Nutrient recycling circular economy model for large cities – water treatment sludge and ashes to biomass to bio-energy – NutriBiomass4LIFE
- Beginning – 01/07/2018
- Ending – 30/03/2022
- Total budget – EUR 4 million
60% EU LIFE programme (EUR 2,4 mil.)
23% Lithuanian Ministry of Environment (EUR 0,9 mil.)
2% Swedish Energy Agency (EUR 0,1 mil.)
15% partner contributon (EUR0,6 mil.)
Municipal wastewater treatment sludge management has always been one of the most challenging waste management issues as it has both positive and negative sides. The positive side is that MWTS is one of the major sources with abundant nutrients, which are vitally needed by the plants – primary nitrogen and phosphorus. The negative side – presence of various toxic elements and pathogens, as well negative perception from the local communities due to stenches. EU Sludge directive (86/278/EEC) provides wide possibilities for the recycling of MWTS in agriculture, but despite this opportunity and the fact, that over the years toxic elements in MWTS have been substantially reduced due to implementation of much stricter environmental regulations, MWTS usage for fertilization of food crops has very diverse practices over the EU. Most of the EU members are tightening safety regulations for food production, therefore MWTS usage in food production chain is getting less attractive and less feasible solution for nutrient recycling.
On the other hand, nutrient recycling from nutrient rich waste in agriculture and forestry is one of the top priorities for circular economy. Because nutrient rich wastes, such as municipal water treatment sludge and biomass ashes, besides abundant nutrients contain a number of toxic elements, nutrient recycling from MWTS and biomass ashes in non-food crops such as biomass growing, could successfully become one of best practices all over the Europe and could successfully compete with landfilling and waste incineration – both economically and following the priorities in the hierarch of waste management.
Lithuania has quite a unique situation to become a successful demonstration platform for municipal wastewater treatment sludge recycling using circular economy model.
While implementing Lithuanian sludge management program, which was developed in 2006, and State strategic waste management plan, Lithuania invested hundreds of millions in into 13 large modern regional MWTS management centers, which had installed modern technologies for sludge thickening, anaerobic digestion, drying and final processing into MWTS digestate pallets. 6 smaller MWTS processing companies were upgraded as well, which after sludge thickening are composting MWTS. As MWTS digestion and dry pallet production is installed in all the largest agglomerations all over Lithuania, 85% of total country’s sludge may be processed into fine dried MWTS digestate pallets. Total Lithuania’s annual MWTS production is about 40000 dmt.
While implementing complete modernization of all municipal wastewater treatment facilities, it was not decided how the fine processed sludge would be further used. Large cities do not have practices to use MWTS for nutrient recycling – typically MWTS has been stored in special facilities. There are no special MWTS incineration facilities in Lithuania as well. The only waste incineration plant in Klaipeda may incinerate dried sludge in case sludge suppliers would additionally invest into further sludge agglomeration / briquetting. New waste incineration facility which will be build in Vilnius will not be able to incinerate sludge due to funding status (EU funding requirements) – only municipal waste could be incinerated. Another waste incineration facility in Kaunas is being build and will be able to incinerate sludge since 2020-2021.
Due to unsolved problem of the final usage of fine processed dried MWST digestate, today modern municipal wastewater treatment facilities operate only at limited capacities and do not perform complete environmental functions as it was designed in modernization projects.
The other environmental issue that is emerging all over the EU and that is related to highly promoted usage of biomass in the renewable energy production – is rapid increase in another type of waste – biomass ashes. Biomass ashes are poised with similar dilemma as municipal wastewater treatment sludge - biomass ashes are abundant with certain nutrients (primarily potassium (K) and calcium (Ca), which are not so scare as phosphorus (P), concentration of which in biomass ashes is 10 times less than in MWTS) but they have significant concentrations of heavy metals (e.g. cadmium (Cd), concentration of which in biomass ashes may be several times higher than in MWTS). Due to high concentrations of cadmium (Cd) biomass ashes usage in agriculture is widely avoided on the EU level and large part of the biomass ashes are being landfilled. The countries with intensive usage of forest biomass in renewable energy production (e.g. Finland and Sweden) have developed practices to return biomass ashes to forest land, and biomass ashes are becoming a valuable soil improver especially in higher acidity organic forest soils, which are very scare with phosphorus as well.
In Lithuania, rapid shift from natural gas towards biomass-based district heating sector led to the situation that volume of biomass ashes approached MWTS volume. It is estimated that in 2016 appr. 37,000 t of biomass ashes were produced by biomass boilers and biomass based power plants (18,000 t by district heating system operators, 13,000 t by independent heat suppliers (private) to district heating network, and 6,000 t by industrial biomass boilers) and the number is expected to rise over 40,000 in the nearest years due to continuing biomass usage growth for renewable energy production.
The reuse of raw materials that are now disposed as waste is one of the key principles of the Circular economy package adopted in December 2015. About 2% of the world's energy is used to produce synthetic nitrogen fertilisers. The EU is also highly dependent on imports of phosphates. Around 90% of the phosphate rock used to produce fertilisers is imported. Considering the expected global population growth and the related increase of food demand, it is expected that the demand for nitrogen and phosphate fertilisers will grow. Therefore, there is a need to find alternative plant food sources such as recycling nutrients. Phosphorus and nitrogen cycles are subject to losses in the environment, as well. The leaching of nutrients into the environment has led to deterioration of surface water through eutrophication. Other valuable nutrients are wasted and end up in landfills instead of being recycled for plant nutrition. By implementing circular economy models, the value of raw materials and energy used in products could be maintained in recycled products and contribute to a more resource efficient Europe.
