Circular Water Economy in the EU: Findings from Demonstrator Projects
2. Circular Economy for Water in Europe
- Local regulations to make circular water solutions mandatory or defining requirements for its integration within the local practice;
- Technical requirements for buildings and planning established by an institutional actor, such as minimum water quality requirements and the sizing process of components of rainwater- and greywater-reuse systems;
- Financial incentives for the purchase of circular water systems or in the form of tax reduction;
- Experimental projects, including in newly developed residential areas;
- Communication with the public and stakeholders to raise awareness and increase acceptance of circular water solutions.
- Water reuse at multiple scales supported by nature-based storage, optimal management strategies; advanced treatment technologies, engineered ecosystems, and compact/mobile/scalable systems.
- Specific to wastewater reuse, the European Parliament recently released Regulation (EU) 2020/741 , establishing the minimum requirements for water reuse, to “facilitate the uptake of water reuse whenever it is appropriate and cost-efficient, thereby creating an enabling framework for those Member States who wish or need to practice water reuse”.
- Other significant related regulations for circular water solutions and the description of the CE Action Plan and relevant regulations are summarised in Table 1.
- Energy (combined water-energy management, treatment plants as energy factories, water-enabled heat transfer, storage and recovery for allied industries and commercial sectors) and materials (nutrient mining and reuse, manufacturing new products from waste streams, regenerating and repurposing membranes to reduce water reuse costs, and producing activated carbon from sludge to minimise costs of micro-pollutant removal).
3. Materials and Methods
3.1. Overview of the Cases
3.2. Data Collection
- The project, water application; building, urban, irrigation, etc.
- Characteristic of the circular water solutions available in the project.
- The motivations which led to the use of circular water solutions in the project.
- The evaluation of the project: does it meet one or more set objective (s)? Other purposes? … If it does not work, what are the barriers?
- The operation of the system and its cost.
- The maintenance of the system.
3.3. Data Analysis
4.1. Barriers and Challenges
4.1.1. Policy and Regulations
4.1.2. Cost and Incentives
4.1.3. Permit and Authorisation
4.1.4. Overlapping Spheres of Influence
4.1.5. Users and Customers’ Appreciation
4.1.6. Possible Harm to Water Companies
- Opportunities to optimise rather than create new legislations: There already exist some water-saving requirements in most building codes and legislations that can be altered and tweaked to include compulsory circular water solutions. This is appropriate if suitable financing options and incentives were provided to increase the uptake of these solutions.
- CE for water can support flooding and other climate-resilience strategies: Local government and water authorities/companies are open to the idea of reusing water, as there is likely a need for major investments in the centralised water infrastructure if the system has not been modernised. A circular solution for water on housing and local street levels can help fix existing issues with sewage and storm drainage, which can directly benefit local municipal and water authorities. In addition, green spaces, soft landscapes, and water features require a significant amount of water to maintain, which drives the need for communal circular solutions. Most participants have reported that due to increasing water stress, especially in the summertime, there might be a rethinking of water reuse policy, which could bring circular water solutions more into focus. However, they all agree there is much work to be done on a political level to promote water reuse in Europe.
- Early-stage integration in large-scale housing and urban schemes: High-density and mixed-use developments provide both economic advantages and better chances to deliver circular solutions in design and urban planning. New housing developments provide good opportunities to implement and drive circular innovation solutions. Housing developers in many EU countries already usually install rainwater butts and rainwater control measures on plots as they are required by most planning frameworks. These can be made to be retrofitted or upgraded in the future for rainwater harvesting. Similarly, new mixed-use housing developments could be built with a dual piping system (one for greywater and one for blackwater) in a way that allows future house owners to install greywater treatment and heat-recovery systems. There is also still a possibility of implementing circular regulations on ongoing projects if the timing is right.
- Demonstrator projects help to raise awareness, explore, and enhance financial and non-financial value of CE for water solutions: The cost-benefit analysis of schemes should include other value metrics such as water-saving requirements and environmental beliefs. Innovative circular water solutions combined with good marketing strategy make schemes more attractive and competitive for investment. It was demonstrated that successful demo case projects can drive and encourage local and national legislation. First, it is important to have pilot projects as demonstration/reference points of innovative circular technologies. Then, it is important to train, educate, and sensitise the local authorities to be able to support the operation of such configurations and technologies. This should be done in a well-structured manner through a dedicated piece of legislation. This kind of activity can be implemented through a top-down approach as first the decision of the planning is down to a high level and then the implementation part is performed by a user/technician.
- Maximise existing opportunities for decentralised treatment and reuse: Current circular-water technologies allow water to be extracted from sewers and treated locally in space-limited units for reuse at the point of demand. What is left is the optimisation of the configuration in terms of efficiency and cost-benefit balance for developers and users.
