Project Appreciation and Objectives
As the UK endeavours to meet its obligations for renewable sources of energy, reduction of greenhouse gases and landfill diversion targets, an increasing range of wastes is being treated using anaerobic digestion. Many of the resultant digestates will be suitable for recycling to agricultural land. This will create a competitive threat for the wastewater industry, where such recycling is a critical route for the disposal of sludge biosolids from wastewater treatment. To maintain and secure this route it will be necessary to prevent any negative impacts from recycling biosolids to agricultural land.
Odour generated from sludge biosolids storage and recycling to land has resulted in complaints and bans at some locations. The wastewater industry needs to have a robust understanding of the root causes of odour generation so that they can manage the cycle of sludge production and recycling effectively and be in a position to take appropriate up-front mitigation action to prevent odours. This project will define and develop the scientific building blocks and specific conditions/sets of circumstances that lead to increased odour at all stages of the production and recycling of biosolids, including storage and application of the biosolids to land.
The objectives of the project are to:
- Define and fully understand the circumstances that lead to odour issues from recycling biosolids to agricultural land.
- Identify mitigation options for minimising odour emissions and provide clear guidance on their implementation.
Benefits to Clients
- Reduced incidence of complaints resulting from odour generation from sludge biosolids recycling.
- Improved image of sludge biosolids within the rural and agricultural community to enable continued and secure long term use of agricultural land in the face of competition from other waste management companies.
- Review knowledge on factors that affect odour emissions from recycling biosolids to agriculture. Root-cause analysis to understand the science behind main "building blocks" that cause odour.
- Investigate chemical signatures present in odours from biosolids that are known to cause odour issues. Investigate factors that cause odour problems and can be reliably linked to biosolids.
- Identify mitigation options to minimise odours. Develop spreadsheet tool to identify site specific odour issues and produce good practice factsheets.
A report containing a thorough understanding of the causes of odour emissions from recycling biosolids to agriculture, a spreadsheet decision tool to estimate the risk of significant odour arising from biosolids recycling; and factsheets with guidance on minimising the risk of odour problems
- "Reducing Odours from Sludge" (CP149) project which developed a method to measure the odour potential of biosolids and odour emission models for mechanically handling biosolids.
- Review of the agronomic and environmental impacts of a diverse range of organic wastes to agricultural land.
- Odour investigations and environmental impact assessments (EIAs) regarding biosolids.