A review of LCA studies on waste management solutions

Report of the Circwaste project coordinated by the Finnish Environment Institute

A review of LCA studies on waste management solutions Helena Dahlbo, Jaakko Karvonen, Tiina K. M. Karppinen, Jáchym Judl, Kiia Mölsä, Elisa Salmi, Mariam Abdulkareem, Musharof Khan, Tuuli Teittinen, Joni Kemppi, Antti Niskanen

Report of the Circwaste project coordinated by the Finnish Environment Institute

A review of LCA studies on waste management solutions Helena Dahlbo, Jaakko Karvonen, Tiina K. M. Karppinen, Jáchym Judl, Kiia Mölsä, Elisa Salmi, Mariam Abdulkareem, Musharof Khan, Tuuli Teittinen, Joni Kemppi, Antti Niskanen

Authors: Helena Dahlbo1), Jaakko Karvonen1), Tiina K. M. Karppinen1), Jáchym Judl1), Kiia Mölsä1) Elisa Salmi2), Mariam Abdulkareem2), Musharof Khan3), Tuuli Teittinen4), Joni Kemppi5), Antti Niskanen5) Finnish Environment Institute (Syke) LUT-University 3) Natural Resources Institute of Finland (Luke) 4) Ramboll 5) Etteplan

1)

2)

Funder: EU LIFE IP programme Publisher: Finnish Environment Institute (Syke) Latokartanonkaari 11, 00790 Helsinki, Finland, phone +358 295 251 000, syke.fi Pictures and other contents of the publication can be quoted by referring to the original source: Dahlbo, H., Karvonen, J., Karppinen, T.K.M., Judl, J., Mölsä, K., Hupponen, M., Abdulkareem, M., Khan, M., Teittinen, T., Kemppi, J. & Niskanen, A. 2024. A review of LCA studies on waste management solutions. Report of the Circwaste project coordinated by the Finnish Environment Institute. 2023.

Ulkoasu ja taitto: Satu Turtiainen, Suomen ympäristökeskus The publication is available on the internet (pdf): Circwaste.fi/en > Current > Publications Syke-hankkeiden julkaisuja (helsinki.fi) Publications of Syke's projects (issuu.com) ISBN 978-952-11-5645-8 (online) Year of issue: 2024

2

A review of LCA studies on waste management solutions

Abstract A review of LCA studies on waste management solutions Circwaste – Towards a circular economy in Finland is an EU LIFE IP funded project that promotes the circular economy and improved waste management in Finland. The project implements the goals of the national waste plan.

Life cycle assessment (LCA) is an important tool for the overall sustainability assessment of different waste management practices. LCA methods have been used in Circwaste to assess the impacts of pilot projects carried out in the project as well as to assess the sub-national impacts of changes in the waste management system based on sub-national data on waste amounts and recycling.

LCA results on waste management systems can be challenging to interpret. The applied environmental impact assessment method omits the fact that the waste we recycle and give environmental credit to when recycled, has itself an embedded environmental burden inherited from the time before turning into waste. This may result in a false interpretation that generating waste is positive.

This is because the recycling processes generate less (negative) impacts than what could be avoided by utilising the waste in the production of new materials and energy instead of virgin raw materials or fuels. As a result, the net impact in the calculus will generally show higher environmental benefits when there is more waste to be recycled. However, the best option for the environment would always be to reduce consumption and the generation of waste. This is also clear from the studies reviewed in this report. Reducing the amount of mixed MSW and hence increasing recycling instead of incineration has the potential to reduce the overall environmental impacts of MSW management.

The case studies reviewed in this report demonstrate solutions which can be taken in use to reduce the generation of waste or to increase the recycling of different waste fractions. If these solutions were adopted in all Finland, significant reductions in the environmental impacts could potentially be obtained. However, the applicability and restrictions of all the solutions shall be carefully assessed before adoption.

LCAs on environmental impacts of waste management is a complex discipline. Ideally the assessments require country, or even region, specific primary data on waste management processes.

This kind of data is not publicly available for the Finnish waste management systems. It would be necessary to produce this kind of primary data on different waste management processes for public use.

This calls for joint efforts between the LCA practitioners and the operators of the waste management sector, or even more broadly, the operators within circular economy.

Key words: LCA, life cycle assessment, environmental impacts, waste management, circular economy, municipal solid waste, construction and demolition waste

A review of LCA studies on waste management solutions 3

Tiivistelmä Katsaus erilaisten jätehuoltoratkaisujen LCA-tarkasteluihin Circwaste – Kohti kiertotaloutta Suomessa on EU LIFE IP -ohjelman rahoittama hanke, joka edistää kiertotaloutta ja parempaa jätehuoltoa Suomessa. Projekti toimeenpanee Valtakunnallisen jätesuunnitelman tavoitteita.

Elinkaariarviointi (LCA) on tärkeä työkalu erilaisten jätehuoltoratkaisujen kokonaiskestävyyden arviointiin. LCA-menetelmää on käytetty Circwaste-hankkeessa toteutettujen kokeilujen vaikutusten arvioinnissa sekä jätehuollon muutosten alueellisten vaikutusten arvioinnissa. Alueellisten vaikutusten tarkastelua varten on koottu tietoa alueellisista jätemääristä ja kierrätyksestä.

Tässä raportissa luodaan yhteenvetokatsaus tästä LCA-työstä: käytetyistä menetelmistä sekä saaduista tuloksista. Lisäksi raportti kokoaa yhteen päähavaintoja muissa suomalaisissa jätehuoltoon ja kiertotalouteen liittyvissä tutkimuksissa tehdyistä LCA-tarkasteluista. Raportti luo lyhyen katsauksen yhteensä seitsemän Circwasten kokeiluhankkeen ja yhdeksän täydentävän hankkeen LCA-tuloksiin.

Jätehuoltojärjestelmien elinkaariarviointien tulokset voivat olla haasteellisia tulkittavia.

Tarkasteluissa ei yleensä oteta huomioon jätteeksi päätyvien tuotteiden valmistuksen päästöjä. Tämän takia LCA-tulokset voivat harhauttaa ajattelemaan, että jätteen tuottaminen olisi ympäristön kannalta suotuisaa, koska jätteen kierrätys yleensä pienentää järjestelmän ympäristövaikutuksia. Ympäristön kannalta paras vaihtoehto on kuitenkin kulutuksen välttäminen ja täten jätteen synnyn ehkäiseminen.

Tätä tukevat selvästi myös tässä raportissa referoidut tarkastelut. Yhdyskuntien sekajätteen vähentäminen kierrätystä lisäämällä ja jätteenpolttoa vähentämällä vähentää potentiaalisesti yhdyskuntajätteen jätehuollon ympäristövaikutuksia.

Tässä raportissa tarkastelluissa tapaustutkimuksissa demonstroidaan ratkaisuja, joita voidaan ottaa käyttöön jätteen muodostumisen vähentämiseksi tai eri jätejakeiden kierrätyksen lisäämiseksi. Jos nämä ratkaisut otettaisiin laajasti käyttöön Suomessa, niillä olisi mahdollista merkittävästi vähentää jätehuollon ympäristövaikutuksia. Ratkaisujen soveltuvuus ja niiden käyttöönoton rajoitukset on kuitenkin tarkasteltava huolella ja tapauskohtaisesti ennen käyttöönottoa.

Jätehuollon ympäristövaikutusten elinkaariarviointi on monimutkainen aihepiiri. Parhaassa tapauksessa arviointi tehtäisiin jätehuollon prosessien maa- tai jopa aluekohtaista primääridataa käyttäen. Tällaista dataa ei kuitenkaan ole julkisesti saatavilla suomalaisista jätehuoltojärjestelmistä.

Olisikin erittäin tärkeää tuottaa ja julkaista eri jätehuoltoprosessien primääridataa julkiseen käyttöön.

Tämä edellyttää yhteistyössä elinkaariarviointien tekijöiden sekä jätehuollon tai vieläpä laajemmin, kiertotalouden, toimijoiden kesken tehtävää tutkimusta.

Asiasanat: LCA, elinkaariarviointi, ympäristövaikutukset, jätehuolto, kiertotalous, yhdyskuntajäte, rakennus- ja purkujäte

4

A review of LCA studies on waste management solutions

Sammandrag Översikt över livscykelanalyser av avfallshanteringslösningar Circwaste – Mot en cirkulär ekonomi i Finland är ett projekt som får finansiering av Europeiska unionens LIFE program. Projektet främjar den cirkulära ekonomin och en förbättrad avfallshantering i Finland. Projektet genomför målen av den nationella avfallsplanen.

Livscykelanalys (LCA) är ett viktigt verktyg för analysering av hållbarhet av diverse lösningar för avfallshantering. LCA metoden har använts i Circwaste för att analysera miljöpåverkan av pilotstudien genomförda under projektet. Likaväl har regionala påverkan av förändringar i avfallshanteringssystemen analyserats baserat på regionala data om avfallsmängder och återvinning.

Denna rapport sammanfattar detta LCA arbete: de använda metoderna och de uppnådda resultaten.

Dessutom granskar rapporten huvudobservation från andra LCA undersökningar genomförda i kompletterande projekt gällande avfallshantering och cirkulär ekonomi i Finland. Rapporten gör en kort översikt över LCA resultat från sju Circwaste pilotstudien och nio kompletterande projekt.

Tolkning av LCA resultat för avfallshanteringssystem kan vara utmanande. Den använda metoden för analysering av miljöpåverkan tar inte hänsyn till faktumet att det avfall som vi återvinner och krediterar för återvinning, har inbäddad miljöbelastning från tiden före omvandling till avfall. Detta kan leda till en fel tolkning av LCA resultat, nämligen att tänka att det skulle vara miljövänligt att producera avfall, eftersom återvinning vanligtvis minskar avfallssystemets miljöpåverkan. Det bästa alternativet ur miljösynpunkt är trots allt att undvika konsumtion och därmed minska avfallsproduktion. Detta framgår tydligt också från analyserna som har granskats i denna rapport. Minskning av blandat kommunalt avfall och i och med detta, ökning av återvinning i stället för förbränning av avfall, har potential att minska miljöpåverkan av avfallshanteringen.

Fallstudien i denna rapport demonstrerar lösningar som kan tas i bruk för att minska avfallsgeneration eller för att öka återvinning av olika avfallstyp. Om man tog dessa lösningar i bruk i hela Finland, betydelsefulla förminskningar av miljöpåverkan kunde potentiellt uppnås. Dock måste man försiktigt analysera tillämplighet och begränsningar av alla lösningar före man tar dem i bruk.

Livscykelanalys av avfallshanteringens miljöpåverkan är en komplex disciplin. Helst kräver bedömningarna lands eller även regionspecifika primärdata om avfallshanteringen och processerna.

Sådana data är inte offentligt tillgängliga för de finska avfallshanteringssystemen. Det vore nödvändigt att producera sådana primära data för offentlig användning. Detta förutsätter samarbete av LCA praktiker och avfallshanteringsoperatörer, eller även mer vidsträckt, operatörer av cirkulär ekonomi.

Nyckelord: LCA, livscykelanalys, miljöpåverkan, avfallshantering, cirkulär ekonomi, kommunalt avfall, bygg och rivningsavfall

A review of LCA studies on waste management solutions 5

Preface

Circwaste – Towards a circular economy in Finland is an EU LIFE IP funded project that promotes the circular economy and improved waste management in Finland. The project implements the goals of the national waste plan.

Life cycle assessment (LCA) is an important tool for the overall sustainability assessment of different waste management practices. LCA methods have been used in Circwaste to assess the impacts of pilot projects carried out in the project as well as to assess the sub-national impacts of changes in waste management system based on sub-national data on waste amounts and recycling.

This report summarises this work: the methodologies used, and results gained. In addition, the report reviews key findings of other current LCA studies from complementary projects related to waste management and the circular economy in Finland.

LCAs have been carried out in Circwaste since 2017. The report itself has been prepared in 2023.

The report is intended for the use of experts working with waste management and circular economy as well as students and others interested in LCA of the waste management sector.

The writers wish to thank everyone who contributed to the report, such as project partners providing background data for the assessments, experts working in complementary projects and providing that data for the reviews as well as all the colleagues who supported the work.

6

A review of LCA studies on waste management solutions

Contents

A review of LCA studies on waste management solutions

Abstract ..................................................................................................................................... 3 Tiivistelmä ................................................................................................................................ 4 Sammandrag ............................................................................................................................. 5 Preface ...................................................................................................................................... 6 1 Introduction .............................................................................................................................. 9 2 Estimating the environmental impacts of Circwaste............................................................. 10 2.1 Assessment of potential environmental impacts of regional or municipal waste management during Circwaste ............................................................................................... 10 2.2 Assessment of potential environmental impacts of some Circwaste sub-actions............. 11 2.3 Assessment of potential environmental impacts of selected complementary actions ...... 11 2.4 Scaling up results from individual case studies to national estimates .............................. 11 3 Potential impacts due to development in regional waste flows and their management ... 12 4 Potential impacts of some Circwaste sub-actions ................................................................. 16 4.1 Reducing food waste generation in schools (Pori case) ................................................... 16 4.2 Extending the separate collection of plastics packaging in Central Finland .................... 17 4.3 Improving sorting and separation of wastes at construction sites (Puhas case) ............... 18 4.4 Environmental Impacts of WPC Production for C&DW Material Recovery .................. 19 4.5 A comparative LCA study on Wooden, Plastic, and WPC Pallets ................................... 20 4.6 Piloting the use of recycled materials in a highway construction application .................. 22 4.7 Utilisation of industrial waste and contaminated sediments in the construction of Sampaanala Bay...................................................................................................................... 23 5 Impacts of selected complementary actions ......................................................................... 24 5.1 Intensifying waste sorting with different practices (LAJITEHO project) ........................ 24 5.2 Co-mingled collection of plastic from sparsely populated regions (PLASTin project) ... 25 5.3 Speeding up the circular economy by recycling municipal waste (JÄTEKIVA project) . 27 5.4 Developing recycling concepts for challenging plastics streams (PLASTin project) ...... 28 5.5 Extending the life cycle of a cotton roller towel (Finix project) ...................................... 30 5.6 Recycling wood waste into various products in the Nordics ............................................ 33 5.7 Developing the utilisation of ceramic wastes (KERPUR project).................................... 33 5.8 Using industrial side stream materials in dredging sludge stabilisation – comparisons in terms of GHGs, strength and economy (Circvol / Circvol 2 projects) .......... 34 5.9 Developing geocomposites from industrial side streams to compensate concrete in construction (UIR project) ...................................................................................................... 35 5.10 Promoting the use of LCA (CONSOLCA project)......................................................... 36

A review of LCA studies on waste management solutions 7

6 Summary of the environmental impacts of Circwaste and its complementary actions ...... 37 6.1 Municipal Solid Waste ..................................................................................................... 37 6.2 Biowaste ........................................................................................................................... 40 6.3 Construction and Demolition Waste ................................................................................. 41 6.4 Other ................................................................................................................................. 42 7 Final remarks ........................................................................................................................... 43 References .................................................................................................................................. 44

8

A review of LCA studies on waste management solutions

1 Introduction

This report summarises and evaluates the environmental impacts of the project Circwaste – Finland towards a circular economy, funded by the LIFE programme of the European Commission. This is a long project with a large consortium with 20 partners and ca. 20 sub-actions. Hence, it is important to evaluate its direct and indirect environmental impacts. The report also investigates the overall impacts of the changes in the field of waste management in Finland, as well as impacts of individual cases with best practices to evaluate the potential impacts as the best practices are broadly adopted. The impacts have been assessed with life cycle-based approaches. The assessments (materials, methods, results, conclusions) are reported in detail in the reports or articles referred to in the case descriptions of this report.

