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We provide a complete biosolids recycling service for farmers through our contractor ACS. The service is fully accredited under the biosolids assurance scheme (BAS). This ensures compliance with regulatory requirements and best practice guidance.


Agricultural benefits of biosolids

Biosolid products contain good quantities of most major plant nutrients and organic matter. They also contain valuable amounts of micronutrients. Recycling biosolids for agriculture is a sustainable way of reducing the usage of manufactured fertiliser products.

Our biosolids recycling service for farmers includes:

  • Soil sampling (pH, PTEs, available phosphorus)
  • Detailed stockpile and field risk assessments carried out by experienced advisors
  • Delivery
  • Spreading

Nutrient benefits


Depending on the crop type, time of year and product type, biosolids can supply around 10-15% of the nitrogen needed. The nitrogen supplied is mainly in the organic form and, as such, releases slowly as the soil warms. Thus, it remains present over the crop's entire growth cycle.

A typical biosolids application will replace crop offtake and help maintain or build up soil phosphorus (P) to target levels. This will help with obtaining optimal yields by reducing the risk of P deficiency.

Sulphur has become an important crop nutrient as deposition from the atmosphere has decreased. Used at standard application rates, biosolids contain enough sulphur to meet the typical requirements of cereal and oilseed rape crops.

Biosolids applications contain significant amounts of magnesium. This can help provide a maintenance dressing for soil and prevent deficiencies (sometimes seen on light sandy or acidic soils).

Micronutrients are normally required in relatively small amounts, depending on the crop and soil type. If not addressed properly, they can cause crop deficiencies. Biosolids contain a wide range of micronutrients. This includes boron, copper, zinc, iron, sodium, manganese, aluminium and molybdenum.

Biosolid products contain a large amount of organic matter. This is a vital component of good quality agricultural soils and helps provide a good growing medium for crops. Repeat applications of biosolids can help maintain organic matter levels in soil. This is especially so in intensive arable farming, where there is often no alternative source of organic matter. The key benefits of organic matter include improved: soil structure rooting drainage soil workability water retention soil biology reduction in soil erosion.

Product analysis

A typical biosolid digested cake (25% dry matter) product applied at a rate of 20 t/ha can provide the following:


Nutrient content (kg/t)

Applied total nutrient (kg/ha)

Potential availability year one (%)

Available nutrient year one (kg/ha)

Total nitrogen





Total phosphate (P2O5)





Total potash (K2O)





Total sulphur (SO3)





Total magnesium (MgO)






Depending on soil P and K indices and crop being grown.
** Assume 10–20% available following autumn applications and 20% following spring applications.

Quality assurance with HACCP

We use the Hazard Analysis Critical Control Point (HACCP) system in our treatment processes. This guarantees the required bacterial standards for biosolid products.

The HACCP system was developed in the food industry to ensure that standards are met at each stage of the process. In the UK, the water industry uses the same approach for the treatment of raw sludges into biosolids.

Under this system, limits are set for factors which are critical to maintaining end product quality. These factors are Critical Control Points (CCPs). Operating within the CCP limits ensures the quality of the end product.

Enquire about biosolids

For further information about our biosolids recycling service for farmers, please fill out this form in as much detail as possible to help us assist with your query.

Alternatively call Austin Contract Services Ltd on 01795 410852 for more information.

Biosolids form

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