Identifying Cost Savings Through Energy Conservation Measures at Mechanically Aerated Activated Sludge Treatment Processes in Southeast Florida

This paper presents the results of a model developed to estimate energy and cost savings that can be realized by implementing Energy Conservation Measures (ECMs), using as examples three mechanically aerated wastewater treatment plants (WWTPs) in southeast Florida. Historical data is used to estimate potential energy savings achieved through implementing more efficient aeration technologies including; 1) Fine Bubble Diffusers; 2) High Speed Direct Drive Single Stage (Turbo) Blowers; and 3) Automatic Dissolved Oxygen (DO) Control. Key assumptions for modeling performance are researched and discussed, such as trends in the future cost of electricity, equipment efficiencies, and practical DO concentrations. Capital cost estimates and operation and maintenance (O&M) costs are estimated to complete life-cycle cost and payback analyses. The benefits are quantified on an individual and cumulative basis to prioritize ECM projects. The results demonstrate that levels of payback of 20 years or less are available at the three WWTPs studied.