To develop and demonstrate full-scale self-sustainable closed loop circular economy model for nutrient rich waste recycling for Vilnius (the largest city in Lithuania, with population of 540 thousand), the following actions and means will be employed:
- Mobilization of land within 60 km radius from Vilnius city for full-scale CE demonstration model: 900 ha of existing biomass plantations and 900 of new land will be mobilized to ensure full-scale nutrient rich waste recycling
- Environmental permitting for nutrient rich waste recycling: 100% of environmental permits and full legal compliance will be ensured for CE demonstration model operations;
- Establishing of missing biomass plantations: 900 ha of new biomass plantations will be established to ensure full scale nutrient rich waste recycling capabilities of CE demonstration model;
- Recycling of nutrients from dried MWTS digestate of Vilnius city: 100% of MWTS digestate from Vilnius wastewater treatment plant will be recycled for three consecutive years, each year on new land plots included in CE demonstration model;
- Recycling of nutrients from biomass ashes from renewable energy production of Vilnius city: calculated amount of biomass ashes, from combustion of biomass supplied from CE demonstration model annually, from renewable energy production for Vilnius city will be recycled for three consecutive years;
- Biomass supply and conversion into renewable energy for Vilnius city: biomass from CE demonstration model will be harvested and supplied to renewable energy production for Vilnius;
- Water, soil and biomass quality impact monitoring: comprehensive monitoring of impact of nutrient rich waste recycling in biomass plantations will be performed to ensure environmental sustainability of CE demonstration model and to develop recommendations for policy and regulatory improvement for nutrient rich waste recycling;
- LCA analysis, biomass yield improvement assessment and business planning: LCA analysis will be performed and, based on biomass yield improvement results, business plan will be developed to prepare for replicability of CE model in other regions of Lithuania and other EU countries
- Increase of public awareness on circular economy benefits: dissemination of project result within project target groups to promote circular economy models and to transfer results in other regions inside and outside of Lithuania.
The main objective of the project is to create and demonstrate the first of its kind on the EU level full scale self-sustainable closed loop circular economy (CE) model for large cities’ nutrient rich waste - municipal wastewater treatment sludge (MWTS) and biomass ashes – recycling into renewable energy for city’s needs via environment friendly biomass plantation phytoremediation filter.
The specific objectives of the project will include:
- promoting resource efficiency through reuse of nutrients (less usage of mineral fertilizer) and decrease in transportation distances and flows;
- promoting waste management pyramid priorities via changing path from landfilling and incineration of nutrient rich waste towards reuse in biomass growth improvement;
- mitigation of food chain contamination risks via changing path of nutrient rich waste from uncontrolled usage in food crop growing towards 100% legally compliant and monitored non-food biomass yield improvement;
- creating new best practices for dried MWTS digestate usage for non-food biomass;
- developing new business models to make biomass growing / forestry on marginal and less suitable to agriculture soils economically attractive via substantial biomass yield improvement;
- promoting soil organic content improvement via bio-solids applications; - promoting renewable energy production;
- promoting afforestation of less suitable for agriculture / marginal lands;
- contributing significantly to climate change impact reduction by sequestrating significant volume of CO2 in the whole circular economy model value chain, promoting renewable energy production, soil carbon content improvement;
- promoting of EU and national legislation and policies and contributing to their development by promoting safe and environment friendly reuse of nutrients from wastes.
A. Preparatory actions
A1 Mobilization of land for CE demonstration modelMore about activities
A2 Permitting for nutrient recycling from waste
B. Implementation actions
B1 Establishment of biomass plantations for CE demonstration model
B2 Recycling of nutrients from municipal water treatment sludge
B3 Recycling of nutrients from biomass ashes
B4 Biomass to renewable energy
B5 Business plan developmentMore about activities
D. Public awareness and dissemination of results
D1 Activating key target groups
D2 Public awareness program and networkingMore about activities
C. Monitoring of the impact of the project actions
C1 Sludge and biomass ashes quality, soil impact and water impact monitoring
C2 Biomass yield improvement assessment
C3 Life cycle assessment (LCA)
C4 Biomass quality assessment
C5 Performance monitoring and socio-economic impact assessmentMore about activities
E. Project management
D1 Activating key target groups
D2 Public awareness program and networkingMore about activities
(project manager, “Pageldyniu plantacija”)
(project manager Agrochemical research laboratory of Lithuanian Research Centre for Agriculture and Forestry)
(project manager, Swedish university of agricultural sciences)
(project manager, “Pramonės energija”)
(project financial manager, “Pageldyniu plantacija”)
(project manager, Forest and Land Owners Association of Lithuania)
(project manager, “Vilniaus vandenys”)
- UAB “Pageldyniu plantacija”
- – coordintaing partner
- UAB “Vilniaus vandenys”
- – municipal water suply and sewage treatment plant
Forest and Land Owners Association of LithuaniaSwedish university of agricultural sciences
- UAB “Pramonės energija”
- – private biomass boiler (20MW) in Vilnius city
Agrochemical research laboratory of Lithuanian Research Centre for Agriculture and Forestry
Board of Observers
- Foundation Baltic Sea Action Group
- Vilnius city municipality
- UAB “Kauno vandenys”
- IKEA Industry Slovakia
- UAB “Klasmann – Deilmann”
- Latvian state forestry research institute SILAVA