B1-Summary description of the project
Contents
(Max. 3 pages; to be completeddiscuss in English)[edit]
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Project title:[edit]
COWS - Sustainable sewage sludge management by optimisation of co-digestion with municipal solid waste organic fraction
Project objectives and key messages:[edit]
With a view to breaking the link between growth and waste generation, the European Union has provided itself with a legal framework aimed at the whole waste cycle from generation to disposal, placing the emphasis on recovery and recycling.
The Waste Framework Directive sets the long-term strategy aims to help Europe become a recycling society that seeks to avoid waste and uses waste as a resource, in accordance with smart and sustainable development targets set by Europa 2020.
The Urban Waste Water Treatment Directive, under the Water Framework Directive, and a future Sludge Directive now under discussion, regards producers of sewage sludge.
Treatment routes and use of sewage sludge is very similar to that of biowaste.
Waste streams such as sewage sludge (SS) and the organic fraction of municipal solid waste (OFMSW) are underexploited feedstock for bioenergy, withdrawing valuable resources irrevocably from economic and natural cycles.
Anaerobic codigestion can be considered one of the most promising way to give a proper disposal to the organic fraction of municipal solid waste (OFMSW) coming from source or separate collection systems.
The two flows of OFMSW and SS may converge into anaerobic co-digestion for the production of biogas.
In Europe there are more than 35000 facilities that already use anaerobic fermentation for stabilizing sewage sludge. Because of the composition of SS these plants in most case just use the low quantity, low quality biogas obtained for maintaining process heat sending the remaining to flare-torch. This is impressive European asset can be upgraded to co-digestion to produce heat and power if there is sufficient quantity and quality of inflow material.
OFMSW coming from separate collection may secure the required additional supply of biodegradable matter.
While, municipalities are interested in keeping collection and treatment costs low, biogas plants are only able to treat OFMSW with low plastics contamination. As a result OFMSW is often sent to composting.
In order to solve this drawback to widespread upgrading of existing SS treatment facilities, COWS project partners Sea Risorse, Sea Ambiente and the Municipality of Viareggio devised an innovative processing solution that implemented at experimental small-scale, achieving positive results.
That solution is now brought to demonstration scale upgrading the sewage sludge plant of Viareggio to a biogas power-generation facility, diverting 15,000 tonnes/year of OFMSW from composting, and innovating also the business model of cooperation between municipal waste services and water/wastewater services who are producers of sewage sludge.
The objective of COWS project is to demonstrate how most sewage sludge treatment plant can be upgraded to co-digestion with OFMSW with sustainable outcomes on environmental, social and economic sides.
The project addresses the Italian national priority (10 a,b,c) in that it contributes to the enforcing of European waste policy and legislation, of waste prevention, and of sustainable use of natural resources.
COWS project will implement a full scale process upgrade (15.000 ton/year) that will include a prototype pre-treatment unit for high-performance separation of a clean and most useful fraction of OFSMW as slurry to be mixed with sewage sludge and the forwarded to anaerobic digestion.
Improved digestion performances will avoid sending 1800 ton/year of sludge to composting to be added to 15.000 ton/year of OFMSW, saving 599 TCO2/year from avoided transportation and 853 TCO2/year from power not used for running composting process.
The biogas obtained exceeds by large the heating and power needs of the plant, allowing a to upload more that 11.000 KWh/day to the grid power, enough ti satisfy the needs of 3.000 people equivalent.
Actions and means involved:[edit]
COWS will be carried out making use of human, technical and financial resources of the beneficiaries in addition to the requested Community contribution. Beneficiaries are committed to invest in co-digestion, but Community financial contribution is essential to develop COWS full scale demonstration and innovation characters and to put in place effective dissemination.
COWS implementation will firstly ensure the participation of all stakeholders: citizens and CSOs, utilities interested to apply the same approach, technology providers.
COWS plant & process design prepare the essential conditions for implementation of the project, i.e. completion of the final design and obtaining of the necessary permits. COWS design will then be the base of the terms of reference for public procurement of works and supplies.
Works for modifying current stabilization process will run parallel to the development of the pre-treatment prototype, which will make use of a stable industrial technology that will be adapted for the purpose.
The modification of the process will affect almost all parts of the plant because flows will change: primary and secondary digesters, pre- and post- thickeners, gasometer and torch, dewatering chamber, power sub-station, de-aeration and treatment plant, finally adding CHP (cogeneration of heat and power) units.
COWS pre-treatment prototype will be adjusted to obtain optimal particle size and separation of contaminants and non-biodegradable ingredients.
The process will then be integrated, adjusted and balanced to optimal performances and finally run on "showcase" mode. Showcase mode is intended as running the plant in such a way to facilitate the sharing of knowledge gained during the implementation of the project and allowing interested parties (professionals, utility managers, environmental scholars and activists, CSOs, etc.) to understand better how the COWS approach solved an environmental problem in Viareggio and how to replicate or transfer it.
After commissioning all parameters will be kept under constant monitoring and made available for evaluation and improvements.
Documentation of COWS design, model, implementation guidelines, results, will be made freely available.
Expected results (outputs and quantified achievements):[edit]
COWS will deliver an upgraded SS-OFMSW co-digestion plant processing 15000 ton/year of OFMSW and 62000 m3/year of SS. An essential part of COWS process is a pre-treatment separation subsystem, working on extrusion principle, that allows low cost calibration of optimal cleaning levels of OFMSW inflow and of output slurry properties for best mixing with SS.
At full scale operations, COWS will deliver 1000 m3/day of biogas resulting in 13200 KWh/day electric of which 11700 KWh/day sent to the grid, the remaining being used for running the plant.
Comparing with pre-COWS operations, 400 TOE/year savings and 1452 TCO2/year will be spared to the environment, reducing impact on climate change;
During the implementation of COWS 5 new temporary jobs will be created.
By the end of the demonstration run, and as a consequence of it, it is expected that at least another SS treatment plant will start its conversion to COWS-like process.
Can the project be considered to be a climate change adaptation project? YES___NO___discuss[edit]
COWS core action affects directly GHG reduction (1452 TCO2/year), use of resources linked to energy use (400 TOE/year) and efficient use of waste. Moreover the cooperation between water and waste services is a strategy that can improve urban systems resilience to adverse events related to climate change (e.g. stormwater and flood management, long periods of temperatures above average, etc.)