The Circwaste sub-actions all aimed at promoting the implementation of the national waste plan (Laaksonen et al. 2017; Ministry of the Environment 2022), i.e., reducing the generation of waste and its hazardous properties and increasing recycling of different wastes. Hence, the impacts of these activities are reflected in the amounts of waste and the way they are managed in the Circwaste regions and forerunner municipalities. Waste management is regulated to some degree at a regional or local level.

Therefore, the overall assessment of the environmental impacts of the Circwaste project focused on the regional or municipal waste flows and their management and any changes in these during the project.

Additionally, some sub-actions carried out more in-depth environmental impact analyses on their specific planned or performed activities.

The project has collaborated with several research and development projects promoting circular economy and improved waste management. The network of these complementary projects brings additional understanding on the environmental impacts of the circular transition in specific sectors, and complements the work carried out in Circwaste.

Overall, it must be emphasised that environmental impact assessments may be conducted with different goals and scopes. The flexibilities in the calculation rules render calculation setups to serve different purposes. For example, an LCA may be calculated for comparing raw materials, products, processes, or companies, and the set of indicators can be adjusted according to the purpose of the study.

Narrower system boundaries may reduce the data demand as only the relevant information needs to be collected, for example by including the so-called direct impacts only. However, the downside of the variation in environmental impact assessments is that different assessments may not be comparable nor addend, although the public often seek for clear comparisons.

In this report an attempt is made to combine the results from different studies to produce a summary of the environmental impacts that the Circwaste project with its complementary projects has had. However, this is a very theoretical exercise and, as always with LCAs, this only estimates potential environmental impacts, not something that has been gained.

A review of LCA studies on waste management solutions 9

2 Estimating the environmental impacts of Circwaste 2.1 Assessment of potential environmental impacts of regional or municipal waste management during Circwaste The potential environmental impacts of the management of the regional or municipal waste flows were assessed following the question how much the recovery of these flows would cause impacts when processed and recovered (as material or energy) and then reduce impacts by substituting virgin materials or energy. The data on municipal solid waste (MSW) from households was collected from the MSW operators three times during the Circwaste project. Majority of the data, including the amounts and treatment of mixed MSW, biowaste, and partially the separately collected waste from the properties, was retrieved from regional, public waste management companies that provide waste management services for households. The data include estimates, since MSW from households is not usually separated from MSW from other sources, such as public services. These data were complemented with municipality-specific or regional data from national, extended producer responsibility schemes for packaging, national data on waste electric and electronic equipment (WEEE), batteries, accumulators, and paper, national MSW statistics, and estimates e.g., on home composted biowaste (Pitkänen et al.

2023, Myllymaa et al. 2021). Gardening waste and home composted biowaste were excluded from the LCA calculations. Majority of the data is not municipality-specific, yet they cover larger sub-national geographic regions. Hence, the analyses do not reflect the potential, municipality-level differences in household waste production. There are differences in the background data between the different regions, and thus the results are not comparable between the regions. The results ought to be seen rather as trends within the regions. Waste amounts and environmental impacts are calculated per capita based on the region in question. Overall, the regional waste data generally reflects well the situation within the forerunner municipalities, since they mostly are central cities within their regions with a high population compared to the rest of the region.

The regional assessments on construction and demolition waste (C&DW) were based on national statistics (Pitkänen et al. 2023, Myllymaa et al. 2021). The C&DW quantities and their treatment types on a national level can be found in the official national waste statistics (Statistics Finland, 2023a). Since C&DW amounts correlate with construction and demolition activity, the national waste amounts were allocated for each of the key regions based on the business activity of construction branch within the region each year (Statistics Finland, 2023b). Due to lack of more accurate, regional data, the analyses do not consider the potential regional differences in the production or management of C&DW. The environmental impact assessment was performed for these datasets taking into consideration any possible changes taken place in the management of the waste flows.

The applied environmental impact assessment method omits the fact that the waste we recycle and give environmental credit to when recycled, has itself an embedded environmental burden inherited from the time before turning into waste (Pitkänen et al. 2023, Myllymaa et al. 2021). The method may result in a false interpretation that generating waste is positive. This is because the recycling processes generate less (negative) impacts than what can be avoided (i.e., benefits generated) by utilising the waste in the production of new materials and energy instead of virgin raw materials or fuels. As a result, the net impact in the calculus will generally show higher negative value (which is a positive result) when there is more waste to be recycled.

Further, the environmental impacts of processes change over time (Myllymaa et al. 2021). In the period of this project, for example the LCA-data on paper production and recycling was labelled as

10

A review of LCA studies on waste management solutions

obsolete at one point in time in the LCA-database and new datasets replaced them. We assumed that the update resulted from better data quality rather than from changes in technical processes themselves, and thus, we were able to recalculate the impacts for all years with the newest data. This assumption also enabled comparing waste flows’ impacts from different years in cases where there had been major changes in the emission factor data. Another alternative would have been to use different data sets for the last year(s), had we assumed that the change was because of major technological changes.

Since the collection of background data for LCA requires quite a lot of manual work, the analyses were targeted to the regions and municipalities involved in the project, and not all the regions and municipalities in Finland (Myllymaa et al. 2021). The geographic regions targeted in the analyses follow the key project regions on NUTS 3 level involved in the project: Central Finland, North Karelia, South Karelia, and Southwest Finland (Satakunta and Varsinais-Suomi regions). The set of municipalities included in the assessments include forerunner municipalities from two national networks: Circwaste forerunner municipalities’ network and Finnish Sustainable Communities (Fisu) Network.

2.2 Assessment of potential environmental impacts of some Circwaste sub-actions Descriptions of seven environmental impact assessments using LCA were obtained for this report from the Circwaste sub-actions. They examine very different issues; food waste reduction, plastics packaging waste recycling, sorting and separation of construction waste, recycling of C&DW, and recovery of soil.

Hence, the set-ups for these sub-action assessments as well as the impact categories included, vary.

However, all studies have used the principles of LCA as a basis. The studies are briefly summarised in Chapter 4 and more detailed descriptions of them can be found from the reports or articles referred to in the text.

2.3 Assessment of potential environmental impacts of selected complementary actions Chapter 5 contains summaries of altogether ten projects complementary to Circwaste, and in nine of them environmental impact assessments using LCA have been carried out. The projects have looked at various issues: intensifying sorting of MSW, commingled collection of packaging waste, increasing recycling of MSW, recycling of WEEE and other challenging waste materials, lengthening the life cycle of textiles, recycling of wood waste, recycling of ceramic waste, using side streams in dredging sludge stabilisation, and developing geocomposites from industrial side streams. Hence, the set-ups for the assessments as well as the impact categories assessed, also vary. The studies are briefly summarised in Chapter 5 and more detailed descriptions of them can be found from the reports or articles referred to in the texts.

2.4 Scaling up results from individual case studies to national estimates To get an indication of the potential of the different actions and solutions developed in Circwaste and its complementary projects to affect environmental impacts, an attempt was made to scale up the results from some of the individual case studies to the national level. Data large enough allows a scale up of the impacts to larger contexts. For example, the data on school food waste in Pori (Chapter 4.1) allowed multiplying it to represent the volume of the school food waste in the whole Finland, as well as to assess its reduction potential with practices utilised in Pori. However, scaling up over regions includes an assumption that the conditions are similar in all other locations, which may be untrue. Hence, the greater the scale-up multiplier the greater the risk of error.

A review of LCA studies on waste management solutions 11

3 Potential impacts due to development in regional waste flows and their management The waste flows were assessed in two data sets with different geographical and waste flow resolution: C&DW on a regional level (NUTS 3) based on regional statistics, and MSW from households (household waste) on a more detailed regional and partly municipal resolution.

The household waste flow volumes were derived mainly from the geographic operating regions of regional waste management companies that cover multiple municipalities. These data were complemented with other municipality-level or national data. Each regional dataset was divided by the population it covered. Thus, the results are calculated as per person for each area in question. In the results the dataset is named after the forerunner municipality the dataset includes. As for the C&DW, the waste flows were calculated by multiplying the national waste volumes generated by the Finnish construction sector with the share of the regional turnover of the national turnover in the construction sector.

The household waste flows included WEEE, batteries and accumulators, plastics packaging, paper, cardboard, glass, aluminium cans, mixed metal, biowaste and mixed waste for the collection regions including municipalities of Riihimäki, Hyvinkää, Joensuu, Jyväskylä, Kuopio, Lappeenranta, Porvoo, Turku, Forssa and Lahti. The years accounted for were 2016, 2017, 2019 and 2021 (for Turku, Forssa and Lahti only years 2019 and 2021). The regions for which data on C&DW flows were obtained, were Central Finland, North Karelia, South Karelia, and Southwest Finland. The waste flows included in this data set were metal, plastics, wood, mixed combustible, mineral waste, and soil and dredging.

The environmental impacts of the waste flows were calculated by comparing the impact of waste recycling/management to production of their virgin counterparts. For example, by recycling aluminium or iron, the mining and refining of these metals can be avoided but casting cannot. By paper and cardboard recycling, the harvesting and processing of wood before pulping can be avoided.

Additionally, recycling of glass reduces virgin raw material consumption and energy inputs needed in glass making. On the other hand, combusting municipal waste causes more greenhouse gas (GHG) emissions than average energy generation in Finland and paper recycling may cause more eutrophicating emissions than production of paper from virgin wood.

Biowaste is a special case as it may be composted of digested and substitute for fuel, growing medium and fertilizers. When composted it was assessed as to substitute for peat (as a growing medium) and fertilizers. If digested in a biogas plant, it was assumed to substitute for petrol in transportation, and fertilizers. The biogas plants in Jyväskylä and Lappeenranta started operating in 2017 and 2020, respectively. Until these years biowaste was assumed to be composted. The rest of the municipalities included in this assessment had biogas plants in use already in 2016.

What was excluded from the household waste LCA calculations were yard and gardening waste as well as home composting of biowaste. This was because we wanted to focus on the wastes that pile up from the things we buy from stores (excludes yard and gardening waste) and are managed industrially (excludes home composting). In addition, yard and gardening waste data included uncertainties that would have affected the LCA results significantly. The environmental impacts of home composting depend on how the compost is managed and hence are very case specific. These waste fractions make a significant contribution (ca. 10%) to the total amount of household waste, for which the total waste flow changes below may differ from that presented elsewhere in Circwaste reports.

As for the regional assessments on C&DW, metals, plastics and the combustible fraction are managed in the same way as in the household waste data set. Wood is combusted but with different credits than mixed waste. Mineral waste (largely concrete) is crushed to substitute for gravel. The soil

12

A review of LCA studies on waste management solutions

and dredging wastes are assumed to be transported one kilometre but are not credited for any substitution.

The total amount of waste per person (excluding yard and gardening waste as well as home composted biowaste) in the respective areas showed, that in five municipalities the waste volume per person decreased and in three it rose. The largest drop of took place in Hyvinkää and Riihimäki (-13%, same collection area) followed by Joensuu (-8%), Jyväskylä (-8%), Kuopio (-4%) and Lappeenranta (+6%), whereas Porvoo had the highest rise (+11%). In Turku, Forssa and Lahti the changes from 2019 to 2021 were 0%, 2% and -2%, respectively. There have been some changes in the waste collection areas during the monitoring period. For example, it might be, that the rise in waste generation in Porvoo is explained by the fusion of two waste collection areas, which has generated differences in the data production for the area and resulted in inconsistencies in the background data. Similarly, Nurmijärvi municipality joined the area of Hyvinkää and Riihimäki, which may have had an influence in the figures, however the change was smaller than that for Porvoo.

Starting (in 2016) and expanding the plastic packaging waste collection in Finland by legislation during the observation period has made an obvious change in plastic waste flows. From 2016 to 2021 the plastic packaging waste volume has more than doubled in all the studied municipalities. The amount of separately collected cardboard waste has increased significantly, too. On non-weighted average (i.e., average of averages) per person it increased by ca. 75% from 2016 to 2021. This is probably a result of the constantly increasing trend of online shopping. The largest drop, on the other hand, was in the separately collected paper (-27%), which is in line with the global trend caused by digitalisation.

Perhaps one interesting observation is the increase of WEEE. This may be a result of increased consumption of electronic devices, resulting also in increasing the volume entering the recycling loop.

When we look at the overall impacts, we must first remember, that in these calculations we compare the recycling processes with obtaining the same material from virgin sources. Hence, we omit making of the original product which becomes finally the waste. This results into a situation, where less waste results in both lower impacts and lower benefits, and consequently in less net benefits. This means that in high metal consumption and recycling scenario the net benefit would be high, but in zerowaste situation it is zero. Thus, careful interpretation must be practiced.

In general, the benefits of recycling have increased from 2016 to 2021. This is because mixed waste flows have (in most cases) decreased while those with large credits (metals for example), have increased. Also, introducing biogas plants in Lappeenranta and Jyväskylä are reflected as increased net benefits. The biogas plant generates more impacts than composting, but the benefits from utilising the outputs of the biogas plant outweigh the impacts with greater difference than in composting.

The average of averages of the waste amounts per person in the studied municipalities has decreased only for mixed waste (-4%) and paper (-19%). The total waste volume per municipality has increased by 4% on average, led by significant increases in plastic and cardboard. It could be interpreted, that since the amount of mixed MSW has decreased while the total amount of wastes in the municipalities has increased, the level of recycling has risen. This trend in the forerunner municipalities’ regions is contrary to the one observed in the MSW on a national level: increasing amounts and decreasing recycling rates (Statistics Finland, 2023a). While increased waste quantity refers to growing material consumption and is, thus, an undesirable development, improved recycling can alleviate the negative impacts of both the material consumption and the waste generation.

It must be noted that the results shown in Figure 1 should be interpreted with care. Since the impacts of the production of the products that have become waste, are not included, the results may mislead to make a conclusion that generating waste is preferable, because recycling a unit of waste produces net positive impact. The best option for the environment would be to reduce consumption, and not to generate waste in the first place. Recycling generates also negative impacts, although (generally) less than production with virgin materials. Additionally, recycling processes may differ from those used in this assessment. For example, in paper and cardboard production and recycling the data has

A review of LCA studies on waste management solutions 13

uncertainties, namely the product produced from the recycled material. WEEE on the other hand is a heterogenous group of materials and has no accurate data available for its recycling emissions nor its production.

