The Grease Rises to the Top: Use of Grease Interceptor Waste as a Supplemental Carbon Source

The implementation of Enhanced Nutrient Removal processes in the Chesapeake Bay region will increase demand for supplemental carbon addition to support denitrification. The historical supplemental carbon source of choice, methanol, has well defined design parameters but is not without challenges. Another industry focus area is the effect of Fats, Oils and Grease on collection and treatment systems. Increased attention on eliminating SSOs has resulted in increased pumping of grease interceptors. This requires WWTPs to accommodate additional grease waste and identify beneficial means of treating this waste. This paper presents the findings of a bench scale pilot test that seeks to combine these challenges and identify an innovative solution. The pilot test evaluated performance of a reactor to ferment grease interceptor waste and produce volatile fatty acids, a potential supplemental carbon source. The pilot test also evaluated the fermenter effluent as a supplemental carbon source in a denitrification pilot reactor.