Project Appreciation and Objectives
Future beneficial opportunities for recycling sludge are reliant on access to the agricultural landbank as a cost effective and sustainable outlet. Sludge is now in direct competition with organic wastes from the digestion of commercial wastes being spread to land under the PAS110 quality scheme and environmental permits.
Attention across the EU is now turning to a specific list of emerging priority pollutants - persistent organic pollutants or POPs. These are characterised by perceived potential environmental or human health threats but lack published standards or risk evaluations. The food retail chain and consumers have concerns that sludge and other organic wastes may contain harmful levels of residual organic chemicals. Future regulation is likely to require a reduction in the permitted concentrations of these substances in treated effluent and will draw attention to the possibility of increased organic contamination of sludge. Without clear evidence the wastewater sector will be vulnerable to poorly informed conjecture from lobby groups and to a loss of this important recycling market.
This project will provide evidence and increase current understanding of the potential risks from emerging priority substances and POPs on monitoring burdens and agricultural recycling outlets for sewage sludge and the risk that they pose to future sludge recycling markets.
Business Benefits to Clients
- More secure long term planning and proactive management of sludge treatment and disposal options.
- Evidenced based protection of the efficacy and appropriate use of the landbank for sludge recycling.
- Identify and short-list emerging priority substances and candidate POPs.
- Determine the sources and occurrence of these substances.
- Assess chemical and physical properties of short-listed POPs to inform on the fate and behaviour of these substances during treatment, storage and land application of sludge to identify conditions that maximise removal of target contaminants.
- Quantify the risks to agricultural crops from POPs that remain in sewage sludge and which could limit future application of sludge to land to allow for mitigation planning.
Project Output and Implementation
- A short-list of emerging priority substances and POPs, each supported by a technical description of its fate and behaviour through the wastewater treatment train and practical measures that can be used by operators to minimise its presence in sludge through appropriate treatment and storage of sludge.
- Generic guidance for use by Sludge Strategy Managers on emerging priority substances and POPs to inform discussions to protect recycling markets.
Related WRc Work
- Agronomic benefits and environmental impacts of spreading organic waste to land (Defra, 2008-09).
- Technical Assistance for Implementation of the Prior Informed Consent Regulation (EU, 2004-13).
- Evaluating waste treatment standards for selected treatment operations, for an assessment of the impacts of EU legislation (EU, 20011-12).