Figure 1. Climate impacts and potential benefits per person in eight municipalities’ regions monitored. The white dots in the bars indicate the net impact, i.e., the sum of impact generated, and impact avoided, where negative value is interpreted as a positive impact (reduction of impacts).

There are also uncertainties related to the background data on waste amounts. Estimates on MSW from households are combinations of data from many data sources, some of which include regional or municipality-level data but some only national averages. There is always a risk of data errors, such as double counting, when combining data on waste streams from multiple sources. A significant uncertainty in the waste amounts is related to estimating the share of waste produced by households out of the total amount of MSW collected by public waste management operators. The study only focuses on household waste since data on all MSW could not be collected due to scattered data. All the waste operators, who participated in the survey, had their own data systems that somewhat differ from one another. Some of the operators were not able to include all the MSW fractions to their data sets and different operators used somewhat different definitions for MSW in their data collection. Hence, the data on waste amounts from different regions cannot be compared to the others. However, the data collection has been carried out using the same method for the whole time series, which allows monitoring of the trends within the regions.

Since 2016, there have been changes in the waste legislation, and in many cases also in the local waste guidelines. These changes are also reflected in the results. Even though the study results are illustrated for the forerunner municipalities, most of the background data is either regional, or in rare

14

A review of LCA studies on waste management solutions

occasions, national. The geographical area for most of the data on waste streams includes the operational area of the public waste management operator responsible for the household waste management within the region of each of the forerunner municipalities. Majority of the forerunner municipalities are central towns or cities for their region with comparably high population. Thus, their influence on the regional MSW amounts is significant. When interpreting the results, it ought to be born in mind that the background data may have implications on the results, as waste management somewhat differs e.g., in urban and rural areas.

The regional C&DW streams are estimated based on national statistics on C&DW production in Finland and regional statistics on business activity in the construction sector. Overall, the extent of construction and demolition activities correlates with the amount of C&DW. However, this estimation does not consider any regional or local variation in source-separation, collection, or recycling practices.

For example, long distances to recycling facilities may lead to less active source-separation compared to areas in the vicinity of recycling services. In this estimation, there has been no closer examination on the waste streams from construction or demolition activities separately, even though their material composition may vary. In some regions, demolition activities may also be more predominant compared to construction activities, which may also affect waste composition and the environmental impacts of C&DW management. In the national statistics, there have been some fluctuation in certain material streams within C&DW. This fluctuation is also reflected in the environmental impacts, however, the reason behind the fluctuation remains unclear.

A review of LCA studies on waste management solutions 15

4 Potential impacts of some Circwaste sub-actions 4.1 Reducing food waste generation in schools (Pori case) Pori case refers to the efforts which the City of Pori took to reduce food waste in schools. In Finland, children in kindergartens and students in schools from the 1st to the 12th year are provided with free school lunch. This results to roughly 840,000 meals served every school day. Noticing that the total population of Finland is approximately 5.5 million, the school lunch is a significant part of daily routine in Finland. Of this, in Pori approximately 8,000 school lunches are served daily.

Pori launched a week-long campaign in September 2021 aiming to reduce food waste. They set up a system for monitoring the quantity of surplus food left in the serving line and of that thrown into waste bins from plates. During the week they promoted the importance of reducing plate waste. Also, Pori has an online platform through which students may report if they are absent from school so that the kitchen may react to changes in the number of students attending the lunch.

The total amount of food served during the observation week was 10.7 tons, of which 8.8 t was eaten. Of the 1.7 t gap (17%), plate waste represented roughly 0.2 t and dining line leftovers contributed the rest 1.5 t. The share of leftovers and plate waste vary from 2% to 23% between food courses.

According to some estimations, 20% is a good approximation in general for food waste from restaurants.

In the Circwaste project, the global warming potential (GWP, CO2e) of the food, leftovers and food gone into waste in Pori schools were calculated for the main dishes (e.g., minced meat sauce) and their sides (e.g., potatoes) according to the reports Pori had comprised during the campaign week.

Thus, from the total amount of 10.7 t, about 9.3 t was included in the calculations, of which 1.5 t was left to the dining line. We assumed the plate waste was of main dishes, thus remaining at 0.2 t, however it could also be of those not included in the calculations.

In total, the GWP embedded in the food was 19.2 t CO2e, of which 3.3 t was left on the serving line and the 0.5 t was lost from plates. As a rough thumb rule, 1 kg of food meant 2 kg CO2e. For reference, Finland’s total GWP per citizen is a bit over 10 t CO2e annually. As nutritional energy, this means 700850 persons’ daily intake (2,000–2,500 kcal).

The leftovers on serving line may be served again, sold, or given away when handled appropriately (cooled fast enough). In Pori, the leftovers have been given mainly to charity. Pori estimates that 70% of the leftovers have found a taker. This way it can be said that the amount of actual food waste has been reduced greatly, also resulting in less need to produce food. In Pori, this results in 2.3 t CO2e savings per week.

On a national level 160 million school lunches is served annually. Using the Pori data for a scale up, 38 million kilos of food is served, of which 6.1 mill.kg is left over in serving line and 1 mill.kg is wasted as plate waste in one school year in Finland. In CO2e these numbers equal to 78,000 t, 12,000 t and 2,500 t CO2e, respectively. With the Pori example, the 70% reduction in service line waste by charity results in 8,400 t CO2e reduction in emissions. As per energy, the wasted amount of food in total from lines and plates equals up to 3.5 mill. person day needs with 2,000 kcal energy demand.

While the food left on serving line is far bigger an issue than the plate waste, much of it may be sold out or served the next day, thus reducing the wasted share. Plate waste is all wasted, and each gram of food per plate laid to waste produces 160,000 kg more food waste per annum in Finland. In Pori, the average was as low as roughly 7 g/plate, however, this was assumed to be a bit lower than it is on average in Finland.

16

A review of LCA studies on waste management solutions

4.2 Extending the separate collection of plastics packaging in Central Finland In 2018 ambitious European targets were adopted for the recycling of packaging waste. The targets for plastic packaging are 50% recycling by 2025 and 55% by 2030. In Finland, the separate collection of plastic packaging waste started in 2016 on regional collection points (over 500 points around Finland) and later increasing on-site collection in some municipalities, and finally nationally. The collected plastic waste is sorted, separated, and treated at the Fortum Plastic refinery, Riihimäki. However, the recycling rate of plastic packaging is still today way below the target, in 2020 it was 26%. In 2023 the amount of regional collection points for plastic packaging has increased to 1,000 and property-based collection is required in houses with more than five apartments. The effects of these extensions in the collection are not yet known.

The case study described here (Kemppi & Niskanen 2018) was performed by LCA Consulting (now Etteplan Finland) for the Regional Council of Central Finland in 2018 and focused on the environmental and economic impacts of extending the separate collection and recovery of plastic packaging in the Central Finland. The extended solutions were compared to the prevailing situation in 2018. The modelling utilised Life Cycle Assessment (LCA) and an optimisation tool for the separate collection of wastes (JEKOTM) developed by LCA Consulting (now Etteplan Finland).

The modelling was done for 10 municipalities of various sizes: Jyväskylä, Muurame and Hankasalmi representing the area of the Mustankorkea waste management company and Äänekoski, Saarijärvi, Karstula, Uurainen as well as Kinnula, Kivijärvi and Kannonkoski as a combined area, representing the area of the Sammakkokangas waste management company.

The three alternatives for extending the separate collection were: 1) supplementing the regional collection points, 2) launching property-based collection in properties with more than 20 apartments, and 3) launching property-based collection in properties with more than 5 apartments. Additionally, the situation of 2018 was modelled.

For all municipalities it was assumed that the separately collected plastic packaging waste was transported for baling and storage to the Mustankorkea waste centre in Jyväskylä and from there on for treatment to Fortum, Riihimäki. Changes in the separate collection affect the amount and composition of mixed waste, hence also the energy recovery of the mixed waste (the plastic packaging) was taken into consideration.

The results show that in small municipalities (<6,000 inhabitants), supplementing the regional collection points may generate climate benefits, whereas extending the collection further to properties would not generate additional benefits. However, the climate benefits in small municipalities showed to be lower than in larger municipalities, such as Jyväskylä. In small municipalities, the collection of the regional points could be carried out economically efficiently compared to property-based collection. In some cases, collection from properties could even increase the climate impacts as well as the costs of plastics packaging waste.

In larger municipalities (>9,000 inhabitants), e.g., Jyväskylä, Äänekoski, Saarijärvi and Muurame the alternative that generated most climate benefits was the combination of supplementary regional collection and property-based collection from properties with more than 5 apartments. However, this would increase collection costs significantly (with some hundreds of thousands of euros per year in Jyväskylä). Divided by the population, the additional cost remained under 3 euros per person per year.

There are several assumptions used in this assessment that are crucial for the results. The annual yield of property-based collection was assumed to be 6 kg per person and that of regional collection 2 kg per person. Since there are little data on the issue, the actual yield can in practice be above or below these. If citizens perform better in sorting than assumed, the yields increase and simultaneously the climate impacts decrease. The quality of the collected waste also significantly affects the results. It was assumed that 70% of the collected plastic packaging waste would be fit for recycling, but a sensitivity check was performed with 50% assumption. With 50% recycling rate the separate collection of plastics

A review of LCA studies on waste management solutions 17

packaging would not generate climate benefits, although the overall impacts from plastics packaging waste management (including energy recovery of mixed waste) would decrease. As for the transportation needed for the collection, the property-based collection was assumed to be performed separately from the regional collection, which significantly effects the results especially for the smaller municipalities where collection times and fuel consumption per plastic waste yield are high. Hence the impacts of collection could be reduced by optimising the logistics of collection, e.g., collecting from regional and property-based points with the same collection round, utilising co-collection with regional collection points, taking in use compressing containers or other, innovative solutions. Changing the fuel from diesel to bio-based fuels would additionally reduce climate emission.

Based on the results, extending the regional collection points in the municipalities as suggested, could double the amount of plastic packaging waste directed to recycling. Additional extension to property-based collection would triple (collection from properties with >20 apartments) or quadruple (collection from properties with >5 apartments) the amount. The largest municipality, Jyväskylä, has the most impact on the potential yields, since most of its population live in large properties where propertybased collection would be efficient. In small municipalities most people live in single-family homes, where collection generates more emissions.

Overall, the study concludes that increasing separate collection and thereby making sorting easier for citizens is one way of getting people sort plastics packaging more efficiently.

4.3 Improving sorting and separation of wastes at construction sites (Puhas case) Puhas is a publicly owned waste management company operating in North Karelia. In Circwaste project, the company piloted an improved waste separation resolution performed at a construction site compared to typical business-as-usual (BAU) level.

The coarse resolution, i.e., the number of different waste fractions collected addressed only 7 categories: asphalt, rocky materials in two different particle sizes, metals, wood, combustible waste, and mixed waste. The piloted fine resolution separation included 20 sort of wastes. The coarse resolution, render recycling difficult or even impossible due to heterogeneity of the waste in each pile.

The largest waste material volumes were generated by asphalt (bitumen and rock mineral), rock, and soil. Asphalt waste assumedly originated from removing the old asphalt at the site. However, these materials were already separated in the BAU. So was most of the metal waste.

The improvement towards the fine resolution is made with better separation of the mixed, combustible and wood waste fractions. This includes such possibilities as separating wood into treated and untreated wood, and plastics into general plastic (recyclable) and PVC-plastic (recyclable only in limited applications, should not be mixed with other plastics). Additionally, aerosols, paints and varnishes, pressurised packages/containers, wool, bitumen, gypsum window glass, combustibles, concrete dust, and cardboard can be separated from the mixed and combustible waste fractions for recycling.

The total amount of wastes was 884 tons and their embedded CO2e emissions were estimated to be 82 tons. The quantity of the waste that was separated better than in BAU was 22 tons with 22 tons of embedded CO2e, meaning that the average CO2e -factor for those 22 tons was much higher than the average emission factor for all wastes.

According to the calculations made, utilising those materials obtained by better recycling, we could produce the same products or materials again with less than 7 tons of CO2e, which is 70% less CO2e emissions than their virgin counterparts. Much of this reduction is explained by plastic and gypsum recycling. Positive changes took place with most of the other impact categories, too, but the plastics’ recycling, however good in climate sense, caused negative impacts in a few impact categories.

It must be said that the figures presented here should be interpreted with care. It may be difficult in practice to sort and operate as efficiently as in theory. Also, if the materials are unclean, recycling them

18

A review of LCA studies on waste management solutions

might be impossible. Nevertheless, as the construction sector produces over ten billion tons of waste annually - estimated to double in few decades - even if the realistically additional recoverable share through better waste separation is small, it accumulates in great volume due to the enormous total waste volume in the sector.

4.4 Environmental Impacts of WPC Production for C&DW Material Recovery This case study (Liikanen et al. 2019) presents an in-depth analysis of a project that aimed to assess the environmental implications of introducing Wood Polymer Composite (WPC) production as a novel material recovery option for C&DW in Finland. The project focused on specific C&DW fractions, including wood, plastic, mineral wool, and plasterboard. Its primary objective was to compare the environmental consequences of this innovative approach to the conventional C&DW disposal methods, such as landfilling and incineration.

The project had three main objectives: • Evaluate the environmental impact of utilising C&DW as raw materials in WPC production compared to traditional C&DW disposal practices.

• Identify the C&DW fractions best suited for WPC production.

• Assess the influence of substituting virgin materials with WPCs. To quantify and assess the environmental impacts comprehensively, the project employed the rigorous methodology of LCA, which allowed for a holistic evaluation of the project's environmental footprint. The study primarily focused on two critical impact categories, climate change and depletion of fossil resources. The climate change analysis considered the emissions generated during waste treatment, WPC production, and the production of virgin materials that WPCs could replace. It excluded biogenic carbon. The impact category depletion of fossil resources evaluated the consumption of fossil resources, particularly fuels, throughout the entire life cycle of WPCs. The results of these two impact categories are summarised in Table 1 for the two WPC recipes and 10 scenarios studied in Liikanen et al. (2019).

Table 1. Environmental impacts of different solutions for C&DW management (Liikanen et al. 2019).

Climate change impacts (excluding biogenic carbon) and fossil depletion calculated with the ReCiPe 2016 v.1.1 (mid-point hierarchist timeframe) characterisation method. Scenarios: S0=no material recovery, S1: material recovery of plastic and plasterboard, S2-S4: WPC production with two recipes and WPC substituting various materials. In S2.1-S2.3 different plastic types are substituted with WPC, in S3.1-3.4 different wood containing products are substituted, and in S4 aluminium profiles are substituted.

Scenario

Recipe1)

Climate change (excl.

