caggelop@iceht.forth.gr

Experimental procedure/Experimental setup

Introduction/Motivation Textile dyes and antibiotics represent some s of the most complicated environmental pollutants due to their variety var and complex structure.

Antibiotics are widely used as pharmaceutical agents against human diseases (e.g. bacterial infections) but also for enhancing agricultural production, in terms of animal and crop breeding/protection.

The limited biological degradation of antibiotics due to the slow metabolism by living organisms is responsible for their extended presence in water systems including natural reservoirs, drinking water, aquacultures and wastewaters.

Textile dyes do not decompose through biological methods and resists light irradiation and chemical oxidation. Therefore, several scholars have studied their degradation. [1, 2] So far, many techniques have been applied for wastewater degradation, such as adsorption, chemical, membrane degradation and the combined treatment of different methods. Among them, plasma treatment is one of the most promising technologies with high efficiency for wastewater treatment [3, 4].

9 Water is contaminated by commercial dyes and enrofloxacin (>99% purity) with initial concentration: 40 mg/L 9 Contaminated water sample (15mL) is placed in plate above the grounded electrode 9 Dry air is streamed into the reactor at constant flow rate 9 Water solution samples are treated by DBD at i) various pulse frequencies ii) various applied voltages and iii) various flow rates 9 Treatment time ranges from 2 to 20 minutes

Experimental setup used to treat contaminated water solution

Objectives Examination of the applicability of Cold Atmospheric Plasma (CAP) discharge techniques as advanced oxidation methods for the efficient, sustainable and cost-effective remediation of water contaminated by textile dyes and antibiotics Testing of a gas-liquid dielectric barrier discharge (DBD) reactor operating with air at atmospheric pressure to investigate the removal of textile dyes and antibiotics from water solutions Investigation of the role of (i) treatment time; (ii) voltage amplitude; (iii) pulse frequency; (iv) flow rate on the degradation efficiency

To identify the degradation efficiency of textile dyes and enrofloxacin after CAP treatment, the samples are analyzed by Ultraviolet–visible spectroscopy (UV-Vis) and High Performance Liquid Chromatography (HPLC)

Picture of the DBD reactor

Main Results Textile Dyes

Antibiotics (Enrofloxacin)

Effect of pulse voltage on ENRO degradation

Effect of pulse frequency on ENRO degradation

26.2 kV 23.4 kV 20.2 kV

100

60 0.24

40

26.2 kV

0.20

20

0.16

23.4 kV

0.12 0.08 20.2 kV

0.04

0

4

8

12

16

20

0.20

The TOC removal as a function of NSP-DBD treatment time for five different types of dyes (SY, OII, MO, MV and MB)

300 Hz

0.16

40

20

200 Hz

0.12 0.08 100 Hz

0.04 0.00

0

24

0

4

8

Treatment time (min)

12

16

20

24

Treatment time (min)

Enrofloxacin degradation efficiency as a function of treatment time in the presence of CaO2

Enrofloxacin degradation efficiency as a function of treatment time after the addition of H2O2

100

Degradation efficiency (%)

100

Degradation efficiency (%)

The degradation efficiencies as a function of NSP-DBD treatment time for five different types of dyes (OII, MB, MV, MO and SY)

60

0.00

0

300 Hz 200 Hz 100 Hz

80

k (min-1)

Degradation efficiency (%)

80

k (min-1)

Degradation efficiency (%)

100

80

60

DBD 5 mM H2O2/DBD

40

10 mM H2O2/DBD

20

20 mM H2O2/DBD

80

60

40

DBD 6.24 mM CaO2 /DBD

20

8.32 mM CaO2 /DBD

Action efficiency of .OH radicals and 1O2 as a function of NSP-DBD treatment time (bars, left aaxis) and the degradation efficiency as a function of NSP-DBD treatment time in the presence of the scavengers (symbols, right axis)

0

0 0

2

4

6

8

10

12

14

16

18

20

22

0

2

4

6

8

10

12

14

16

18

20

22

24

Treatment time (min)

Treatment time (min)

Conclusions ¾ ¾ ¾ ¾ ¾ ¾

Plasma treatment is highly effective towards the removal of structurally different dyes and enrofloxacin from aqueous solutions in short time.

Voltage amplitude and discharge frequency affect substantially the degradation efficiency.

The complete degradation of textile dyes and enrofloxacin in water at high-energy yield, suggests that the gas-liquid nspDBD system has the potential to be an extremely cost-effective technology for the treatment of polluted wastewater.

CaO2 and H2O2 as promoting additives should be considered both as an extra source of the highly reactive H2O2 which is actively involved in pollutants degradation.

The different degradation rate accomplished with the same cold plasma system for different classes of dyes is due to their structural features and their chemical reactivity towards plasma species. .OH and 1O have high contribution in the plasma-assisted degradation process of textile dyes and antibiotics.

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References 1.

2.

3.

4.

M. Tichonovas, E. Krugly, V. Racys, R. Hippler - Chemical Engineering Journal, 2013, 229, 9-19.

P. Shia, R. Sua, S. Zhua, M. Zhua, D. Lia, S. Xua - Journal of Hazardous Materials, 2012, 229–230, 331– 339.

C.A. Aggelopoulos, S. Meropoulis, M. Hatzisymeon, Z.G. Lada, G. Rassias - Chemical Engineering Journal, 2020, 398, 125622.

S. Meropoulis, G. Rassias, V. Bekiari, C.A. Aggelopoulos - Separation and Purification Technology, 2021, 274, 119031.

WWSS21: e-Book of Proceedings

Posters Session

PHOTOCATALYTIC TREATMENT OF LANDFILL LEACHATE UNDER SIMULATED SOLAR IRRADIATION USING TITANIUM DIOXIDE AS CATALYST ENHANCED BY OXIDANTS

N. Malesic, E. Evgenidou, D. Bikiaris and D. Lambropoulou Abstract In this study the photocatalytic treatment of a landfill leachate has been investigated using TiO2 as catalyst under simulated solar irradiation. The main objectives were to evaluate the efficiency of the photocatalytic system on the treatment of landfill leachate in terms of organic content and color removal and to explore the effect of the addition of oxidants like hydrogen peroxide and persulfate.

For the photocatalytic experiments, a solar simulator was employed equipped with a xenon lamp. At the beginning, the appropriate amount of catalyst together with the diluted leachate (100 mL) were kept in the dark under stirring for 30 minutes, to achieve adsorption equilibrium on the catalyst’s surface. During irradiation, samples were withdrawn from the reactor at different time intervals and proceed to analysis. All measurements for organic content (at 254 nm) and colour (Color number, CN calculated at 436, 525 and 620 nm) were conducted spectrophotometrically. The photocatalytic treatment of the leachate in the presence of different concentrations TiO2 (1, 2, 3, and 5g/L) was investigated. A decrease in the UV254 absorbance and in CN, ranging from 2% to 25%, and from 17% to 67 % respectively, after 30 minutes treatment in the dark was observed due to the adsorption of the organic compounds on the catalyst’s surface. After the initiation of the illumination a further decrease in the UV254 absorbance and in CN is subsequently taking place leading finally to a 50%75% or 74%-99% reduction respectively. Obviously, increase in the concentration of the catalyst leads to higher degradation percentages of the organic content and color. Addition of hydrogen peroxide cause an increase in the decolorization rate however, no enhancement in the reduction of organic content was observed. On the contrary, addition of persulfate cause complete decolorization within 4 hours of treatment while a 81% reduction in UV254 adsorbance was finally achieved.

Obviously, photocatalytic treatment can be considered as a promising tool for the treatment of landfill leachate under solar irradiation.

Acknowledgments This research has been co‐financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation (2nd cycle), under the call RESEARCH – CREATE – INNOVATE (acronym: UV-leach, project code: Τ2ΕΔΚ-00137).

Affiliations PhD candidate, Neda Malesic, Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR–541 24 Thessaloniki, Greece of Chemistry, Aristotle University of Thessaloniki, 54006, Thessaloniki, Greece/ Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, Thessaloniki, GR-57001, Greece, +302310997685, nmalesice@chem.auth.gr Dr, Eleni Evgenidou, Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR–541 24 Thessaloniki, Greece of Chemistry, Aristotle 12

University of Thessaloniki, 54006, Thessaloniki, Greece / Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, Thessaloniki, GR-57001, Greece, +302310997446, evgenido@chem.auth.gr Professor, Dimitrios Bikiaris, Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece, +302310997812, dbic@chem.auth.gr Associate Professor, Dimitra Lambropoulou, Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR–541 24 Thessaloniki, Greece of Chemistry, Aristotle University of Thessaloniki, 54006, Thessaloniki, Greece / Center for Interdisciplinary Research and Innovation (CIRI-AUTH), Balkan Center, Thessaloniki, GR-57001, Greece, +30 2310 997687, dlambro@chem.auth.gr

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WWSS21: e-Book of Proceedings

14

Posters Session

PHOTOCATALYTIC TREATMENT OF LANDFILL LEACHATE UNDER SIMULATED SOLAR IRRADIATION USING TITANIUM DIOXIDE AS CATALYST ENHANCED BY OXIDANTS N. Malesic1,2, E. Evgenidou1,2, D. Bikiaris3 and D. Lambropoulou1,2* 1Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of 2

Thessaloniki, GR–541 24 Thessaloniki, Greece Center for Interdisciplinary Research and Innovation (CIRI‐AUTH), Balkan Center, Thessaloniki, GR‐57001 3Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR‐541 24 Thessaloniki, Greece *Corresponding author: E‐mail: dlambro@chem.auth.gr

INTRODUCTION Leachate is categorized as a special wastewater containing high organic pollutant concentrations. The photocatalytic treatment of a landfill leachate has been investigated using of different concentrations TiO2 (1, 2, 3, and 5 g/L) as catalyst under simulated solar irradiation. The main objectives were to evaluate the efficiency of the photocatalytic system on the treatment of landfill leachate in terms of organic content and color removal and to explore the effect of the addition of oxidants like hydrogen peroxide and persulfate. For the photocatalytic experiments, a solar simulator was employed equipped with a xenon lamp. All measurements for organic content (at 254 nm) and colour (CN calculated at 436, 525 and 620 nm) were conducted spectrophotometrically. Increase in the concentration of the catalyst leads to higher degradation percentages of the organic content and color. Addition of hydrogen peroxide cause an increase in the decolorization rate however, no enhancement in the reduction of organic content was observed. On the contrary, addition of persulfate cause complete decolorization within 4 hours of treatment while a 81% reduction in UV254 adsorbance was finally achieved.

The results showed that performed experiment was efficient in the photocatalytic degradation of the landfill leachate under solar irradiation.

EXPERIMENTAL

RESULTS AND DISCUSSION 1g/L_TiO2 2g/L_TiO2 3g/L_TiO2 5g/L_TiO2

illuminati

1,0

0,6 0,4

A solar simulator Atlas Suntest CPS+ equipped with a xenon lamp providing irradiation at 750 W m‐2. Experiments were performed using a Pyrex glass reactor containing 100mL of aqueous solutions, the appropriate amount of catalyst together with the diluted leachate (1 : 10).

0

100

200 Time (min)

300

400

For analytical measurements was used Hitachi U‐2000 spectrophotometer.

3%_TiO2

3g/L_TiO2+5g/L_H2O2

0,0 ‐100

0

3g/L_TiO2+5g/L_K2S2O8

80,0 60,0 40,0 20,0

100

200 Time (min)

300

400

The photocatalytic treatment of a landfill leachate has been investigated using different concentrations of TiO2 as catalyst under simulated solar irradiation. Increase in the concentration of the catalyst leads to higher degradation percentages of the organic content (50‐75%) and CN (74‐99%).

3

• In case of addition of hydrogen peroxide, it was not noticed significant reduction of organic content. In case of addition of persulfate 81% of reduction was achieved. Decolorization rate was increased in both cases.

4

Photocatalytic treatment can be considered as a promising tool for the treatment of landfill leachate under solar irradiation.

Figure.2. Degradation (%) of the organic content of the leachate during photocatalytic treatment in the presence of the TiO2/TiO2 and H2O2/TiO2 and K2S2O8 under simulated solar irradiation

Time (min)

Figure.3. Degradation (%) of the CN of the leachate during photocatalytic treatment in the presence of the TiO2/TiO2 and H2O2/TiO2 and K2S2O8 under simulated solar irradiation

3%_TiO2

3g/L_TiO2+5g/L_H2O2

3g/L_TiO2+5g/L_K2S2O8

100,0 Degradation (%)

Degradation (%)

Filtrated leachate sample

Filtrated leachate sample after 6 h of photocatalytical experiment.

CONCLUSIONS

2

0,4

a) b)

0,0

1

0,6

Figure.1. a) Reduction in the UV254 absorbance and b) reduction of the calculated values of CN of the leachate during photocatalytic treatment in the presence of the TiO2 under simulated solar irradiation

100,0

Degussa P25 TiO2 (Evonic, Germany)

1g/L_TiO2 2g/L_TiO2 3g/L_TiO2 5g/L_TiO2

0,2

0,2

0,0 ‐100

0,8 CN/CN0

[UV254]t/[UV254]0

0,8

illuminati

1,0

80,0 60,0 40,0 20,0 0,0

Time (min)

ACKNOWLEDGMENT UV‐LEACH This research has been co‐financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship, and Innovation, under the call RESEARCH – CREATE – INNOVATE (2 nd Cycle) (Project acronym: UV‐LEACH; Project code: T2EDK‐00137)

WWSS21: e-Book of Proceedings

Posters Session

ANAEROBIC DIGESTION OF COMPLEX SUBSTRATES: A PROPOSED PROTOCOL FOR THE PROCESS RATE-LIMITING STEP DETERMINATION K. Tsigkou, 1 D. Zagklis1, C. Zafiri2, M. Kornaros1 Abstract Anaerobic digestion (AD) is a complex four-step process (hydrolysis, acidogenesis, acetogenesis and methanogenesis), in which various groups of microorganisms are involved. According to literature, hydrolysis or methanogenesis are usually considered as the rate-limiting steps of AD due to the substrate composition or the low doubling rate of methanogens, respectively. Identifying the ratelimiting step during the anaerobic digestion of a substrate allows to take steps towards accelerating the entire process. Some attempts (batch and CSTR) have been reported in literature to develop a protocol for this type of analysis, but all exhibit room for improvement. The purpose of this study was to establish an easily replicable protocol that can be used in a wide range of substrates for the determination of AD rate-limiting step.

Three substrates, namely fruits and vegetables (FV) mixture, yoghurt (0% fat) and fried olive oil were tested using the proposed protocol, each of which was considered representative of a specific macronutrient group (carbohydrates, proteins, and lipids respectively). Anaerobic inoculum (boiled inoculum with reduced acetoclastic methanogens was used for the examination of hydrogenotrophic methanogens, and conventional inoculum for the overall process), sodium acetate (SA) and representative polymers (cellulose, casein, triolein) and monomers (glucose, glutamic acid, oleic acid) of each macronutrient group were also used. Finally, a medium was required for the dilution of the reactor broth. The developed protocol is divided into two stages. The first step targets the acetate consumers activation and the validation of the amount of inoculum added in each reactor by using acetate as substrate and measuring the maximum methane production rate achieved in each reactor.

The second step consists of the addition of different combinations of substrate, polymer and monomer of each macronutrient group and measuring their effect on the maximum methane production rates observed. Regarding the AD stages, hydrolysis, acidogenesis/acetogenesis and methanogenesis are examined, with acidogenesis and acetogenesis being treated as a single step. The Bioprocess Control AMPTSII BMP assessment system was used in this analysis, consisting of 15 (0.5 L) bioreactors with CO2 absorption units (0.1 L) filled with NaOH solution and the CH4 flow meter.

For the three substrates examined, acidogenesis/acetogenesis was identified as the rate-limiting step of the AD process. Depending on the substrate composition, the contribution of hydrogenotrophic and acetoclastic methanogens to total CH4 production can significantly vary indicating the converted COD ratios by the different microorganisms’ consortia.

