EngD Studentship in Water Engineering (Anaerobic Digestion of Sewage Sludge)

Career overview

Professor Stephen R. Smith is a Professor of Bioresource Systems in the Department of Civil and Environmental Engineering at Imperial College London. He graduated from the University of Reading with a BSc in Horticulture in 1983 and subsequently received his PhD from the same institution, focusing on the horticultural and agricultural reuse of biosolids products. In 1989, he joined WRc (Water Research Centre) as a senior soil scientist, where he was responsible for research programmes on the agricultural recycling of sewage sludge. He transitioned to Imperial College in 1997 as a lecturer in Environmental Engineering. Professor Smith has over 25 years of experience in investigating the treatment and agronomic properties of sludges and organic wastes recycled to land, along with their environmental impacts, including nutrients, potentially toxic elements, organic contaminants, and pathogens. He has served as the Principal Investigator for a significant programme funded by EPSRC in collaboration with the Environment Agency and the Water Industry, focusing on the agricultural utilisation of biosolids products. He has acted as a specialist adviser to Defra on the agronomic value of biosolids during the recent revision of the UK Fertiliser Recommendations (RB209). His work for Defra has included quantifying the agronomic benefits 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 also been involved in research for the Food Standards Agency regarding the environmental impact of nonylphenol in sludge-treated agricultural soil. He was a member of the Expert Group on Risk Assessment of Sewage Sludge for the European Branch of the International Life Sciences Institute (ILSI), which reviewed the European risk assessment of the surfactant linear alkylbenzene sulphonate for agricultural use of sewage sludge. His international experience includes consulting on sewage sludge disposal and recycling in warm climates, notably in Egypt, where he contributed to the Cairo Sludge Disposal Study funded by the European Investment Bank. He is the Senior Technical Adviser for a Smart Water Fund project in collaboration with the Department of Biotechnology and Environmental Biology at the Royal Melbourne Institute of Technology (RMIT), evaluating the pathogen risk and nutrient status of air-dried and stored biosolids in Victoria, Australia. Additionally, he has led studies on home composting of household waste in the UK and has chaired national meetings on the subject. His ongoing projects in Cyprus involve developing biodrying technologies to produce auxiliary fuels from biodegradable municipal and other wastes and the anaerobic digestion of industrial biowastes in collaboration with the University of Cyprus. Professor Smith has acted as an expert witness for the Environment Agency and local authorities in the UK concerning hazardous and biodegradable waste management practices on land. He has authored over 230 scientific papers, reports, and publications on recycling biosolids in agriculture, including a standard reference textbook published by CABI International. His contributions to scientific reviews for the UK Government and the European Commission have addressed contaminant behaviour and environmental impacts, including recent reports on organic contaminant inputs to soil for Defra and heavy metal bioavailability in compost for WRAP. Professor Smith has presented invited contributions and keynote lectures at major international meetings on biosolids and has organised significant meetings on related topics in the UK. He is a member of various professional bodies, including the Wastewater Management Panel of CIWEM and the Expert Advisory Group of SORP, and is registered as a Chartered Environmentalist.

Research interests

Professor Smith''s research focuses on the treatment and agronomic properties of sludges and organic wastes recycled to land, as well as their environmental impact, including nutrients, potentially toxic elements, organic contaminants, and pathogens. He has significant experience in investigating the agronomic value of organic wastes and has led major research programmes on the agricultural utilisation of biosolids products. His recent work includes examining the survival and significance of enteric pathogens in sludge-treated agricultural soil and quantifying the agronomic benefits of industrial and treated biowastes for Defra. Professor Smith has also contributed to research on the environmental impact of nonylphenol in sludge-treated agricultural soil and has worked on sewage sludge disposal and recycling issues in warm climates, particularly in Egypt. He is involved in projects evaluating the pathogen risk and nutrient status of biosolids in Australia and developing biodrying technologies for waste management in Cyprus. He has authored over 230 scientific papers and reports on recycling biosolids in agriculture, including a textbook published by CABI International, and has provided expert contributions to various governmental and international bodies on the implications of recycling sewage sludge in agriculture.