ES1202
WG1: Efficient technologies
TGA1 Energy efficient nutrient removal
Conceiving Wastewater Treatment in 2020 - Energetic, environmental and
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
no
Organization
Project title
Communication
1
KTH Royal Institute of Technoogy
E. Plaza
2
Silesian University of Technology Poznan University of Technology AquateamCOWI
3
University of Verona Alto Trevigiano Servizi S.r.l.
4
Middle East Technical University
5
University of Brescia
6
National Technical University of Athens
7
Istanbul Technical University
8
University of Cantabria
9
VTT
Partial nitritation/Anammox for a cost effective nitrogen removal from a main stream of municipal wastewater Integrated technology for improved energy balance and reduced greenhouse gas emissions at municipal wastewater treatment plants Short-Cut Enhanced Nutrient Abatement (SCENA) from Anaerobic Supernatant Reuse of domestic wastewaters after treatment using a vacuum rotating MBR Air supply regulation and process optimization by a fuzzy logic system in activated sludge WWTPs Biological nitrogen removal from wastewaterthrough bypassing nitrate production Minimization and Stabilization of Wastewater Treatment Sludge in Turkey Innovative Integrated Biological Processes for carbon and nutrient removal (i2BP) Hydrothermal carbonization for sludge nutrient reclamation
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
J. SurmaczGórska J. Mąkinia
F. Fatone D. Renzi C. Gokcay
G. Bertanza
G. Lyberatos
O. Ince
A.L. Esteban
A. Mona
Application of the partial nitritation/Anammox process for a cost effective nitrogen removal from a main stream of municipal wastewater The number of full-scale applications of the Anammox process for nitrogen removal from anaerobic digestion reject water showed that energy and chemicals requirements can be substantially lowered, comparing to the traditional nitrification/denitrification process, when treating wastewaters with a low C:N ratio. A new challenge is to apply the partial nitritation/Anammox process for nitrogen removal in a main stream of the WWTP, at low temperatures and low ammonium concentrations. Application of the Anammox process is especially interesting in A-B systems where organic matter is removed in A stage, which can be based on high rate activated sludge, precipitation of organic matter with metal salt and polymer, upflow anaerobic sludge blanket (UASB) reactor or a combination of these methods. Technical description Removal of nitrogen from a main stream using the Anammox process is done in two separate pilot-scale moving bed biofilm reactors (MBBR), each of 200 L volume. One of the reactors is used for studying the system based on a nitrogen removal following an organic matter removal from municipal wastewater in the UASB reactor (T=20-25 °C). The other reactor is used for a nitrogen removal from wastewater at low temperatures (T=13-17 °C). The reactors are installed at the Hammarby SjÜstadsverk research facility and have been treating low-concentrated wastewater for more than two years. After the long-term operation it was found that Anammox bacteria can be mantained in a biofilm even when treating low-concentrated wastewater and the main challenge is to limit a growth of nitrite-oxidizing bacteria (NOB) and nitrate accumulation. The system treating the UASB reactor effluent relies on NOB out-selection, applying transient anoxia mechanism and increasing the proportion of aerobic ammonium oxidizing bacteria (AOB) by suspended sludge recirculation (IFAS mode). A novel control strategy that uses a variety of on-line measurement signals allows to reach 65-75% nitrogen removal. The scope of ongoing research on nitritation/Anammox in a main stream at a low temperature is to find the effective and feasible control method of NOB growth and then optimization of the process. The following strategies and factors have been tested: intermittent aeration strategy; pH increase; influence of inorganic carbon concentration on Anammox bacteria activity; interactions between ammonia nitrogen concentrations, pH and dissolved oxygen concentrations and their influence on NOB suppression; mathematical modeling of nitritation/Anammox process in the MBBR reactor. Development by the year 2020: This technology will be implemented in full scale for mainstream of municipal wastewater treatment plant in Sweden. Main contacts: Elzbieta Plaza (elap@kth.se - www.kth.se) and Jozef Trela - (jozef.trela@ivl.se www.ivl.se)
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
