3. Residual Biogas Potential Test Improvements and Alternatives

"Evaluation of the potential for the improvement of the Residual Biogas Potential test and investigation of alternative test procedures for PAS110 biofertilisers"

Project Overview

The project aimed to evaluate potential improvements and/or alternatives to the current digestate stability test specified in PAS 110, known as the Residual Biogas Potential (RBP) Test. The project was motivated by operational challenges associated with the test as well as an expectation that the EA is likely to revise the RBP limits during the 2023 ADQP revision.

Project objectives:

  1. To identify any patterns with respect to test failures and non-responses, for example nature of feedstock, time of year, lab inoculum source, etc.
  2. To investigate whether it is possible to predict the 28-day result by analysis earlier in the RBP test procedure.
  3. To investigate the efficacy of using different inocula in the standard test to achieve greater reliability as a way forward if alternative tests cannot be identified.
  4. To investigate whether there are any alternative procedures which might replace the standard RBP test. The EU in its Fertiliser Regulations recommends BS EN 16087-1:2020, Soil improvers and growing media. Determination of the aerobic biological activity. Oxygen uptake rate (OUR) for both fresh crop digestate and other digestates.
  5. To investigate whether there are any alternative rapid procedures to evaluate digestate stability and residual biogas potential.

Access

CCS and BCS participants are eligible to receive a copy of the report free of charge. All other requests for access may be subject to a fee. Email the Research Hub Manager (contact details here) to request access.

The fee to access the report is £160.00 (excl. VAT)—equal to the average Research Fees each Scheme participant paid towards the project. Access may also be subject to agreement with REAL’s confidentiality agreement.

Project Selection and Delivery Details

In 2021, the Research Panel recommended the project for funding. Following a competitive tender period, REAL appointed Aqua Enviro as the project contractor. Work commenced in April 2022 and was completed in April 2023. The total cost to deliver the project was £70,369 (excl. VAT).

Associated Documents

  • The Project Brief, which summarises the research scope and objectives, can be found here. 
  • The Tender Invitation Document (TID), which was used to invite potential contractors to tender for the work, can be found here.