Turning your Digesters into Cash Cows, Accepting High Strength Organic Wastes into the Digesters makes Financial Sense

Anaerobic digesters are normally considered a necessary evil in the facilities that operate them; A do-not-touch attitude to the operation of the digesters has always been observed. As long as they are working “we don't touch them” is the standard for most utilities. Grease and other high strength organic wastes are normally nightmares at the wastewater treatment facilities. They clog the sewers, increase the maintenance and stink the entire facility.This project will show that properly handled the nightmare and the necessary evil can become the main attraction and produce a benefit for the utility in more ways than one. High strength organic wastes released into the sewer system through legal and illegal operations, reduce the capacity of the sewer system and increase the cost and maintenance. Once at the treatment plant, these organic loads decrease the capacity of the treatment plant and increase the operational costs and maintenance. Pound-per-pound, grease has twice as much aeration demand than normal sewage solids.The City of Waco owns and operates the Waco Metropolitan Area Regional Sewer System (WMARSS) wastewater treatment facility. This facility operates four 2-million gallon anaerobic digesters. The City is also home to several industrial facilities that discharge high strength organic wastes into the sewer system.This project was developed by the WMARSS staff to identify the parameters of operation and the capacity available in the digestion system to bring these organic wastes into the digesters in concentrated form and obtain the anaerobic digestion gas benefit from the anaerobic degradation of these materials.