Analysis shows economic benefits of slurry treatment

New analysis from Envirosystems shows that SlurryBugs®-treated slurry has over 25% more Nitrogen than its untreated counterparts

Farmers who add a specialist blend of beneficial bacteria and enzymes to slurry have significantly higher levels of total nitrogen, phosphorus and potassium compared to farmers who left their slurry untreated, with the economic value of the slurry being around 20% higher. 

This is according to a review conducted by Dr David Townsend – head of research at Envirosystems, which assessed the nutrient value of 250 slurry samples from a range of different UK farms, independently analysed by NRM laboratories. 

Just over half of the farms in the study had treated their slurry with EnviroSystems’ SlurryBugs®, while the rest had not undergone slurry additive treatment. Dr Townsend assessed the data to determine the impact the inoculant was having on nutrient content and the slurry’s monetary value, in light of the current “new era” of £600+ fertiliser prices, and the obvious need to make better use of farmyard manures.


Dr David Townsend, Head of Research at Envirosystems

The bacteria and enzymes in SlurryBugs® work by effectively unlocking the value of the crust and other solid matter; breaking it down to mobilise the trapped nutrients within the slurry, and making them available in the liquid section which can be spread on land. 

Overall, the analysis showed that treated slurry had higher total nitrogen (+27%), phosphate (+45%) and potassium (+16%) levels compared to untreated slurry. Economically the fertiliser value of the treated slurry was worth £2.25/tonne more than untreated slurry (based on November 2021), equivalent to around 20% more.

The treated slurry also had a higher average DM content of 7.0% compared to 5.6% for the untreated. This was due to the solid fibrous crust being broken down by the bacteria’s enzymatic reactions, releasing smaller particulate matter into the liquid section making a more homogenous slurry. 

The breakdown of the crust means slurry requires less ongoing agitation, thus saving time and reducing diesel and wear and tear on machinery. The reduction in diesel and bought-in fertiliser also contributes to a reduction in a farm’s carbon footprint.

Dr Townsend’s analysis showed that you would need 151 tonnes of untreated slurry to replace the nitrogen content of one tonne of bought in ammonium nitrate fertiliser, compared to only 119 tonnes of treated slurry. The cost of treating 119 tonnes of slurry with SlurryBugs is approximately £35, compared to £728 for the ammonium nitrate at November 2021 prices.    

“With nitrogen prices currently at over £600/t and energy firms saying prices are likely to remain high for the foreseeable future, we are undoubtedly in the era where maximising the nutrient and financial potential of slurry is an absolute economic priority,” says Dr Townsend.

“At these inflated prices, it now takes over 2000 litres of milk to pay for one tonne of nitrogen fertiliser, compared to the 900L it took between January 2019 and June 2021.”

To show a slurry lagoon which is homogenous and ready to spread

Biochemist Rebecca McStay at Envirosystems


EnviroSystems has recently upgraded its analytical facilities in its dedicated Research and Development laboratories to further improve the information it can supply to its customers. This includes offering a slurry analysis service which provides a nutritional valuation of the slurry, helping to ensure farmers make the most of their on-farm fertiliser. Along with Dr Townsend, microbiologist Rebecca McStay, has recently joined the research team to assist with enhancing Envirosystems’ existing product range and deliver new sustainably-beneficial products for farmers.


Dr Henry Russell, biochemist and director  at Envirosystems will be sharing details of Envirosystems’ new research project investigating slurry emissions at Dairy Tech on Thursday 7th April 2022. The 10 minute presentation will be held in the Innovation Hub, Environment Session at 12.25pm. Alternatively, for more information visit Envirosystems at Dairy Tech – Stand L2.

Henry web pic

Henry Russell, Operations Director at Envirosystems

For more information on SlurryBugs call Envirosystems on 01772 860085.