Environmental science students at Carthage are getting their hands dirty these days — and helping the City of Kenosha Wastewater Treatment Facility operate more efficiently in the process.
Since 2007, the City of Kenosha Wastewater Treatment Facility (WWTF) has been working with the Carthage College Environmental Science Program to investigate how the treatment facility can reduce its energy consumption. The initial efforts of this unique collaboration have led to a $5,000 grant from Focus on Energy to continue their research for the next year. If successful, their findings could lead to reductions of up to 1,000,000 kWh/yr and savings of up to $50,000/yr for the WWTF.
Historically, the WWTF has used large blowers to oxygenate their aeration tanks at a level of 4-5 ppm of dissolved oxygen (DO). This level of aeration is required to break down filamentous bacteria that can cause bulking problems if left untreated in the tanks. However, this amount of aeration requires significant input of energy. Other treatment plants have been successful at lowering their oxygen demands below 2.0 mg/l DO without causing filamentous growth to occur. However, when the Kenosha WWTF has attempted to operate at a reduced DO, the aeration tanks have always been taken over by filamentous organisms.
In come the environmental scientists at Carthage. During the spring semester of 2007, students in an environmental science class (ENVS 161, co-taught by Profs. Tracy Gartner and Joy Mast) partnered with the WWTF. Their work resulted in a preliminary study report that combined literature and laboratory research to identify potential causes and provide suggestions to eliminate the problem. Based on these suggestions, the plant altered the chemical (ferrous chloride) that they use to remove phosphorus from the wastewater to a chemical (ferric chloride) that uses less oxygen to bind to phosphorus. Since the switch, the WWTF has not had problems with bulking, even though two of their blowers were temporarily off-line, reducing overall DO in the tanks.
With this promising start, the Kenosha WWTF is assembling and operating a pilot facility in which additional suggestions from the preliminary report can be tested. The ultimate goal of this study would be to verify the best modification for Kenosha WWTF to implement in order to reduce the DO and save energy.
Students from Carthage’s Environmental Science Program will assist the City in the operation and record keeping of data during the duration of the study. The continued involvement of Carthage students may serve to attract students to a profession in which staff will be vitally needed, as approximately 50 percent of the present staff involved with wastewater treatment will be at their retirement age within the next five to 10 years. This interfacing of Carthage with the WWTF showcases the mutual value of linking local colleges and universities with municipal services.