Mr Graham Howell

Professional biography

Most of my research has centred on biodegradable waste processing and emissions. I have been involved in a range of projects relating to biodegradable waste processing including composting, vermicomposting, and anaerobic digestion. These involve biologically active systems at a process-level, with gaseous emissions including greenhouse gases. Examples include studies on biofilters aimed at mitigation of environmental impact from composting sites producing odorous gases. A study on vermicompost in 2003 was the first to confirm significant emission of nitrous oxide from composting facilities which employ earthworms as the main processing agent.

Other research projects I’ve been involved in include soil acidification of volcanic soils, and methane emissions from paddy rice soils.

I have worked with academic colleagues, industrial partners and government agencies in developing standard aerobic and anaerobic biodegradability tests. For example, the DR4 and BM100/BMc tests, developed by The Open University and WRc PLC, are used for determining biodegradability losses during Mechanical and Biological Treatment (MBT) of household waste. Both of the test methods were subsequently adopted by the Environment Agency for use in the statutory evaluation of MBT plants commencing in 2005. A further Defra-funded research project used these tests to characterise a wide range of untreated and treated waste types to help predict the relationship between biodegradability and environmental impact from disposal and application to land. This both validated the use of the DR4 and BM100 test methods and provided an extensive biodegradability data base. I also adapted the upflow percolation leaching test for solid organic waste samples.

As part of a WRAP-funded project with Southampton University team, I ran the laboratory trials for development of the anaerobic “Residual Biogas Potential (RBP)” test. This test forms a key part of the PAS110 evaluation criteria for determining anaerobic digestate stability prior to application to land.

I was involved in the development and review of B.S.I. UK specification for waste-derived compost (PAS100) methods for WRAP in 2005 and 2009 including the PAS100 bioassay compost quality tests.

I have also overseen the development of a range of techniques related to my research interests and for commercial clients. The Ecosystems technical team have undertaken biodegradability and other characterisation services for compliance testing, expert witness and other contracts.