Fossil depletion biogenic carbon) kg CO2e. (range) kg oil eq. (range) S0 R1 4.8E+02 -2.5E+02 R2 6.2E+02 -2.1E+02 S1 R1 1.8E+02 -3.1E+02 R2 3.2E+02 -2.7E+02 S2.1-2.3 R1 -1.8E+03 - -1.3E+03 -1.4E+03 – - 1.0E+03 R2 -1.8E+03 - - 1.3E+03 -1.4E+03 – - 1.0E+03 S3.1-3.4 R1 1.0E+02 – 2.0E+02 1.6E+02 – 1.9E+02 R2 1.0E+02 – 2.0E+02 1.6E+02 – 1.9E+02 S4 R1 -2.1E+03 -5.0E+02 R2 -2.1E+03 -5.0E+02 1) R1= Recipe 1 (wood 54%, plastic 40%, lubricant 3%, coupling agent 3%) and R2= Recipe 2 (wood 24%, plastic 40%, mineral wool 15%, plasterboard 15%, lubricant 3%, coupling agent 3%)

A review of LCA studies on waste management solutions 19

Additionally, the project assessed 17 other impact categories in less detail to gain a comprehensive understanding of the broader environmental implications. The LCA analysis leveraged GaBi LCA modelling software and adopted the ReCiPe 2016 v.1.1 method for impact assessment.

Scaling Environmental Impacts Nationally: The project explored the potential scalability of WPC production for C&DW material recovery at the national level, taking into account Finland's specific context. It estimated that establishing a large-scale WPC production facility with an annual capacity of around 20,000 tonnes could contribute to a 1%-unit increase in the C&DW material recovery rate.

However, a crucial point emerged from this assessment: WPC production alone cannot be the sole solution to meet material recovery targets.

The project strongly advocated for a comprehensive and diversified approach to C&DW management. It emphasised the need to prioritise mono-material recovery over WPC production, particularly when dealing with wood. The rationale behind this recommendation stemmed from the finding that wood production generally had lower environmental impacts than WPC production.

The study acknowledged that C&DW management entails various factors beyond environmental considerations, such as the quality of raw materials, market demand for WPCs, end-of-life phases for WPC products, and the optimisation of manufacturing processes.

In conclusion, this case study delved into the environmental implications of adopting WPC production as an innovative material recovery strategy for C&DW in Finland. It underscored the potential environmental benefits of utilising C&DW in WPC production, particularly when substituting energy-intensive materials like plastics or aluminium.

Nevertheless, the project emphasised that the environmental viability of WPCs hinged on specific scenarios and that wood might remain a more sustainable choice in certain cases due to its unique properties. Furthermore, the study advocated for a holistic approach to C&DW management, taking into consideration not only environmental factors but also other critical aspects of sustainability.

Overall, this case study contributed to a deeper understanding of the environmental impacts of C&DW-derived WPCs within the broader context of C&DW material recovery. It highlighted the need for a multifaceted and sustainable approach that goes beyond environmental considerations and incorporates various facets of waste management and resource utilisation.

4.5 A comparative LCA study on Wooden, Plastic, and WPC Pallets Pallets are a ubiquitous yet often overlooked component of the global logistics industry. They play a crucial role in the transportation and storage of goods, making them an essential part of supply chains worldwide. However, the choice of pallet material can have significant environmental implications, prompting a growing interest in assessing their life cycle impacts. In this study (Khan et al. 2021), we conducted an LCA to compare the environmental performance of three types of pallets: wooden, plastic, and WPC pallets. The assessment included the production, use, maintenance, and end-of-life (EoL) phases of the pallets.

Wooden pallets are known for their cost-effectiveness and ease of manufacturing and repair compared to plastic pallets. However, one significant downside is their impact on forests. To address this, a carbon-neutral approach is often applied to wood incineration, where the carbon emitted during combustion is considered equivalent to the carbon absorbed by trees during growth. Wooden pallets also have a higher weight, which affects their environmental performance during transportation.

Plastic pallets are lighter and more durable than wooden pallets but have energy-intensive production processes. Unlike wooden pallets, they cannot be easily repaired, as plastic materials must be melted down and remoulded. Recycling is a key strategy for plastic pallets to align with circular economy goals.

20

A review of LCA studies on waste management solutions

WPC pallets are a sustainable alternative, as they are made from C&DW and consist of both wood and plastic components. This recycling approach reduces waste and harnesses the benefits of both materials. However, conducting a comprehensive LCA is essential to determine their overall environmental performance.

The LCA of these pallets considers various impact categories, including abiotic depletion potential, acidification potential, eutrophication potential, global warming potential (GWP), and ozone layer depletion potential. The analysis encompasses four phases: production, use, maintenance, and EoL. The summarised LCA results (calculated with both attributional and consequential LCA approach) are reported in Table 2.

Wooden pallets' production involves timber production, nail production, and transportation consuming 3,809 MJ of energy. Plastic pallets' production requires 21,337 MJ of fossil fuels, mainly natural gas and crude oil. The production of WPC pallets involves less energy consumption, with 293 MJ used in various processes.

The weight of the pallets significantly influences their environmental impact during the use phase.

Wooden pallets, due to their higher weight, consume more fuel in transportation. In this phase, wooden pallets showed higher fuel consumption than plastic and WPC pallets.

Maintenance is considered only for wooden pallets, as plastic and WPC pallets cannot be repaired.

Wooden pallet maintenance includes wood harvesting, timber production, transportation, and the production of repair components.

The EoL phase's impact depends on carbon emissions, heating value, and biogenic carbon content of the materials. Plastic pallets generated the highest emissions during incineration due to their higher carbon emissions factor, while wooden pallets showed the most substantial avoided environmental impact.

While this study provides valuable insights into the environmental performance of pallets, it's important to consider scaling these impacts to a national level. The choice of pallet material, especially when used extensively throughout a country, can have a substantial cumulative effect on the environment. Therefore, it's crucial to assess the potential national-level impacts of pallet material choices.

In conclusion, the comparative LCA of wooden, plastic, and WPC pallets highlights several key findings: • Wooden pallets demonstrate environmental benefits, particularly when considering carbon neutrality in wood incineration. However, this approach requires careful consideration and debate.

• Plastic pallets, made from virgin materials, tend to have higher environmental impacts, primarily due to energy-intensive production processes. Exploring recycled plastic pallets may yield more favourable results.

• WPC pallets: WPC pallets, derived from C&DW and composed of both wood and plastic, exhibit promising environmental performance, especially when considering their lower weight and circularity potential.

• Scaling to national level: The choice of pallet material can have cumulative environmental effects when scaled to a national level. Therefore, policymakers and industries must consider these implications in their sustainability strategies.

• Carbon neutrality debate: The carbon neutrality approach to wood incineration requires further scrutiny, as its environmental impact varies based on factors like forest regeneration rates and the choice of energy sources in production.

This study underscores the importance of conducting LCAs to inform sustainable decision-making, particularly in industries with significant environmental footprints like logistics. It also emphasises the need for circular economy strategies to reduce waste and promote recycling, as seen in the case of WPC

A review of LCA studies on waste management solutions 21

pallets. Ultimately, making environmentally conscious choices in pallet materials can contribute to a more sustainable and responsible supply chain management system.

Table 2. The summarised attributional LCA (ALCA) and consequential LCA (CLCA) results of wooden, plastic and WPC pallets (Khan et al. 2021). Classification and characterisation according to the CML 2001–Jan. 2016.

ADPf (MJ (1,000 trips) -1) AP (kg SO2 eq. (1,000 trips) -1) EP (kg phosphate eq. (1,000 trips) 1) GWP (kg CO2e. (1,000 trips) -1)

Wooden pallet 4,397 1

ALCA

0.4 95

ODP (kg R11 eq. (1,000 trips)-1)

6.3E-05

ADPf (MJ (1,000 trips) -1) AP (kg SO2 eq. (1,000 trips) -1) EP (kg phosphate eq. (1,000 trips) 1) GWP (kg CO2e. (1,000 trips) -1) LUC (kg CO2q. (1,000 trips) -1) ODP (kg R11 eq. (1,000 trips) -1)

11,485 1

CLCA

0 1,296 1,836 3.2E-05

Plastic pallet 22,375 2

WPC pallet 3,422 0.3

0.2 1,502

0.2 368

2.0E-04

2.9E-13

27,618 2

4,760 0.4

27,618 2,170 2,165 187

4,760 342 360 -1

4.6 Piloting the use of recycled materials in a highway construction application The aim of this action was to carry out piloting activities in selected sites in Finland in order to test and demonstrate the utilisation of various waste streams as valuable construction materials in versatile construction applications.

In total 54 road projects of the Finnish Transport Infrastructure Agency (FTIA) were mapped for their suitability as pilot sites. In total 9 road projects were selected as pilots for this action.

The use of recycled materials in infrastructure construction applications reduces the use of virgin natural aggregates. For example, in Hiedanranta pedestrian and cycle way pilot, piloted structures reduced the use of natural resources 40–76% compared to the conventional structure (Teittinen 2023a).

Replacing virgin natural aggregates with recycled materials typically reduces material emissions of infrastructure construction projects. In stabilisation applications, the use of recycled binder materials instead of conventional lime-cement binders with high carbon footprint, reduces CO2e emissions of binder production with up to 70%. CO2e-calculation has been done in pilots Hämeenkyrön ohikulkutie, Hiedanranta pedestrian and cycle way and Suurmetsäntie. The average CO2e emission saving in these pilots is over 50% and it is estimated that greenhouse gas savings in other pilots are of similar magnitude.

Poor quality soft soils were utilised instead of landfilling in pilots Hämeenkyrön ohikulkutie, Tikkakoski interchange and Suurmetsäntie. Directly in these pilots, ca. 650,000 m3 of soft soils were utilised. Utilisation of soft soils instead of landfilling also diminishes the need for construction of new landfills for surplus soils.

Various industrial by-products (ashes, slags) and waste materials (crushed concrete, old tyres) were utilised in the pilots of this action. At least 44,000 t of industrial by-products and waste materials were utilised directly in the pilots. The use of recycled materials typically reduces material costs, as the price of recycled materials is lower than the price of virgin materials.

In addition to the direct impacts of these pilots, the action will have wider impacts in the future through the guidelines prepared in the project together with the Finnish Transport Infrastructure Agency

22

A review of LCA studies on waste management solutions

(FTIA), e.g., Guidelines for resource efficient road construction, Recycled materials in road design process, and Experiences of using recovered materials in road structures. The guidelines published by FTIA have significant impact on the whole infrastructure construction sector in Finland. Indirect impacts of the above-mentioned guidelines were examined through the mass quantities of the FTIA projects. It is estimated that the amount of landfilled surplus soils (2,500,000 t annually) in the FTIA projects reflects the magnitude of materials that could be utilised instead of landfilling in Finland. A rough estimate of the potential environmental savings from this utilisation would be 10,000 t CO2e (0.004 kg CO2e/kg gravel; Finnish Environment Institute 2023). In addition, the amount of external aggregates (1,300,000 t annually) describes the potential that could be partly replaced with recycled materials.

4.7 Utilisation of industrial waste and contaminated sediments in the construction of Sampaanala Bay In this action a large-scale pilot application was conducted in the Sampaanala Bay area in Rauma, Western Finland (Teittinen 2023b). Industrial waste fractions and contaminated dredging masses generated nearby were utilised in the construction of the Sampaanala Bay basin B. The area is stabilised and will become a storage area for the needs of the nearby industry.

The use of cement in mass stabilisation causes most of the greenhouse gas emissions from the construction of the bay, so by replacing part of the cement with fly ash, significant emission reductions were achieved. According to the results, CO2e emissions of the implemented mass stabilisation with recycled binders were 56% lower when compared to the business-as-usual scenario, where the construction would have been done without recycled materials. The use of recycled materials in the stabilisation also brings cost savings when compared to the use of traditional cement. By utilising dredging masses and fly ash in construction, landfilling of these materials was avoided, which would have required establishment of a new landfill and thus caused additional environmental impacts and costs.

Alternative structures for the superstructure were piloted on top of the stabilised basin. The pilot included a reference structure made of traditional aggregates and five alternatives in which different amounts of recycled materials (bottom ash, fly ash and stabilised fly ash) were used. The piloted recycled material alternatives make it possible to reduce the CO2e emissions of the superstructure by up to 58% compared to a traditional solution, while saving up to 48% in costs. If the entire surface structure of the Sampaanala basin B is implemented with one of the piloted recycled material solutions, 36,000 t–45,000 t of bottom and fly ash can be used to replace virgin natural aggregates.

A review of LCA studies on waste management solutions 23

5 Impacts of selected complementary actions

5.1 Intensifying waste sorting with different practices (LAJITEHO project) LAJITEHO project (Salmenperä et al. 2019) on practices to intensify waste sorting, explored weightbased PAYT (Pay-as-You-Throw) methods that can be used in increasing the rate of municipal waste recycling, to develop PAYT systems into customer-oriented systems that promote waste sorting, and to identify solutions suitable for the conditions in Finland. The project gathered information and compiled tools to support waste management facilities in implementing a weight-based waste management system. The project report includes information on the legal and administrative limits of weight-based PAYT systems, three case studies on weight-based PAYT systems implemented in Europe, a SWOT analysis, information on the use of weighing technology when emptying waste collection equipment, a study of the environmental impacts of the system, materials to support communications and a pricing model for waste payments. The project was carried out by the Ministry of the Environment, the Finnish Environment Institute (Syke), Finnish Circular Power KIVO and Pirkanmaan Jätehuolto Oy. The environmental impacts study applied the life cycle thinking to estimate climate change impacts of a future situation where PAYT principle would have been taken in use in the whole of Finland. This was compared to a prevailing baseline situation. The assessment was purely theoretical. The waste flows included in the estimation were biowastes and plastics wastes, for which increased sorting, separation and recovery was assumed. Additionally, the mixed waste from municipalities was included in the assessment since increased sorting and separation of biowaste and plastics waste will have effects on the quantity and quality of the mixed waste. The assessment was performed on the national level.

The impact of the implementation of the PAYT was estimated based on literature. The sorting efficiency of biowaste was estimated to increase by 28% and of plastics waste by 56%.

In modelling the system, mixed waste was recovered as energy in a waste-to-power plant and the produced energy was assumed to compensate average heat and power production. The biowaste was either composted (two thirds of the flow) or digested anaerobically (one third of the flow), based on the most recent waste statistics (Statistics Finland 2018). The compost product was assumed to compensate peat and fertilizer production. The solid fraction from anaerobic digestion was assumed to compensate fertilizer production, whereas the biogas was assumed to compensate natural gas. The share of anaerobic digestion in biowaste treatment is growing, but in this assessment the share was kept constant in both the baseline and future scenarios in order for the results to indicate the impacts of the PAYT and not the changes in the treatments.

The sorted and separated plastics waste was assumed to be treated at the Fortum plastics refinery, where 60% of the incoming post-consumer plastics packaging waste was assumed to be recovered as material. Of this flow, 60% was utilised as granulates and were assumed to compensate virgin plastics production and 40% as plastics profiles compensating the production of impregnated wood.

The rejects from the bio- and plastics waste treatments were assumed to be recovered as energy together with the mixed waste. The share of reject per one separately collected waste ton was assumed to stay constant in both the baseline and the future scenarios.

