Recuperative Thickening at Eastern Treatment Plant, Melbourne, Australia: Opportunities and challenges

Melbourne Water’s Eastern Treatment Plant (ETP) is experiencing significant growth in the catchment resulting in increased influent flow and loads. As sludge production increases in proportion to influent loads, the ETP’s mesophilic anaerobic digesters are approaching their hydraulic capacity limit.Melbourne Water selected recuperative thickening as it provides an adaptive approach to increasing the capacity of existing assets, delaying capital expenditure on additional digesters, and supporting alternative innovative sludge treatment options in the future. Implementation of recuperative thickening at the ETP is challenging due to the complexity of integration with existing digester operational cycles and sludge pumping, mixing and heating systems. An extensive practical limitation assessment was conducted to plan implementation of recuperative thickening to the maximum extent feasible at the ETP. This enabled Melbourne Water to make informed decisions on staging the implementation of recuperative thickening, providing a flexible and adaptive approach to capacity augmentation.