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 aims 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.