Sequencing batch reactor technology: the key to a BP refinery (Bulwer Island) upgraded environmental protection system - a low cost lagoon based retro-fit

BP Refinery (Bulwer Island) Ltd (BP) located on the eastern Australian coas t is currently undergoing a major expansion as a part of the Queensland Cle an Fuels Project. The associated wastewater treatment plant upgrade will pr ovide a better quality of treated effluent than is currently possible with the existing infrastructure, and which will be of a sufficiently high stand ard to meet not only the requirements of imposed environmental legislation but also BP's environmental objectives. A number of challenges were faced w hen considering the upgrade, particularly; cost constraints and limited plo t space, highly variable wastewater, toxicity issues, and limited available hydraulic head. Sequencing Batch Reactor (SBR) Technology was chosen for t he lagoon upgrade based on the following; SBR technology allowed a retro-fi t of the existing earthen lagoon without the need for any additional substa ntial concrete structures, a dual lagoon system allowed partial treatment o f wastewaters during construction, SBRs give substantial process flexibilit y, SBRs have the ability to easily modify process parameters without any ph ysical modifications, and significant cost benefits. This paper presents th e background to this application, an outline of laboratory studies carried out on the wastewater and details the full scale design issues and methods for providing a cost effective, efficient treatment system using the existi ng lagoon system.