Affiliations 1

Laboratory of Biochemical Engineering & Environmental Technology (LBEET), Department of Chemical Engineering, University of Patras, 26504 Patras, Greece.

2

Green Technologies Ltd, 5 Ellinos Stratiotou Str., 26223 Patras, Greece.

16

ANAEROBIC DIGESTION OF COMPLEX SUBSTRATES: A PROPOSED PROTOCOL FOR THE PROCESS RATE-LIMITING STEP DETERMINATION K. Tsigkou1#, D. Zagklis1, C. Zafiri2 and M. Kornaros1* 1Department

of Chemical Engineering, University of Patras, University Campus, Patras, 26504, Greece 2 Green Technologies Ltd., 5 Ellinos Stratiotou Str., Patras, 26223, Greece

Anaerobic digestion (AD) is a biological process, recognized as one of the best methods for organic wastes valorization (Fig.1). AD process takes place through 4 successive stages (Fig. 2). The process rate is depended on the interactions between the diverse microorganisms, which can carry out the aforementioned stages. Usual assumptions made concerning the AD process consider that the hydrolysis or the methanogenesis are the slowest steps due to the substrate composition or the low doubling-rate of methanogens, respectively. It is also assumed that the acidogenesis & the acetogenesis are the fastest steps. The aim of this study is the modification of a published protocol for the rate limiting step Fig. 2: Anaerobic digestion steps.

Fig. 1: Anaerobic digestion products & applications. determination and its application on complex substrates with different composition.

INTRODUCTION

MATERIALS AND METHODS Inoculum H2 Typical Pretreated monitoring (100oC, 20’) Incubation CO2 traps CH4 measurement Process monitoring Volume: 0.5 L, T: 37oC Volume: 0.08 L, T: 25oC T: 25oC, T & P sensors Continuous recording, Cont. stirring NaOH solution 3D H2O calculations & corrections

1st STEP: Activation of the acetate-consumers • CH3COONa (3 g COD/L) • 4 g VSS inoculum /L • Addition of anaerobic medium (final work. volume 0.5 L) Test Initial Organic Load (gCOD/L) Substrate SA M P Blank Substrate 3 Substrate + SA 1.5 1.5 Substrate + Monomer 1.5 1.5 SA 3 Monomer 3 Polymer 3

Figure 3: Experimental configuration.

Fruits & Vegetables

Representative polymer group

Carbohydrates

Proteins

Lipids

Cellulose/ Glucose

Casein/ Glutamic acid

Triolein/ Oleic acid

Tested polymer (P)/ Monomer (M) Acetogenesis Intermediate

RCH4=0

6 4 2 0

8 6 4 2

200

300

Yoghurt Yoghurt (Pret. Inoculum)

8 6

RCH4=0

4

50

20

2 0

100 Time (h)

150

100

5

200 Time (h)

300

Yoghurt Yoghurt + Glut. Acid Glut. Acid

15 10 5

400

CH4 (NmL/h)

3

RCH4=0

2

0 400 Time (h)

600

800

150

Time (h)

200

4 2 0

50

100 Time (h)

20

150

10 5

0

50

10

100

150

Time (h)

200

250

Olive Oil Olive Oil + SA SA

8 6 4 2 0

0

100

200 Time (h)

300

400

0

100

200 Time (h)

300

Figure 4: H2 & CH4 production rates for all the tested substrates during the rate limiting step determination.

CONCLUSIONS

200

Yoghurt Yoghurt + SA SA

15

250

4

0 200

100

Olive Oil Olive Oil + Oleic acid Oleic acid

6

2

0

50

8

1

6

0 0

10

Olive Oil Olive Oil (Pret. Inoculum)

4

8

200

0 0

RESULTS AND DISCUSSION

FV FV + SA SA

0 0

CH4 (NmL/h)

Time (h)

CH4 (NmL/h)

100

10 CH4 (NmL/h)

10

FV FV + Glucose Glucose

0 0

CH4 (NmL/h)

2nd STEP: Substrate addition

CH4 (NmL/h)

CH4 (NmL/h)

8

H2 & CH4 monitoring

10

FV (Pret. Inoculum) CH4 (NmL/ h)

FV

When CH4 rate start decreasing

Sodium Acetate (SA)

H2 monitoring

10

Olive oil (after frying)

Expired Yoghurt (0%)

CH4 (NmL/ h)

Table 1: The substrates and representative compounds according to substrates’ composition.

The CH4 production rates differed significantly, depending on the substrate characteristics. The converted COD ratios by the H2 or acetate consumers can be estimated. The rate limiting step for the acetate consumption pathway was the acetate production for the three tested substrates.

H2 & CH4 monitoring

400

For all the tested substrates, the unchanged CH4 rate after monomer addition shows that hydrolysis is not the rate limiting step of the process.

In the CH4 production pathway from acetate consumption, the rate limiting step is the acetate production, while 100 % of the COD was removed by the acetate consumers. In case of FV, two presented rates indicate the presence of easily (first) and noneasily (second) biodegradable compounds, while concerning the substrate of olive oil after frying, mild inhibition due to the lipids’ presence was identified.

ACKNOLEDGEMENTS

This research has been co-financed by the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code:T1EDK-03148)»

6th distance education e-learning Summer School on "Wastewater and Biosolids Management" (WWSS21), Patras, Greece, July 26 - 31, 2021

WWSS21: e-Book of Proceedings

Posters Session

REMOVAL OF PHARMACEUTICAL COMPOUND FROM WASTEWATERS WITH ADSORPTION ONTO ACTIVATED CARBONS PRODUCED FROM ORANGE PEELS, SUCROSE, TEA STALKS AND KIWI PEELS

Efstathios V. Liakos, Athanasios C. Mitropoulos, George Z. Kyzas Abstract The aim of the present work is the preparation of various types of activated carbons (AC) derived from various agricultural sources as carbonaceous precursors, like sucrose, kiwi peels, orange peels, and tea stalks. The AC preparation was achieved with the process of chemical activation using KOH and H3PO4. The synthesized samples of AC were tested as adsorbents for the removal of pharmaceutical compound namely pramipexole dihydrochloride (PRM) from aqueous solutions. The higher yield of synthesis was achieved with the sucrose AC ~ 58%, using H3PO4 85% w/w as activation agent, while for kiwi peels (H3PO4 85% w/w), orange peels (3M KOH), and tea stalks (3M KOH) the yield was 10, 9, and 8.6%, respectively. The activation temperature was 650 ℃ for 1 h under N2 for all cases. The physicochemical features of the obtained materials were analyzed by SEM, BET and FTIR spectroscopy. The sucrose AC had the highest specific surface area, 1977 m2/g, with external surface area, total pore volume, and mesopore volume equal to 751 m2/g, 1.382 cm3/g, and 0.819 cm3/g, respectively. The initial pH-effect and concentration of PRM were also examined, while the results of equilibrium (isotherms) were fitted to the Langmuir and Freundlich equations. The maximum adsorption capacities for the samples of AC derived from sucrose, kiwi peels, orange peels, and tea stalks were found to be 213, 190, 155, and 115 mg/g, respectively.

Acknowledgment The financial support received for this study from the Greek Ministry of Development and Investments (General Secretariat for Research and Technology) through the research project “Intergovernmental International Scientific and Technological Innovation-Cooperation. Joint declaration of Science and Technology Cooperation between China and Greece” with the topic “Development of monitoring and removal strategies of emerging micro-pollutants in wastewaters” (Grant no: T7DKI-00220) and it is gratefully acknowledged.

Affiliations Department of Chemistry, International Hellenic University, Kavala, Greece

18

Removal of pharmaceutical compound from wastewaters with adsorption onto activated carbons produced from orange peels, sucrose, tea stalks and kiwi peels E.V. Liakos, A.C. Mitropoulos, G.Z. Kyzas Department of Chemistry, International Hellenic University, Kavala, Greece

Abstract The aim of the present study is the preparation of various types of activated carbon (AC) derived from various agricultural sources as carbonaceous precursors, like sucrose, kiwi peels, orange peels, and tea stalks. The AC preparation was achieved with the process of chemical activation using KOH and H3PO4. The synthesized samples of AC were tested as adsorbents for the removal of pramipexole dihydrochloride (PRM) from synthetic aqueous synthetic solutions. The selection of the sources to produce the activation carbons and the reasons behind were based on the following: (i) one of the most valuable agricultural wastes for the synthesis of AC is orange peels (ORP), which are mainly discarded in large quantities from juice industries. The pollution of land space with orange peels is becoming problematic due to the phenolic functional groups; (ii) sucrose (α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside) (SG) is an inexpensive chemical produced by sugar cane and sugar beet cultivation, having a lot of carbons in its structure (iii) one of the most widely consumed beverages is tea (TEA), and it is consumed on a daily basis all around the world. The tea wastes are not useful in any area of industrial activity and can be used probably only as fertilizers; (iv) kiwi peels (KWP) were selected because they have high cellulose content. The activation temperature was 650 Ԩ for 1 h, under N2 (99.999% pure) flow of 30 STP cm3/min, for all cases. The physicochemical features of the obtained materials were analyzed via SEM imaging, N2 physisorption, and FTIR spectroscopy.

Methodology

Results The higher yield of synthesis was achieved with the sucrose as carbonaceous precursor (yield ~ 58%), using H3PO4 (85% w/w) as activation agent, while for kiwi peels (H3PO4 85% w/w), orange peels (3M KOH), and tea stalks AC (3M KOH) the yield of AC was 10, 9, and 8.6%, respectively. The sucrose AC had the highest specific surface area, 1977 m2/g, with external surface area, total pore volume, and mesopore volume being 751 m2/g, 1.382 cm3/g, and 0.819 cm3/g, respectively. The obtained correlation coefficients (R2) from the Langmuir model ranged from 0.929 to 0.986, while those of the Freundlich model ranged from 0.783 to 0.856. The Langmuir model fits the experimental results of all AC samples better. For low concentrations (10-100 mg/g), the adsorption of PRM using the AC adsorbents was very intense and reached the phase of equilibrium rapidly. For higher concentrations (100-250 mg/g), the highest Qmax of SG-AC may indicate the formation of multilayer coverage due to higher amount of oxygen groups; the same is also presented for all AC samples but with lower Qmax. As it can be observed, the highest pramipexole adsorption capacity (Qmax) at 25 Ԩ was achieved with the use of SG-AC and KWP-AC, respectively, at pH 3.

Finally, according to SEM images the AC derived from sucrose has particles in very small size, result which indicates that a small amount of monosaccharides didn’t achieve to aggregate with the other monosaccharides for tthe e ac achievement e e e to of so solid d surface. su ace

Conclusions The synthesis of activated carbon derived from sucrose, as a carbonaceous precursor, gave an excellent yield (~58%) with a mesoporous structure (~59.3%) at a very low impregnation ratio of the activation agent (H3PO4) per SG (1.7:1).

It is worth noting that the other synthetic protocols require a prolonged duration for the preparation of AC when compared with the synthesis of sucrose activated carbon. The equilibrium results (isotherms) fitted the Langmuir model better. The adsorption capacities were found to be 213, 190, 155, and 115 mg/g for AC samples produced from sucrose, kiwi peels, orange peels, and tea stalks, respectively. The optimum pramipexole dihydrochloride removal in the case of sucrose activated carbon was found to be 95% for pH 3 at a temperature of 25 ℃. A future work may be the activation of sucrose by using microwave oven, autoclave, or other devices at various temperatures under N2 flow.

Table 1. Details of textural parameters of yielded AC samples.

AC sample Surface Micropore External area surface area surface area (m2/g) (m2/g) (m2/g) SG-AC 1977 1226 751 ORP-AC 1298 340 928 TEA-AC 1284 922 361 KWP-AC 1446 976 471

Total pore volume (cm3/g) 1.382 1.421 0.784 0.815

Micropore volume (cm3/g) 0.563 0.152 0.439 0.454

Table 2. Equilibrium parameters for the adsorption of PRM onto AC samples.

Langmuir equation Freundlich equation Qm KL R2 KF n Material mg/g L/mg mg1-1/n L1/n g-1 SG-AC 213 0.678 0.984 87.66 4.047 ORP-AC 155 0.094 0.929 47.73 4.800 TEA-AC 115 0.744 0.986 30.58 2.917 KWP-AC 190 0.517 0.968 72.02 3.988

Mesopore volume (cm3/g) 0.819 1.270 0.345 0.361

R2 0.793 0.856 0.783 0.788

Acknowledgment: The financial support received for this study from the Greek Ministry of Development and Investments (General Secretariat for Research and Technology) through the research project “Intergovernmental International Scientific and Technological Innovation-Cooperation. Joint declaration of Science and Technology Cooperation between China and Greece” with the topic “Development of monitoring and removal strategies of emerging micro-pollutants in wastewaters” (Grant no: T7DKI-00220) and it is gratefully acknowledged.

WWSS21: e-Book of Proceedings

Posters Session

MONITORING MICROPLASTICS IN WASTEWATER TREATMENT PLANT OF THESSALONIKI: SAMPLING, IDENTIFICATION AND QUANTIFFICATION OF PARTICLES

Dimitrios Kalaronis, Nina Maria Ainali, Eleni Evgenidou, Dimitrios Bikiaris, Dimitra A. Lambropoulou Abstract Objectives: The main objective of this study was the monitoring of different polymeric particles and fibers contained in wastewaters which are the main pathway for releasing of them in Ecosystems.

These polymeric particles are named microplastics (MPs) and their size is ranged between 5 mm and 1 μm.

Methods: Sampling took place in wastewater treatment plant (WWTP) of Sindos where 25 L of wastewater samples were collected through autosampler from the effluent of WWTP from March to July of 2021. Samples were transported to laboratory and sieved through metals sieves with mesh size (4.0 - 0.125 mm) with aim to prepare a concentrated sample. Then, samples were filtered under a vaccum-pressure apparatus equipment through glass filters with pore size 1.6 μm. An oxidative digestion step was applied in order to remove the organic matter from the filters and 30 ml of 30% v/v H2O2 was added to each one respectively. Filters were put into glass vessels with H2O2 under continuous stirring at 200 rpm and room temperature for 3 days. Dried filters were checked through Stereoscopic Microscope and a digital camera for mapping them. Then, Gas Chromatography-Mass Spectroscopy analysis was carried out with aim to identify and quantify the possible MPs. Results: Regarding our results, many polymeric fibers were identified and particles (including fragments and films) in different colors and shapes. According to the identification part, the majority of MPs particles were several types of polyethylene, polypropylene, polystyrene, and acrylics, while the polyethylene particles were quantified with a range value between 0.06-0.04 mg/m3.

Conclusions: The domestic wastewater and industrial wastewater of Thessaloniki urban area contained a large amount of microplastics. A part of these particles cannot remove from the treatment processes applied in WWTP and released in Thermaikos Gulf posing a threat to the marine ecosystem of Axios Delta.

Acknowledgments Part of this work has also been done after financial support received from the Greek Ministry of Development and Investments (General Secretariat for Research and Technology) through the research project “Intergovernmental International Scientific and Technological InnovationCooperation. Joint declaration of Science and Technology Cooperation between China and Greece” with the topic “Development of monitoring and removal strategies of emerging micro-pollutants in wastewaters” (Grant no: Τ7ΔΚІ-00220) and it is gratefully acknowledged.

