Lodge, B., and Spooner, S., Atkins, UK(free)
Water quality modelling of the Upper Thames Tideway was used to agree new ecological standards between Thames Water and the Environment Agency and used in the specification of a novel effluent oxygenation scheme. The innovative scheme will introduce more oxygen into the effluent from Mogden sewage treatment works and thereby raise dissolved oxygen levels in the River Thames during seasonal periods of low river flow. This should improve the ecological conditions in the river and reduce the risk of fish migrations being deterred due to low oxygen levels. An array of surface aerators will be installed into the existing main effluent culvert; a cost effective and robust solution designed for the demanding, high flow, tidal conditions within the culvert. There are several novel details to minimise disruption to critical Thames Water assets during construction, and to maintain a safe working environment for construction workers as well as operators of the plant. The SimBasinQ water quality model used to specify the system was also used to develop the control rules to regulate the output of the array. The effluent channel aeration system will optimise energy use in the main activated sludge lanes aeration systems without compromising achievement of dissolved oxygen concentrations in the river. This is an exemplar project at the interface between environmental science, regulation and engineering; applied through cooperative working between a water company, the Environment Agency and capital investment programme delivery partners.