- Lastly, an opportunity for European countries lies in the implementation of the new EU regulation on minimum requirements for water reuse, which will provide the legal baseline for water reuse for agriculture and encourages local authorities to adopt suitable regulations in the future for urban reuse as well.
6. Conclusions and Recommendations
- Adopt the fit-for-purpose water principle: In addition to reducing the unnecessary water abstraction and treatment processes and streamlining water quality requirements, it will engender a new and innovative wastewater service innovation model, which will better reflect the value of water, in any form, and promote its circular lifecycle use.
- It is a matter of scale: Policy, guidelines, processes, and protocols for circular water reuse should reflect the context, application (quality), and scale (system). Permit processes for small-scale domestic schemes and prosumers should be streamlined and accessible and should not be as complex as those of urban-scale, public-oriented systems.
- Mitigate cost and financial risks by allocating investments and incentives along with three deployment scales: capture and treatment, distribution, and use. Rainwater, greywater, and nutrient recovery can operate at centralised, satellite, and local scales. This means that life-cycle cost-benefits and risks should be assessed, and incentives should be targeted at those more capable to provide the necessary infrastructure and upscaling but least likely to directly benefit from such investment. This will address the value disparity in water processes, e.g., industry pay per water discharged, end-user pays per water used, or new versus retrofit projects. Studies have shown that incentives at the bottom—end-use scale—are minimal considering the already low cost of water, whereas direct costs to companies and industry are more significant as projects could be high-risk, high-cost, and high-uncertainty. Therefore, the key driver should be ensuring that the correct systems are installed, serviced, and maintained at scale to maximise updates and make circular water solutions more widely used.
- Address the process, performance, and route-to-market gaps: In the cases studied, one to more than six permits could be required for projects by different regulatory bodies or authorities. The complexity of bureaucratic processes and durations for obtaining permits also varies. This can be particularly burdensome for those proposing small-scale systems or solutions, who may also lack the technical and administrative expertise to navigate the various rules and requirements. In addition, once permits are issued, quality and other maintenance requirements may be too burdensome and bureaucratic to make endeavours profitable. These rules are also less likely to be monitored or enforced. Therefore, permits should be designed based on scale, application (fit-for-purpose principle), and risks. Reporting and monitoring processes ranging from self-reporting and certification to approved certifiers should be considered.
- Improve knowledge and awareness across all sectors and user groups: The sustainability basis for circular water technologies relies on a coherent justification of the environmental, economic, and social benefits and impact. Social impacts include maintaining the health and wellbeing of people. This includes overcoming perceptions of health risks of decentralised water sources. Therefore, in addition to points 1–4 above, improving access to information and technical support; commissioning, publicising, and making more demonstration projects available for visits, question, and answer sessions; and offering training and certifications for policymakers and skilled professionals would collectively raise awareness and improve the positive uptake of decentralised water solutions.
Informed Consent Statement
Conflicts of Interest
Appendix A. Project’s Leader Interview Guide
- Would you please introduce yourself?
- What is your current job title/position?
- How many years of experience do you have in your current role?
- What do you consider your main area of expertise?
- In which ways? Can you please elaborate?
- Can you please describe your responsibilities and your role within this project?
- What circular water solution does the project utilise?
- What was the main motive and reason for implementing these circular solutions in the project? (e.g., sale, environmental, or regional authorisation)
- Did the project achieve those goals? If yes, how? If not, why?
- Do developers in your region prefers one type of circular water solution over the other? Which one is more prevalent? Why?
- In addition to these circular solutions what other water-related design and specifications were required by local or national building code? (e.g., reduction of water consumption or wastewater discharge requirements)
- Did the installation of circular water/water reuse solutions in your project required any prior authorisation or planning permits?
- If no, why? If yes, who required the approval/permit?
- Can you describe the process required to get the permit? How long did it take? Do you think the regulation requirements are reasonable?
- Did you or the developer/owner of the projects face any issues while planning, designing, or acquiring authorisation for the circular water/water reuse solutions in this project?
- If Yes, what were they? (e.g., permit-related, technical, bureaucratic)
- If no, are you aware of any common regulatory or planning issues that similar projects face in your country/region? What are they? Why?
- Do these issues reoccur with each project? Why? Were they solved? Why? How could they be avoided?
- What were the main building codes and regulations that applied to the project including the design, planning, operation, and maintenance phases?
- What are the requirements? What conditions apply?
- What would you consider to be the positive and negative aspects of these planning codes, regulations and planning requirements?
- What are the challenges to compliance and implementation?
- Do you have any concerns about legislations? What are they? Why?
- Are there planning rules and requirements that apply to the implementation of circular water technologies and solutions to buildings?