The assessment includes uncertainties which are dealt with in the report. However, the basic results show that the summarised change in the net climate change impacts of the three studied waste flows was approximately 13 Mt CO2e/a. In the baseline scenario the net climate change impact was -43.2 Mt

24

A review of LCA studies on waste management solutions

CO2e/a, and in the future scenario -56 Mt CO2e/a. Hence, changing to the PAYT principle in the pricing of municipal waste management in the whole of Finland could save around 13 Mt CO2e annually.

5.2 Co-mingled collection of plastic from sparsely populated regions (PLASTin project) In Finland’s sparsely populated areas, the collection rate for plastic packages has remained low, possibly due to the inconvenience of the current system where the households are expected to transport their separated waste to regional waste points. The problem of extending the household collection to sparsely populated areas include concerns related to increase in environmental impacts and costs of collection.

One solution could be a system where plastic packages are collected from the households with other packaging materials mixed in the same bin.

This study (Salmi et al. 2023) compared two scenarios that differ in the way the plastic, metal, and cardboard (PMC) waste fractions are separated and collected. The regional collection scenario (S1) represented the current practice in Finnish sparsely populated areas where PMC waste fractions are source separated at households and transported to a regional collection point by the waste generator with a passenger car. In the co-mingled collection scenario (S2), the PMC waste fractions are source separated in a mutual bin that is collected by a waste truck from the households. The environmental performances of these scenarios were calculated and analysed by performing life cycle assessment (LCA) of the collection systems.

First, the generated amounts and separation rates of PMC waste from households needed to be determined using multiple sources. For co-mingled collection, the estimated collection rate was assumed the same as in the conventional household collection.

The separately collected plastic waste included HDPE, LDPE, PP, other plastic grades, dirty packages and non-plastic material. Separately collected metal waste was assumed to include ferrous metals, aluminium, and mixed waste. The separated cardboard waste was assumed to include recyclable and unrecyclable fibre as well as rejects in forms of plastic and aluminium.

In S1, the source separated plastic, metal and cardboard were first transported from households to a regional collection point with a passenger car. In most cases, bringing the PMC waste to the collection point is not the only reason for the transportation, making allocation of the emissions necessary. In this study, 50% allocation was used, and this parameter was further analysed in the sensitivity analysis. All transportation in the S2 and the further transportations in the S1 as well as the collection of municipal residual waste (MRW) were assumed to be done by EURO 6 waste trucks fuelled by diesel. The distances of all transportations were assumptions based on literature.

The co-mingled PMC waste in S2 was first treated in a mechanical separation (MS) plant where the ferrous metals, aluminium, cardboard, and plastic waste fractions are separated. The separately collected plastic waste in S1 and the plastic fraction from MS in S2 were then mechanically separated into four fractions - LDPE, HDPE, PP, and other plastic. The plastic recovery process further included shredding, washing, extrusion, and granulation. The plastic profiles from “other plastic” fraction were assumed to substitute construction timber. The recycled LDPE, HDPE, and PP granulates were assumed to substitute virgin granulates. Metal recovery was assumed to include mechanical separation, steel recycling, and aluminium recycling. In the ferrous metal recycling, the separated ferrous metal was assumed to be supplied straight to the steel making process. The separated aluminium was assumed to be remelted into wrought alloy ingot. The cardboard recovery was assumed to include repulping, mechanical removal of impurities, and deinking.

The waste that was not separately collected, i.e., municipal residual waste (MRW), as well as separation losses from MS, removed impurities, losses from processes and unrecyclable material were assumed to be incinerated with energy recovery. The energy efficiencies for heat and electricity used

A review of LCA studies on waste management solutions 25

were 59% and 12% respectively. The generated electricity was assumed to substitute Finnish electricity consumption mix and generated heat substituted Finnish district heat mix.

Due to multiple assumptions made in the life cycle inventory, a thorough analysis of the used parameter values was necessary. The sensitivity analysis included contribution analysis, perturbation analysis and break-even analysis.

The environmental impacts were calculated for multiple impact categories relevant to the study field. The co-mingled collection (S2) performs better in most impact categories mainly due to lower impacts from transportation and higher benefits from material recovery in avoided emissions. In climate change impact category, the emissions in S2 are 76% lower.

The waste-to-energy (WtE) of MRW results in highest direct emissions in climate change impact category in both scenarios. From the emissions, approximately 98% comes from the incineration of plastic waste in the MRW. In other impact categories, especially the transportation and cardboard recovery are also significantly contributing to emissions. The emissions of cardboard recovery mostly result from high energy demand and the incineration of plastic impurities. Notably, the passenger car transport in S1 is a very relevant emission source in most impact categories, it is responsible of 11% of all climate change impact. The negative impacts of increased truck transportation in S2 can mostly be seen in the eutrophication and human toxicity (non-cancer) impact categories. The mechanical separation of the co-mingled PMC does not have very significant impact.

In avoided emissions, the energy substitutions from the MRW WtE are the biggest contributions in most categories. From material recovery, metal and plastic recycling yields the highest benefits in most categories. The cardboard recovery mostly affects the avoided emissions in eutrophication impact categories, but the direct emissions of the recovery process exceed the avoided emissions, making WtE more viable option for cardboard in this study.

The parameters with the highest effect to the results are the electricity and heat efficiencies of MRW incineration, the collection rates, MS recovery rates and passenger car parameters. From the plastic substitution rates only the ones for LDPE and PP are noteworthy.

When determining the values for minimum increase in the collection rate to minimise the climate change impact, the allocation for the passenger car has a big impact. With the 50% allocation used in the baseline calculation, there would be no applicable collection rate where the S1 would have performed better. However, if the passenger car is excluded altogether, the co-mingled collection would have to achieve at least 1% higher collection rate than regional collection in order to have lower impact in the climate change category. In order to perform better in climate change category, the collected waste fractions in S2 can contain maximum of 56% of impurities. This is 34% more than what was used in the baseline calculations. Here also the impact of the passenger car allocation can be seen: if allocation is 25% or 0% the maximum share of impurities should be less than 47% and 38% respectively.

Further discussion should be focused on the low recycling rate for plastics even with the comingled collection (approximately 24%). This is mostly due to the material losses in the mechanical separation and assumed impurities remaining in the separated plastic fractions. In order to meet the recycling rate target of 50%, the collection rate and mechanical separation efficiency would need to improve drastically. The economic aspects should also be assessed to verify the feasibility of comingled collection in Finland. For example, in order for a co-mingled system to be implemented, a mechanical separation facility is needed requiring possibly high investment costs. Also, it should be noted, that the temporal scope of the study focused on current situation or near future and no alternative electricity or heat mixes were considered. As Finland has made commitments to reduce the carbon emissions of the energy sector meaning for the that the benefit of collecting more waste, plastic especially, is even greater in the future making a case for co-mingled collection to be preferred.

26

A review of LCA studies on waste management solutions

5.3 Speeding up the circular economy by recycling municipal waste (JÄTEKIVA project) The JÄTEKIVA project (Salmenperä et al. 2019) for speeding up the circular economy by recycling municipal waste studied what kind of steering methods could be used to reach the stricter municipal waste recycling goals set by the Waste Framework Directive (at least 55% of municipal waste recycled by 2025, 60% by 2030, and 65% in 2035) and assessed the effects and suitability of the methods proposed by the Commission in the Finnish conditions. The suggested methods included e.g., setting recycling goals on municipalities as well as an obligation to collect packaging waste, or alternatively a closer cooperation between municipalities and producer responsibility organisations. In addition, the implementation of various policy measures was recommended, such as financial steering methods to encourage recycling. The goal of the JÄTEKIVA project was to produce information to support the reform of the Waste Act. By modelling municipal waste streams, information was produced on the extent of making the separate collection of municipal waste more efficient and how areas with different geography and population densities were considered. The cost analysis produced during the project provided information about the cost impacts of measures to increase recycling and opportunities for savings. In addition, information was collected on factors that had emerged during the life cycle assessments of biowaste collection and recycling, that have the most significant impact on the environmental and cost effectiveness of biowaste collection and recycling. The project also assessed the functionality of the current packaging producer responsibility systems as well as different kinds of options for the division of responsibilities for developing the producer responsibility system. In addition, models of obligations on separate collection, cooperation obligation between municipalities and producers as well as the division of responsibilities in packaging waste management were assessed from the perspective of the need to make changes to waste legislation.

For the purposes of this report, the separate study on environmental impacts connected to biowaste collection and treatment (Niskanen & Kemppi 2019) is summarised. The study was performed by LCA Consulting (now Etteplan) and reviewed previous LCA studies on biowaste collection and treatment to reveal the most important factors affecting the environmental and economic performance of biowaste value chain. Additionally, possibilities to improve this environmental and economic performance were identified and LCA modelling performed on some specific factors.

The potential environmental impacts of biowaste collection and treatment chain originate from the direct and indirect emissions generated in collection and treatment of biowaste, and the emissions avoided by compensating virgin materials or energy with waste-based products. The importance of life cycle phases varies for different impact categories and according to case specific circumstances. The most significant climate benefits can be gained from utilising biogas from digestion to compensate fossil fuels, e.g., as transport fuel in the biowaste collection. The average diesel consumption per one ton of collected biowaste has varied a lot in different studies, from 6.5 litres to 99 litres. On average, one ton of biowaste produces biogas to compensate 100 litres of diesel. Based on these figures the biowaste collection could be carried out carbon neutrally by using the biogas produced from the collected biowaste, and biogas could even be left for other vehicles use.

Studies have shown that extending the requirement for separate collection of biowaste to residential areas with a predominance of detached houses, the climate change impacts and costs per collected waste amount rise notably more for biowaste than other waste fractions. This is due to the fact that shorter drain intervals have been set for biowaste than other wastes to eliminate smell from the biowaste containers. This results in biowaste bins being half or less full when emptied. For detached houses one week interval is far too short.

There are several options for reducing the emissions and costs generated from the collection phase when separate collection of biowaste is extended to areas of detached houses. The requirements for the

A review of LCA studies on waste management solutions 27

frequency for emptying the biowaste bin can be changed from the common one week to two weeks. In a study performed for the capital region, by prolonging the emptying interval from one to two weeks a 34% reduction in climate emissions and a 33% reduction in costs were gained. In regions were e.g., two weeks interval has been in use instead of one week, smell has not been experienced as a problem, but depending on the winter, freezing of biowaste may cause challenges.

With multi-compartment collection the emissions and potentially also costs may be reduced, but no generally applicable conclusions can be drawn from studies since the benefits of multi-compartment collection are highly case-dependent. In the capital region the environmental impacts of biowaste were reduced by 14% with multi-compartment collection, but since the bins had to be emptied more often than one-compartment bins, the costs were not reduced. Shared bins have had small impacts on the emissions and costs of collection and there has been challenges in getting people to accept the sharing of biowaste bins. Additionally, home composting is applicable for detached houses and is a way to eliminate the need for collection.

5.4 Developing recycling concepts for challenging plastics streams (PLASTin project) The ALL-IN for Plastics Recycling (PLASTin, Clic Innovation 2022) project was established to help the plastics industry actors to develop systemic, and environmentally optimised recycling concepts for selected challenging plastics streams including plastics from liquid packaging board (LPB), and plastics from WEEE. The vision of the project was to help the Finnish industry to take a lead in recycling these challenging streams and turn the challenges into new business opportunities of the plastic cluster in Finland. This would be achieved with the new knowledge gained about recycling processes and technologies such as sorting, pre-treatment, mechanical treatment and reject handling, and about system-level understanding, allowing improved business opportunities based on recycling. By this way, we promote the circular economy.

One of the roles of the Finnish Environment Institute in the PLASTin project was to quantify the system-wide climate impacts of plastic packaging in Finland. A study by Judl et al. (2023) presents this work. The study was a combination of LCA and MFA (material flow analysis). The goal was to study the Finnish post-consumer plastic packaging waste system (falling under the extended producer responsibility, EPR) in 2019 and estimate its climate impacts, as well as to explore the climate impacts of alternative future scenarios. The study excluded recycling of deposit-based plastic beverage packages. The analysed product system is illustrated in Figure 2.

28

A review of LCA studies on waste management solutions

Figure 2. Product system analysed in the LCA done in the PLASTin project. (From Judl et al.

2023).

The functional unit of the study was defined as the collection and treatment of plastic packaging waste falling under the EPR (excluding deposit packaging) in Finland in one year. The selected baseline year was 2019. The same functional unit was used for calculating the results for future scenarios. The scenarios studied are presented in Table 3.

Table 3. PLASTin scenarios Scenario Baseline Increased collection Improved recycling yield Increased recycling capacity Chemical recycling introduced

Description The current situation, where plastic packaging waste is collected and transported for sorting. Part of it is mechanically recycled and part is assumed to be exported.

The separate collection increases by 75%. Due to increased collection, more waste is exported and less is incinerated.

The yield of mechanical recycling improves from 37% to 55.5%.

The annual processing capacity of mechanical recycling increases from 18,000 t to 50,000 t. Due to increased domestic recycling capacity, no waste is exported.

Chemical recycling is introduced. Chemical recycling processes 65% of the reject from mechanical recycling.

The climate impacts of the post-consumer plastic packaging waste processing system in Finland in 2019 were 178 kt CO2e, excluding exports and credits from avoided production. Including exports, the total impacts were 182 kt CO2e. The contribution of exports, energy recovery and mechanical recycling are 2.3%, 95.7% and 1.5%, respectively. The remaining 0.5% is attributed to collection and sorting.

When avoided production is included in the equation, the net climate impacts of the system are 155 kt CO2e, or 151 kt CO2e if export is excluded. The analysed system’s emissions were equivalent to approximately 0.34% of total Finnish CO2eq emissions.

The impacts allocated per tonne of waste are 2.3 t CO2e/t when export is excluded, 2.4 t CO2e/t when export is included, 1.9 t CO2e/t for net impacts without export and 2 t CO2e/t for net impacts with export.

A review of LCA studies on waste management solutions 29

In isolation, each individual measure (scenario) leads to a relatively small reduction of net climate impacts; between 2.2% and 11.2%. With some of the measures being mutually reinforcing, the joint implementation of various measures was found to be more effective. In 2019, the amounts of separately collected plastic waste exceeded the total capacity of mechanical recycling. Therefore, an increase in separate collection alone did not deliver substantial reductions of the overall impacts (3.7%). The small impact reduction is mainly a result of less plastic waste reaching energy recovery as a fraction of MSW. The further sequential results reveal that increased collection, coupled with improved operational yields of mechanical recycling, can lead to an up to 9.1% reduction of climate impacts, but the reduction can be further facilitated by the currently planned increase of the capacity of mechanical recycling (16.6%).

In the scenario implementing all measures, including chemical recycling, the reduction can reach up to 30.4% in total. The introduction of chemical recycling and the combination of all measures allows for the system to deal with challenging and previously unrecyclable waste fractions, bridging the gap to the recycling targets (Figure 3).