Affiliations PhD candidate, Dimitrios, Kalaronis; Laboratory of Environmental Pollution Control; Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24; tel. +30 2310997685, email: dkalaron@chem.auth.gr 20

PhD candidate, Nina Maria, Ainali; Laboratory of Polymer Chemistry and Technology; Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24; tel. +30 2310997818 , email: nsainali@chem.auth.gr Dr., Eleni, Evgenidou; Laboratory of Environmental Pollution Control; Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24; tel. +30 2310997446, email: evgenido@chem.auth.gr Professor, Dimitrios, Bikiaris; Laboratory of Polymer Chemistry and Technology; Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24; tel. +30 2310997812, email: dbic@chem.auth.gr Assoc. Professor, Dimitra A., Lambropoulou; Laboratory of Environmental Pollution Control; Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24; tel. +30 2310997687, fax. +30 2310 997859, email: dlambro@chem.auth.gr

21

WWSS21: e-Book of Proceedings

22

Posters Session

MONITORING MICROPLASTICS IN WASTEWATER TREATMENT PLANT OF THESSALONIKI: SAMPLING, IDENTIFICATION AND QUANTIFFICATION OF PARTICLES Dimitr Kalaronis1, Nina Maria Ainali1,2, Eleni Evgenidou1,, Dimitrios Bikiaris2, Dimitra A. Lambropoulou1,3 Dimitrios 1Laboratory of Environmental Pollution Control, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece 2Laboratory of Polymer Chemistry and Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece 3Center for Interdisciplinary Research and Innovation (CIRI-AUTH), GR-57001, Balkan Center, Thessaloniki, Greece

Email: dlambro@chem.auth.gr

Introduction Microplastics (MPs) are defined as the polymeric particles and fibers which size is ranging between 1 μm and 5 mm. MPs are formed by the fragmentation of the larger plastic particles released in the environment. In fact, these released plastic items are subjected to several photo- and thermal oxidation processes after their interaction with solar radiation, as well as mechanical abrasion in the environment or are detected either as pellets released directly from several care products or fibers derived from the laundry and textile industry. According to the literature these items have been detected in wastewaters and the conventional treatment processes cannot remove them. Thus, a quantity of MPs are released in Ecosystems and the wastewater treatment plant (WWTP) is one of the main pathway for MPs deposition in environment.

Materials and Methods Samples were collected from the effluent of WWTP in Sindos and sieved through metal sieves (4.0 -0.125 mm) as to prepare a concentrated sample.

Concentrated samples were filtered through fiberglass filters (1.6 μm) and oxidative digestion was applied adding H2O2 to each filter. Filters were settled under continuous stirring for 3 days to remove the organic matter.

Filters were rinsed with ultrapure water and oxidative solution was filtered again to new filters and settled to dry.

Dried filters were checked via Stereoscopic microscope and a digital camera with aim to map them and determine the possible MPs on filters.

Filters were analyzed via Py-GC/MS to identify and quantify the MPs particles and fibers existing on filters surface.

Stereoscopic microscope and camera

Mapping filters

Results and Discussion Fibers were in abundance and found in different colors and size.

Different particles were detected in various colors and shapes (including fragments and films).

The most particles were identified as polyethylene, polypropylene, polystyrene and polyamide.

The polyethylene polymeric fragments were quantified, and this value ranged from 0.06-0.04 mg/m3.

The significant occurrence of fibers in results can be explained, as the WWTP services a large urban area and a huge quantity of domestic wastewater is treated there.

Polyethylene is one of the most used polymers in industry and daily life, thus is chosen as reference polymer for the quantification via Py-GC/MS analysis.

A chromatogram of PET MP particle Py-GC/MS analysis

Conclusions 9 Various MPs particles and fibers were identified in wastewater samples.

9 The majority of polymeric particles were fibers, due to high quantity of domestic wastewater influent.

9 A significant amount of MPs are released in environment, and maybe affect to marine ecosystem of Thermaikos Gulf.

References A. Dyachenko, J. Mitchell, and N. Arsem, “Extraction and identification of microplastic particles from secondary wastewater treatment plant (WWTP) effluent,” Anal. Methods, vol. 9, no. 9, pp.

1412–1418, 2017, doi: 10.1039/c6ay02397e.

A. L. Andrady, “The plastic in microplastics: A review,” Mar. Pollut.

Bull., vol.

119, no.

1, pp.

12–22, 2017, doi: 10.1016/j.marpolbul.2017.01.082.

A chromatogram of PP MP particle

Acknowledgments Part of this work has also been done after financial support received from the Greek Ministry of Development and Investments (General Secretariat for Research and Technology) through the research project “Intergovernmental International Scientific and Technological Innovation-Cooperation. Joint declaration of Science and Technology Cooperation between China and Greece” with the topic “Development of monitoring and removal strategies of emerging micro-pollutants in wastewaters” (Grant no: Τ7ΔΚІ-00220) and it is gratefully acknowledged.

WWSS21: e-Book of Proceedings

Posters Session

RECOVERY OF N AND P FROM MUNICIPAL WASTEWATER Panagiota D. Natsi1, Dimitris Vlachos2, Petros G. Koutsoukos3 Abstract Phosphorus recovery from wastewater by precipitation in the form of crystalline struvite (MgNH4PO4·6H2O, MAP), is an attractive option contributing toward sustainable development, as it may be used as a slow-release fertilizer. The presence of low magnesium concentrations in wastewater make it necessary to find low cost solutions for the enrichment of wastewaters with the respective ions. In the present work, we have used metallic magnesium anodes, which upon anodic polarization, release in the aqueous medium enough magnesium for the selective precipitation of MAP. In this study, the effect of the application of constant current between a low cost magnesium metal anode (4cm diameter) and a platinum cathode electrode, both immersed in ammonium phosphate solutions, without adjustment of the solution pH was investigated. Constant current density was applied through a Potentiostat over the range 10-100 A·m-2, through the electrolyte working solution with known ammonium hydrogen phosphate concentration. In the absence of ammonium phosphate, the main crystal phases obtained in the electrolyte solutions formed on the magnesium anode and the bulk solution, was Mg(OH)2 (brucite). In the presence of NH4+ and PO4-3, the magnesium ions dissolved anodically, resulted in the struvite precipitation, even at low applied current (10mA), low concentrations of ammonium phosphate in the solutions. Struvite crystals with average size 20μm, were formed. The behavior of the cell for the electrolyte solutions used was Faradaic as long as surface coverage of the anode was relatively low. The anodic dissolution yielded the solutions pH highly alkaline (pH 11) eliminating the need for alkali addition.

Affiliations 1

Postdoctoral Researcher, Department of Chemical Engineering, University of Patras, P.C 26504, Patras, Greece, giota_nat@hotmail.com 2

Undergraduate student, Department of Chemical Engineering, University of Patras, P.C 26504, Patras, Greece, up1055987@upnet.gr 3

Professor Emeritus, Department of Chemical Engineering, University of Patras and Foundation for Research and Technology Hellas-Institute of Chemical Engineering Sciences, P.C 26504, Patras, Greece 26504 Patras, Greece, pgk@chemeng.upatras.gr

24

Recovery of N and P from municipal wastewater Panagiota D. Natsi1,2, Dimitris Vlachos1, Petros G. Koutsoukos1,2

1. Department of Chemical Engineering, University of Patras, P.C 26504, Patras, Greece Found as Greece 2. Foundation for Research and Technology Hellas-Institute of Chemical Engineering Sciences, 26504 Patras,

Results

Introduction

Most of the phosphorus needed to cover industrial and Calculated released mass of electrochemically household needs and commodities come from mining magnesium at different constant current densities (10phosphate rock, which is considered a limited mineral resource. 100 A·m-2) . 9,0x10 i=4mA 8,0x10 i=5mA Meanwhile, municipal, agricultural, and industrial wastewaters i=10mA 7,0x10 i=15mA are found to have high levels of phosphorus and ammonia i=20mA 6,0x10 i=40mA responsible for water pollution and eutrophication. An estimated 5,0x10 20% of the raw phosphate ores used for P production could be 4,0x10 recovered effectively from municipal and/or agricultural 3,0x10 wastewaters [1]. Effective P and N recovery from wastewater is 2,0x10 1,0x10 vital for the circular economy. Existing methods for phosphorus 0,0 recovery presently, consist of chemical and physical methods 0 20 40 60 80 100 120 [2],[3]. Classic chemical methods include the precipitation of t(min) Ca3(PO4)2 or MgNH4PO4 by the addition of suitable chemicals, Applied current density I=25 A·m-2 eventually harmful to the environment. Physical methods mainly 9 10-2M NaCl 9 10-2M NaCl & [PO3-4]=[NH4+]=10-3M based on membrane separation technologies (ion exchange, 1,0x10 Theoretical reverse osmosis) have extremely high operating costs. One of the 9,0x10 10 M NaCl 10 M NaCl, 1mM NH H PO promising techniques mostly studied the recovery of phosphorus 8,0x10 and nitrogen, present at high concentration in the form of 7,0x10 6,0x10 struvite (MgNH4PO4·6H2O). Struvite is an effective slow-release 5,0x10 fertilizer [4]. Struvite may be directly precipitated out of 4,0x10 wastewater using simple and controllable processes. The 3,0x10 precipitation of struvite is described by: +2 + + 2,0x10 Mg +NH4 +6H2OÆ Æ MgNH4PO4·6H2O +H 10 20 30 40 50 60 The presence of low magnesium concentrations in wastewater t(min) make it necessary to find low cost solutions for the enrichment of 9 The deviation from Faradays law was about wastewaters with the respective ions. In the present work we 12 to 24%. have used metallic magnesium anodes, which upon anodic polarization release in the aqueous medium the concentrations SEM needed to precipitate selectively struvite.

The main electrochemical reactions taking place at the cathode and the In absence of anode respectively are : phosphorus and Cathode reaction: O2+2H2O+4e-Æ4OHammonia 2H2O+2e-ÆH2 +2OHAnode rection: Mg-2e-ÆMg+2 Mg (OH)2 In this study, the, the effect of the application of constant current between a low cost magnesium metal anode and platinum 200nm cathode immersed in ammonium phosphate solutions without adjustment of the solution pH was investigated.

-3

-3

-3

CMg (mol L-1)

-3

-3

-3

-3

-3

-3

-3

-4

-4

-2 -2

4

2

4

CMg (mol L-1)

-4

-4

-4

-4

-4

-4

Materials and Methods

H

Mg+2

Cathode

(24.305 g·mol-1 ) I: electric current (A) A: electrode surface 4cm2 t: time elapsed (s) n: magnesium valence (2) F: Faraday constant (96485 C·mol-1)

Ag/AgCl

Mg

In presence of The working solution was either electrolyte (NaCl) or electrolyte phosphorus and with known ammonium hydrogen phosphate concentration. A ammonia cell consisting of Mg anode and Pt cathode with a reference MgNH4PO4·6H2O electrode (Ag/AgCl), was used. Constant current density was -2 applied through a Potentiostat over the range 10-100 A·m .

20μm Samples were withdrawn from the solution and magnesium and phosphorus concentrations were measured. The potential Conclusions applied across the electrodes and solution pH were monitored.

In absence of phosphorus and ammonia, the main crystal The release of magnesium led to the voltage and pH increase. phases obtained in blank electrolyte were either in The main assumption was that the magnesium released from the magnesium anode electrode, or in the bulk solution, was anode, maybe used for struvite precipitation.

Potentiostat Mg(OH)2 (brucite). In presence of NH4+ and PO4-3, the magnesium ions dissolved anodically, resulted in the eestruvite precipitation, even at low applied current (10mA), ࢓࢚ ࡵࡹ Faraday’s Law ൌ in presence of low concentration of phosphorus and ࡭࢚ ࢔ࡲ ammonia in the working solution. Struvite crystals with H2 average size 20μm, were formed. The behaviour of the mt: theoretical magnesium release (g) cell for the electrolyte solutions used was Faradaic.

M: atomic weight of magnesium + Mg+2 NH4+ PO4-3 STUVITE (MgNH4PO4·6H2O)

References

1. Y. Cai et al., 2020, Science of the Total Environment 726,13822 2.Munir, M.T. et al, 2019, J. Clean. Prod. 232, 1043–1052 3.Xue, Y.J. et al., 2009, J. Hazar. Mater. 162, 973–9 4. Zhang, T. et al., 2020,Sci. Total Environ. 698, 134240

WWSS21: e-Book of Proceedings

Posters Session

UTILIZATION OF WATER TREATMENT RESIDUAL SLUDGE FOR THE IMPROVEMENT OF BARREN SOIL

F.K. Katrivesis1,*, V. Sygouni2, V.G. Papadakis3, C.A. Paraskeva4 Abstract Objectives: Water treatment plants (WTPs) produce safe drinking water; they inevitably produce large amounts of sludge which is potentially hazardous for public health and environment and their management is of high importance. In this work, physicochemical characteristics of water treatment sludge and its toxicity were investigated in order to evaluate its use as means of barren soils improvement.

Methods: Phytotoxicity experiments were performed on plants and seeds cultured in barren field soil mixed with residual sludge from water treatment plant. To investigate sludge’s toxic effects on the germination of grass seeds and the growth of young lettuce plants, the effect of three different proportions of soil-sludge (soil-sludge: 85-15%, 70-30%, 55-45%) were studied. During phytotoxic experiments, daily visual observation and experimental measurements were done (leaf width, leaf length, number of leaves, etc.), to quantify the growth progress of the plants.

Results: Lettuce and grass growth planted in soil enriched with residual sludge did not show any phytotoxicity or dormancy issues. Measurements on their agrobiological characteristics did not show vegetation differences greater than 30% from the corresponding characteristics of the control sample, as well as, death, or growth inhibition were not observed in more than 30% of the plants.

Conclusions: Evaluation of plant cultivation in soil mixed with water refinery sludge did not show any phytotoxicity or dormancy of plants and the growth of plants were not affected by the proportion of sludge-soil mixes. Thus, the sludge produced from the surface water treatment processes, may be utilized as additive in barren soils, resulting in a more environmentally friendly and sustainable management of the discharged sludge of water refineries.

Affiliations 1,*

Fotios Katrivesis, Department of Environmental Engineering, University of Patras, 30100Agrinio, Greece, fkatrivesis@gmail.com 2

Dr, Varvara Sygouni, Department of Chemical Engineering, University of Patras, 26504-Rion, Greece, sygouni@upatras.gr 3

Prof., V.G. Papadakis, Department of Environmental Engineering, University of Patras, 30100Agrinio, Greece, vgpapadakis@upatras.gr 4

Prof., C.A. Paraskeva, Department of Chemical Engineering, University of Patras, 26504-Rion, Greece, takisp@chemeng.upatras.gr

26

UTILIZATION OF WATER TREATMENT RESIDUAL SLUDGE FOR THE IMPROVEMENT OF BARREN SOIL F.K. Katrivesis, V. Sygouni, V.G. Papadakis, C.A. Paraskeva E1nvironmental Engineering Department, University of Patras, 30100-Agrinio, Greece, katrivesis@gmail.com Chemical Engineering Department, University of Patras, 26504-Rion, Greece, sygouni@upatras.gr Environmental Engineering Department, University of Patras, 30100-Agrinio, Greece, vgpapadakis@upatras.gr Chemical Engineering Department, University of Patras, 26504-Rion, Greece, takisp@chemeng.upatras.gr

O b j e c t i ve s : Water treatment plants (WTPs) produce safe drinking water; they inevitably produce huge quantities (up to 30mL/litre of clarified water) of sludge (water treatment residuals-WTRs), which is potentially hazardous for public health and environment and their management is of high importance.

From the total amount of the sludge produced in Greece, 60% disposed to landfills, 25% to adjacent water bodies and sewers and 15% for building materials and other routes.

Given that stricter water quality requirements and enhanced coagulation produces larger amounts of sludge, the total cost of residual sludge management and dewatering reaches up 20% of the total water treatment cost. Thus, the idea of utilizing sludge for plant growth is a challenge that although has many variables to be considered, including the cropping system and existing soil conditions, its viability due to soilenrichment and cost reduction, turns it to big achievement.

Results :

Me t h o d s : This work studied the physicochemical characteristics of water treatment sludge and its toxicity to the environment and investigated sludge use for plants growth by supplementing - modifying the proportions of the fine soil of the ground. Phytotoxicity experiments were performed on plants and seeds cultured in barren field soil mixed with residual sludge from Glafkos river treatment plant. To investigate sludge’s toxic effects on the germination of grass seeds and the growth of young lettuce plants five different proportions of soil/sludge (100/0, 85/15, 70/30, 55/45, 0/100 w.w) were studied.

From the weight and length measurements of young lettuce, it appears that all the plants showed growth on weight and length, both in their leaf and in the root system. Greater weight growth was observed in the samples with 15% and 30% sludge, while in terms of length the plants in sludge samples had the largest growth of those in field soil.

