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ThamesGrow is a leading range of biosolid products produced by Thames Water for use in agriculture.

Biosolids are organic materials generated from the wastewater/sewage treatment process. They provide a valuable source of nutrient-rich fertiliser for crop growth.

As the country’s largest water and wastewater supplier, Thames Water produces more than 750,000 m3 of biosolids each year. This provides a sustainable, cost effective and environmentally sensitive solution for farmers throughout the south east.

About our products

ThamesGrow biosolid products are high organic matter fertilisers and soil conditioners which provide a rich source of slow release nutrients.

Suitable for application on a wide range of combinable and forage crops throughout the growing season, our products will help to build strong and healthy harvests. Products include:

Conventional digested biosolid

We treat the wastewater and return the resulting clean water back to the environment. Any remaining waste is stored in an oxygen free tank, called an anaerobic digester.

The biogas created is used to power many of our sites as a source of renewable energy. The organic matter left behind is then heated to a high temperature.

The resulting biosolid is a fully compliant product which is pressed ready for delivery.

Thermal Hydrolysis Process (THP) biosolid

At some of our larger sludge treatment centres we use steam to release more energy. This results in a much dryer product to conventional digestion.

Lime biosolid

We blend our biosolid with quicklime (CaO) which gives the benefit of a higher neutralising value. This product is limited to a few key areas.

Pricing and delivery

Our biosolid products are priced on a per hectare basis with a discount offered for spring sown crops.

We’ll haul your biosolids order direct to your farm from our treatment centres throughout the year. We use tracking when appropriate to minimise any damage.

We also carry out the spreading using the latest purpose-built low ground pressure machines.

For more information or to make an order, get in touch with your nearest area sales representative.

Quality assurance

ThamesGrow biosolids are produced in accordance with the Safe Sludge Matrix (an agreement between water companies and the British Retail Consortium), Biosolids Nutrient Management Matrix and the Biosolids Assurance Scheme.

We comply with the Sludge Use in Agriculture Regulations 1989 and operate under ISO status including ISO 9001, ISO 14001 and ISO 18001.

All Thames Water biosolids are certified as 100% compliant with the Biosolids Assurance Scheme (BAS).

The BAS scheme combines the legislative and non-legislative requirements along with best practice, by achieving operational consistency and demonstrating transparency in the delivery of nutrients to agriculture. The scheme covers treatment of sludge (including source material controls), transport, storage and application to agricultural land.

BAS aids the promotion of public acceptance, protection of the environment and the endorsement of sustainability, thus providing assurance to food chain stakeholders.

Get in touch

For general enquiries, please contact our Bio recycling Head Office on 0203 577 9592.