Figure 3. PLASTin results. (From Judl et al. 2023).

5.5 Extending the life cycle of a cotton roller towel (Finix project) The environmental impacts of current life cycles of textiles are widespread and substantial. The traditional, linear model of textile production and consumption is based on virgin raw materials, including no significant repairs and discarding the fabric into landfills or by incineration. There are different options for improving the circularity of textile production and consumption, the most predominant being reuse and recycling. The textile material recycling routes are typically classified as mechanical, chemical, thermal, or a mix of these. Depending on the route, the quality and strength properties and thus the technical lifetime of the fibre and applications vary.

The aim of this case study (Mölsä et al. 2022) was to compare the environmental impacts of introducing different CE strategies (reuse, recycle) into the life cycle of cotton roller towels in terms of climate change impact and water consumption. The LCA method was used to compile and evaluate the inputs, outputs and potential environmental impacts of our product system throughout its life cycle. The goal of the study was to assess the selected environmental impacts of a roller towel during its life cycle.

The study assessed 1) the climate change impact and water consumption of a roller towel during its full life cycle and compare selected CE strategies with a scenario approach, and 2) the impact of various substitution assumptions on the environmental performance of the roller towel.

30

A review of LCA studies on waste management solutions

Ideally, a roller towel can be used for 100 wash cycles, each lasting for around 105 pulls (total of 10 500 uses) until the fabric wears out. Often, the towel gets stained already before the 100 washes (typically, and in certain uses, during the first 40–60 washes) and cannot reach its maximum lifetime. At this point, the roller towel is usually discarded and incinerated. The life cycle of these roller towels can be extended by dying them with a darker colour (blue) to hide the blemishes. According to the roller towel operator, the dyed towels can be reused to reach the total 100 washes, after which the fabric is incinerated. The roller towel operator currently uses three life cycle models for the roller towels: the linear model and the extended life cycle by reuse or recycling. After the roller towel can no longer be used for hand-drying, it could be chemically recycled into new man-made cellulosic fiber (MMCF) products, which can maintain the value of the fibre (upcycling). To study the different scenarios available for the roller towel operator, four scenarios were distinguished for the life cycle after the towel no longer fulfils the visual standards: Scenario 1 (S1): Incinerating the tarnished roller towel. Scenario 2 (S2): Dyeing and reusing the tarnished roller towel and incinerating it at the end of its lifetime. Scenario 3 (S3): Recycling the tarnished roller towel either as viscose (Scenario 3.1, S3.1) or as urea-treated cellulose carbamate (CCA) (Scenario 3.2, S3.2). The functional unit (FU) of the assessment was defined as one hand-drying (i.e., towel pull). Substitution impacts were considered for processes connected to the end-of-life of the product, such as the energy recovery of the discarded roller towel by incineration and material recovery by recycled yarn production. No allocation procedures were used.

According to the results, a linear life cycle of a cotton roller towel causes a climate change impact of 12.4 g CO2e/hand-drying and water consumption of 2.4 l/hand-drying. Combining different CE strategies (reuse and recycling), the roller towel’s impacts could be reduced to as low as 8.9 g CO2e and 0.5 l water/hand-drying (Figures 4 and 5). The most important life cycle phases contributing to climate change impact in all studied scenarios are the use and manufacture of the roller towel. The contribution of the use phase, 6.24 g CO2e/hand-drying, is the same for all scenarios, causing 43–66% of the total climate change impact. The climate change impact of the use phase is primarily caused by electricity used for washing the towel.

The results indicate that the key to reducing the climate change impacts and water consumption of the towel is the increase of use times of the product, but the impacts are more ambiguous for recycling.

The benefits of recycling, and even the prioritisation between different CE strategies depends on the type of recycling technology and substituted material. For gaining clearer benefits from CE of cotton roller towels or any cotton textiles, there is a further need for technological development and support for selecting the correct strategies and processes.

For scaling the results to national level, we can estimate the potential for environmental savings looking at the roller towels that are annually removed from service. Altogether 138,517 roller towels were removed by the company studied in 2022, of which 115,129 roller towels were recycled and the rest recovered as energy. For each roller towel Mölsä et al. (2022) estimated 10,500 pulls (handdryings). We assume that all the roller towels that are now recycled, would be first dyed to prolong their lifetime and then recycled chemically at the end of life. The application of such circular approach instead of the linear use and discard -approach, would potentially reduce between 2,889 t and 4,183t of CO2e. In water consumption the saving would be 1,341,828 m3 to 2,321,001 m3. The variations are due to varying assumptions on the technology used for chemical recycling and the material compensated by the roller towel fibres. A small share of the reduction potential is already obtained since some 2% of the recycled roller towels are currently dyed and 80% recycled. In practice, all roller towels are probably not good enough for dyeing at any point of the life cycle (due to heavy dirt etc.). However, there is potential for environmental savings here.

A review of LCA studies on waste management solutions 31

Figure 4. Climate change impact results for scenarios 1–4. The bars below zero represent the avoided impacts through substitution. Net values are presented on top of the bars. (From Mölsä et al. 2022).

Figure 5. Water consumption results for scenarios 1–4. The bars below zero represent the avoided impacts through substitution. Net values are presented on top of the bars. (From Mölsä et al. 2022).

32

A review of LCA studies on waste management solutions

5.6 Recycling wood waste into various products in the Nordics The study aimed at increasing understanding of the environmental impacts of alternative scenarios for wood waste treatment to produce recycled products and at providing support for informed decisionmaking on wood waste treatment options in a form that is applicable and genuinely useful both for the national Nordic authorities and for the wider audience in the public and private sector alike.

The environmental impacts of several scenarios for the treatment of wood waste were studied via life cycle assessment (LCA). The first phase of the work included establishing the scope and boundaries for the LCA work. A preliminary desk study to assess the availability of relevant wood-waste-related statistics and data on different methods for treating wood waste enabled tuning the scope and boundaries, thereby ensuring the LCA study’s production of the indicative results sought as a basis for decision-making. The second phase involved inventory analysis (LCI), impact assessment (LCIA), and interpretation of the results.

The scenarios considered were modelled via both attributional and consequential approaches to LCA. In the former (ALCA), the system boundary begins with the generation of wood waste and includes its transport, industrial sorting, and processing, and it is bounded at the end by various treatment methods’ production of the system outputs: the recycled products examined here. Use of those products and the end-of-life treatment after the second lifecycle lay outside the system boundaries. The ALCA covered the following recycled products: particle board, composite, insulation, bioethanol, biochar, and textile fibre. Incineration of the wood waste with energy recovery was studied as a reference scenario. The system boundaries for the consequential life cycle assessment (CLCA), in turn, included the same processes, but it expanded the consideration to address substitution too: both the products that would be substituted in consequence of the manufacture from wood waste and the marginal energy, displacing the energy production otherwise handled via incineration of wood waste.

Natural gas and wood-based biomass were the sources of marginal heat and electricity in the scenarios considered. The methods employed the standards ISO 14040 and 14044 as applicable, while the study overall did not follow the procedure set forth in those standards. Generic data from the Ecoinvent database was used in combination with other literature, for filling in the gaps in data and enabling the required assumptions.

The ALCA results indicate that producing insulation from wood waste appears to be a good alternative to incineration, whereas incineration outperforms the production of all the other recycled products in almost all impact categories studied. When the substituting products and marginal energy are taken into account in the CLCA, other recycled products too seem to show good environmental performance relative to incineration. The results from CLCA scenarios suggest that, in addition to insulation, the production of textile fibre from wood waste is a solid alternative to producing viscose and cotton. Also, wood waste-based composite outperforms composite from virgin wood in many of the impact categories studied, depending on the marginal-energy source. As for particle board from wood waste, the environmental performance is better in relation to abiotic depletion and ecosystem impacts when compared to plasterboard. For bioethanol and biochar, the substitute production seems to promise better environmental performance than production from wood waste, especially with biomass for marginal energy. In general, the choice for marginal energy has a significant impact on the results, especially in terms of biogenic global warming potential, and if marginal energy with even smaller environmental impacts than biomass was used, other products could well become compelling alternatives.

5.7 Developing the utilisation of ceramic wastes (KERPUR project) KERPUR stands for Ceramic demolition waste in circular economy, a project that tries to find new use for ceramic waste generated in demolition of constructions. The project runs for two years between

A review of LCA studies on waste management solutions 33

8/2021 - 8/2023. While ceramics is a heterogenous group of products with varying attributes (i.e., raw materials' and production processes’ specifications vary), the ceramics scrutinised here are sanitary ceramics (i.e., porcelain WCs and basins) and ceramic tiles.

“Good” applications for ceramic waste are not all that easy to find, because the waste generally is inert and will not dissolve or decompose. These, however, are also the very good attributes of ceramic materials. Some ceramic wastes are allowed to be used in infrastructural base material, for example in roadbeds among crushed rock, while the rest is dumped in landfills. In this use neither the high embedded energy of ceramics nor their terrific properties can be exploited efficiently. Further, both legislation and product standardisation impose challenges to use of waste ceramic in new products. For example, if there is a standard for certain construction product which does not include ceramic waste as an acceptable raw material, the product cannot be brought onto the market. Depending on the recycling method, recycling of ceramics may also be affected by regulations arising from the End of Waste criteria, the REACH regulation and environmental protection act, too, for example.

There are ways to recycle ceramic waste, however. It could be mixed in cementitious products, for example, or replace chamotte in refractory products. The problem is that prior to its use, the ceramics should be collected efficiently, it must be crushed and ground in sizes according to whatever the application in question. The smaller the desired particle size is, the higher is the costs and energy consumption are, too, and so are its environmental impacts, and thus, the substituted product should also be more energy-intensive and expensive to gain profits and environmental benefits. Clinker cement and refractories, e.g., chamotte, are such products, for example. Also, it should be remembered, that recycling of ceramics reduce the need for land occupation and consumption of clay or other types of soils. Hence, even if climate impacts would be negative in recycling, there should always be positive impacts on land use.

The aim of the project is to discover new uses for ceramic waste while studying the environmental impacts that the recycling causes (i.e., footprint). A few example products containing recycled ceramic waste materials are introduced with respect to their impacts in terms of global warming, land occupation and energy demand, and compared to their virgin raw material-based counterparts. In addition, geopolymers are studied as an alternative to traditional cement-based binders.

The results confirm that there are applications in which certain ceramic construction and demolition waste may technically be used and can bring positive impacts in terms of GHG emissions, land occupation and energy consumption. It is recognised, that in practice the use of the ceramic waste is not so simple given the realities of economics, practicality and laws and regulations. However, these are obstacles to conquer, not reasons to give up on recycling.

5.8 Using industrial side stream materials in dredging sludge stabilisation – comparisons in terms of GHGs, strength and economy (Circvol / Circvol 2 projects) Circvol 2 -project reported in Eriksson et al. (2022) the global warming potential, cost, and strength of stabilising dredging sludge with unconventional industrial side stream materials. Typically soil stabilisation is carried out by using cement, but here blast furnace slag, gypsum dust, and ashes from two different combustion plants were used to replace all or some of the cement. This way it is possible to avoid the environmental impacts from cement production while reducing the need to dump the side streams into landfills as waste materials.

Soil stabilisation makes it possible to solidify soft soils for construction. At the same time, harmful substances can be bound and, for example, acid formation in sulphur-containing soils can be controlled.

The production of cement, which is typically used for stabilisation, causes a lot of CO2e emissions, and involves changes in land use. Industrial waste and side streams can be used for stabilisation, including

34

A review of LCA studies on waste management solutions

binders that currently end up in landfills. This subproject report of the CircVol2 project examines the stabilisation of dredged material in terms of GHG emissions, achieved strength, and costs of the binders.

The stabilisation field test, dredging, and disposal, which are the subject of the calculation, were performed in Matalahti, Naantali, in 2020. The field test was performed in different experimental plots, in which different binder mixtures were tested. The binders used were cement, blast furnace slag, ash from a co-fired combined heat and power plant, bottom ash from municipal waste incineration, lime kiln dust, and ready mixtures from two commercial companies. It is possible to stabilise the soil to sufficient strength by using industrial waste and side streams as part of the stabilisation mix, while significantly reducing climate emissions and costs compared to stabilisation with cement alone. With the binder mixtures of this project, the cost of raw materials could be reduced by a third and the amount of emissions by a tenth compared to cement-based mixtures. In conclusion, it is possible to utilise industrial waste and side streams for soil stabilisation. This can significantly reduce GHG emissions and costs, while still achieving sufficient strength. The labour’s share of emissions and costs can be significant, while transport often plays a minor role. The optimal binder or binder mixture in terms of emissions and costs should be chosen on a case-by-case basis. As urbanisation continues and construction expands to sites that need soil stabilisation, it will be possible to find cost-effective alternatives with significantly less impact on the climate, while promoting circular economy.

5.9 Developing geocomposites from industrial side streams to compensate concrete in construction (UIR project) New generation urban development is focusing a lot on smart technologies, but modern construction engineering has an important role when creating smart cities. The Urban infra revolution, UIR project, developed circular economy and low-carbon solution to revolutionise the urban construction engineering. Side streams from industry were utilised in urban construction by combining them into a high-value material to replace concrete. Side streams were analysed, characterised and modified by activation. Novel material formulas were created, containing suitable side streams to be used as geopolymer binder (replacing cement) and as inorganic aggregates in geocomposites. Innovative fibre reinforced geocomposites were developed to achieve the high standards of construction industry. (Urban Innovative Actions 2023).

In this study (Abdulkareem et al. 2021), life cycle assessment (LCA) of conventional concrete and a proposed innovation of geopolymer composites were performed to estimate the environmental impacts of geopolymer composite in comparison to conventional concrete.

Firstly, environmental performance was conducted for different mix-designs of fibre reinforced geopolymer composites in comparison to conventional concrete and steel fibre reinforced conventional concrete. This assessment was conducted to identify the main factors contributing to the environmental burdens of these products that could be considered for the future development. The functional unit was defined as the environmental impact generated due to the activities involved in the production of 1m3 of concrete. The result showed sodium silicate followed by steel fibre and sodium hydroxide to be the highest contributor to the impact categories global warming potential, acidification potential, eutrophication potential, ozone depletion potential, abiotic depletion potential, freshwater aquatic ecotoxicity potential, marine aquatic ecotoxicity potential, photochemical ozone creation potential, terrestrial ecotoxicity potential, human toxicity potential. The fibre reinforced geopolymer composites showed 0.8%-23% decreased emissions when compared to conventional concrete. (Abdulkareem et al.

2019).

Secondly, environmental performance was conducted for chemically modified waste-derived geopolymer composite mortar in comparison to conventional geopolymer composite mortars, to estimate the influence of activator on environmental impact of mortar and to assess if waste-derived

A review of LCA studies on waste management solutions 35

activators improve environmental performance of the geopolymer composites. The functional unit was defined as the environmental burdens generated due to the activities involved in the production of 1 m3 of geopolymer composite mortar with compressive strengths between 52 MPa–60 MPa at 28 days.