Integrated technology for improved energy balance and reduced greenhouse gas emissions at municipal wastewater treatment plants BARITECH State of the art solutions for WWTPs call not only for meeting stringent effluent quality standards but also for maximum energy recovery from wastewaters. Typically, aeration consumes over 50 % of total plant energy requirements where nitrification is one of the most energy consuming processes. Additionally, the increasing sludge production is causing serious and growing problems with its management, but also greenhouse gases emission is an emerging issue. The aim of the project is to develop a novel sustainable technology that combines increased biogas production with enhanced nutrients removal from reject water. Description of the project To improve the energy balance the separate treatment of reject water is required as well as increase of renewably energy production from biogas. The project focuses on development and implementation of an integrated novel technology of nutrients removal from sewage sludge digester liquors that allow for reduction of cost by reduced aeration energy for BOD removal and overall N-removal as well as due to increase electricity production from biogas. The aim of the project is practical application of sustainable management including technology, energy, greenhouse gases emission and economy aspects of WWTP activity. The project plan consists of seven Work Packages divided into detailed tasks of project’s partners. WP. 1. The coagulation/floculation process in a primary clarifier. WP. 2.1. Nitrogen removal in the anammox process. WP. 2.2. Nutrients removal by algae. WP. 2.3. Nutrients removal by wetland treatment system. WP. 3. Biogas generation in the anaerobic digestion process with additional substrates. WP. 4. Model-based optimization of selected treatment processes. WP. 5. Energy balance and greenhouse gases (GHG) emissions estimation. WP. 6. Techno-economic analysis. The proposed novel technology is implemented in the side stream of digested sludge reject water with high concentration of nitrogen and phosphorus. The outcomes of the project are two-fold: optimization of novel treatment technologies anammox, nutrient removal using algae or wetlands) for side stream treatment and an integrated and optimized scheme for sludge management. Technology will contribute to energy recovery and savings, greenhouse gases emission reduction, nutrients removal, sludge minimization and improvement of economic aspects of WWTP. Project Promoter: Project Partners:
Development by the year 2020: The BARITECH project will be applied and the results will be published Main contacts: www.baritech.org.pl Short-cut nitrogen removal and enhanced via-nitrite phosphorus bioaccumulation for the treatment of the anaerobic supernatant from digested sewage sludge S.C.E.N.A. Short-Cut Enhanced Nutrients Abatement The extensive application of anaerobic digestion for sewage sludge treatment, results in the production of high quantities of nutrients-rich anaerobic effluents that must be properly managed.
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
The usual practice is to return the anaerobic supernatant to the inlet of the wastewater treatment line. Although this liquid stream represents a small percentage of influent flow, it increases significantly (15-30%) the nitrogen (N) and phosphorus (P) load. The separate post-treatment of the anaerobic supernatant can relieve the wastewater line from such loads, avoiding both N and P overloads which are biologically removed at very high rates and low carbon footprint. Technical description The pilot scheme consists of a sludge alkaline fermentation (SAF) unit coupled to a short-cut sequencing batch reactor (scSBR). The integrated SAF-scSBR has been installed and is operating in Carbonera municipal WWTP (Veneto-Italy). The system is applied to treat the real anaerobic supernatant for the short-cut N removal and via nitrite enhanced P bioaccumulation. It is composed of three main units: sewage sludge alkaline fermentation unit (reaction volume 250 L), a membrane (UF) filtration skid for the solid/liquid separation of the fermentation effluent, an SBR (3 m3) for the treatment of the anaerobic supernatant to remove nutrients via nitrite pathway. The system is treating up to 6 m3/d of anaerobic supernatant from the full-scale anaerobic digester of sewage sludge in Carbonera. The main processes involved are: Nitritation/denitritation coupled with the best available mix of short-chain fatty acids (SCFAs) to enhance the denitrifying via nitrite biological phosphorus removal (DNBPR). Sludge alkaline fermentation to recover the best available mix of SCFAs for P removal and/or PHA production Membrane filtration for the solid/liquid separation of the fermentation The fermentation liquid is used as carbon source for denitritation and enhanced biological phosphorus removal in the scSBR, improving the rate and efficiency of nutrients removal