- What are the requirements? What conditions apply?
- What are the challenges to compliance and implementation?
- What would you consider to be the positive and negative aspects of these codes and regulation requirements?
- Do you have any concerns about the legislations concerning the use of circular water technologies in buildings? E.g., Technical, procedural (time, cost), financial (general/overall costs), water quality requirements, capacity to implement etc.
- Did these codes and regulations include incentives including tax, financial support?
- If yes, was this project eligible? In what way or form?
- What were the criteria required to get the funding/to subsidise? Can you describe the application process? How long did it take?
- To what extent does the planning and building regulations impact on decisions to implement circular water/water reuse solutions in your scheme?
- Do you think the current regulatory framework and building code encourage developers to use circular water and energy solutions? If no, why? If yes, how?
- What barriers did you experience? How can they be avoided?
- Are you aware of any new building/planning or circular water/water reuse solutions regulations that are due to be active soon? What are they? How are they different?
- What are the challenges?
- How do you think these can be addressed?
- Who were the beneficiaries of the scheme?
- How do they benefit?
- Were they and other stakeholders consulted? During which stages of the project?
- Are there any stakeholders not benefiting or being affected negatively by the use of circular solutions in the project? Who are they? How? How could this be fixed?
- Some water companies and authorities’ price water and tax sewage based on consumption alone and not discharge, is that is the case in your region? If this is the case, would large scale domestic circular water/water reuse solutions harm water companies financially? Why? How? What can be done?
- Did the use of circular solutions for water impact the unit’ value, sale, lease of the building or property? If so, How?
- Who is responsible for maintaining the system and paying the energy bill? What is the current arrangement?
- In your opinion are the circular water/water reuse solutions valued, effectively utilised by end-users?
- Was the use of circular water/water reuse solutions profitable? For whom, the provider or the end-user? Why? What are the main issues? What could be done?
- In your opinion, do current planning and building regulations drive innovation in practices toward circular water/water reuse solutions in housing projects?
- Why? How? What barriers did you experience/exist? How can it be improved?
- Can most developers be innovative when it comes to circular water/water reuse solutions in domestic projects? Can they be innovative and profitable? Why? How?
- Do local authorities currently have enough legal and legislative tools to influence developers towards using circular water/water reuse solutions? How? Why?
- What innovative planning policies and regulations do you think are needed? What legislations are missing?
- Should they be implemented top-down or bottom-up? Why? How?
- How can these be adopted and implemented? Where are the bottlenecks?
- Is the developer interested in using circular solutions in future projects? Why? What are their concerns? How to overcome it? What would your future advice be? Why?
- What else can be done to improve the uptake of domestic water circular solution?
- What other factors inform your decisions to implement circular water technologies
- Any other comments, observations?
Appendix B. Case Study Survey Form
- Project’s name:
- Location (City, Country):
- Year constructed or installed:
- The main use/purpose of the project:
- If it is residential, what types are available (please select all that apply):
- Detached Houses
- Semi-Detached Houses
- Terraced Housing
- The approximate number of units:
- The approximate number of occupants/users:
- What types of water reuse systems were implemented in the project? (Please select all that apply)
- Rainwater harvesting
- Greywater recycling
- Black (waste) water recycling
- Nutrition recovery
- Wastewater Heat recovery
- Who were the main beneficiaries of the circular water/water reuse solutions? (Please select all that apply)
- The owner/developer of the scheme
- Occupants/users of the project
- The managing companies
- Local authority/municipality
- What are the main applications for the recycled or reclaimed water or energy? (Please select all that apply)
- Non-potable domestic use e.g., toilet flushing, cleaning
- Non-potable industrial use e.g., cooling systems
- Garden and other irrigation uses
- Outdoor communal purposes only e.g., Vehicle washing
- Water and/or space heating
- If known, what was the approximate cost of the system?
- Was the answer for the previous question (Q.12) per:
- Unit installation
- What was the expected rate of return on investment (ROI) for the circular water/water reuse solutions?
- Less than 2.0%
- More than 8.0%
- What is the expected Payback Period for the circular water/water reuse solutions?
- Less than 12 months
- 1–2 years
- 2–5 years
- 5–10 years
- 11–20 years
- More than 20 years
- What types of incentives/subsidies were available for the project? (Please select all that apply)
- None were available/offered.
- Direct financial subsidies/grant
- Indirect financial subsidies (e.g., Tax breaks)
- Logistic aid and planning/design
- Special building permit authorization
- Who provided the incentive?
