Moving Towards Smart WWTP's Through Advanced Aeration Control

Christies Beach Wastewater Treatment Plant (CBWWTP) in Adelaide (South Australia) consumes a large amount of energy to produce water suitable for reuse applications, as well as ensuring that any discharge to Gulf St Vincent meets the quality requirements for the sensitive receiving environment. Operator-driven optimisation of the treatment process and energy usage over the past five years has resulted in substantial improvements. However, to achieve the next step change in enhancements and take CBWWTP towards a ‘Smart Plant’, a new approach was needed. The Advanced Aeration Control (AAC) approach was selected to be trialled (using the innovative Suez algorithm Greenbass™ Plug Flow and HACH AMTAX Ammonia Analysers) as it aims to automatically and accurately match aeration needs in the activated sludge process with real-time ammonia load measurements. The automatic predictive control avoids over-aeration during low flows and under-aeration during peak flows and high Ammonia load events leading to improved energy efficiency and nutrient removal. The 18-month trial has demonstrated that 16% (143 kWh/day) energy savings can be achieved in addition to carbon dosing (ethanol) savings of 20 to 40% (25 to 45 L pure ethanol/day). The AAC trial proved to be successful through the robustness of the instrumentation selected, the reliability of Greenbass™ Plug Flow algorithm, the thoroughness of on-site integration within existing control systems, and the gradual commissioning and adjustments of the algorithm’s set-points and coefficients. The outcomes of the trial are being used to help inform implementation at other WWTPs. This paper provides details of all aspects of the AAC trial at CBWWTP.