I am a researcher and laboratory manager for the Ecosystems Laboratories, School of Environment, Earth and Ecosystem Sciences. While at The Open University, I have led development of the Ecosystems Research Group laboratories with facilities for analysis of compost and organic waste, soil, water, and liquid and gaseous emissions. A key interest has been the development of respirometry and anaerobic digestion facilities for studies on stability and biodegradability of compost and waste materials. As a researcher I have focussed on biodegradable waste management.
Previous experience ranges from running soil laboratories and soil amendment trials on papaya and chilli at Srisaket Horticulture Research Centre in Thailand, to editing the Peat Alternatives Manual (Friends of the Earth, 1991).
Chartered Resource and Waste Manager, Chartered Institution of Wastes Management (CIWM).
Full member, British Society of Soil Science/ Institute of Professional Soil Scientists.
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.
A comparison of methods for early prediction of anaerobic biogas potential on biologically treated municipal solid waste (2019-02-15)
Howell, Graham; Bennett, Chris and Materić, Dušan
Journal of Environmental Management, 232 (pp. 887-894)
Improved Precision and Efficiency of a Modified ORG0020 Dynamic Respiration Test Setup for Compost Stability Assessment (2017-12-18)
Guillen Ferrari, Diana; Howell, Graham and Aspray, Thomas J.
Sustainability, 9, Article 2358(12)
Static, dynamic and inoculum augmented respiration based test assessment for determining in-vessel compost stability (2015-08)
Aspray, Thomas J.; Dimambro, Mary E.; Wallace, Phil; Howell, Graham and Frederickson, James
Waste Management, 42 (pp. 3-9)
Suppression of rice methane emission by sulfate deposition in simulated acid rain (2008-07-30)
Gauci, Vincent; Dise, Nancy B.; Howell, Graham and Jenkins, Meaghan E.
Journal of Geophysical Research: Biogeosciences, 113(G00A07) (pp. 1-6)
Effect of pre-composting and vermicompositing on compost characteristics (2007)
Frederickson, James; Howell, Graham and Hobson, Andrew
European Journal of Soil Biology, 43(1) (S320-S326)
Large-scale vermicomposting: emission of nitrous oxide and effects of temperature on earthworm populations (The 7th international symposium on earthworm ecology, Cardiff, Wales 2002) (2003)
Frederickson, James and Howell, Graham
Pedobiologia, 47(5-6) (pp. 724-730)
Suppression of rice methane production and emission by low dose sulfate application (2006-12)
Gauci, V.; Dise, N. B. and Howell, G.
In : American Geophysical Union, Fall Meeting 2006 (11-15 Dec 2006, San Francisco, USA)
Safety in Composting Halls: Managing the risks from Carbon Monoxide (2018-09-10)
Johnson, David N. and Howell, Graham
Chartered Institution of Wastes Management (CIWM)
Evidence: Biofilter performance and operation as related to commercial composting (2013-04)
Frederickson, J.; Boardman, C. P.; Gladding, T. L.; Simpson, A. E.; Howell, G. and Sgouridis, F.
Environment Agency, Bristol.