in a cost effective way and decreasing N2O and NO emissions. The optimization focuses on the production of fermentation liquid rich in the desired SCFAs (i.e. propionate and butyrate), the minimization of chemical use and use of alkaline silicates for pH control, the minimization of P and N release in the fermented liquid and the maximization of via nitrite N and P removal, PHAs accumulation in the subsequent scSBR process. A robust real time control strategy is based on indirect parameters. Development by the year 2020: The S.C.E.N.A. process will be applied in full scale in 2014. Main contacts: University of Verona (francesco.fatone@univr.it - www.labicab.it) and Alto Trevigiano Servizi srl - (drenzi@altotrevigianoservizi.it - www.altotrevigianoservizi.it)
Reuse of domestic wastewaters after treatment by using a vacuum rotating MBR M.E.T.U. Vacuum MBR Application plant Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
The Membrane Biological Treatment (MBR) process is gaining popularity throughout the world and more so in countries with arid and semi-arid climates. A full-scale MBR plant has been build and operated in the METU campus in the last ten years to test its long term dependability in reuse for both as potable water supply and irrigation. Technical Description A flat plate type vacuum membrane bioreactor (MBR) with nominal pore size of 0.038 Îźm, having a total membrane surface area of 540 m 2 and a total tank volume of 100 m3, was operated for over nine years in METU campus treating daily 200 m 3 of wastewater from dormitories and academic village. The hydraulic retention times ranged between 18 and 22h and SRT between 10 days and infinity. A vacuum is applied to the membranes for suction and the drum-like membrane holder constantly rotates on a centrally located shaft where course air is sparged through the center to create cross flow. Plant operates 9 mins. with suction and membranes are relaxed for 1 min., without suction or back pulse, at every operating cycle. During this period, apart from routine analysis of pollution parameters, effect of sludge concentration and temperature on sludge rheology was analyzed. This was deemed important since fouling of inter-plate spaces is a major concern in operating such plants as damage thereof may be irreversible on the membranes. Performance of membrane reactors in removing model emerging pollutants, mainly pharmaceuticals and natural endocrine disrupters, from wastewaters was studied on this plant and compared with those obtained in conventional biological treatment. Costing of plant operation was studied as it is extremely important for long term operation and adoption by the public. Plant produces excellent effluent quality with almost free from coliforms and NTU (<1.0). The COD and BOD removals were close to 95 % and 100 % respectively. Although it was not designed to remove nitrogen, the plant was able to nitrify and denitrify in summer months and this was simulated using an ASM model. Air supply regulation and process optimization by a fuzzy logic system in activated sludge WWTPs Air supply plays a key role in the operation of Waste Water Treatment Plants (WWTPs): in fact, it strongly affects process efficiency in several aspects such as nitrogen removal, sludge settling, growth of floc-forming or filamentous microorganisms etc. and, at the same time, represents one of the most significant cost items. Consequently, there is a great deal of interest in studying techniques for optimising air supply. The aim of this research is the study, implementation and full-scale application of a non-conventional control system for air supply, based on fuzzy logic. The fuzzy system was applied to some real municipal WWTPs and is now under further development and optimization. A patent is pending on the present version on the
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
controller which was developed during a research activity conducted at the Verona WWTP (Acqueveronesi) in cooperation with Hach-Lange SpA and SDI Automazione Industriale (Milan). Technical description The system consists of the following components: NH 4+-N on-line sensors; oxy-meters, devices for automatic control of air supply; a PC (Personal Computer) with MATLAB™ (Fuzzy Logic Toolbox) and a SCADA software system; an I/O management system in charge of physically interfacing the PC with the field. The control system is composed of two main modules, one devoted to determining the DO set point, while the second is responsible for air flow regulation. The module in charge of determining the DO set point defines a suitable DO concentration (continuously adjusted) so as to ensure that the effluent ammonia concentration remains within a predefined range. The second