Sewer Processes and Networks

Wastewater, biofilms and sediments in sewers are subject to important physical, chemical and microbial changes and interactions affecting not only the sewer itself but also the subsequent wastewater treatment and receiving waters via combined sewer overflows or separate sewer outfalls. This was a motivating theme behind two previous conferences (published in Water Science and Technology) on ?The sewer as a physical, chemical and biological reactor?. This third conference, building on its predecessors, aimed to bring together scientists and practising engineers in the area of environmental process engineering and management of sewer systems to present their results and discuss physical, chemical and biological processes in sewers, and related structural aspects of sewer systems. Key topics covered included: interactions between sewers and the urban wastewater system including wastewater treatment, combined sewer overflows and receiving waters; characterisation, processes and physical interactions of sewer biofilm, sediments, wastewater and air; microbial and chemical processes; solutes and sediments transport including sedimentation and erosion; sulphide formation, corrosion and odour problems; bacteriology; specific pollutants; design, operation and control related to sewer processes; and interactions between sewer structure and processes. From the 45 available papers, 22 have been selected, reviewed and revised for publication in this issue, which reflects the most important aspects of the conference. Together they are a major step towards a more comprehensive and multidisciplinary understanding of sewer behaviour and functioning, of prime importance for the design, operation and upgrading of urban sewer and wastewater systems.