Optimizations of the Secondary Wastewater Treatment Operations

An investigation was initiated as part of the secondary treatment optimization efforts to solve the operational problems associated with the low flow and to save operating costs in the Detroit Wastewater Treatment Plant. The objectives of the study were to identify the critical factors that caused operational difficulties during low flow period s, find a quick field indicator to help operators adjust the flows going to the aeration tanks, and identify other operational parameters that the operators could use to help them make accurate and timely decisions in adjusting the oxygen feed. The study showed that the imbalance of the F/M ratio was the major cause of the operational difficulties. In an attempt to regulate the imbalance, a useful and quick field indicator was proposed. The optimizations of the secondary operations could be achieved by switching the operating approach from being “reactive” mode to “proactive” mode. Understanding operational parameters and being alert to the changes in the parameters are critical.