Sodium silicate powder and sodium silicate solution were the most contributing materials to the impact categories. Overall, chemically modified waste-derived mortars had 58%–62% lower impacts than conventional mortars because of substituting conventional activator with waste-derived activator. Result also show that waste-derived activators can completely substitute conventional alkali-activators while also producing materials of equivalent strengths. It also construes the fact that majority of environmental impacts from geopolymer composites are associated with the type of alkali-activator used and a waste-derived activator can significantly improve their environmental performance.

(Abdulkareem et al. 2021a).

Lastly, comparative environmental impact study was conducted for low-height noise barriers made from traditional concrete and locally developed geopolymer composite to evaluate improvement potentials in the product design. The functional unit is to reduce railway noise through a noise barrier with a length of 20m with an assumption of 5dB transmission loss for 50 years. Results show that geopolymer composite noise barrier can achieve 7%–78% lower global warming effects when compared to noise barrier from conventional concrete. Although, the geopolymer composite noise barriers are of different compressive strength. The result shows the feasibility of developing geopolymer composite from 83% industrial by-products and 0.3% alkali-activator. (Abdulkareem et al. 2021b).

Scaling up of these results was not carried out, since information on the demand for the type of structure developed here was not readily available.

5.10 Promoting the use of LCA (CONSOLCA project) Life Cycle Assessment (LCA) is a widely accepted methodological approach for assessing the environmental impacts of products and services over their life cycle and it is increasingly used in decision-making both in businesses and in public sector.

The internal Finnish Environment Institute (Syke) seed money project CONSOLCA (Judl et al.

2021) aimed to: • consolidate Syke’s practical LCA skills, • develop new, and improve existing, LCA internal operational standards, • identify new knowledge on emerging issues in LCA from across Syke, • reinforce Syke’s capacity, and identify knowledge/skills gap, in LCA, and • ensure that Syke will be one of the key and competitive players of LCA in Finland, also in the future.

Moreover, the project aimed at strengthening national and international collaboration to create a more solid grounds for future research. The project thus contributed to Syke’s strategic objective to base decision-making on reliable and robust research-based data.

Moreover, LCA is a practical method in assessing the environmental impacts of possible solutions to strengthen a sustainable circular economy, as well as low-carbon and urban scale solutions. However, in order to deliver on its promises, LCA requires a strong scientific basis, ethical practices and nationwide collaboration. These aspects were in the core of the CONSOLCA project.

36

A review of LCA studies on waste management solutions

6 Summary of the environmental impacts of Circwaste and its complementary actions The focus waste fractions of the national waste plan are municipal solid waste (MSW), biowaste, construction and demolition waste (C&DW), and waste electrical and electronic equipment (WEEE).

The potential environmental impacts connected to these waste flows, except for WEEE due to lack of adequate background data, were assessed repeatedly during the Circwaste project as described in chapters 2.1 and 3. These impacts and changes in them reflect the development of both the amounts of the wastes and the ways they are utilised. Below we summarise the development in the environmental impacts connected to the three focus waste fractions. Additionally, the solutions developed and analysed in the Circwaste sub-actions and complementary actions reported in chapters 4 and 5 all show potential to reduce the environmental impacts connected to the focus waste fractions as summarised below.

6.1 Municipal Solid Waste The data used for the LCA calculations on the amount of MSW from households per person (excluding yard and garden waste as well as home composted biowaste) showed, that in five municipalities the waste volume per person decreased and in three it rose.

Starting (in 2016) and expanding the plastic packaging waste collection in Finland by legislation during the observation period has made an obvious change in plastic waste flows. From 2016 to 2021 the plastic packaging waste volume has more than doubled in all the studied municipalities. The amount of separately collected cardboard waste has increased significantly, too. On non-weighted average (i.e., average of averages) per person it increased by ca. 75% from 2016 to 2021. This is probably a result of the constantly increasing trend of online shopping. The largest drop, on the other hand, was in the separately collected paper (-27%), which is in line with the global trend caused by digitalisation.

Perhaps one interesting observation is the increase of WEEE. This may be a result of increased consumption of electronic devices, resulting also in increasing volume entering the recycling loop.

The average of averages of the waste amounts per person in the studied municipalities has decreased only for mixed waste (-4%) and paper (-19%). The total MSW volume per municipality has increased by 4% on average, led by significant increases in plastic and cardboard. It could be interpreted, that since the amount of mixed MSW has decreased while the total amount of MSW in the municipalities has increased, the level of recycling has risen. Additionally, in general, the environmental benefits of recycling have increased from 2016 to 2021. This is because mixed waste flows have (in most cases) decreased while those with large credits (metals for example), have increased.

While increased waste quantity refers to growing material consumption and is, thus, an undesirable development, improved recycling can alleviate the negative impacts of both the material consumption and the waste generation. This is shown in Figure 6 where the credits from recycling have increased more than the emissions from waste management in terms of CO2e from 2016 to 2021, resulting in increased net positive impact potential. Main reason for this is the increased plastics recycling. Since the intension of this calculation was to show the potential benefits of recycling, all separately collected plastics packaging was assumed to be recycled. However, the result is an overestimation of the current situation.

A review of LCA studies on waste management solutions 37

600 400

kg CO2e/t waste

200 0 -200 -400 -600 -800 -1000 -1200

2016

2021

Emission

481

495

Credit

-903

-1062

Net

-422

-568

200 150

kg CO2e/person

100 50 0 -50 -100 -150 -200 -250 -300 -350

2016

2021

Emission

135

133

Credit

-253

-286

Net

-118

-146

Figure 6. Average impacts (from waste management), credits (from recycling) and net (Emission + Credit) in terms of CO2e in the selected municipalities on average in 2016 and 2021 per ton of all wastes in the upper and per person in the lower figure.

When considering the different municipal waste materials, we can state that the extension of the separate collection of plastics that was studied in Central Finland (chapter 4.2) has now been carried out in the whole Finland. This extension is awaited to be reflected in increased amounts of separately collected plastics packaging as well as increased recycling rate for plastics. The latest data on recycling is from 2020 and shows a 26% recycling rate for plastics packaging which lies way behind the targeted 50% recycling by 2025 and 55% by 2030.

In Finland’s sparsely populated areas, the collection rate for plastics packaging has remained low, possibly due to the inconvenience of the current system where the households are expected to transport their separated waste to regional waste points. The problem of extending the household collection to the sparsely populated areas include concerns related to increase in environmental impacts and costs of collection. One solution could be a system where plastic packaging is collected from households with other packaging materials mixed in the same bin. The complementary action reported in chapter 5.2 (Salmi et al. 2023) compared the current regional collection scenario (S1) where PMC (Plastic, Metal

38

A review of LCA studies on waste management solutions

and Cardboard) waste fractions are source separated at households and transported to a regional collection point by the waste generator with a passenger car, to the co-mingled collection scenario (S2), where the PMC waste fractions are source separated in a mutual bin that is collected from households by a waste truck. The co-mingled collection (S2) performed better in most impact categories mainly due to lower impacts from transportation and higher benefits from material recovery. In climate change impact category, the emissions in S2 were 76% lower. The parameters with the highest effect to the results were the electricity and heat efficiencies of MRW (Municipal Residual Waste) incineration, the collection rates, mechanical separation (MS) recovery rates and passenger car parameters. From the plastic substitution rates only the ones for LDPE and PP are noteworthy. To meet the recycling rate target of 50%, the collection rate and mechanical separation efficiency would need to improve drastically even in the co-mingled system. Also, it should be noted, that the commitments of Finland to reduce the carbon emissions of the energy sector means that the benefits of collecting and recycling more waste, plastics especially, will be even greater in the future making a case for co-mingled collection to be preferred.

Currently majority of the plastic waste collected and recycled on the national level is plastics packaging, and the collection of other types of plastics is scarce. However, other plastics have potential for recycling as well, and solutions need to be developed for several types of products and plastics in order to move towards higher recycling rates. The complementary action reported in chapter 5.4 (Judl et al. 2023) quantified the system-wide climate impacts of plastics packaging in Finland. The goal was to study the Finnish post-consumer plastics packaging waste system (falling under the extended producer responsibility, EPR) in 2019 and estimate its climate impacts, as well as to explore the climate impacts of alternative future scenarios. The climate impacts of the post-consumer plastic packaging waste processing system in Finland in 2019 were 178 kt CO2e, excluding exports and credits from avoided production. Including exports, the total impacts were 182 kt CO2e. When avoided production is included in the equation, the net climate impacts of the system are 155 kt CO2e, or 151 kt CO2e if export is excluded. The analysed system’s emissions were equivalent to approximately 0.34% of total Finnish CO2e emissions. The impacts allocated per tonne of waste are 2.3 t CO2e/t when export is excluded, 2.4 t CO2e/t when export is included, 1.9 t CO2e/t for net impacts without export and 2 t CO2e/t for net impacts with export. The study looked at how different measures (scenarios) affect the impacts. In isolation, each individual measure (scenario) leads to a relatively small reduction of net climate impacts; between 2.2% and 11.2%. With some of the measures being mutually reinforcing, the joint implementation of various measures was found to be more effective. In 2019, the amounts of separately collected plastic waste exceeded the total capacity of mechanical recycling. Therefore, an increase in separate collection alone did not deliver substantial reductions of the overall impacts (3.7%). The further sequential results reveal that increased collection, coupled with improved operational yields of mechanical recycling, can lead to an up to 9.1% reduction of climate impacts, but the reduction can be further facilitated by the currently planned increase of the capacity of mechanical recycling (16.6%). In the scenario implementing all measures, including chemical recycling, the reduction can reach up to 30.4% in total. The introduction of chemical recycling and the combination of all measures allows for the system to deal with challenging and previously unrecyclable waste fractions, bridging the gap to the recycling targets.

The overall recycling rate for the MSW, 39% in 2021, also lies behind the targets set by the Waste Framework Directive (WFD) (at least 55% of municipal waste recycled by 2025, 60% by 2030, and 65% in 2035) (Statistics Finland, 2023a). Since 2016, the amount of MSW per person has increased and recycling rate decreased (Statistics Finland, 2023a). Hence additional measures are required to improve the overall sorting of household wastes with different practices. As shown by the complementary action in chapter 5.1 notable climate benefits can be obtained with improved sorting. The sorting efficiency of biowaste was estimated to increase with 28% and of plastics waste 56% if the weight-based Pay-asYou-Throw (PAYT) system would have been taken in use in the whole of Finland. Taking into

A review of LCA studies on waste management solutions 39

consideration also the changes in the mixed waste flows, the basic results show that changing to the PAYT principle in the pricing of municipal waste management in the whole of Finland could save around 13 Mt CO2e annually.

Textiles have gained a lot of focus lately, due to the rapidly growing consumption of textiles and amount of textile waste. The whole textile systems have a lot of problems from the perspective of sustainability. One of the key development issues with textiles is prolonging the life of garments and textiles to reduce the need for new textile production. Also recycling of textile fibres needs to be increased significantly. The results of the complementary action on roller towels (Mölsä et al. 2022), reported in chapter 5.5, indicate that the key to reducing the climate change impacts and water consumption of the towel is the increase of use times of the product, but the impacts are more ambiguous for recycling. The benefits of recycling, and even the prioritisation between different CE strategies depend on the type of recycling technology and substituted material. By scaling the results to national level, we estimated that by prolonging the lifetime of all the roller towels that are now recycled (115,129 roller towels), would potentially save between 2,889 t and 4,183t of CO2e and 1,341,828 m3 to 2,321,001 m3 of water annually when compared to the linear produce-use-incinerate scenario. The variations are due to varying assumptions on the technology used for chemical recycling and the material compensated by the roller towel fibres. A small share of the reduction potential is already obtained since some 2% of the recycled roller towels are currently dyed and 80% recycled. In practice, all roller towels are probably not good enough for dyeing at any point of the life cycle (due to heavy dirt etc.). However, there is potential for environmental savings here. For gaining clearer benefits from CE of cotton roller towels or any cotton textiles, there is a further need for technology development and support for selecting the correct strategies and processes (Mölsä et al. 2022).

6.2 Biowaste Biowaste collection and management has been pushed forward in the recent past years. Many biogas plants have begun operating and stricter collection regulations have been set in Finland, of which some will come in force by June 2024. Nevertheless, it has been estimated, that about 1/3 of the mixed MSW currently combusted could be sorted as biowaste (Suomen kiertovoima ry, 2020). Biowaste mixed in combustible waste results in lower efficiency in incineration and fewer benefits obtained.

In the seven municipalities surveyed from, the quantity of separately collected biowaste per person has ranged from 36 kg–68 kg per person in 2016 and decreased to that of 34 kg–67 kg in 2021 (Pitkänen et al. 2023). The data may inherit inaccuracies and it is incomparable between municipalities or regions.

There may be differences between typical housing types or home composting. Based on the results, there is still quite some room for improvement.

Biowaste can be either composted and utilised as soil amendment or anaerobically digested for biogas and fertilizers. In municipalities, or regions, where biowaste management was changed from composting to anaerobic digestion, the benefits from biowaste recycling increased notably, implying that composting is the less beneficial method to manage biowaste. In the big picture, however, the biowaste volume is relatively small, and so are the impacts and benefits obtainable. This does not mean that food waste is not a problem, because most of the inputs needed in the life cycle of food are used before the food is on our plates. These inputs (and emissions/impacts) cannot be outweighed by the benefits available through recycling. For example, in section 4.1. we can see that a ton of food served in schools generate approximately 560 kg CO2e emissions, which is roughly five times that of the net benefit gained if biowaste is processed into biogas and fertilizers (net ca. -120 kg CO2e/t).

Most of the food waste is generated in households. Yet, probably the most visible biowaste comes from restaurants and catering services as people leave food on plates which is then thrown away; however, much larger quantity is the leftovers on the dining line. In Finland school lunch is served by

40

A review of LCA studies on waste management solutions

municipalities for free to all students in comprehensive, vocational, and upper secondary schools. The City of Pori wanted to reduce the food waste in the schools they provide food with, for both environmental and economic reasons. They show an example of how food waste can be reduced significantly from catering service both with better information on how many students come to eat and by giving the surplus to charity (sect.4.1). In addition to school lunches, there is also a strong work lunch culture in Finland. Considering that typically about 20% of edible food in caterings becomes leftovers, much of which is thus wasted, there is a great potential both to reduce food waste and food consumption if the supply and demand of food could be better matched.

Biowaste collection phase is also important to optimise. In JÄTEKIVA-project (sect. 5.3) it was studied that when collection is expanding to detached housing areas, up to one third reduction both in costs and emissions may be avoided just by changing the collection interval from weekly to biweekly.

Also, sharing biowaste bins is a way to improve the collection efficiency, and home composting can eliminate the need of collection completely. This said, while waste is wanted to be collected better and new acts are set in force, it is important to consider the practical execution of them.