During phytotoxic experiments plants were grown for one and a half months and daily visual observations and measurements (leaf width, leaf length, number of leaves, etc.) were made to quantify growth progress.

Corresponding results were obtained from the experimental grass series. Of particular interest was the increase in growth, at a rate higher than the blank soil sample, of the sample with 100% sludge as it consistently showed improved characteristics due improved available water.

Conclusions : The evaluation of plant cultivation in soil mixed with water refinery sludge did not show any phytotoxicity or dormancy of plants and the growth of plants were not affected by the proportion of sludge-soil mixes. Sustainable utilization of WTRs is of high importance for the prevention of environmental pollution and reduction of water production cost.

Thus, the residual sludge from Glafkos surface water g produced p treatment processes, may be utilized as additive in barren soils, resulting in a more environmentally friendly and sustainable management of the discharged sludge of water refineries.

References : U.S-EPA and AWWA, "Technology Transfer Handbook: Management of Water Treatment Plant Residuals", Office of Research and Development, Washington DC, 1996.

P. Verlicchi, L. Masotti and F. Sangiorgi, «Reuse of drinking water treatment plants sludges in agriculture: problems, perspectives and limitations», Environmental Science, 2000. Κ. Β. Dassanayake, G. Jayasinghe, A. Surapaneni and C. Hetherington, "A review on alum sludge reuse with special reference to agricultural applications and future challenges", Waste Management-Elsevier, 2015

Acknowledgements : This work was financially supported by the project “Re-Water Eco-technologies for the wastewater management” (MIS 5003390) which is implemented under the “Interreg Greece-Italy 2014-2020”, co-financed by European Regional Development Fund and Greece. .

6th distance education e-learning Summer School on "Wastewater and Biosolids Management" (WWSS21), Patras, Greece, July 26-31, 2021

WWSS21: e-Book of Proceedings

Posters Session

GREEN HOUSES FOR OLIVE MILL WASTEWATER TREATMENT Asmaa Mohammad Mohsen, Lara Mohammad Saleh, Maram Shaher Alhamdan, Zaynab Mohammad Dabash, Supervisor: Prof. Dr- Mohammed Matouq Abstract This project aims to develop a new approach to recover freshwater from olive mill wastewater (OMWW). This is done by using chemical engineering principles and many kinds of research to finally create a new method that has never been used before to treat OMWW using greenhouses. This project resolves a severe case to the environment due to phenol compounds in high concentrations in OMWW. Therefore, causing deterioration of soils, hindrance of plant's growth, contamination of drinking water, and impacting aquatic life and human health if it was dumped to lands or the sea.

The greenhouse's simple design and technique allow the exploitation of solar energy so that the inner temperature could reach almost 70 degrees to evaporate and collect freshwater from the OMWW sample.

The solar unit consists of a basin for wastewater collection and evaporation with a greenhouse made from glasses attached to the basin, a solar panel unit with 20W connected to a liquid battery with a 12-volt capacity. The PV panel will work as a charger for the battery. The unit has attached several heathers. During the cold weather, the heaters will be in use.

The experimental results have revealed the excellent performance of the unit. During the hot weather (summer season), the unit fed with an initial volume of 900 ml of OMW, having a total phenol content of 822mg/l and less than 0.02 mg/l for water condensate collected without heaters. In using heaters during cold weather, the entire phenol content in condensate water reaches 8.26mg/l in its maximum value. The COD measured in the initial feed content of OMW has been measured and found to be equal to 13500mg/l. The collected concentration in condensate water has been measured and found similar to 661mg/l for non-heaters use experiments and 925mg/l for heater use experiments.

The unit performance has given 40% water collection from original samples on average. The maximum temperature reached during cold weather indie the basin is about 88oC and 78oC during hot weather. The optimum conditions have been studied and obtained. The removal efficiency of total phenol in this study reached up to 99%.

Affiliations Al-Balqa Applied University

28

Green Houses for Olive Mill Wastewater Treatment Al-Balqa Applied University

Asmaa Mohammad Mohsen, Lara Mohammad Saleh, Maram Shaher Alhamdan, Zaynab Mohammad Dabash, Supervisor: Prof. Dr- Mohammed Matouq

Abstract

Introductions

This project aims to develop a new approach to recover freshwater from olive mill wastewater (OMWW). This is done by using chemical engineering principles and many kinds of research to finally create a new method that has

processing, olives are crushed and mixed with water in mills.

never been used before to treat OMWW using greenhouses. This project resolves a severe case to the environment due to phenol compounds in high

solid residue are discarded. In Jordan, initial estimates indicate

concentrations in OMWW. The greenhouse's simple design and technique

more than 150,000 m3 of OMW are produced by extraction

allow the exploitation of solar energy so that the inner temperature could

mills. The objectives of this study is to find a new technique to

sample. The solar unit consists of a basin for wastewater collection and evaporation with a greenhouse made from glasses attached to the basin, a solar

Results with electrical heaters inside the basin

Thermometers with temperature sensors are attached to each side of the glass to measure the temperature of the OMWW sample inside. the sensors are distributed randomly in the basin to cover up most temperatures from different locations. Sample in its original shape, collection at basin after evaporation collected condensate water

liquid associated with the production of olive oil during The oil is separated out of this mixture, and the dirty water and

reach almost 70 degrees to evaporate and collect fresh water from the OMWW

Results

treat wastewater by low cost and recover the water as a new resources. The green house used here

Table 2 experiment 2 and 3, Dilution with tap water 50% and 80%percent, outside temp 11.9⁰C

Tap Vol. wate of.OM r vol. W (ml) (ml)

panel unit with 20W connected to a liquid battery with a 12-volt capacity. The PV panel will work as a charger for the battery. The unit has attached several

Loss Cond. for Cond. (ml) Cond. Cond. Cond. sample for for tap for for after collecte water O.W.W sample evaporat d water mS/cm mS/cm mS/cm ion ms/cm mS/cm

450 450

0.921

8.52

4.62

7.35

0.243

250 650

0.921

3.04

2.41

4.00

0.240

heathers. During the cold weather, the heaters will be in use. The experimental

25

results have revealed the excellent performance of the unit. During the hot weather (summer season), the unit fed with an initial volume of 900 ml of

20

OMW, having a total phenol contented of 822mg/l and less than 0.02 mg/l for water condensate collected without heaters. In using heaters during cold

Methodology

weather, the entire phenol content in condensate water reaches 8.26mg/l in its

Procedure

maximum value. The COD measured in the initial feed content of OMW has been measured and found to be equal to 13500mg/l. The collected

COD results Experime nts no.

The new design of green house for O.M.W

concentration in condensate water has been measured and found similar to 661mg/l for non-heaters use experiments and

1 2 3

925mg/l for heater use

experiments. The unit performance has given 40% water collection from

COD of OMW before (mg/L) 13500 13500 13500

COD of OMW after 30100 26200 14600

COD of collected water (mg/L) 1420 4650 952

original samples on average. The maximum temperature reached during cold weather indie the basin is about 88oC and 78oC during hot weather. The optimum conditions have been studied and obtained.

Removal of Phenols

With heaters

Introduction Olive oil production is considered as one of the most important

The experimental work using heaters has been

agricultural activities in Mediterranean countries. Olive oil is a product of

conducted with the same condition without heaters to

exceptional nutritional value; its production is associated with several

Experim ents no.

compare the two results. The weather condition was cold

adverse effects to the environment, mainly due to the formation a large amount of two by-products, a solid residue and a liquid effluent known as

during the practical work has undertaken. Three

Olive Mill Wastewater (OMW).Approximately 2,572,721 of olive oil are

conditions were selected to do these experiments. Case

produced annually in the Mediterranean area. Jordan comes in eighth place

1 2 3

phenol conc. Of phenol phenol OMW conc. of conc. In % removal OMW Before after collected of Phenols (mg/L) water (mg/L) (mg/L) (%) 822 1570 4.63 99.43 822 1010 7.09 99.14 822 819 8.26 98.99

one is using the same samples with dilutions the 900ml

among olive Oil-producing nations in 2019, with 20 million olive trees

The design is very simple, it is a typical greenhouse which looks like a

supporting 180,000 families and 24,000 tons of oil per year. As of the year

hut. It consists of seven plates of glass. Four on the sides, two on top, and

of OMW with tap water. Two instances where the OMW

Conclusions

2000, Jordan achieved self-sufficiency in the production of both olive oil

finally one plate creates the base of the greenhouse. At the same time, the

sample was diluted with 50% and 80%. Table below

and table olives, reaching a record high of 37000ton of olive oil in the

inside of the house contains an inner rectangular basin where the sample

2006/07 crop year. Most of this production is consumed nationally, where

(OMW) is placed. This basin is placed in the middle of the base, few

average annual consumption stands at 2.5kg/person. On the other hand

centimeters away from each side. As a result, the space between the

Olive Mill Wastewater (OMW) is generated in the production of olive oil

container and the sides create channels for distilled water. Solar panels are

and its treatment is a major environmental problem in Mediterranean

attached to the greenhouse that converts the sun energy into electricity which

countries. Approximately 20 million tons of fresh water is required for

charges the batteries to power the heaters. 12 volt heater cartridges are

olive oil production in the Mediterranean area, resulting in up to 30 million

attached to the downside of the basin , connected to the batteries charged by

No

the solar panels.

heaters 1 900

The total organic phenols have been reduced significantly in both cases of the experiment, and the collected condensate water is in the range of 0.028.26mg/l. The COD has a value for the collected condensate water in a range of 661-4650 mg/l, an acceptable one compared to its original sample, where the COD is 13500mg/l. The performance efficiency in removing phenols in the basin is calculated, and it is equal to 99.99% in the case of experiments with heaters and 98.99% when heaters are used.

tons of solid–liquid waste per year. Olive oil wastewater (OOW), a toxic POSTER TEMPLATE BY:

www.PosterPresentations.com

summarizes the results without heaters .

Experime OMW

Conductivity

Water

Conductiv Sample

Conductivi losses

nt

(mS/cm)

volume

ity

remaini

ty (mS/cm)

(ml)

(ml)

(mS/cm)

ng

4.72

20

sample volume (ml)

volume (ml) 3.20

300

0.252

580

WWSS21: e-Book of Proceedings

Posters Session

EVALUATION OF THE ADSORPTION OF THE ANTIDEPRESSANT CITALOPRAM BY GRAPHENE OXIDE (GO) C. Drosou1, K. Tyrovola1, N.P. Xekoukoulotakis1* Abstract In the last decade, the presence of organic pollutants in the environment has aroused great interest as there is a general concern about their possible adverse effects on the environment and living organisms. These pollutants, also known as Emerging Organic Contaminants (EOCs), are detected in the environment in traces. EOCs include a group of artificial substances such as pharmaceuticals and personal care products (PPCPs), pesticides, plasticizers and their transformation products. The main source of EOCs in the environment is the effluents from Wastewater treatment plant (WWTPs) as their treatment is incomplete. In recent years, antidepressants, antibiotics, antihistamines, β- blockers, are just some of the many categories of pharmaceuticals that have been detected in WWTPs effluents, surface water, groundwater and drinking water. Selective serotonin reuptake inhibitors, SSRIs, belong to the prevalent class of antidepressants and used to treat mental illness. SSRIs have detected in different countries and aquatic systems, at high and low concentrations levels, ranging from ng/L to few mg/L. Citalopram, CIT, belongs to SSRIs and is used to treat stress and compulsion.

Citalopram has been detected in WWTPs effluents at the order of ng/L. In this work, we studied the adsorption of citalopram (CIT) with graphene oxide (GO) from aqueous solutions. GO was synthesized according to the modified Hummers’ method and characterized by FTIR, XRD, and RAMAN analyses. In order to further investigate and to understand the interaction between GO and CIT, kinetic and studies were also conducted. Moreover, various experimental parameters such as the contact time, the temperature, the pH, the water matrix and the ionic strength were investigated.

According to the experimental results it was found that GO presents excellent adsorption properties compared to other conventional adsorbents such as activated carbon. In particular, the adsorption capacity of activated carbon was found to be 152.0 μmol∙g-1 (after 108 hrs) while that of GO was 206.9μmol∙g-1 (after 6 hrs). Moreover, the adsorption of CIT is favoured at neutral pH and at ambient temperature, i.e., at 25oC.The adsorption capacity of GO decreases as the ionic strength increases as in aqueous matrices such as bottled water (BW) and wastewater (WW). The proposed mechanism of interaction of CIT with graphene oxide is the interaction π-π as well as electrostatic forces that develop between the GO and the antidepressant.

Affiliations 1

School of Chemical and Environmental Engineering, Technical University of Crete, GR73100, Chania *

Email for correspondence: nikos.xekoukoulotaki@enveng.tuc.gr (N.P. Xekoukoulotakis)

30

EVALUATION OF THE ADSORPTION OF THE ANTIDEPRESSANT CITALOPRAM BY GRAPHΕΝE OXIDE (GO) C. Drosou1, K. Tyrovola1, N.P. Xekoukoulotakis School of Chemical and Environmental Engineering, Technical University of Crete, GR73100, Chania

1 . I n t ro d u c t i o n  In recent years, antidepressants, antibiotics, antihistamines, βblockers etc., have been detected in WWTPs effluents, surface water, groundwater and drinking water.  Selective serotonin reuptake inhibitors, SSRIs, belong to the prevalent class of antidepressants.  SSRIs have detected in different countries and aquatic systems, at high and low concentrations levels, ranging from ng/L to few mg/L.

 Citalopram, CIT, belongs to SSRIs and is used to treat stress and compulsion.  CIT has been detected in WWTPs effluents at the order of ng/L.

Objectives  The study of the adsorption of citalopram (CIT) with graphene oxide (GO) from aqueous solutions.  Various experimental parameters such as the contact time, the temperature, the pH, the water matrix and the ionic strength were investigated.

Picture 2 Batch laboratory reactor connected with a temperature control unit Picture 1 The steps of GO synthesis according to a modified Hummers’ method

CIT Chemical Structure

MW (g·mol-1)

CAS #

C20H21FN2O·HBr 405,30

59729-32-7

3. Results

Figure 1. Adsorption of CIT on graphene oxide and activated at 25°C in ultrapure water. Experimental Conditions: [CIT]= 25μmol∙L-1 . [Adsorbent]0= 100 mg∙L1. (Inserted figure: adsorption of CIT on activated carbon after 108 hours).

Figure 2 Effect of contact time on adsorption of CIT on graphene oxide. Experimental conditions: [CIT] = 25 μmol ∙ L-1, [graphite oxide] = 100 mg ∙ L-1, at 25oC.

Figure 3 Effect of pH on the adsorption of CIT on graphene oxide. Experimental conditions: [CIT] = 25 μmol ∙ L-1, [graphite oxide] = 100 mg ∙ L-1, at 25oC.

Figure 4 Effect of temperature on the adsorption of CIT on graphene oxide. Experimental conditions: [graphite oxide] = 100 mg ∙ L-1, at 25oC.

Figure 5 Effect of ionic strength on the adsorption of CIT on graphene oxide. Experimental conditions: [CIT] = 25 μmol ∙ L-1, [graphite oxide] = 100 mg ∙ L-1, at 25oC.

Figure 6 Effect of water matrix on the adsorption of CIT on graphene oxide. Experimental conditions: [CIT] = 25 μmol ∙ L-1, [graphite oxide] = 100 mg ∙ L-1, at 25oC.

4. Conclusions  Graphene oxide has excellent adsorption properties compared to other conventional adsorbents such as activated carbon.  The adsorption capacity of activated carbon was found to be 152.0 μmol∙g-1 (after 108 hrs) while that of GO was 206.9μmol∙g-1 (after 6 hrs).  The adsorption of Citalopram is favored at neutral pH, a significant finding, taking into account the fact that this pH value found in wastewater and natural water. Moreover, seems to be favored at ambient temperature, i.e. at 25oC.  The adsorption capacity of GO decreases as the ionic strength increases as in aqueous matrices such as bottled water (BW) & wastewater (WW).  The interaction π-π is a possible mechanism of interaction of CIT with graphene oxide as well as electrostatic forces.

