Proposed digestion and cogeneration improvements at Seneca and Piscataway wastewater treatment plants may reduce energy use, carbon footprint, and cost
Understanding the Issue
Anaerobic Digestion is the natural decomposition of organic materials by microbes that thrive in an oxygen free environment (An–Aerobic = “Without-Oxygen”)
Cogeneration is the beneficial utilization of heat that is normally discarded during electrical generation.
WSSC’s Seneca and Piscataway Advanced Wastewater Treatment Plants (AWWTPs) currently produce approximately 30,000 tons of biosolids per year. Biosolids are AWWTP sludge that has been treated to allow beneficial reuse as a soil fertilizer.
WSSC is considering anaerobic digestion with cogeneration as an alternative to the chemical intensive lime stabilization process currently used to treat the sludge. Anaerobic digestion is a biological process much like human digestion that converts waste sludge to methane gas. This methane is in turn used to power clean-burning engines, producing electricity and heat needed for the digestion process.