6.3 Construction and Demolition Waste Construction and demolition sectors are major waste producers globally. The construction and demolition waste (C&DW) composes of various materials used in building and in buildings. Most of the waste are soil and dredging waste, but concrete and bricks (categorised as mineral waste), metals, plastics, wood, bitumen, mineral and glass wool, glass, paints, for example, are all typical C&DW. Many of these materials are not separated and end up in mixed waste but could be recycled if collected separately at the site. For example, Puhas company piloted improved C&DW separation at construction site and increased waste categories to 20 from earlier 7 categories (sect. 4.3). Largest waste categories, asphalt, rock, and soil were already separated in normal waste separation, but the better separation allowed for recycling of additional 22 tons (out of the total of 880 tons) compared to normal separation level. These wastes included plastics, metallic containers, glass, wool, and gypsum, for example. These materials have high emission reduction potentials when they substitute for virgin materials. In our calculations recycling these materials into new products could save up to 70 % of CO2e emissions compared to that if made from virgin raw materials. This value may be optimistic because some of these materials may not be recyclable because of contaminants or impurities. Nevertheless, the case shows that in theory improved C&DW separation has potential to high relative emission reduction.

Much C&DW may be utilised in infrastructure construction. This applies especially to concrete that may be crushed and installed in roadbeds. Concrete is also a material that comes in large volumes from demolition projects. In addition, soils excavated from construction sites are considered as C&DW and may be used in infrastructure construction instead of final depositing in landfills. Even soft soils may be used if stabilising aggregates, e.g., ash, slag, clinker, are used to harden the soft soil material (sect. 4.6 and sect 5.8). This lessens the need for landfill sites and mining of aggregates such as gravel, from nature. Although the emissions connected to soil materials are relatively low, the amounts of materials are extremely high and therefore emission savings from the recycling of such materials can be considerable. The study reported in section 4.6 (Teittinen 2023a) estimated that around 2,500,000 t of landfilled surplus soils annually in the Finnish Transport Infrastructure Agency (FTIA) projects could be utilised instead of landfilling in Finland. Without any consideration on transportations, a rough estimate of the potential environmental savings from this utilisation would be around 10,000 t CO2e (0.004 kg CO2e/kg gravel; Finnish Environment Institute 2023).

Some of the C&DW may be complicated to recycle and new methods are needed. One such way is to use waste in wood polymer composite materials (sect. 4.4.); however, this alone cannot be the sole solution for reaching recycling targets, but a small piece of it. Also, the study emphasised that mono-

A review of LCA studies on waste management solutions 41

material recovery is preferred over composites, especially for wood. Also, the benefit was yet again depending on the assumption of what the composite material substitutes for. In pallets (sect. 4.5) composite materials are potential addition to wooden and plastic pallets and have certain benefits and disadvantages compared to both alternatives. Functioning recycling schemes for composite products can be considered as a prerequisite for the sustainable composite production.

Ceramics are a heterogenous group of materials such as tiles, sanitary ware, bricks, glass, mineral wool. In addition, they are another C&DW material, and difficult to recycle due to their inert nature.

Nevertheless, ceramic materials from construction and demolition sites, such as tiles and sanitary ware, are recyclables but are currently deposited in landfills due to the lack of recycling system in place.

Technically these materials could be recycled in different applications if collected as free of impurities, such as gypsum, asbestos, or plaster. They could be used to substitute raw materials with high embedded energy consumption and GHG-emissions in new ceramics, for example chamotte in fire resistant tiles and boards. However, the problem in recycling these materials is more than just technical: it may be that laws, regulations and standards are more the obstacles than anything else (sect. 5.7). For example, if there is a harmonised standard for certain construction product in force and it does not include ceramic recycling material as an acceptable raw material included in the product, it cannot be rolled out on the markets. Also, End of Waste, Environmental permit and REACH regulation may need to be followed, depending on the choices of management and utilisation.

Construction sector is largely dependent on clinker used both in mortar and concrete production.

Clinker production is an energy intensive process and involves high carbon emissions. The share of clinker in concrete and thus emission intensity may be alleviated by using industrial side streams instead of clinker. There are also clinker-free “concrete” products, geocomposites, being developed to substitute for clinker-based products (sect.5.9). Geocomposite products may reach lower climate impacts compared with their traditional clinker-made counterparts. In the project described in section 5.7. geopolymers were also studied and it was noted that the emission factors for alkaline activators used in geopolymers have large variation depending on the source. If the emission factor is high, then geopolymers perform poorly and vice versa. Thus, the results should be interpreted with care.

There are many materials that cannot be recycled currently or can be recycled only to a very limited extend, for example, PVC-plastics. However, many applications already exist where C&DW may be utilised, and new ways are being discovered. It should be expected that solutions for those that cannot yet be recycled will be found in the future. Currently the main bottleneck is perhaps that construction sites lack possibilities (space, knowledge, obligations) to sort and separate different waste fractions and that it is seen economically more profitable to put minimal effort in sorting.

6.4 Other Life Cycle Assessment (LCA) is a widely accepted methodological approach for assessing the environmental impacts of products and services over their life cycle and it is increasingly used in decision-making both in businesses and in public sector. It is important to constantly develop both the know-how of the LCA practitioners and the methodologies and data used for LCAs. The Finnish Environment Institute’s internal project CONSOLCA (section 5.10) was set up to promote the LCA skills and knowledge within the institute, but also to strengthen national and international collaboration to create a more solid grounds for future research.

Moreover, LCA is a practical method in assessing the environmental impacts of possible solutions to strengthen a sustainable circular economy, as well as low-carbon and urban scale solutions. However, in order to deliver on its promises, LCA requires a strong scientific basis, ethical practices and nationwide collaboration. These aspects were in the core of the CONSOLCA project and need to be prioritised also in the future discussions and development.

42

A review of LCA studies on waste management solutions

7 Final remarks

This report attempts to combine the results from different studies to produce a summary of the environmental impacts that the Circwaste project with its complementary projects has had. The report also reviews the potential environmental benefits of larger-scale adoption of some of the practices used in pilot projects. However, this is a very theoretical exercise estimating potential environmental impacts, not something that has been gained.

LCA results on waste management systems can be challenging to interpret. The impacts of the production of the goods that have become waste are not included in the LCA. Therefore, the LCA results may mislead to make a conclusion that generating waste is preferable for the environment, since recycling a unit of waste typically reduces the environmental impacts of the system. Hence less waste results in both lower impacts and lower benefits, and consequently in less net benefits. However, the best option for the environment would be to reduce consumption, and not to generate waste in the first place. This is also clear from the studies reviewed in this report. Reducing the amount of mixed MSW and hence increasing recycling instead of incineration has the potential to reduce the overall environmental impacts of MSW management.

The case studies reviewed in this report, altogether seven Circwaste pilot projects and nine complementary projects, demonstrate solutions that can be taken in use to reduce the generation of waste or to increase the recycling of different waste fractions. These case studies have shown to have potential for reducing the environmental impacts connected to waste management. If these solutions were adopted in all Finland, significant reductions in the environmental impacts could be obtained.

However, the applicability and restrictions of all the solutions shall be carefully assessed before adoption.

LCAs on environmental impacts of waste management is a complex discipline. Ideally the assessments require country, or even region, specific primary data on waste management processes.

This kind of data is not publicly available for the Finnish waste management systems. However, performing assessments with country or region-specific primary data would significantly benefit the planning and evaluations of adjustments and improvements required in the waste management systems.

It would be necessary to produce this kind of primary data on different waste management processes for public use. This calls for joint efforts between the LCA practitioners and the operators of the waste management sector, or even more broadly, the operators within circular economy.

A review of LCA studies on waste management solutions 43

References Abdulkareem, M., Havukainen, J. & Horttanainen, M., 2019. How environmentally sustainable are fibre reinforced alkaliactivated concretes?. J of Cleaner Prod 236, p.117601.

Abdulkareem, M., Havukainen, J., Nuortila-Jokinen, J. & Horttanainen, M., 2021a. Environmental and economic perspective of waste-derived activators on alkali-activated mortars. J of Cleaner Prod 280, p.124651.

Abdulkareem, M., Havukainen, J., Nuortila-Jokinen, J. & Horttanainen, M. 2021b. Life cycle assessment of a low-height noise barrier for railway traffic noise. J of Cleaner Prod 323, p.129169. https://doi.org/10.1016/j.jclepro.2021.129169 Clic Innovation 2022. All in for Plastics Recycling Plastin, Final report 2022. Available from https://www.clicinnovation.fi//wp-content/uploads/2019/08/PLASTIN_Raportti_FINAL-27.5.2022.pdf Eriksson, J-E., Karvonen, J., Kronberg, T., Salminen, J. 2022. Ruoppausmassan stabilointi uusiosideaineilla - Hiilijalanjäljen, lujuuden ja kustannusten tarkastelu Matalahden kenttäkokeessa. Suomen ympäristökeskuksen raportteja 31/2022. ISBN 978-952-11-5504-8 (PDF).

Judl, J., Horn, S., Karppinen, T. 2023. Towards a Low-Carbon Plastic Waste Recycling in Finland: Evaluating the Impacts of Improvement Measures on GHG Emissions. Circular Economy and Sustainability. DOI:10.1007/s43615-023-00306-w Judl, J., Horn, S., Niemistö, J., Suikkanen, J., Lazarevic, D., Lepistö, K. 2021. Life Cycle Assessment supports Sustainability Transformation. SYKE Presents, Life Cycle Assessment (LCA). Helsinki 12/2021. ISBN 978-952-11-5450-8. https://issuu.com/suomenymparistokeskus/docs/en_syke-presents_life-cycle-assessment-lca_12-2021 Kemppi, J. & Niskanen, A. 2018. Muovipakkausten erilliskeräyksen täydentäminen Keski-Suomen alueella.

Ilmastonlämpenemisvaikutukset ja kustannukset. LCA Consulting (now Etteplan). https://keskisuomi.fi/wpcontent/uploads/sites/3/2020/09/26140-C_17_10_optimization.pdf Khan M.H., Deviatkin, I., Havukainen, J., Horttanainen, M. 2021. Environmental impacts of wooden, plastic, and wood‑polymer composite pallet: a life cycle assessment approach. J Life Cycle Assess 26:1607–1622. DOI https://doi.org/10.1007/s11367-021-01953-7 Liikanen M., Grönman K., Deviatkin I., Havukainen J., Hyvärinen M., Kärki T., Varis J., Soukka R., Horttanainen M. 2019.

Construction and demolition waste as a raw material for wood polymer composites - Assessment of environmental impacts. J of Cleaner Prod 225: 716-727. DOI: 10.1016/j.jclepro.2019.03.348 Ministry of the Environment 2022. From Recycling to Circular Economy. National Waste Plan to 2027. Publications of the Ministry of the Environment 2022:13. http://urn.fi/URN:ISBN:978-952-361-266-2 Myllymaa, T., Pitkänen, K., Karppinen T. K. M., Savolahti, H., Dahlbo, H., Judl, J., Neuvonen, J., Ahponen, H., Lepistö, K., Savolainen, H., Ukkonen, A., Rehunen, A., Nurmio, K., Karhinen, S., Alhola, K., Kautto, P., Salmenperä, H., Haavisto, T., Holma, A., Mönkkönen, I., Antikainen, R., Kaminen, K., Turunen, S., Alt, S. & Sederholm, C. 2021. Executing circular economy strategies in practice in Finland – Results and experiences from the Circwaste project. Reports of the Finnish Environment Institute 19 / 2021. http://hdl.handle.net/10138/329090 Mölsä K., Horn, S., Dahlbo, H. & Rissanen, M. 2022. Linear, reuse or recycling? An environmental comparison of different life cycle options for cotton roller towels. J of Cleaner Production 374(2022)133976. https://doi.org/10.1016/j.jclepro.2022.133976 Niskanen, A. & Kemppi, J. 2019. Yhdyskuntajätteen kierrätyksellä vauhtia kiertotalouteen (JÄTEKIVA). Työpaketti 1.4.

Analyysi biojätteen erilliskeräyksen ja käsittelyn kestävyystarkasteluista näkökulmana mahdollisuudet kestävyyden tehostamiseksi. Yhdyskuntajätteen kierrätyksellä vauhtia kiertotalouteen – JÄTEKIVA | Tieto käyttöön (tietokayttoon.fi) Pitkänen, K., Karppinen, T.K.M., Kylmänen, N., Kyynäräinen, A. & Myllymaa, T. 2023. Kiertotalousbarometrit 2023 : Kiertotalous suomalaisten arjessa ja yritysten toiminnassa. Suomen ympäristökeskuksen raportteja 38/2023. http://hdl.handle.net/10138/569826 Salmenperä, H., Dahlbo, H., Turunen, S., Ukkonen, A., Hämäläinen, T., Nummela, E., Ojala, S., Haavisto, T., Laaksonen, J. & Vanhatalo, M. 2019. A weight-based household waste payment system – Information pack for implementation.

Publications of the Ministry of the Environment 2019:1. http://urn.fi/URN:ISBN:978-952-361-000-2 Salmenperä, H., Kauppila, J., Kautto, P., Sahimaa, O., Dahlbo, H., Kaitazis, N., Autio, I., Niskanen, A., Kemppi, J., Papineschi, J., von Eye, M., Durrant, C. & Tomes, T. 2019. Yhdyskuntajätteen kierrätyksen lisääminen Suomessa –

44

A review of LCA studies on waste management solutions

toimenpiteet ja niiden vaikutukset. Valtioneuvoston selvitys- ja tutkimustoiminnan julkaisusarja 15/2019. https://urn.fi/URN:ISBN:978-952-287-644-7 Statistics Finland 2018. Tilastokeskus (2018). Jätteiden hyödyntäminen on korvannut yhdyskuntajätteiden kaatopaikkasijoittamisen https://www.stat.fi/til/jate/2016/13/jate_2016_13_2018-01-15_tie_001_fi.html. [Accessed 31.12.2023] Statistics Finland 2023a. Waste statistics. Official Statistics of Finland. https://statfin.stat.fi/PxWeb/pxweb/en/StatFin/.

[Accessed 31.12.2023] Statistics Finland 2023b. Regional statistics on entrepreneurial activity. Official Statistics of Finland. https://statfin.stat.fi/PxWeb/pxweb/en/StatFin/ [Accessed 31.12.2023] Suomen kiertovoima ry 2020. Koostumustietopankki. https://kivo.fi/ymmarramme/koostumustietopankki/. [Accessed 31.12.2023] Teittinen, T. 2023a. Circwaste C.22. Final LCA/LCC report (unpublished).

Teittinen, T. 2023b. Circwaste C.10, Sampaanalanlahti. LCA/LCC report (unpublished).

Urban Innovative Actions (UIA) 2023. Urban infra revolution - Circular economy materials and novel method development to produce recyclable and functional urban construction products, https://www.uia-initiative.eu/en/uia-cities/lappeenranta

A review of LCA studies on waste management solutions 45

Report of the Circwaste project coordinated by the Finnish Environment Institute:

A review of LCA studies on waste management solutions ISBN 978-952-11-5645-8 (online) Syke, 2024.