WWSS21: e-Book of Proceedings

Posters Session

THE POTENTIAL OF ACTIVATED CARBON FROM TEA TREE SAWDUST IN EFFICIENT DIESEL OIL REMOVAL

R. I. Kosheleva, G. Z. Kyzas, N. C. Kokkinos, A. Ch. Mitropoulos Abstract Diesel oil is a complex petroleum hydrocarbon which is obtained during crude oil distillation, and is made up of low molecular weight alkanes and polycyclic aromatic hydrocarbons. The hydrocarbon composition of diesel fuel makes it toxic to the environment and its widespread application in human activity makes diesel fuel one of the most hazardous hydrocarbon pollutants. In large quantities in water, due to its hydrophobicity, diesel oil forms a layer on water surface and it becomes easy to remove. However, in small quantities, diesel oil forms emulsion with the water and more elaborated removal methods should be applied. Remediation of contaminant water by diesel oil can be performed by a number of methods such as biodegradation and Fenton oxidation. Although the implemented methods showcase good performance, most of the times they are energy consuming and not costeffective approaches. In this work, activated carbon from tea tree sawdust is investigated regarding its potential as eco-friendly and cost effective diesel oil adsorbent. Teat tree activated carbon was synthesized by KOH activation at 700oC. The adsorption capacity of the material was examined at 25oC and 35oC for a maximum of 2h. In order to measure the diesel oil uptake, samples were weighted before and after the immersion in the pollutant. The samples were collected at 5, 10, 15, 30, 45, 60, 90 and 120min and then air-dried for 24h before recording the exact weight of the sample.

Experimental results indicate that tea tree activated carbon is a promising material for hydrocarbon contaminant removal. Further research will be focused on the specific material performance within a solution of diesel oil in both fresh and sea water.

Acknowledgement This research is co-financed by Greece and the European Union (European Social Fund- ESF) through the Operational Program «Human Resources Development, Education and Lifelong Learning 2014- 2020» in the context of the project: “ADSORPTION CAPACITY ENHANCEMENT OF ACTIVATED CARBON FROM AGRICULTURAL WASTES UNDER A ROTATIONAL FIELD (SPIN ADSORPTION): APPLICATION FOR OIL SPILS CLEANING”(MIS 5048225 ) Affiliations Department of Chemistry, School of Science, International Hellenic University, St. Lucas, 65404 Kavala, Greece Ph.D student, Ramonna I. Kosheleva, +30 2510462247, kosheleva.ramonna@gmail.com Assoc. Professor, George Z. Kyzas, +30 2510462218, kyzas@chem.ihu.gr Assoc. Professor, Nikolaos C. Kokkinos, +30 2510462294, nck@chem.ihu.gr Professor, Athanasios Ch. Mitropoulos, +30 2510462123, amitrop@chem.ihu.gr

32

THE POTENTIAL OF ACTIVATED CARBON FROM TEA TREE SAWDUST IN EFFICIENT DIESEL OIL REMOVAL R. I. Kosheleva, G. Z. Kyzas, N. C. Kokkinos, A. Ch. Mitropoulos ABSTRACT Diesel oil is a complex petroleum hydrocarbon which is obtained during crude oil distillation, and is made up of low molecular weight alkanes and polycyclic aromatic hydrocarbons. The hydrocarbon composition of diesel fuel makes it toxic to the environment and its widespread application in human activity makes diesel fuel one of the most hazardous hydrocarbon pollutants. In this work, activated carbon from tea tree sawdust is investigated regarding its potential as eco-friendly and cost effective diesel oil adsorbent. Experimental results indicate that tea tree activated carbon is a promising material for hydrocarbon contaminant removal.

EXPERIMENTAL PROCEDURE Activated carbon (AC) from tea tree sawdust was chemically activated by KOH at 700 °C and impregnation ratio of 1:3. Commercial diesel engine oil was used as the pollutant.

After AC was dried and sieved, fine powder of 60-45 μm was used for the experiments. The sorption capacity of the material was examined at 25oC and 35oC for a maximum of 2h (5, 10, 15, 30, 45, 60, 90 and 120 min). The amount of each AC sample was 0.250 g placed into a paper bag (Fig. 1b) while the volume of diesel oil in each flask was 25 ml. After the run, samples were air-dried for 24h.

a b Fig. 1: a) sorption experiment, b) sample bags (after run)

RESULTS & DISCUSSION 1,250 1,200

Diesel oil uptake on the AC was obtained by mass difference: Mass uptake uptake=m mfin-m min

In conclusion, diesel oil sorption is affected by system complexity while time dependence is not so pronounced. Additional experiments of dynamic conditions and different seawater/ diesel oil volume fraction must be conducted .

35 °C 25 C 25°C

1 100 1,100 Mass uptake, g

The top graph of Fig. 2 shows the results of diesel oil uptake on AC at 25 °C and 35 °C. The performance of sorption at higher temperature was better due to decrease of kinematic viscosity, while for both conditions, optimal contact time is 1h. Material performance was investigated under more complex system and results indicate that the diesel oil uptake is minimized by 6% when seawater is present.

1,150

1,050 1,000 1,250 1,200 1,150 1,100 1,050 1,000 0,950 0,900

35 °C-seawater 35 °C

0

50

100

150

Time, min

Fig. 2: Diesel oil uptake at different systems. Top; pure diesel oil/AC, bottom; diesel oil and seawater/AC

Acknowledgement: This research is co-financed by Greece and the European Union (European Social FundESF) through the Operational Program «Human Resources Development, Education and Lifelong Learning 2014- 2020» in the context of the project: “ADSORPTION CAPACITY ENHANCEMENT OF ACTIVATED CARBON FROM AGRICULTURAL WASTES UNDER A ROTATIONAL FIELD (SPIN ADSORPTION): APPLICATION FOR OIL SPILS CLEANING”(MIS 5048225).

WWSS21: e-Book of Proceedings

Posters Session

ADSORPTION OF METHYLENE BLUE FROM AQUEOUS SOLUTIONS BY ACTIVATED CARBON IN TUBES: THE EFFECT OF ROTATION IN BATCH PROCESS

Sofia Kouvalakidou, Athanasios Varoutoglou, George Bomis, George Z. Kyzas Abstract Dyes are widely used by plenty of industries. One major problem caused is the large amount of wastewater produced, which contain non-biodegradable dyes with toxic outcome, high pigmentation and huge impact in the photosynthesis of aquatic organisms. There are many wastewater treatment methods used until now as physical, chemical or biological, that appear limitations (i.e. high cost, complex operation, etc), which is the reason of the need to search for efficient alternatives. Adsorption is a process applicable for the removal of dye components from industrial wastewaters. The aim of this work is to develop an improved procedure, easily scaled-up, which will present high dye removal efficiency and other organic/inorganic content. A device was constructed in order to study the effect of rotation on adsorption of the cationic dye (Methylene blue) by activated carbon in aqueous solutions. The tubes used had capacity of 12 mL and examined under different angles (inclination).

The parameters tested were pH, contact time, rotation speed, initial dye concentration and adsorbent’s mass. Adsorption isotherms and kinetic equations were also illustrated. The optimum results of this process were used for comparison with experimental data of traditional batch methods, such as adsorption in shaking bath (agitation).

Acknowledgment: The financial support received for this study from the Greek Ministry of Development and Investments (General Secretariat for Research and Technology) through the research project “Research-Create-Innovate” with the topic “Development of an integration methodology for treatment of micropollutants in wastewaters and leachates coupling adsorption, advanced oxidation processes and membrane technology” (Grant no: Τ2ΕΔΚ-04066) and it is gratefully acknowledged.

Affiliations Department of Chemistry, International Hellenic University, Kavala, Greece

34

ADSORPTION OF METHYLENE BLUE FROM AQUEOUS SOLUTIONS BY ACTIVATED CARBON IN TUBES: THE EFFECT OF ROTATION IN BATCH PROCESS S. Kouvalakidou, A. Varoutoglou, G. Bomis, G.Z. Kyzas Department of Chemistry, International Hellenic University, 65404 St. Lucas, Κavala, Greece

ABSTRACT In the current work, a device was constructed in order to examine the effect of rotation in adsorption of the cationic dye methylene blue by activated carbon in aqueous solutions. The parameters tested were pH, contact time, number of rounds per minute, inclination angle, initial concentration and mass of adsorbent. Adsorption isotherms were constructed to determine the adsorption mechanism. The optimum results of this process were used for comparison with experimental data of traditional methods, such as agitation.

INTRODUCTION

METHODS AND MATERIALS

Dyes are widely used by plenty of industries. One major problem caused is the large amount of wastewater produced, which contain non biodegradable dyes with toxic outcome, high pigmentation and huge impact in the photosynthesis of aquatic organisms. There are many wastewater treatment methods used until now, that appear limitations such as high cost and complex operation. This is the reason why finding new, more efficient alternatives is necessary.

Adsorption is a process already applicable for the removal of organic pollutants from wastewaters. The goal of this project is to develop an improved procedure, easily scaled up, with high removal of dyes and other organic or inorganic content.

For the rotation device a tube with capacity 12 mL was used. The activated carbon was Sigma Aldrich’s, while the dye methylene blue was from Panreac.

Figure 1: Rotation device a) picture, b) design

RESULTS The optimum pH found to be 12. Equilibrium is achieved after 45 min of rotation for initial concentration of 300 ppm, 0.02g of AC and 10 ml of dye solution. The adsorption mechanism fits better with Langmuir model. For rotation, the adsorption capacity Qm is 184.21 mg/g, k is 2.38 and R2=0.95, while for agitation Qm is 140.42 mg/g, k is 2.51 L/mg and R2=0.92.

100 300 300

100 100 99 99

250 250

80

Ct (mg/L) Ct (mg/L)

40

200 200 150 150 100 100

Rotation Rotation Agitation Agitation

50 50

0 4

6

8

2

4

6

pH

10

8

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00

Figure 2: Effect pH of pH

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0

0

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20

30

30

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40

50 ο

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φ ( )ο φ( )

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Figure 6: Comparison between rotation and agitation

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Figure 7: Effect of adsorbent mass

CONCLUSIONS The results of this work showed that by applying rotation and inclination angle in adsorption processes, the removal of MB from wastewater could be improved significantly, on average by 3% comparing with agitation. It is important to mention that after 45 min, 820 rpm and 45 o inclination angle 99.63% of the dye is removed from the solution. Due to these high percentages, rotation could be used in large scale adsorption procedures as an easily applicable,low cost and high effectiveness operation with vital impact in sustainability and preservation of aquatic life.

ACKNOWLEDGMENT: The financial support received for this study from the Greek Ministry of Development and Investments (General Secretariat for Research and Technology) through the research project “Research-Create-Innovate” with the topic “Development of an integration methodology for treatment of micropollutants in wastewaters and leachates coupling adsorption, advanced oxidation processes and membrane technology” (Grant no: Τ2ΕΔΚ-04066) and it is gratefully acknowledged.

WWSS21: e-Book of Proceedings

Posters Session

EFFECT OF PACKED BEDS WETTABILITY ON SALT PRECIPITATION A. Tzachristas1,2, D. G. Kanellopoulou1,2, P.G. Koutsoukos1,2, C.A. Paraskeva1,2, V. Sygouni1,2,* Abstract Objectives: Salt deposition is a phenomenon taking place in a wide range of processes such as in Carbon Capture Utilization and Storage (CCUS), during membranes operation for desalination or wastewater treatment, etc. Control of precipitation requires the deep knowledge of precipitation mechanisms. Apart of pH, temperature, supersaturation ratio (SR), the presence of other substances or seeds, the pore surface wettability of membranes or filters plays significant role.

Methods: In the present work, packed beds with spheres of varying wettability were used for the investigation of wettability effect on calcium carbonate precipitation for various supersaturation ratio values. During the experiments, samples were selected at the outflow of the beds for pH and total calcium concentration measurements. Total calcium concentration was measured by Atomic Adsorption Spectrometry (AAS). X- Ray Diffraction measurements and Scanning Electron Microscopy (SEM) all along the beds after the end of the experiments, allowed the characterization of precipitated polymorphs.

Results: Total calcium concentration at the outlet of the beds showed that the slopes of the curves reduced as hydrophilicity increased. Thus, precipitation was accelerated with increasing hydrophilicity of the packed bed filling material.

Conclusions: Pore surface wettability of filters used in wastewater treatment or in desalination processes was found to affect salt deposition and pore clogging.

Acknowledgements We acknowledge support of this work by the Project “WetμFluid” (Code 172) which is implemented under the Action “1st Call for H.F.R.I. Research Projects for the support of Post-doctoral Researchers” funded by Hellenic Foundation for Research and Innovation.

Affiliations 1

Chemical Engineering Department, University of Patras, Rion, GR 26504, Greece

2

Foundation for Research and Technology Hellas- Institute of Chemical Engineering Sciences, Stadiou

Str., Platani, GR-26504, Patras, Greece *Corresponding author, tel: +30 2610 997574 E-mail address: sygouni@upatras.gr

36

EFFECT OF PACKED BEDS WETTABILITY ON SALT PRECIPITATION A. Tzachristas1,2, D. G. Kanellopoulou1,2, P.G. Koutsoukos 1,2, C. A. Paraskeva1,2, V. Sygouni1,2 1

Chemical Engineering Department, University of Patras, Rion, GR 26504, Greece GR-26504

2Foundation for Research and Technology Hellas- Institute of Chemical Engineering Sciences, Stadiou Str., Platani,, Patras, Greece

Introduction Mineral scaling is a phenomenon taking place in a wide range of processes taking place including Carbon Capture Utilization and Storage technologies (CCUS) during membranes operation, CO2 storage in underground formations etc. Control of precipitation requires deep knowledge of precipitation mechanisms. Several parameters i.e. pH, temperature, supersaturation ratio (SR), the presence of other substances or seeds as well as solid surface wettability, play significant role in the kinetics of precipitation. In the present work, calcium carbonate precipitation in beds packed with hydrophilic and hydrophobic spheres was investigated for various supersaturation ratio values to investigate the effect of wettability on calcium carbonate precipitation. Solutions supersaturated with respect to calcium carbonate passed through the packed beds and samples of the fluid taken at the outflow of the beds were analyzed for pH and total calcium concentration measurement. X-Ray Diffraction and Scanning Electron Microscopy (SEM) of the beds’ packing material past completion of deposition, allowed the characterization of precipitated calcium carbonate polymorphs.

Methods and Materials

Experimental Results 60 55 50 45 40 35 30 25 20

Crystals on hydrophobic spheres

Ca=50 mM Hydrophobic Ca mix Ca equilibrium Ca= 50 mM Hydrophilic

Ca (mM)

• Simultaneous injection of solutions (CaCl2͘, NaHCO3) in the packed bed • Total fluid rate: 2 mL/h from synchronized injection pumps • Ambient temperature • Bed: cylindrical of stainless steel (diameter: 2.5cm, height: 2.5cm) • Packing material: PTFE or Glass spheres d=1.5mm

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References

5,5

• Pavlakou E. I., Sygouni V., Lioliou M.G., Koutsoukos P.G. and C.A. Paraskeva, “Precipitation of sparingly soluble salts in packed sandbeds in the presence of miscible and immiscible organic substances”, Crystal Research and Technology, 51 (2), pp. 167-177, (2016).

• Tzachristas, A., Malamoudis, R.-I., Kanellopoulou, D. G., Skouras, E., Parthenios, J., Koutsoukos, P. G., Paraskeva, C. Α., V. Sygouni “Mineral scaling in microchips: effect of substrate wettability on CaCO3 precipitation” Industrial & Engineering Chemistry Research 59, 45, 20201–20210, (2020).

0

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10 μm

Conclusions Acknowledgements We acknowledge support of this work by the Project “WetμFluid” (Code 172) which is implemented under the Action “1st Call for H.F.R.I. Research Projects for the support of Post-doctoral Researchers” funded by Hellenic Foundation for Research and Innovation.

• The deposition of calcium carbonate in hydrophobic beds, precipitation was inhomogeneous along the beds and was more intensive at the inlet of the beds.

