BERGEN COUNTY UTILITIES AUTHORITY DIGESTS CHEESE WHEY – GETS GAS AN ENERGY-COMMUNITY WIN-WIN

摘要

Bergen County Utilities Authority (BCUA) operates a 413 ML/d (109 MGD) wastewatertreatment facility in Little Ferry, New Jersey. Digester gas produced in the anaerobic digesters isfed to a Combined Heat and Power (CHP) facility. Increasing digester gas production has theimmediate benefit to BCUA of reducing purchased natural gas used to operate the InternalCombustion (IC) engines.Two major producers of cheese products are located just 5 km (3 miles) away. BCUA engaged astudy team to perform bench scale testing to experimentally determine the potential for increasedgas production from whey co-digestion as well as potential deleterious effects on digesteroperation. Bench testing consisted of Biochemical Methane Potential (BMP) and nutrientdeficiency testing.Based on the encouraging bench testing findings, BCUA commenced a full-scale demonstrationof CW co-digestion in October, 2010. Primary objectives were to confirm gas productionpotential and assess the impact on solids generation, which represents an off-setting cost to thesavings from reduced natural gas purchases. Preliminary results, while qualitative, were quitefavorable, and extended full scale testing has continued through June 2011. No significantadverse effects have been noted during extended testing. Drawing firm conclusions with respectto additional gas produced and net solids generated has proved challenging for reasons discussedbelow. The most demonstrable benefits are a “win-win” for the community. The cheeseproducers are no longer faced with intolerable costs for disposing of the whey. One hasabandoned plans to relocate, and the other is now expanding production.