Oisin Gibson of the Murphy Group gave a talk recently to the Great Britain region at the Radisson Hotel Kenilworth Hotel on 29 November last about a £40 million project at the Deephams Sewage Treatment Works in North London. The task was to upgrade the inlet works at the plant which serves almost 900,000 people and can have peak flows of up to 14,860l/s during storm conditions. The works will radically increase the ability of the plant to deal with storm events and its effectiveness in day-to-day sewage treatment. The project will make the nearby River Lee cleaner and healthier for aquatic life and improve the riverside environment Thames Water Utilities awarded Murphy the contract for the civil, mechanical and electrical design of the new works. This included a new pumping station to deliver a dry weather flow of 1,800l/s and storm flow 3,600l/s. The pumping station construction required a shaft which is 18.5m in diameter and 24m deep. Oisin described how Murphy challenged the industry norm and opted to complete the excavation using a secant piled wall traditionally limited to 15m deep instead of diaphragm walling methods. The challenges the location presented included the presence of a connecting low level live sewer requiring a complex, high risk diversion. Two new reinforced concrete storm tanks were also constructed with a capacity 5,600m3 each, on what is a very restricted site in suburban north London. Gibson gave a detailed description of the challenges The Murphy Group faced, as well as some of the novel methods that were used to deal with such a large project in a densely populated area. The success of the project was recently acknowledged when it was awarded the prestigious Concrete Society Civil Engineering Award.