Project Appreciation and Objectives
Renewable bioenergy crops which include tree species, arable crops and grasses can be grown on unused land at wastewater treatment works using treated effluent which is rich in nutrients. Co-digestion of energy crops with biosolids using spare anaerobic digestion capacity can generate additional electrical energy reducing use of imported electrical energy. Wood can be burnt in incinerators as supplementary fuel. The cultivation of bioenergy crops will enhance energy production thereby lowering greenhouse gas emissions, reduce nutrient enrichment of surface waters through uptake for plant grownth, and avoid inorganic fertiliser application to replace soil nutrients whic are depleted by the removal of large amounts of biomass from land.
The objectives of this project will be to develop tools to:
- Assist in implementation and management of energy crops on spare land at wastewater treatment works;
- Assess means for generating energy from bioenergy crops using existing assets through co-digestion with biosolids in digesters and co-incineration with sludge solids;
- Identify cost effective Water Company sites for bioenergy crop production.
Benefits to Clients
- Exploitation of existing assets for enhanced energy production using energy crops irrigated with final effluent.
- Ability to prioritise and phase schemes for co-digestion of energy crops with biosolids.
- Confident in dealing with regulators in relation to impacts of effluent reuse for energy crop production on groundwater, sludge treatment, and biosolids recycling.
- Identify potential energy production crops.
- Cost-benefit assessment of site preparation, planting, irrigation,monitoring and harvesting of energy crops.
- Review of biosolids recycling approaches with response to handling bioenergy crop residuals and groundwater monitoring techniques to mitigate the impact of effluent reuse.
- Development of a decision support tool for life cycle analysis.
Strategies to enable implementation of energy beneficial effluent reuse at pilot sites, with prioritisation and lifecycle analysis tools for wider exploitation.
- WRc led a consortium on treatment of wastewater using renewable energy crops, such as willow and poplar grown under short rotation coppice (SRC) management.
- WRc was a partner in a consortium that reviewed currentt status and future trends in sludge treatment and recycling, with recommendations made to the EU on revision of of the Sewage Sludge Directive 86/278/EEC.