• In hydrophilic bed, calcium carbonate precipitated homogeneously along the packing material.

• In hydrophobic beds, aragonite and vaterite were also detected in addition to calcite, the thermodynamically most stable calcium carbonate polymorph .

6th distance education e-learning International Summer School and Workshop on “Wastewater and Biosolids Management” (WWSS21), Patras, Greece, July 26 – 31, 2021

WWSS21: e-Book of Proceedings

Posters Session

CAN WE ESTIMATE THE EMITTED N2O FROM CONSTRUCTED WETLANDS TREATING WASTEWATER? Olga P. Koutsou, Michail S. Fountoulakis, Christos Matsoukas, Nikolaos M. Fyllas, Athanasios S. Stasinakis Abstract Nitrous oxide (N2O) is an important greenhouse gas with a global warming potential 298 times higher than CO2 on a 100 year horizon. So far, numerous articles have pointed out the importance of conventional Wastewater Treatment Plants for N2O emissions as well as their contribution to total GHG emissions. The main biological processes of N2O production during wastewater treatment are nitrification and denitrification through the hydroxylamine oxidation pathway by ammonia-oxidizing bacteria, nitrifier denitrification and heterotrophic denitrification by heterotrophic denitrifiers. On the other side, beside the extensive use of constructed wetlands (CWs) for wastewater treatment in small settlements, it is not clear yet the amounts of N2O emitted from these systems.

A literature review on studies published between 1999 and 2020 was initially conducted using Scopus database. The reported N2O emission factors (EFs) from CWs treating wastewater and the applied operational/physicochemical parameters in these systems were recorded. An empirical model was afterwards created relating N2O EFs with raw wastewater characteristics. Specifically, Ordinary Least Squares multiple regression method was used and the developed model related N2O EFs with COD concentrations, TN concentrations and the ratio of COD/TN in influent wastewater. The empirical model was applied at Greek small settlements (< 10,000 inhabitants) for estimating the N2O emissions in case that CWs configuration would be applied for municipal wastewater treatment. According to the results, the estimated N2O EFs in these settlements ranged between 0.25% and 3.02% (as N2O/TN influent load), while the average value was equal to 0.92%. The specific N2O emission was estimated to 60.6 mg N2O per day and person equivalent. The calculation of the expected daily N2O emissions at the studied settlements showed N2O emissions lower than 0.20 kg/d for 40% of the studied settlements, between 0.20 and 0.40 kg/d for 30% of the studied sites, between 0.40 and 0.60 kg/d for 19% of them and up to 1.27 kg/day for the rest.

Affiliations Olga, Koutsou: PhD candidate at University of the Aegean, Department of Environment, Mytilene Greece, koutsou@env.aegean.gr Michail, Fountoulakis: Assistant Professor, University of the Aegean, Department of Environment, Mytilene, Greece, fountoulakis@env.aegean.gr Christos, Matsoukas: Associate Professor, University of the Aegean, Department of Environment, Mytilene Greece, matsoukas@aegean.gr Nikolaos, Fyllas, Assistant Professor, University of the Aegean, Department of Environment, Mytilene, Greece, nfyllas@aegean.gr Athanasios S. Stasinakis, Associate Professor, University of the Aegean, Department of Environment, Mytilene Greece, astas@env.aegean.gr

38

Can we estimate the emitted N2O from constructed wetlands treating wastewater?

Olga P. Koutsou*, Michail S. Fountoulakis*, Christos Matsoukas*, Nikolaos M. Fyllas*, Athanasios S. Stasinakis* *University of the Aegean, Department of Environment, Mytilene, Greece Email: astas@env.aegean.gr (Athanasios S. Stasinakis)

Materials & Methods

Introduction Nitrous oxide ¾Nitrous oxide (N2O) is an important greenhouse gas with a global warming potential 298 times higher than CO2 on a 100 year horizon. ¾So far, numerous articles have pointed out the importance of conventional Wastewater Treatment Plants for N2O emissions as well as their contribution to total GHG emissions. ¾The main biological processes of N2O production during wastewater treatment are nitrification and denitrification through the hydroxylamine oxidation pathway by ammonia-oxidizing bacteria, nitrifier denitrification and heterotrophic denitrification by heterotrophic denitrifiers.

¾A literature review on studies published between 1999 and 2020 was initially conducted using Scopus database. ¾The reported N2O EFs from CWs treating wastewater and the applied operational/physicochemical parameters in these systems were recorded. ¾The Ordinary Least Squares (OLS) multiple regression method was applied to develop an empirical mathematical model relating N2O EFs and influent characteristics. ¾For the application of the mathematical equation in small Greek settlements (< 10,000 inhabitants) for N2O emission estimation in case that CWs configuration would be applied for municipal wastewater treatment, data was received from Koutsou et al.

(2018).

N2O

Fig. 1: Nitrous oxide

Constructed wetlands ¾ Constructed wetlands (CWs) are extensively used for wastewater treatment in small settlements. However, it is not clear yet the amount of N2O emitted from these systems.

The main objective of the current research was to present and discuss the emission factors (EFs) that have been reported for N2O in CWs treating wastewater and to find an empirical mathematical model that relates EFs with wastewater characteristics.

Fig. 2: Constructed wetland

Results & Discussion ¾An empirical model created relating N2O EFs with raw wastewater characteristics. ¾Ordinary Least Squares multiple regression method was used and the developed model related N2O EFs with COD concentrations, TN concentrations and the ratio of COD/TN in influent wastewater. ¾The empirical model was applied at Greek small settlements (< 10,000 inhabitants) for estimating the N2O emissions in case that CWs configuration would be applied for municipal wastewater treatment. ¾Influent COD and TN concentrations of the studied Greek settlements ranged between 31 to 941 mg/L and 1.9 to 169 mg/L respectively (Fig. 3).

¾The calculation of the expected daily N2O emissions at the studied settlements showed N2O emissions lower than 0.20 kg/d for 40% of the studied settlements, between 0.20 and 0.40 kg/d for 30% of the studied sites, between 0.40 and 0.60 kg/d for 19% of them and up to 1.27 kg/day for the rest (Fig. 5).

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Flow rate (m3/d)

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Fig. 3: Influent COD (mg/l) and influent TN (mg/l) for the studied Greek settlements.

Fig. 5: N2O emissions (as kg/d) in 57 Greek settlements with PE<10000 for the case that CWs configuration would be applied for municipal wastewater treatment.

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Fig. 4: Estimated N2O emission factors (EFs) in CWs and COD/TN ratio for the studied Greek settlements

22 100 193 228 300 324 370 380 404 515 575 600 612 644 750 860 900 959 1012 1073 1123 1159 1216 1250 1300 1560 1625 2166 4410

3,50 3,00 2,50 2,00 1,50 1,00 0,50 0,00 0,00

¾The specific N2O emission was estimated to 60.6 mg N2O per day and person equivalent. ¾No important correlation was observed between specific N2O emission (as mg/day.PE) and influent flow rate (Fig. 6).

N2O (mg/d PE)

EF % (N2O/TNinfluent)

¾The estimated N2O EFs for the studied Greek settlements ranged between 0.25% and 3.02% (as N2O/TN influent load), while the average value was equal to 0.92% (Fig. 4).

Flow rate (m3/d)

Fig. 6: N2O emissions (as mg/day.PE) in 57 Greek settlements with PE<10000 for the case that CWs configuration would be applied for municipal wastewater treatment

References: ¾ Duan, H., Ye, L., Erler ,D., Ni, B.-J., Yuan, Z. (2017) Quantifying nitrous oxide production pathways in wastewater treatment systems using isotope technology - A critical review. Water Research 122 , 96-113. ¾ Koutsou, O.P., Gatidou, G., Stasinakis, A.S. (2018) Domestic wastewater management in Greece: greenhouse gas emissions estimation at country scale. Journal of Cleaner Production, 188, 851–859. ¾ Kyung, D., Kim, M., Chang, J., Lee, W. (2015) Estimation of greenhouse gas emissions from a hybrid wastewater treatment plant. Journal of Cleaner Production 95, 117-123. ¾ https://en.wikipedia.org/wiki/Constructed_wetland#/media/File:Schematic_of_the_Free_Water_Surface_Constructed_Wetland.jpg

6TH DISTANCE EDUCATION E-LEARNING SUMMER SCHOOL ON "Wastewater and Biosolids Management" (WWSS21) 26 – 31 July 2021, Patras, Greece

WWSS21: e-Book of Proceedings

Posters Session

ENERGY REQUIREMENTS BY MUNICIPAL WASTEWATER TREATMENT PLANTS OF GREECE Alexandra Siatou 1, Anthoula Manali 2, Petros Gikas 3 Abstract It is estimated that about 20% of the overall electric energy consumption by the Municipalities is used for wastewater treatment applications. It is thus important to understand the behavior of Wastewater Treatment Plants (WWTPs), with respect to energy requirements, as the first step to optimize the energy consumption of WWTPs. The majority of WWTPs in Greece, employ the activated sludge process, with most of those operating as extended aeration WWTPs. The aforementioned processes are particularly energy intensive. The present study examined the energy consumption in 17 activated sludge WWTPs, in Greece, serving between 1,100 to 56,000 inhabitants (PE), with average daily incoming flowrates between 300 to 27,300 m3/d, per WWTP. The daily wastewater production per inhabitant was measured between 0.052 to 0.426 m3/(PE·d), with average volume of 0.217 ± 0.114 m3/(PE·d). The electric energy consumption (EQ (kWh/m3)) per annual wastewater flow (Q (m3/yr)) was calculated by dividing the electric energy consumed in a calendar year by the annual wastewater inflow into the WWTP. The above energy was calculated between 0.128 to 2.280 kWh/m3, following a near logarithmic descending correlation with the WWTP capacity (EQ = -0.294lnQ + 3.1891; (R2 = 0.5337)). A similar behavior was found between the daily electric energy requirements for wastewater treatment per inhabitant (EPE (kWh/(PE·d))) and PE served by the plant, which varied between 0.041 to 0.407 kWh/(PE·d) (EPE = -0.073ln(PE) + 0.8425; (R2 = 0.6989)). The above results indicate a large variation of energy requirements per flowrate or per inhabitant, between the studied WWTPs. To some extent, the variations may be attributed to economy of scale, however, such large variations indicate that for many WWTPs there is large ground for improvement, so to reduce the energy consumption.

Keywords: wastewater treatment plant; electric energy; energy consumption; Affiliations 1

Alexandra Siatou, Chemical Engineer; Design of Environmental Processes Laboratory, School of Chemical and Environmental Engineering, Technical University of Crete, 73100, Chania, Greece; alex_siatou@hotmail.com 2

MSc Anthoula Manali, PhD Candidate; Design of Environmental Processes Laboratory, School of Chemical and Environmental Engineering, Technical University of Crete, 73100, Chania, Greece; tel: +30 28210 37839, amanali@isc.tuc.gr 3

Dr. Petros Gikas, Associate Professor; Design of Environmental Processes Laboratory, School of Chemical and Environmental Engineering, Technical University of Crete, 73100, Chania, Greece; tel: +30 28210 37836, fax: +30 28210 37851, petros.gikas@enveng.tuc.gr Name for the certificate: Anthoula Manali

40

ENERGY REQUIREMENTS BY MUNICIPAL WASTEWATER TREATMENT PLANTS OF GREECE Alexandra Siatou, Anthoula Manali, Petros Gikas Design of Environmental Processes Laboratory, School of Chemical and Environmental Engineering, Technical University of Crete, Chania, Greece E-mails: alex_siatou@hotmail.com; amanali@isc.tuc.gr.; petrosǤgikas@enveng.tuc.gr.

• • •

About 20% of the overall electric energy consumption by the municipalities worldwide is used for wastewater treatment applications.

Most of Wastewater Treatment Plants (WWTPs) in Greece operate as extended aeration plants, employing the activated sludge process, which demands particularly high amounts of energy.

The first step to optimize the energy consumption of WWTPs is to study in detail their energy needs.

The electric energy consumption per volume unit of inlet wastewater, EQ (kWh/m3) as a function of the average daily wastewater flow, Qav (m3/d) was also calculated (Figure 3). The results are the followings: • EQ = 0.128 – 2.280 kWh/m3 • Near logarithmic descending correlation with WWTP capacity: EQ = -0.294lnQ + 3.1891; (R2 = 0.5337).

The present study investigated the energy requirements of 17 activated sludge WWTPs in Greece (Figure 1).

Figure 3. Electricity consumption, EQ (kWh/m3) per m3 of treated wastewater as a function of average daily inflow, Qav (m3/d) (blue points) and trend line.

Figure 1. Locations of the WWTPs that participated in the study.

A similar behavior was found between the daily electric energy requirements for wastewater treatment per inhabitant, EPE (kWh/(PE· d)), and PE served by the plant (Figure 4): • EPE = 0.041 – 0.407 kWh/(PE·d) • Near logarithmic descending correlation with population served: EPE = -0.073ln(PE) + 0.8425; (R2 = 0.6989).

In Table 1 several characteristics of the studied WWTPs are presented: • Average daily inlet flow, Qav = 290 – 27,350 m3/d • Population served = 1ǡ157 – 56,050 PE • Average daily energy consumption = 471 – 7,243 kWh/d Table 1. Average daily inlet flow, population served, average daily energy consumption for the 17 examined WWTPs. Average Daily Inlet Population Average Daily Energy WWTP Flow, Qav (m3/d) Served (PE) Consumption (kWh/d) Marpissa 290 471 1ǡ157 Naousa 940 2ǡ555 774 Parikia 927 529 3ǡ215 Thasos 1ǡ150 4ǡ000 933 Elounda 700 539 4ǡ350 Amyntaio 1ǡ550 5ǡ350 1ǡ637 Farsala 935 5ǡ400 1ǡ298 Litochoro 2ǡ625 7ǡ000 1ǡ426 Elassona 644 12,225 1ǡ436 Chrysoupoli 1ǡ987 14,220 1ǡ473 Agios Nikolaos 3ǡ400 22,000 2ǡ179 Lavrio 25,500 2ǡ850 2ǡ301 Florina 11,830 26,000 2ǡ751 Nea Kydonia 35,934 6ǡ687 4ǡ123 Thiva 8ǡ410 40,000 1ǡ634 Lamia 14,285 46,550 7ǡ243 Karditsa 27,350 56,050 3ǡ102

Figure 4. Daily electric energy requirement per inhabitant, EPE (kWh/(PE∙d)) as a function of average inhabitants (PE) (blue points) and trend line.

The average percentage of energy consumption of the main subprocesses for the examined WWTPs is shown in Figure 5. The aeration process is the main energy sink, consuming about 0.618 kWh/m3 (67.2%) of the total electric energy supply to the plant.

As it is shown in Figure 2, the daily wastewater production per inhabitant was measured between 0.052 m3/(PE·d) (Elassona) and 0.426 m3/(PE·d) (Karditsa), with average volume of 0.217 ± 0.114 m3/(PE·d).

Figure 5. Energy distribution in the main processes of conventional activated sludge systems.

• • Figure 2. Daily average inflow per inhabitant (m3/PE∙d) (blue bars), with average value (dashed blue line) and standard deviation (dashed red lines).

•

The large variation of energy requirements of the studied WWTPs indicate that there is large ground for improvement, so to reduce the energy consumption.

Every WWTP should perform a detailed energy assessment study in an effort to improve energy efficiency.

Further research should be carried out, so to develop energyefficient wastewater treatment processes.

This study is supported by the European Commission and the Green Fund, through the LIFE program: “New concept for energy self-sustainable wastewater treatment process and biosolids management (LIFE B2E4SustWWTP)”, LIFE16 ENV/GR/000298.

WWSS21: e-Book of Proceedings

Posters Session

ADDITIONAL OPERATIONAL CHARACTERISTICS OF THE WASTEWATER TREATMENT PLANTS FOR THE ESTIMATION OF THEIR SEISMIC VULNERABILITY

P. Kerpelis1, D. Alexakis2, S. Golfinopoulos3, C. Repapis4* Abstract Engineers estimate the seismic structural vulnerability or the non-structural vulnerability of Public buildings and especially to the Wastewater Treatment Plants (WTPs) without considering their operational vulnerability (OV), that come from the operational processes and the sewage treatment.

