Stephen R. Smith is Professor of Bioresource Systems in the Department of Civil and Environmental Engineering at Imperial College London. Professor Smith has 25 years of experience investigating the treatment and agronomic properties of sludges and organic wastes recycled to land and their environmental impact, including nutrients, potentially toxic elements, organic contaminants and pathogens.

He graduated from the University of Reading with a BSc in Horticulture in 1983 and received his PhD, also at Reading, on the horticultural and agricultural reuse of biosolids products. He joined WRc (Water Research Centre) in 1989 as a senior soil scientist responsible for research programmes on the agricultural recycling of sewage sludge and moved to Imperial College in 1997 as a lecturer in Environmental Engineering. He has a broad base of experience investigating the agronomic value of organic wastes and was the Principal Investigator (PI) of a major programme of work funded by EPSRC and in collaboration with the Environment Agency and Water Industry on agricultural utilisation of biosolids products.

He was a specialist adviser to Defra on the agronomic value of biosolids in the recent revision of the UK Fertiliser Recommendations (RB209). Other related work for Defra has quantified the agronomic benefit of industrial and treated biowastes. Recent research, supported by EPSRC, the Water Industry and Defra has examined the survival and significance of enteric pathogens in sludge-treated agricultural soil.

Professor Smith has written over 230 scientific papers, reports and publications for Government and Industry on recycling biosolids in agriculture including a standard reference text book on the subject published by CABI International. He is author and coauthor of a number of major scientific reviews for UK Government and the European Commission on contaminant behaviour and impacts on the environment. This has included recent reports on the sources and significance of organic contaminant inputs to soil for Defra, heavy metal bioavailability in compost for WRAP and the implications of recycling sewage sludge in agriculture on human health and the environment for Water UK. He has given invited contributions and key note lectures at major international meetings. Professor Smith is a member of the Wastewater Management Panel of the Chartered Institution of Water and Environmental Management (CIWEM), the Chartered Institution of Wastes Management (CIWM), the Expert Advisory Group of SORP, and he is registered as a Chartered Environmentalist (CEnv).