fuzzy module is devoted to regulate air flow in order to keep DO concentration in the tank as close as possible to the (dynamically varying) set point. A fine regulation of air supply can be successfully obtained as a function of the real biomass requirement taking into account the standard limits to be complied with. Among the advantages obtained we mention the following: long term (diurnal scale) process stability: the average fluctuation amplitude of effluent ammonia concentration is remarkably reduced; short term (minute scale) process stability: oscillations of the DO concentration around the set point are practically eliminated; promising energy savings: a payback period of about 2-3 years for the additional required instruments has estimated. DO
DO
3,5
DO set point
10
NH4+-N concentration
10
NH4+-N concentration
3
9
9
2
6 5
1,5 4
DO
1
3 2
0,5
-1 -1
)
8 DO concentration (mg L
7
NH 4+-N concentration (mg L
) -1
DO concentratione (mg L
8
+
NH4 -N
2,5
)
)
3
2,5 7
+
NH4 -N
2
6 5
1,5 4 1
3
DO
2 0,5 1
1 0 0.00
0 2.30
5.00
7.30
10.00
12.30
15.00
time (hours)
17.30
20.00
22.30
-1
DO set point
NH 4+-N concentration (mg L
3,5
0 0.00
0 2.30
5.00
7.30
10.00
12.30
15.00
17.30
20.00
22.30
time (hours)
Development by the year 2020: Additional full scale applications of this system are expected and a more powerful version is being studied. Main contacts: University of Brescia (giorgio.bertanza@unibs.it).
BIOLOGICAL NITROGEN REMOVAL FROM WASTEWATER THROUGH BYPASSING NITRATE PRODUCTION
The removal of nitrogen from wastewaters is a necessary wastewater purification step before disposal to natural water bodies. Among the problems associated with the various nitrogen forms found in wastewaters (ammonia, nitrites, nitrates, organic nitrogen) we can mention toxicity to fish, eutrophication and reduction of dissolved oxygen concentration. Nitrogen removal used to be accomplished through physicochemical processes such as ammonia stripping, chlorination and ion-exchange. In the recent years, however, biological nitrogen removal has been established as the most economical and environmentally friendly approach to nitrogen removal. Nitrification,
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
i.e. the sequential oxidation of ammonia to nitrites (ΝΟ2-) (nitritification) and nitrates (ΝΟ3-) (nitratification) is the first stage of biological nutrient removal. Since nitrites are an intermediate chemical form for both nitrification and denitrification, in the recent years there have been significant research efforts aiming at bypassing nitrate, i.e. direct reduction of the generated nitrites to gaseous nitrogen. It has been proved that such a bypass leads to:
* * * *
Reduction of the required concentration of organics for denitrification by up to 40% Higher denitrification rate up to 63% Reduction of the requirements for aeration by up to 25% Reduction of the generated sludge by up to 75%.
with obvious economic benefits, due to the reduction of both the capital (smaller tank size) and the operating costs (cost for chemicals, electricity for aeration and treatment of the generated sludge) of the wastewater treatment plants. It becomes apparent that nitrate bypass during biological nitrogen removal requires the suppression of nitratifiers, such as Nitrobacter, something particularly difficult because of the close symbiotic relationship of such bacteria with ammonia oxidizers. The present process developed in the Laboratory of Biochemical Engineering and Environmental Technology of the Dept. of Chemical Engineering concerns a Sequencing Batch Reactor (SBR) for biological nitrogen removal from wastewaters. SBR systems are particularly flexible systems that ensure (through a succession of operating phases) nitrification, denitrification and sludge settling in a single tank. A suitable operation of the system suppresses the growth of nitrite oxidizers and leads to an effective bypass of nitrate. The benefits that result from this mode of operation include the reduction of organic carbon requirements for denitrification, of aeration requirements (which implies energy savings) and of the amounts of generated sludge. The most important achievement is that the effective biological nitrogen removal via bypassing nitrates does not require costly modifications of either the system itself or of the wastewater characteristics, since it is based exclusively on modification of the system operating characteristics. Two pilot-scale UP-PND reactors have been installed, one in Tirana-Albania and one in Alminia-Egypt. This technology may be applied to SBR systems, either are designed from scratch or already existing. It may also be applied to conventional activated sludge systems through appropriate manipulation of their operation.