WTPs structural, non-structural and OV were analytically investigated in the past. This study presents the minimum main operational parameters for estimating the OV. The investigation included a literature review of thirteen strong earthquakes that affected WTPs. The study extracted nine main OV parameters that obliged to be co-calculated for the estimation of WTPs’ seismic vulnerability.

These parameters are the automatic system for the operational checks and monitoring 7/24, the operation of pumping station, the applicable health and safety devices, and the water supply network.

More operational vulnerability parameters are the soil pollution, the water resources pollution, the air pollution, operation problems like the risks of flammable and toxic materials, foaming, overflow, algae, uneven mixing of sewages and finally the reserves available.

Objective: The investigation and prioritization of the operational parameters of the WTPs that can contribute to the efficient estimation of their seismic vulnerability.

Methods: A literature review was conducted about the seismic impacts of thirteen severe earthquake events world-wide, and focused on the damages due to their operational process.

Results: The extraction of nine main operational parameters absolutely needed for the seismic estimation of WTPs besides the estimation of the structural and the non-structural vulnerability. These operational parameters were investigated, limited and grouped, so as to be more practical. The protection measures will be more extensive and focused in the future.

Conclusion: The present study contributes to the estimation of the OV, using nine critical parameters.

The results of the use of the parameters is the more focusing of the seismic estimation (besides the structural and the non-structural), the minimization of the time needed for it, and furthermore the protection of the people health and the environment.

Affiliations 1,3

University of Aegean, Department of Financial and Management Engineering, School of Engineering, 41 Kountourioti Str., GR-82132 Chios, Greece, Contact 1: kerpelis@uniwa.gr Contact 3: s.golfinopoulos@fme.aegean.gr 1,2,4

University of Attica, Department of Civil Engineering, School of Engineering, Ancient Olive Grove Campus, 250 Thivon Str., GR-12241 Egaleo, Greece, Contact 2:d.alexakis@uniwa.gr, Contact4:crepapis@uniwa.gr

42

WWSS21: e-Book of Proceedings

Posters Session

NON-STRUCTURAL CHARACTERISTICS OF WASTEWATER TREATMENT PLANTS AS FACTORS FOR ESTIMATING THEIR SEISMIC VULNERABILITY

P. Kerpelis1, D. Alexakis2, S. Golfinopoulos3, C. Repapis4* Abstract The estimation of Public buildings’ seismic vulnerability of focuses on structural vulnerability or non-structural vulnerability (NSV). The parameters that affect the estimation of seismic vulnerability were investigated for the Wastewater Treatment Plants (WTPs), focusing on the structural parameters of vulnerability. The deficit about the shortened dedication of the non-structural parameters is investigated in the present study. After the literature review, thirteen severe earthquake events that transpired during the last years were studied for the non-structural impacts on WTPs. After the study of previous severe earthquake events in conjunction with the existing record of non-structural parameters of ordinary buildings and the analytical parameters of NSV in WTPs, there are emerging the most critical factors, for a more optimal approach to the problem. These seven factors are the inadequacy of support for equipment, and pipeline connections, the existence and operation of fire safety and detection, the risks associated with electrical engineering, the absence / elliptical monitoring of WTPs processes, either alert or communication and notification in case of trouble.

Other parameters of NSV for the estimation are the failure to implement the emergency plan, insufficient maintenance of the installation or existing malpractice and the existence of regular inspections – checks.

Objective: The investigation of the priority of the non-structural parameters that may be critical for estimating WTPs' seismic vulnerability.

Methods: A literature review was conducted about the seismic impacts of thirteen severe earthquake events, world-wide and the focus was on the non-structural damages, besides the recorded parameters.

Results: Seven main parameters of the non-structural elements were studied for the evaluation of the seismic vulnerability of WTPs. These parameters were investigated and categorized. The finding of this study may be helpful to provide engineers and stakeholders with a tool to design more safe WTPs infrastructures.

Conclusion: The contribution to the estimation of the NSV, using only seven parameters. The use of the parameters is the best seismic estimation, the minimization of the time needed for it, and the protection of the people health and the environment.

Affiliations 1,3

University of Aegean, Department of Financial and Management Engineering, School of Engineering, 41 Kountourioti Str., GR-82132 Chios, Greece, Contact 1: kerpelis@uniwa.gr Contact 3: s.golfinopoulos@fme.aegean.gr 1,2,4

University of Attica, Department of Civil Engineering, School of Engineering, Ancient Olive Grove Campus, 250 Thivon Str., GR-12241 Egaleo, Greece, Contact 2:d.alexakis@uniwa.gr, Contact4: crepapis@uniwa.gr

44

WWSS21: e-Book of Proceedings

Posters Session

A QUANTITATIVE MICROBIAL RISK ASSESSMENT FOR COVID-19 INFECTION FROM WASTEWATER

Eleni Stathopoulou1 and Eleni Sazakli1,2 Abstract Objectives. The new coronavirus, SARS-CoV-2 is detected in human feces of not only confirmed cases of the disease, but also of asymptomatic or pre-symptomatic infected people. Viral genomes surveillance by wastewater-based epidemiology can serve for estimating community COVID-19 infections and provide alert signals to public health authorities for mitigation measures, when needed. A database from the main Athens wastewater treatment plant (WWTP) concerning virus load in wastewater influents detected in a daily basis along with the confirmed daily new cases is publicly available. This study is a quantitative microbial risk assessment (QMRA) for evaluating the risk of infection after droplet exposure via inhalation. Methods. People that contribute to viral load in the influent of the WWTP are the confirmed cases of 10 days before and 5 days after the wastewater sampling date. A linear regression model was applied to assess the association of viral load in the influent with the calculated number of infected people contributing to viral load. A dose-response model for SARS-CoV-1 is assumed in the QMRA for SARS-CoV-2 using the exponential model P(i) = 1 − e (−d/K), where P(i): probability of infection, d: exposure dose and k: 4.1 × 102. Results. In April, the average viral load was 1.11 x 102 GC/ml, and the maximum value reached 1.62 x 102 GC/ml, corresponding to risk of infection of 2.71 x 10-4 and 3.95 x 10-4 respectively, while the acceptable risk (AR) of infection is slightly higher (5.5 x 10-4). The dose required to reach the AR corresponds to a viral load of 2.27 x 102 GC/mL. This load is expected when the number of people contributing to viral load reaches 35,163 (99% CI = 28,599 - 41,727), that coincide to 2,344 (99% CI 1,907 2,782) new daily confirmed cases. Conclusions. The viral load in raw wastewater, even in April, never exceeded the AR of infection for SARS-CoV-2. However it reached up to 71.4% of AR. Affiliations 1

Hellenic Open University, School of Science and Technology, Aristotelous 18, 26335 Patras, Greece

2

Lab of Public Health, Medical School, University of Patras, 26 504, Patras, Greece

Eleni Stathopoulou: Chemist, M.Sc. student in Postgraduate Study Programme “Waste Management”, Kipon 59, GR-12137, Peristeri, Athens, tel. 6956297110, std138675@ac.eap.gr Eleni Sazakli: Chemist, M.Sc., Ph.D., Collaborating Academic Staff of Hellenic Open University, address: Lab of Public Health, Medical School, University of Patras, 26 504, Patras, Greece, tel. +302610969881, fax. +302610969112, elsazak@upatras.gr Name for the certificate: Eleni Stathopoulou

46

A quantitative microbial risk assessment for COVID-19 infection from wastewater Eleni Stathopoulou1 and Eleni Sazakli1,2 1

Hellenic Open University, School of Science and Technology, Aristotelous 18, 26335 Patras, Greece 2

Lab of Public Health, Medical School, University of Patras, 26 504, Patras, Greece

Background. The new coronavirus, SARS-CoV-2, is detected in human feces of not only confirmed cases of the disease, but also of asymptomatic or pre-symptomatic infected people. Shedding of the virus SARS-CoV-2 in feces may occur approximately 3–5 days before other classic symptoms (i.e. pre-symptomatic), while people being infected continue to release virus RNA to their feces for about 10 days after being found positive.

Viral genomes surveillance by wastewater-based epidemiology can serve for estimating community COVID-19 infections and provide alert signals to public health authorities for mitigation measures, when needed (Fig.1).

Aim. This study is a quantitative microbial risk assessment (QMRA) for infection with Fig.1. Fate of SARS-CoV-2 in the urban water cycle. Adapted by Saawarn and Hait (2020)

SARS-CoV-2 after exposure to wastewater droplets via inhalation.

A database of confirmed new cases, on a daily basis is publicly available by the Hellenic National Public Health Organization. The trend of new cases in Athens is visualized in Fig. 2

The database from Athens WWTP, Psyttaleia, concerning the virus load detected in the influent along with the confirmed daily new cases of SARS-CoV-2 in the population served, is publicly available (Fig. 3).

Methods. People that contribute to viral load in the influent of the WWTP are the confirmed cases of 10 days before and 5 days after the wastewater sampling date.

A linear regression model e. was applied to assess the association of viral load in the influent with the calculated number of infected people contributing to viral load.

A dose-response model developed for SARS-CoV-1 is assumed in the QMRA for SARS-CoV-2.

Assumptions: •

Fig.2. Source link http://trams.chem.uoa.gr/covid-19/

Fig.3. Source link http://trams.chem.uoa.gr/covid-19/

Results Linear regression revealed that the viral load in the influent is associated with the calculated number of people that contribute to the viral load (R2=0.560). The regression equation is: Viral load (in gene copies/mL) = -6.198 + 0.004061 * infected people contributing to viral load During April, the average viral load was 1.11 x 102 GC/ml, and the maximum value reached 1.62 x 102 GC/ml. Τhe Probability of infection P(i) was calculated from 2.71 x 10-4 to 3.95 x 10-4 The dose required to reach the Tolerable Infection Risk, (TIR: 5.5 x 10-4), corresponds to a viral load of 2.27 x 102 GC/mL. This is to be expected when the number of people contributing to viral load reaches 35,163 (99% CI = 28,599 - 41,727), that coincide to 2,344 (99% CI 1,907 - 2,782) new daily confirmed cases.

Confirmed cases with Covid-19

SARS-CoV-2 RNA Concentration of copies in wastewaters viable SARS-CoV-2 in (GC·mL−1) wastewater (PFU·mL−1)

Dose d (PFU)

Probability of infection P(i)

Average values

1453

1.11 x 102

1.11 x 10-1

1.11 x 10-1

2.71 x 10-4

Max values

2097

1.62 x 102

1.62 x 10-1

1.62 x 10-1

3.95 x 10-4

Conclusions: The viral load in raw wastewater, even in April, never exceeded the TIR of infection for SARS-CoV-2. However it reached up to 71.4% of TIR.

The tolerable burden of Disease is set to 10−6 DALYs per person per year (pppy) by WHO (2017) • DALYs loss per case of disease is equal to 2.01 × 10−3 for SARS-CoV-2, as estimated

by Nurchis et al. (2020) • The probability of infection (Zaneti et al.

2021) is given by: P (i) = 1 − e (−d/K) P(i): probability of infection d: exposure dose (number of viable plaque forming units (PFU)) inhaled k: 4.1 × 102 • The exposure dose is estimated by: d = I x VC I: Volume ingested (1 mL) VC = Concentration of viable virus in sewage (PFU/mL) • Gene copies/mL are converted to infectious (viable) SARS-CoV-2 , in units of PFU/mL, by assuming that 103 GC correspond to 1 PFU •

Tolerable Disease risk (pppy):

•

Tolerable infection risk (pppy):

Tolerable Infection Risk: 5.5 x 10-4

References. Saawarn B. & Hait S. (2021) Occurrence, fate and removal of SARS-CoV-2 in wastewater: Current knowledge and future perspectives. J Environ Chem Eng, 9(1) 104870 https://doi.org/10.1016/j.jece.2020.104870 Nurchis et al. (2020) Impact of the Burden of COVID-19 in Italy: Results of Disability-Adjusted Life Years (DALYs) and Productivity Loss. Int. J. Environ. Res. Public Health, 17, 4233. https://doi.org/10.3390/ijerph17124233 Zaneti et al. (2021) Quantitative microbial risk assessment of SARS-CoV-2 for workers in wastewater treatment plants. Sci Total Environ, 754, 142163, https://doi.org/10.1016/j.scitotenv.2020.142163

WWSS21: e-Book of Proceedings

Posters Session

KNOWLEDGE & ATTITUDES OF HIGH SCHOOLS STUDENTS IN GREECE, TOWARDS WASTE MANAGEMENT Karachalios Ilias1*, Plakitsi Katerina2, Vassilia Hatzinikita3, Ioannis Kalavrouziotis1 Abstract Objectives: The effective waste management is essential for the sustainable development (Baud, Grafakos, Hordijk, & Post, 2001; Morrissey & Browne, 2004).and so, the educational system of every country needs to provide its students with the necessary related skills and knowledge. The aims of this research are a) to explore the knowledge and the attitudes of high school students in Greece towards waste management and b) to compare their performance to the ones in UK. Method: Questionnaires from a research study held in UK (Kolbe, 2015) were used in Greek high schools. Data, were collected by a multiple-choice questionnaire, in order to record students’ knowledge and attitudes. The results were compared to a research study held in UK for two schools with a sample of 253 high school students (Kolbe, 2015).

Our research sample were 189 high school students of Greek high Schools, enrolled on the 1st,2nd or 3rd year of lower secondary schools, between 12 and 15 years of age, 64,5% were girls and 35.5% boys. Questionnaires were provided by their teacher and were filled out anonymously in the same period, from 18 February 2021 until 4 April 2021.

Results: The results showed lack of knowledge for students in Greece, comparing to the ones in UK. Greek Students level of knowledge for concepts related to waste management was lower than students in UK. Only 57.7% of Greek Students state that they heard of the waste management concepts (Recycling of Paper, Kerbside collection, Composting, Incineration and Landfill) and knew what they meant. For students in UK the percentage was 80.5%.

It is remarkable that for the concept of Landfill, the Greek students that state they heard and know what it means were only 26.6%, while in UK 70.4% state they knew what it meant.

Greek Students state that they valued the importance of different waste management options (Reduce of waste, Recycling, Composting and Re-use) by giving on average 7.2/10 lower than the students in UK (7.6/10). 79.9% of Greek Students state that they think waste volumes should be reduced, in comparison to almost 100% in UK. Greek students state that they recycle whenever is possible on an average of 54%, less often than the students in UK (67.4%). Students in Greece have also lower level of knowledge on what recyclable is, scoring on average 72.9% of right answers comparing to 77.2% of students in UK. Greek Students state as a major source of knowledge the “school”, comparing to the “family” that students in UK. Conclusions: Even though students in Greece state that their main source of knowledge is school while in UK is family-, their level of knowledge on issues related to waste management is lower, they state they recycle less and value waste management concepts as less important than the students in UK, so further researches should be conducted in order to investigate the reasons.

References Baud, I., Grafakos, S., Hordijk, M., & Post, H. (2001). Quality of life and alliances in solid waste management: Contributions to urban sustainable development. Cities, 18, 3 12.

Kolbe, K. D. (2015). Knowledge, Attitudes and Behaviour regarding Waste Management in a Grammar and a Comprehensive School in England – Results from a School Questionnaire. Journal of Teacher Education for Sustainability, 17(1),pp. 58-71, https://doi.org/10.1515/jtes-2015-0005 48

Morrissey, A. J., & Browne, J. (2004). Waste management models and their application to sustainable waste management. Waste Management, 24, 297 308.