- Transnational government (e.g., EU)
- Central government
- Municipal, Local government
- Private financial institution
- Other governmental agency
- No incentives were received
- What type of permit(s) were required for the installation? (Please select all that apply)
- None required
- Planning permit
- Building regulations or compliance permit
- Environmental permit
- Health and safety permit
- Water abstraction/authority permit
- Waste-water discharge permit
- Municipal permit
- Please rate the following factors associated with securing the right permits for the scheme? (1 = extremely negative, 5 = extremely positive)
1 (Extremely Negative) 2 3 4 5 (Extremely Positive) Completeness of the rules and regulations Clarity of the rules and regulations Ease of application, process Time taken to apply and secure the permit Cost of the permit, process
- Please rank the drivers for implementing the circular water/water reuse solutions in the project? (1 = low, 5 = high)
1 (Low) 2 3 4 5 (High) Environmental benefit Social benefit Financial benefit Corporate image, reputation Competitiveness e.g., more sales, share value, increase in market share. Green building rating and certification purposes
- Please rank the barriers to implementing the circular water/water reuse solutions in the project? (1 = low, 5 = high)
1 (Low) 2 3 4 5 (High) Design and technology limitations Cost of operation and maintenance Obtaining the necessary permits Lack of regulations and guidance Lack of financial support and incentives User, occupant factors Market factors
- Any other comments. Thank you for participating
- Tahir, S.; Steichen, T.; Shouler, M. Water and circular economy: A white paper. Ellen MacArthur Foundation Arup, Antea Gr. 2018. Available online: https://nextgenwater.eu/wp-content/uploads/2018/10/Water_and_circular_economy-Co.Project_White_paper.pdf (accessed on 18 June 2022).
- Van Duuren, D.; van Alphen, H.-J.; Koop, S.H.A.; de Bruin, E. Potential Transformative Changes in Water Provision Systems: Impact of Decentralised Water Systems on Centralised Water Supply Regime. Water 2019, 11, 1709. [Google Scholar] [CrossRef]
- Kakwani, N.S.; Kalbar, P.P. Review of Circular Economy in urban water sector: Challenges and opportunities in India. J. Environ. Manag. 2020, 271, 111010. [Google Scholar] [CrossRef]
- Stuchtey, M. Rethinking the Water Cycle; McKinsey Global Institute: Chicago, IL, USA, 2015. [Google Scholar]
- Nika, C.E.; Vasilaki, V.; Expósito, A.; Katsou, E. Water Cycle and Circular Economy: Developing a Circularity Assessment Framework for Complex Water Systems. Water Res. 2020, 187, 116423. [Google Scholar] [CrossRef] [PubMed]
- Leong, J.Y.C.; Oh, K.S.; Poh, P.E.; Chong, M.N. Prospects of hybrid rainwater-greywater decentralised system for water recycling and reuse: A review. J. Clean. Prod. 2017, 142, 3014–3027. [Google Scholar] [CrossRef]
- Abu-Ghunmi, D.; Abu-Ghunmi, L.; Kayal, B.; Bino, A. Circular economy and the opportunity cost of not “closing the loop” of water industry: The case of Jordan. J. Clean. Prod. 2016, 131, 228–236. [Google Scholar] [CrossRef]
- Hervás-Blasco, E.; Navarro-Peris, E.; Corberán, J.M. Closing the residential energy loop: Grey-water heat recovery system for domestic hot water production based on heat pumps. Energy Build. 2020, 216, 109962. [Google Scholar] [CrossRef]
- Magwaza, S.T.; Magwaza, L.S.; Odindo, A.O.; Mditshwa, A. Hydroponic technology as decentralised system for domestic wastewater treatment and vegetable production in urban agriculture: A review. Sci. Total Environ. 2020, 698, 134154. [Google Scholar] [CrossRef] [PubMed]
- Fonseca, A.; McAllister, M.L.; Fitzpatrick, P. Sustainability reporting among mining corporations: A constructive critique of the GRI approach. J. Clean. Prod. 2014, 84, 70–83. [Google Scholar] [CrossRef]
- Diaz-Elsayed, N.; Rezaei, N.; Guo, T.; Mohebbi, S.; Zhang, Q. Wastewater-based resource recovery technologies across scale: A review. Resour. Conserv. Recycl. 2019, 145, 94–112. [Google Scholar] [CrossRef]
- Gikas, P.; Tchobanoglous, G. The role of satellite and decentralized strategies in water resources management. J. Environ. Manag. 2009, 90, 144–152. [Google Scholar] [CrossRef]
- UN United Nations. World Water Development Report 2017; UN United Nations: Hague, The Netherlands, 2017.
