Operation of the SHARON Denitrification Process to Treat Sludge Reject Water Using Hydrolyzed Primary Sludge to Denitrify

摘要

An efficient biological treatment to treat reject water from anaerobic digestion of wastewater sludge is the SHARON denitrification process, which takes place in a chemostat reactor, where aerobic/anoxic periods are alternated under specific hydraulic retention time (HRT) and temperature conditions that favor ammonium oxidizers growth and ensure the total washout of nitrite oxidizers, achieving the biological nitrogen removal over nitrite. An optimized performance of this process to treat Spanish reject water was obtained using methanol and working at an HRT of 2 days, 33℃, and cycle length of 2 hours. Supernatant of hydrolyzed primary sludge was tested to denitrify. Because biochemical oxygen demand was not extremely high in the primary sludge, the fluid dynamics of the system were changed, with respect to the strategy with methanol, but maintaining the reject water influent flowrate. The use of hydrolyzed primary sludge improved the process efficiency, because the alkalinity present in the primary sludge buffered the process until an optimum pH range.