Environment Agency strategy for safe and sustainable sludge use
We reviewed the current regulatory regime for sludge treatment, storage and use. We looked at the advantages and disadvantages of 4 options. The option we selected will bring sludge and septic tank sludge into the Environmental Permitting (England and Wales) Regulations (EPR). We aim to do this in 2021.
The Sludge (Use in Agriculture) Regulations (SUiAR) will no longer be needed.
1. How sludge can be used
Sewage sludge is the residual solid waste left over from the treatment of urban waste waters.
We use the term sludge as defined in SUiAR. The water industry uses the term biosolids for treated sludge. The Water Services Regulation Authority (OFWAT) use the term bioresources for materials that contain sludge. Sludge is made up of domestic and industrial effluents and surface water run-off. It mostly comes from waste water recycling centres (sewage plants). Some of it comes from private treatment such as package treatment plants or septic tanks.
Sludge contains useful levels of organic matter and plant nutrients. It can also contain chemicals and pathogens that could risk human health and the environment. In most circumstances, the most sustainable option is to recycle it to agricultural land as organic manure. An organic manure is fertiliser which comes from animal, plant or human sources. Organic manures commonly used in agriculture include:
- animal manure or slurry
- anaerobic digestate
- biosolids and septic tank sludge
Sludge can provide beneficial amounts of organic matter and nutrients to the soil. It is important to manage sludge properly to make sure:
- sludge treatment, storage and uses are sustainable
- risks to the environment, soil, plants, animal and human health are understood and addressed
- farmers and land managers can safely spread it to benefit land
If sludge is not correctly managed and used to benefit soil, it needs to be disposed of. For example, by incineration or to landfill. We want sludge to continue to be used as a beneficial resource.