Sludge is a by-product of the sewage treatment process, which requires treatment to remove bacteria before it can be recycled. This guide from Southern Water explains the full treatment process for waste water.
Sludge is also known as biosolids and the most sustainable option for disposal is to recycle it to land. This can also reduce the need for artificial fertiliser and improves soil structure.
The majority (80%) of sludge from waste water treatment plants is treated and recycled to land, including for agriculture, reclamation and composting. Some of the remainder goes to thermal destruction with excess heat from this process used to generate combined heat and power (CHP). The least favoured option is to send the sludge waste to landfill, which is both unsustainable and expensive due to landfill taxes.
Water utility companies often use a variety of recycling options, adapted to regional requirements for a flexible approach. These choices also take into account local circumstances and requirements for transport, energy use and other resources.
We have extensive land bank facilities for recycling sludge to agricultural land. Over many years we have developed close relationships with the farming community in the south east and elsewhere. We also work with strategic partners to deliver this recycling service to water utility industry customers.
Our sludge haulage recycling service includes:
- Sludge cake sampling and soil testing analysis to ensure stringent criteria for spreading are met;
- Sludge haulage and stockpiling on land, avoiding any disruption to farming operations or risk of seepage to watercourses;
- Spreading using precision application by computer with linked vehicle steering guidance systems;
- Full recording and mapping in accordance with all current regulations.