- Adams, K.T.; Osmani, M.; Thorpe, T.; Thornback, J. Circular economy in construction: Current awareness, challenges and enablers. Proc. Inst. Civ. Eng.-Waste Resour. Manag. 2017, 170, 15–24. [Google Scholar] [CrossRef]
- Bouziotas, D.; van Duuren, D.; van Alphen, H.-J.; Frijns, J.; Nikolopoulos, D.; Makropoulos, C. Towards Circular Water Neighborhoods: Simulation-Based Decision Support for Integrated Decentralized Urban Water Systems. Water 2019, 11, 1227. [Google Scholar] [CrossRef]
- Masi, F.; Langergraber, G.; Santoni, M.; Istenič, D.; Atanasova, N.; Buttiglieri, G. Chapter Four-Possibilities of nature-based and hybrid decentralized solutions for reclaimed water reuse. In Wastewater Treatment and Reuse-Present and Future Perspectives in Technological Developments and Management Issues; Environmental Management and Protection; Paola, V., Ed.; Elsevier: Amsterdam, The Netherlands, 2020; Volume 5, pp. 145–187. ISBN 2468-9289. [Google Scholar]
- Estelrich, M.; Vosse, J.; Comas, J.; Atanasova, N.; Costa, J.C.; Gattringer, H.; Buttiglieri, G. Feasibility of vertical ecosystem for sustainable water treatment and reuse in touristic resorts. J. Environ. Manag. 2021, 294, 112968. [Google Scholar] [CrossRef]
- Sgroi, M.; Vagliasindi, F.G.A.; Roccaro, P. Feasibility, sustainability and circular economy concepts in water reuse. Curr. Opin. Environ. Sci. Health 2018, 2, 20–25. [Google Scholar] [CrossRef]
- Ghafourian, M.; Stanchev, P.; Mousavi, A.; Katsou, E. Economic assessment of nature-based solutions as enablers of circularity in water systems. Sci. Total Environ. 2021, 792, 148267. [Google Scholar] [CrossRef]
- Smol, M.; Adam, C.; Preisner, M. Circular economy model framework in the European water and wastewater sector. J. Mater. Cycles Waste Manag. 2020, 22, 682–697. [Google Scholar] [CrossRef]
- Rizzo, L.; Krätke, R.; Linders, J.; Scott, M.; Vighi, M.; de Voogt, P. Proposed EU minimum quality requirements for water reuse in agricultural irrigation and aquifer recharge: SCHEER scientific advice. Curr. Opin. Environ. Sci. Health 2018, 2, 7–11. [Google Scholar] [CrossRef]
- Raso, J. Updated Report on Wastewater Reuse in the European Union. Available online: https://publications.jrc.ec.europa.eu/repository/handle/JRC92582 (accessed on 13 April 2022).
- Cipolletta, G.; Ozbayram, E.G.; Eusebi, A.L.; Akyol, Ç.; Malamis, S.; Mino, E.; Fatone, F. Policy and legislative barriers to close water-related loops in innovative small water and wastewater systems in Europe: A critical analysis. J. Clean. Prod. 2021, 288, 125604. [Google Scholar] [CrossRef]
- Voulvoulis, N. Water reuse from a circular economy perspective and potential risks from an unregulated approach. Curr. Opin. Environ. Sci. Health 2018, 2, 32–45. [Google Scholar] [CrossRef]
- Sodiq, A.; Baloch, A.A.B.; Khan, S.A.; Sezer, N.; Mahmoud, S.; Jama, M.; Abdelaal, A. Towards modern sustainable cities: Review of sustainability principles and trends. J. Clean. Prod. 2019, 227, 972–1001. [Google Scholar] [CrossRef]
- Morales-Pinzón, T.; Lurueña, R.; Rieradevall, J.; Gasol, C.M.; Gabarrell, X. Financial feasibility and environmental analysis of potential rainwater harvesting systems: A case study in Spain. Resour. Conserv. Recycl. 2012, 69, 130–140. [Google Scholar] [CrossRef]
- Tzanakakis, V.A.; Paranychianakis, N.V.; Angelakis, A.N. Water Supply and Water Scarcity. Water 2020, 12, 2347. [Google Scholar] [CrossRef]
- COM/2020/98 Final Communication from the Commission to The European Parliament, the Council, the European Economic and Social Committee and the Committee of the Regions. A New Circular Economy Action Plan for a Cleaner and More Competitive Europe. Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1583933814386&uri=COM:2020:98:FIN (accessed on 29 March 2022).