Main contact: Prof. Gerasimos Lyberatos, School of chemical engineering NTUA lyberatos@chemeng.ntua.gr
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
Minimization and Stabilization of Wastewater Treatment Sludge in Turkey Management of Domestic/Municipal Treatment Sludge Project is a national project which includes national inventory about treatment processes applied in all geographic regions in Turkey, and aimed to present a management plan for treatment sludge. Partners of the project are TUBITAK, TC Ministry of Environment and Urbanisation, Istanbul Technical University, Middle East Technical University, Dokuz Eylul University, Bogazici University, and Kayseri Metropolitan Municipality. One of the main aims of this study was to determine the most applicable methods for reduction of domestic/municipal wastewater treatment sludges in full-scale plants in Turkey. To achieve this goal, samples were collected from 7 treatment plants located in 7 different region of Turkey. Different disintegration methods were evaluated and optimum conditions were determined. Results were summarized in Table 1. Table 1. Optimum conditions for different disintegration methods. Method Chemical Disintegration Fenton Process Ozone Oxidation Mechanical Disintegration Ultrasonic Treatment Biological Disintegration Enzymatic Treatment Thermal Disintegration Microwave Pre-treatment
Optimum Condition 60 g H2O2/kg TS, 0,067 Fe(II)/ g H2O2 0,1 g O2/ g TS 10000 â&#x20AC;&#x201C; 15000 kJ/kg TS Mixture of Alpha amylase, Beta-glucanase (endo-(1,2(4)), Lipase, Potease, Cellulase 175â&#x2014;ŚC, 10 min
Sludge disintegration degrees were evaluated for 7 regions of Turkey. Results indicated that, ultrasonication and microwave methods were very effective for all samples. Besides, disintegration degree got from alkali treatment approximately same than that of ultrasonication. However, alkali pre-treatment is not a proper method for full-scale treatment plants regarding to high chemical requirements and production of sludge with poor dewaterability characteristics. For Aegean, Marmara, and Black Sea regions, enzyme treatment method resulted in significant volatile solids (VS) removal was determined as the optimum method. For Mediterranean region, VS removal in sewage treatment plant sludge increased clearly with microwave treatment. On the other hand, enzyme treatment was more effective for municipal treatment plant sludge. For Central Anatolia region, higher VS removal rate was observed with ultrasonication method. According to the results, it was determined that, both enzyme, microwave and ultrasonication methods improve volatile solids and total coliform removal and also, methane production almost in every region in Turkey (Insel et. al, 2013). Main contacts: Istanbul Technical University (inceor@itu.edu.tr) Reference: G. Insel, E. Kendir, A. Ayol, A. Erdincler, O. Arikan, I. Imamoglu, B.A. Alagoz, E.B. Gencsoy, F.D. Sanin, N. Buyukkamaci, O. Karatas, G.Saygili, G. Sener, E.U. Cokgor, A. Filibeli, 2013. Current Situation and Future Perspectives in Municipal Wastewater Treatment and Sludge Management in Turkey, J. Residual Sci Tech, Vol 3, 10, 133-138. Innovative Integrated Biological Processes for Nutrient Removal (i
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
BP)
2
Integrated biological treatments (IBT) are those that combine the two types of biomasses: suspended (activated sludge) and attached-growth (biofilm), in a single reactor or in separate in series reactors. IBT are intended to achieve the advantages and overcome the drawbacks of the single biomass systems. The main use of such type of process, so far, has been organic matter removal including in few cases nitrogen removal. The overall objective of this project is to propose innovative configurations of integrated biological processes conceived to achieve organic matter and nutrients removal at the same time. Technical description The integrated biological process proposed consists of an anaerobic-anoxic sludge blanket reactor (AnoxAn), followed by a slightly hybrid biofilm reactor, in two different configurations with the following features: Combining the anaerobic and Hybrid ANOXAN-II MABR or FBBR anoxic zones in a single reactor by SETTLER an upflow sludge blanket allows