Affiliations 1. School of Science and Technology, Hellenic Open University, Greece 2. Professor of Science Education, Dept. of Early Childhood Education, School of Education, University of Ioannina, Greece 3. Professor School of Humanities, Hellenic Open University, Greece * Corresponding author: Karachalios Hlias, Environmental Manager, MSc, MEd, Phd Candidate, e-mail: Ilias.karachalios@hotmail.gr, Hellenic Open University, Greece

49

WWSS21: e-Book of Proceedings

50

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WWSS21: e-Book of Proceedings

Posters Session

EXPLOITATION OF BY-PRODUCTS FROM BIOGAS PLANTS FOR GREENHOUSE HEATING AND PRODUCTION OF HIGH ADDED-VALUE AGRICULTURAL PRODUCTS WITH REDUCED ENVIRONMENTAL FOOTPRINT

D. Kouvas1, G. Ntina2 Abstract The aim of the proposed project is the development and exploitation of an innovative and symbiotic management of biogas and greenhouse plants, where the greenhouse will be heated exclusively by renewable energy and will utilize by-products of the biogas plants, such as carbon dioxide from combustion and digestate (liquid fraction). An exhaust heat recovery exchanger between the biogas plant and the greenhouse will feed the second with thermal energy, taking advantage of the excess heat of the exhaust that would otherwise be discharged into the environment. In addition, an intelligent "integrated" greenhouse monitoring system with wireless sensors and appropriate decision-making software will be developed to alert the manager in time for off-boundary parameters.

It will also contribute to the optimal consumption of renewable energy by the biogas unit for heating / cooling of the greenhouse and water / chemicals for the fertirrigation of the hydroponic tomato crop resulting in the production of high added value agricultural products with reduced environmental footprint. Consequently, this project will contribute to the development of circular bio-economy, zero-waste societies and zero-fossil use. The Green_BioHeat project will contribute to the exploitation of by-products from biogas plants, such as thermal energy and digestate as organic fertilizer will provide all the necessary ingredients for proper plant growth and in combination with the hydroponic cultivation method will reduce fertirrigation needs. Raising awareness of all actors involved in agri-food chains and increasing the social acceptance of the project results will lead to the use of agricultural practices that rationally and fully utilize natural resources, maximize the income of our country's farmers and reduce the emissions of greenhouse gases.

Affiliations 1

SCIENTACT AE, BIOGAS HALKIDIKI IKE

2

ELGO-DIMITRA

52

The project is a partnership of the following companies: SCIENTACT AE BIOGAS HALKIDIKI IKE Financial source: ΕΣΠΑ 2014 -2020, NATIONAL ACTION: «RESEARCH-CREATE-INNOVATE B’ PERIOD» Budget: 399.246,57 € (fore the SCIENTACT AE 159.247,03 € the 125.897,62 € is the public contribution) Role:

Member of the partnership The project is implemented with the participation of ELGO-DIMITRA as subcontractor and scientifically responsible the Authorized Researcher Dr. George Dina.

Exploitation of by-products from biogas plants for greenhouse heating and production of high added-value agricultural products with reduced environmental footprint The aim of the proposed project is the development and exploitation of an innovative and symbiotic management of biogas and greenhouse plants, where the greenhouse will be heated exclusively by renewable energy and will utilize by-products of the biogas plants, such as carbon dioxide from combustion and digestate (liquid fraction).

An exhaust heat recovery exchanger between the biogas plant and the greenhouse will feed the second with thermal energy, taking advantage of the excess heat of the exhaust that would otherwise be discharged into the environment. In addition, an intelligent "integrated" greenhouse monitoring system with wireless sensors and appropriate decision-making software will be developed to alert the manager in time for off-boundary parameters.

It will also contribute to the optimal consumption of renewable energy by the biogas unit for heating / cooling of the greenhouse and water / chemicals for the fertirrigation of the hydroponic tomato crop resulting in the production of high added value agricultural products with reduced environmental footprint.

Consequently, this project will contribute to the development of circular bio-economy, zero-waste societies and zero-fossil use.

WWSS21: e-Book of Proceedings

Posters Session

PREDICTING BIOGAS PRODUCTION FROM ANAEROBIC WASTEWATER TREATMENT PLANTS USING A USER FRIENDLY SOFTWARE PLATFORM

G. Anagnostopoulos1,*, G. Syriopoulos1, A. Alexandridis2, O. Sekkas3 Abstract The proposed approach is applied for modeling the biogas production on a real world, full-scale paper mill plant located in Greece equipped with Anaerobic Digestion (AD) and more precisely with anaerobic reactors with internal recirculation (IC). The anaerobic process is based on SIRMET S.A. technology, applied in three (3) anaerobic plants in Greece, treating industrial high COD wastewater streams. The plant can treat up to 4.2 tons/day soluble Chemical Oxygen Demand (sCOD), while the load of organic waste may vary daily according to the changes in the production line, thus allowing for different amounts of biogas to be produced.

Real scale industrial data were acquired from the plant records over a time period of approximately one year (December 2019 - January 2021); the records were collected by SIRMET S.A. via SCADA system sensors installed at multiple points across the AD process. The variables used as inputs, include several chemicals and nutrients necessary to adjust important variables in the process. The data received where processed by employing artificial neural networks (ANNs) and more specifically on the efficient architecture of radial basis function (RBF) networks. In addition the proposed algorithm is enhanced with an optimizer based on differential evolution (DE), which helps to properly tune the algorithm, ultimately boosting the accuracy of the produced models.

As a result a user-friendly software platform has been developed, which is able to monitor in real time the production of biogas as well to propose up to five (5) alternative solutions for optimizing its process based on the daily available data.

Acknowledgements The research leading to these results has derived and financed from project ENVIROBRAIN (project code: T1EDK-03714) / General Secretariat of Research and Technology (GSRT) of the Hellenic Republic. Greece: Funded under European Regional Development Fund (ERDF) and National Resources (GSRT).

Affiliations 1

SIRMET S.A., Filopimenos 4-6, 26221, Patras (Greece)

2

Department of Electrical and Electronic Engineering, University of West Attica, Ancient Olive Grove Campus, Thivon 250 & P. Ralli, 12244, Egaleo, Greece 3

Mobics S.A, 27 Kifissias Ave., 11523 Athens, Greece

54

Predicting biogas production from anaerobic wastewater treatment plants using a user friendly software platform G. Anagnostopoulos 1 , G. Syriopoulos 1 , A. Alexandridis 2, O. Sekkas 3 1SIRMET

S.A., Filopimenos 4-6, 26221, Patras (Greece) of Electrical and Electronic Engineering, University of West Attica, Ancient Olive Grove Campus, Thivon 250 & P. Ralli, 12244, Egaleo, Greece 3Mobics S.A, 27 Kifissias Ave., 11523 Athens, Greece 2Department

info@sirmet.gr

Anaerobic Digestion/Biogas production Anaerobic digestion is a set of biochemical reactions, carried out by microorganisms that operate in the absence of oxygen, through which complex organic biomass molecules are converted into simpler chemical molecules (mainly organic acids) and finally into methane, carbon dioxide, carbon monoxide. ammonia, hydrogen sulfide, hydrogen etc.

Production

Energy Primary Source

Waste (tn/y)

Power (MWe)

Cow farming Pig farming Slaughterhouses Cheese & Milk Industrial Units Summary

14,450,800 2,268,220 204,932

278 37 28

425,647

7.21

17,439,599

350.21

Usages

Source: Greek Center for Renewable Energy Sources

The cost of upgrading biogas in units of 200 - 300 m3/h is 0.01 - 0.015 €/kWh of upgraded biogas

Predicting biogas production in full-scale operational paper mill plant The main objective of the plant is to produce different qualities of paper products from recycled paper, as well as to utilize the fresh organic waste in the production of biogas for power generation A new method for modeling biogas production obtained from anaerobic digestion treatment plants with increased accuracy has been developed based on artificial neural networks (ANNs).

By collecting real time data from the sensor systems (SCADA) of the anaerobic plant, the proposed software can predict as well to optimize the production of biogas

ACKNOWLEDGEMENTS

The research leading to these results has derived and financed from project ENVIROBRAIN (project code: T1EDK-03714) / General Secretariat of Research and Technology (GSRT) of the Hellenic Republic. Greece: Funded under European Regional Development Fund (ERDF) and National Resources (GSRT).

WWSS21: e-Book of Proceedings

Posters Session

TOWARDS TO A MODEL OF A “SMART CITY” USING TREATED WASTEWATER

Sotirios M. Michalopoulos and Ioannis K. Kalavrouziotis Abstract Treated wastewater can be reused for a variety of purposes such as irrigation, landscape use, urban, industry, etc.

The use within urban areas could have adaptive economic and environmental benefits if the reuse planning and management is done in the context of sustainable development. In this context, the introduction of a model for the management and planning of the reuse of treated wastewater using optimization methods, is the goal to address these challenges, utilizing a wide and complex range of design and infrastructure indicators.

The role of the reuse of treated wastewater as an alternative source of water supply for various urban uses is satisfactorily recognized and part of international, European and national strategies, such as the “UN Sustainable Development Goal on Water (SDG 6)”, the "Strategic Implementation Plan of the European Innovation Partnership on Water" and the "Blueprint to safeguard Europe's water resources" which has as its specific goal the maximization of water reuse.

The ongoing COVID 19 pandemic further emphasizes that the water sector in general and treated wastewater in particular play an essential role in protecting human health and the environment. Since the onset of the COVID-19 pandemic, wastewater has been studied as an indicator of the presence of the virus in the population inside and outside the EU. Affiliations Hellenic Open University, School of Science and Technology (HOU), Lab. of Sustainable Waste Technology Management, 26335, Patras, Greece

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Towards to a model of a "smart city” using treated wastewater Sotirios M. Michalopoulos and Ioannis K. Kalavrouziotis Hellenic Open University, School of Science and Technology (HOU), Lab. of Sustainable Waste Technology Management, 26335, Patras, Greece

Abstract Treated wastewater can be reused for a variety of purposes such as irrigation, landscape use, urban, industry, etc.

The use within urban areas could have adaptive economic and environmental benefits if the reuse planning and management is done in the context of sustainable development. In this context, the introduction of a model for the management and planning of the reuse of treated wastewater using optimization methods, is the goal to address these challenges, utilizing a wide and complex range of design and infrastructure indicators.

The role of the reuse of treated wastewater as an alternative source of water supply for various urban uses is satisfactorily recognized and part of international, European and national strategies, such as the “UN Sustainable Development Goal on Water (SDG 6)”, the "Strategic Implementation Plan of the European Innovation Partnership on Water" and the "Blueprint to safeguard Europe's water resources" which has as its specific goal the maximization of water reuse.

The ongoing COVID 19 pandemic further emphasizes that the water sector in general and treated wastewater in particular play an essential role in protecting human health and the environment. Since the onset of the COVID-19 pandemic, wastewater has been studied as an indicator of the presence of the virus in the population inside and outside the EU.

Introduction Rapid urbanization and population growth are associated with increased water demand within urban areas for both domestic and non-domestic uses. In most cities today, water management standards are either conventional (top-down approach) or fragmented and seem to be unable to adequately meet its challenges.

A major challenge for urban water resources management in terms of research and innovation, requires significant changes in the way water is managed. In fact, a growing number of cities in different parts of the world are creating transnational networks to adapt to such needs, that have the potential to formally promote the integration of water management with climate change in the urban context1.

In Greece, the reuse of treated wastewater for various uses in urban centers and buildings in cities such as Agrinio and Patras was studied 2,3.

Additionally, as vital action, the systematic evaluation can identify the main problems,

opportunities and good practices that can enhance the governance capacity of the proposed solutions, based on the “smart city” concept. Thus, a shift to adaptive approaches in urban water management, propose to address these complexities, while ensuring the adequate provision of water services to citizens.

Methodology By the identification of best cases for the treated wastewater reuse, the mapping of existing uses in the urban environment could take place, in the form of data.

Then it is possible to evaluate and select those cities in which, the criterion of how "close" they are to the known operations of the Mediterranean cities. The term "close" technically includes the following: 1) elements that can be applied as it is. 2) elements that could be dynamically adapted to the local or Regional functions. 3) solutions that are feasible but, in order to fully meet the desired functions they will have to change targeting (application in different urban uses from those they already have in the cases that have emerged as best practices). 4) Combined solutions (a kind of integration with existing uses under the possibility of application in Mediterranean climates).

As result there will be an initial (preliminary) assessment of their applicability, and then the modeling could be proceed.

Conclusions The reuse of treated wastewater can not only be considered as a quantitative measure to reduce water pumping but also as an optimal solution to maintain or improve its quality. Quality must be linked to quantity to ensure safety and increase value through the supply chain.

The introduction of an optimal reuse and management planning model for treated wastewater in urban areas requires a wide range of storage and distribution systems for municipal, commercial and domestic applications.

These include supervision of transmission lines, pumping stations, supply systems, injection systems, intelligent disposal automation, etc., which will be variables of the proposed model.

References 1

https://doi.org/10.3390/w11040701 AGGELI K., KALAVROUZIOTIS I.K., BEZERGIANNI S., 2009, ‘A proposal of a treated wastewater reuse design system in urban areas’, Fresenius Environmental Bulletin,Vol. 18, No 7b, pp. 1295-3001.

3 https://doi.org/10.1016/j.buildenv.2006.07.016 2

WWSS21: e-Book of Proceedings

Posters Session

BIOSOLIDS USAGE IN AGRICULTURE OVER THE CENTURIES 1

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Isari E. A. , Kokkinos P. , Zheng X. Y. , Kalavrouziotis I.K.

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Abstract The term biosolids referred to the solid, semisolid, or liquid residues generated from treatment through controlled processes of domestic and industrial sanitary sewage sludge. Biosolids have many applications in agriculture, energy sector, can be used as adsorbent or construction materials and other [1]. The aim of the present study is to follow the course of the recycled organic matter from municipal waste or later of biosolids, over the centuries.

In the Greek and Roman years, the management of household waste was carried out through public sewerage, by removing the waste with running water as well as by applying them to the ground [2] In the following years and until the beginning of the 1800s the public sewerage was almost nonexistent, in fact there have been clear descriptions that in densely populated areas of Europe the sanitary conditions were not correct. Large piles of human feces were piled up between homes, and in a few cases the waste was used as soil conditioner or dumped in water bodies. The first developments to enhance soil fertility with the use of soil conditioners took place in Britain from 1840 to 1890 [3]. In the 1990s there was pressure in some European countries to ban the use of biosolids for agricultural use. Austria, Sweden, and Switzerland, among others, introduced the ban.

Other countries developed strict sanitary and environmental regulations to ensure biosolids safe use for land application (e.g., European Directive 86/278/EEC, US EPA’s Part 503). Today, advanced sludge stabilization treatment methods have been developed in the EU, so the biosolids can be safely applied to the agriculture land [4].

References [1] Torri, S. I., Corrêa, R. S., Renella, G., Valdecantos, A., & Perelomov, L. (2012). Biosolids soil application: why a new special on an old issue?.

[2] Kalavrouziotis I.K., [3] Jewell, W. J., & Seabrook, B. L. (1979). A history of land application as a treatment alternative.

[4] Gianico, A., Braguglia, C. M., Gallipoli, A., Montecchio, D., & Mininni, G. (2021). Land Application of Biosolids in Europe: Possibilities, Con-Straints and Future Perspectives. Water, 13(1), 103.

Affiliations 1.Phd student, Isari C. Ekavi Aikaterini, School of Science and Technology, Laboratory of Sustainable Waste Management Technologies, Hellenic Open University, Parodos Aristotelous 18, 26335 Patras, Greece, ekavi.isari@eap.gr 2. Dr. Kokkinos Petros, School of Science and Technology, Laboratory of Sustainable Waste Management Technologies, Hellenic Open University, Parodos Aristotelous 18, 26335 Patras, Greece, pkokkin@upatras.gr 3.Professor Dr. Zheng Xiao Yun, International Center for Ecologic Culture Studies & Department of Academic Affairs Management, Yunnan Academy of Social Sciences, No. 577, Huan Cheng West Road, Kunming 650034, China, zhengxy68@163.com 4. Professor Dr. Kalavrouziotis K. Ioannis, School of Science and Technology, Laboratory of Sustainable Waste Management Technologies, Hellenic Open University, Parodos Aristotelous 18, 26335 Patras, Greece, ikalabro@eap.gr

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