- Gerolin, A.; Le Nouveau, N.; De Gouvello, B. Rainwater harvesting for stormwater management: Example-based typology and current approaches for evaluation to question French practices. In Proceedings of the 8th International Conference on Planning and Technologies for Sustainable Management of Water in the City, Lyon, France, 24–26 June 2013. [Google Scholar]
- Kirhensteine, I.; Cherrier, V.; Jarrit, N.; Farmer, A.; de Paoli, G.; Delacamara, G.; Psomas, A. EU-Level Instruments on Water Reuse: Final Report to Support the Commission’s Impact Assessment; European Union: Luxembourg, 2016. [Google Scholar]
- Mariya, G.; McNeill, A.; Muro, M. Water Reuse-Legislative Framework in EU Regions; European Committee of the Regions: Brussels, Belgium, 2018. [Google Scholar]
- Gharehdaghy Mianjy, J. Public Acceptance of Greywater Reuse in The Netherlands; Barriers and Motivations. Mater’s Thesis, University of Twente, Enschede, The Netherlands, 2016. [Google Scholar]
- DIN DIN 1989-1: 2002; Rainwater Harvesting Systems—Part 1: Planning, Installation, Operation and Maintenance. German Institute for Standardization (DIN): Berlin, Germany, 2002.
- Ball, T. Harvesting Rainwater for Domestic Uses: An Information Guide; Reference number/codeGEHO0108BNPN-EE; Environmental Agency: Bristol, UK, 2001; pp. 24–28. [Google Scholar]
- Schuetze, T. Rainwater harvesting and management—Policy and regulations in Germany. Water Sci. Technol. Water Supply 2013, 13, 376–385. [Google Scholar] [CrossRef]
- Trapp, J.H.; Kerber, H.; Schramm, E. Implementation and diffusion of innovative water infrastructures: Obstacles, stakeholder networks and strategic opportunities for utilities. Environ. Earth Sci. 2017, 76, 154. [Google Scholar] [CrossRef]
- Braun, V.; Clarke, V. Using thematic analysis in psychology. Qual. Res. Psychol. 2006, 3, 77–101. [Google Scholar] [CrossRef]
- Munaro, M.R.; Tavares, S.F.; Bragança, L. Towards circular and more sustainable buildings: A systematic literature review on the circular economy in the built environment. J. Clean. Prod. 2020, 260, 121134. [Google Scholar] [CrossRef]
- OECD. International Trade and the Transition to a Circular Economy; OECD: Paris, France, 2018. [Google Scholar]
- Maniam, G.; Zakaria, N.A.; Leo, C.P.; Vassilev, V.; Blay, K.B.; Behzadian, K.; Poh, P.E. An assessment of technological development and applications of decentralized water reuse: A critical review and conceptual framework. WIREs Water 2022, 9, e1588. [Google Scholar] [CrossRef]
- Dingemans, M.M.L.; Smeets, P.W.M.H.; Medema, G.; Frijns, J.; Raat, K.J.; van Wezel, A.P.; Bartholomeus, R.P. Responsible water reuse needs an interdisciplinary approach to balance risks and benefits. Water 2020, 12, 1264. [Google Scholar] [CrossRef]
- Bichai, F.; Ashbolt, N. Public health and water quality management in low-exposure stormwater schemes: A critical review of regulatory frameworks and path forward. Sustain. Cities Soc. 2017, 28, 453–465. [Google Scholar] [CrossRef]
- Frijns, J.; Smith, H.M.; Brouwer, S.; Garnett, K.; Elelman, R.; Jeffrey, P. How Governance Regimes Shape the Implementation of Water Reuse Schemes. Water 2016, 8, 605. [Google Scholar] [CrossRef][Green Version]
- Mannina, G.; Badalucco, L.; Barbara, L.; Cosenza, A.; Di Trapani, D.; Gallo, G.; Laudicina, V.A.; Marino, G.; Muscarella, S.M.; Presti, D. Enhancing a Transition to a Circular Economy in the Water Sector: The EU Project WIDER UPTAKE. Water 2021, 13, 946. [Google Scholar] [CrossRef]
- Dionisi, D.; Geris, J.; Bolaji, I.O. Water and the Circular Economy-Where is the Greatest Sustainable Economic Benefit for Resource Recovery in the Water Cycle? Scotland’s Centre of Expertise for Waters: Aberdeen, UK, 2018. [Google Scholar]
|Regulation||Aim||Possible Enabler or Barrier/Constraint for Circular Water Solutions|
|Urban Wastewater Treatment Directive (The Council Directive 91/271/EEC concerning the urban waste-water treatment of 21 May 1991)||To protect the environment from the adverse effects of urban wastewater discharges and discharges from certain industrial sectors (see Annex III of the Directive), concerning the collection, treatment, and discharge of domestic and industrial wastewater||It does not mention decentralised treatment and collection systems. |
Is mainly concerned with the environmental impact of wastewater rather than its reuse applications.
|Sewage Sludge Directive 86/278/EEC||To promote the use of sewage sludge in agriculture and regulate its use to prevent harmful effects on soil, vegetation, animals, and people.||Sludge is one main by-product of treated wastewater that should be treated and disposed of properly. |
The directive objectives reflect core circular water practices.