for a higher biomass concentration, higher treatment efficiency and/or less space requirement. The AnoxAn reactor configuration aims at simultaneous denitrification and P removal, depending on the influent wastewater characteristics. The AnoxAn reactor is meant to be coupled with an aerobic reactor for nitrification and residual organic matter removal. A biofilm reactor is proposed to carry out this function, achieving high SRT. Two kinds of aerobic biofilm reactors will be tested: submerged fixed bed biofilm reactor (SFBBR) and membrane aerated biofilm reactor (MABR). Both reactor types aim at minimizing the energy requirements for aeration: o For SFBBR a patented support (BLAS) that increases oxygen transfer capacity is used. o
MABR is capable of extraordinary elevated energy efficiency due to bubbleless aeration, direct oxygen transfer to the biomass and low pressure air supply.
Such biofilm reactors will be run in a slightly hybrid mode (small concentration of the suspended biomass) in order to remove the residual organic matter and to obtain better settling characteristics of the sludge. The novelty of the proposal consists in the conception of the overall treatment train as well as in the single reactors design and operation systems. Such configurations will be tested in a benchscale pilot plant, in order to prove their feasibility in treating real wastewater and to provide further insight related to design and operation of the integrated configurations proposed. The pilot plant design is meant for a possible scale-up of the technologies thereby implemented. Development by the year 2020: The two i2BP process configurations will be tested in bench-scale by 2015. Main contacts: University of Cantabria (juan.tejero@unican.es - www.gia.unican.es) Hydrothermal carbonisation of sludge
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu
Hydrothermal carbonization (HTC) is a process in which wet organic material is heated at high pressure resulting in dehydration and partial degradation of the carbon compounds and the formation of acids that leach soluble compounds from the solid biomass. The exothermal process results in a hydrophilic, sterile, porous, solid carbon product, biochar, with high relative energy content and an effluent containing a fraction of nutrients originally present in the sludge, depending on the pH, substrate and operating conditions. The process enables easy dewatering of the hydrophobic biochar fraction, separation of nitrogen and phosphorus fractions in the biochar or liquid effluent.. In addition, the high temperatures can destroy pathogens and potentially organic contaminates such as pharmaceutically active compounds (Bridle e al. 1990, S端tterlin et al. 2007). Technical description The aim is to demonstrate the feasibility to treat sludge with different organic matter content and different chemical composition with a HydroThermal Carbonisation process. The work is carried out in cooperation with Aquafin (Belgium) and AVA-CO2 Germany. Based on existing insight in the pH, the presence of ions forming phosphates of low solubility and the reaction time the process can be optimised for different sludge types aiming for end products with maximal value. The demonstration focus is on different sludge types (digested, non-digested, high and low silt content, selected to represent as well as possible the municipal sludge types generated in Europe. All test cases are carbonised in lab scale autoclaves (500 ml) to investigate the dependence of the process parameters temperature, time, concentration, pH-value, type of sewage sludge on the HTC product and process water. The results are compiled in a mathematical model for optimization and up-scaling. The most promising results will be verified in half technical scale in cooperation with the industry.
Development by the year 2020: The HTC process is applied as an alternative energy efficient sludge treatment process in combination with P recovery for waste water treatment plants in a number of EU countries will be applied in full scale in 2014. Main contacts: VTT technical research Centre Finland (mona.arnold@vtt.fi; Johannes.jermakka@vtt.fi; Hanne.wikberg@vtt.fi)
Conceiving Wastewater Treatment in 2020 WG1 - COST Action ES1202 - www.water2020.eu