It does not mention decentralised treatment and collection systems.
In some countries such as the Netherlands, the use of sludge in both agricultural application and landfilling is not legally possible.
|Regulation (EU) 2020/741 on minimum requirements for water reuse||To harmonise minimum water quality requirements for the safe reuse of treated urban wastewaters in agricultural irrigation between EU countries;||There are concerns over the stricter water-quality requirements of the treatment process proposed by this regulation on the financial costs for some EU member countries. |
The regulation could encourage EU countries to increase their uptake of decentralised circular water solutions.
|Regulation (EU) 2019/1009 Safe and effective fertilisers on the EU market||This regulation includes EU-wide end-of-waste criteria for compost, which can be used in organic fertilisers, soil improvers, and growing media.||The regulation is partially concerned with the protection of water quality and its suitability for circular application throughout its cycle.|
|Waste Framework Directive 2008/98/EC||The Waste Framework Directive lays down some basic waste-management principles. It explains when waste ceases to be waste and becomes a secondary raw material and how to distinguish between waste and by-products. The Directive also introduces the “polluter pays principle” and the “extended producer responsibility”.||Most water utility companies in Europe enforce the polluter-pays principle for wastewater based on water consumption and not actual discharge. Therefore, domestic circular water solutions might impose some financial risk on these companies.|
|Industrial Emissions Directive 2010/75/EU (IED)||IED is the main EU instrument regulating pollutant emissions from industrial installations. The IED aims to achieve a high level of protection of human health and the environment taken by reducing harmful industrial emissions across the EU, through better application of Best Available Techniques (BAT) and permits approval.||Permits must consider the whole environmental performance of the plant, including water discharge. |
This might encourage manufacturers to apply decimalised circular water solutions within their plants/factories.
|Energy Efficiency Directive 2012/27/EU||The directive established a set of binding measures to help the EU reach its 20% energy efficiency target by 2020.||One key element of the proposal is a specific requirement for the public sector to achieve an annual energy consumption reduction of 1.7% as part of the objective to enhance the exemplary role of the public sector across a wide range of activities including water. |
Circular water solutions present an opportunity for heat and energy recovery.
|Case Type and Location||Available Circular Solutions||Key Figures||Relevant Sectors||Survey Respondent|
|1||Urban wastewater plant Germany)||Materials, |
|320,000 Population Equivalent, |
30,000 m2 of agriculture
|2||Housing scheme (UK)||Materials |
|2675 homes, 2 nurseries, 3 schools, |
Multi-use commercial centre,
New railway and urban, transport system
|Urban services, |
|3||Urban wastewater plant Timisoara, (Romania)||Materials, |
|2400 L/s Average secondary effluent flow rate, |
38,000 tons/year Annual sludge production,
440,000 m3/year Drinking water supply
|Water and wastewater |
|4||Urban Park |
|25 m3/day autonomous and modular water system||Industry, |
|Research project manager|
|5||Hotel (Spain)||Water, |
|27 Municipalities in the area, |
214 km of coast,
6,400,000 m3/year of total water reused
|Water reuse technologies research centre|
|6||Urban water buffer (Netherlands)||Water, |
|500,000 Households, |
Heavy port industry,
|Urban water research institute|
|Case||Location||Year||Purpose||Types of Water Reuse Systems||Beneficiaries||Water |
|ROI||Payback Period||Incentives||Required Permits|
|1||Athens, Greece||2019–2021||Urban irrigation||Blackwater, Nutrient recovery, Heat recovery||Local authority/municipality.||Garden and other irrigation uses||3.6–5.0%||More than 20 years||Direct financial subsidies/grant||Municipal permit.|
|2||Timisoara, Romania||2021||Mixed-use wastewater treatment scheme||Greywater, Rainwater, Blackwater||Local authority/municipality||Public parks and other irrigation use. Non-potable industrial use||2.0–3.5%||11–20 years||Subsidy from Horizon program at present.||Planning permit; Building regulations or compliance permit; Environmental permit; Health and safety permit; Wastewater-discharge permit; Municipal permit.|
|3||Bristol, UK||Ongoing||Mixed-use urban development||Rainwater, Blackwater, Greywater, Heat recovery, Nutrient recovery||Occupants/users of the project;||Non-potable domestic use; Outdoor communal purposes.||Unknown||Unknown||None were available/offered.||Building regulations or compliance permits; Planning permit.|
|4||Rotterdam, Netherlands||2018||Sports facility and stadium||Rainwater||Local authority/municipality; The managing company; and users of the project;||Football field and other irrigation||5.1–8.0%||11–20 years||Co-provided by the local municipality and Sparta football club initiative for water conservation.||Health and safety permit. Environmental permit. Municipal permit. Permits are necessary for water infiltration and extraction from the regional water authority.|
|5||Braunschweig Germany||2019||Agricultural||Blackwater, Nutrient recovery||Local authority/municipality; Farmers||Garden and other irrigation use; agricultural irrigation;||Unknown||Unknown||financed by wastewater fees;||Building regulations or compliance permits. Health and safety permit.|
|6||Hamburg, Germany||2013–2022||Residential scheme||Blackwater, Greywater, Rainwater||The managing company and residents of the project;||local discharge, irrigation, or commercial use;||Unknown||Unknown||Direct financial subsidies/grants;||Environmental permit; Waste-water discharge permit.|
|7||Lloret de Mar, Spain||Ongoing||Hospitality (Hotel)||Greywater||The managing company and users of the project.||Garden and other irrigation use.||Unknown||Unknown||Direct financial subsidies/grants||Health and safety permit; Municipal permit.|
|Country||Policy Framework||Building and Planning Framework||Circular Water Legislation||Wastewater||Rainwater||Greywater||Governmental Subsidies||Approval Process||Water Discharge Fee|
|Greece||The Joint Ministerial Decree (JMD) 145116/11, and JMD 5673/400/1997||The General Construction Code (Γενικός Oικοδομικός Κανονισμός, or ΓOK), and the Greek urban planning legislation regarding land use mention circular solutions that are required or suggested. In particular, the use of greywater in the buildings is encouraged, as well as the reduction in water consumption by using alternative resources of water, e.g., rainwater, wastewater, etc.||The EU directive on Water Reuse (2019). (JMD) 145116/11, and JMD 5673/400/1997 set minimum requirements for water treatment and reuse in agriculture||Irrigated Agriculture||Non-potable purposes||Non-potable purposes||Non-available||Through local municipality and its sub-divisions (e.g., Health, energy, water) where required or applicable||Unknown|
|Romania||Environmental Protection Law and Law No. 107/1996—the Waters Law||Law No. 197/2016 on the authorisation of construction works (“Construction Law”) and Law No. 350/2001 on Territorial and Urban Planning (“Urban Planning Law”)||The EU directive on Water Reuse (2019) and Law No. 107/1996||No use||No use||No use||Non-available||Unknown||Unknown|
|UK||The water Act (2014) and its implementation. |
The Environment Act (1995), Environmental Permitting (England and Wales) Regulations (EPR)
|BS 8525-1:2010 Greywater a code of practice (BS 8525). |
BS 8515:2009 Rainwater Harvesting Systems—Code of Practice (BS 8515).
The Environment Agency information guide on rainwater and greywater harvesting for more guidance.
|BS EN 16941-1:2018 and the EU directive on Water Reuse (2019)||No use||Non-potable purposes||Non-potable purposes||Non-available||The local water authority notified||None|
|The Netherlands||The Council Directive 91/271/EEC concerning urban wastewater treatment||No local or national building and planning regulation exists for circular or decentralised water solutions||The EU directive on Water Reuse (2019)||Irrigated Agriculture||Non-potable purposes||Football field and other irrigation||Available for RWH in some cities||Unknown||None|
|Germany||Non-available on a national level||Varies by city and state |
The DIN 1989-1 and DIN 4045 work as a recommendation text and guideline for those who wish to use such systems.
|The EU directive toward water reuse of 2019, DIN 1989-1 |
|No use||Non-potable purposes||Garden and other irrigation use; agricultural irrigation;||Available for RWH in some states||Not required||In some regions|
|Spain||The Royal Decree 1620/2007||The Spanish decree for building construction does not specify any requirements for circular water solutions||BS EN 16941-1:2018 and the EU directive on Water Reuse (2019)||Irrigated Agriculture||Non-potable purposes||local discharge, irrigation, or commercial use;||Non-available||Through local municipality||In some regions|
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Qtaishat, Y.; Hofman, J.; Adeyeye, K. Circular Water Economy in the EU: Findings from Demonstrator Projects. Clean Technol. 2022, 4, 865-892. https://doi.org/10.3390/cleantechnol4030054
Qtaishat Y, Hofman J, Adeyeye K. Circular Water Economy in the EU: Findings from Demonstrator Projects. Clean Technologies. 2022; 4(3):865-892. https://doi.org/10.3390/cleantechnol4030054Chicago/Turabian Style
Qtaishat, Yahya, Jan Hofman, and Kemi Adeyeye. 2022. "Circular Water Economy in the EU: Findings from Demonstrator Projects" Clean Technologies 4, no. 3: 865-892. https://doi.org/10.3390/cleantechnol4030054