title: Reduction of the excess sludge production by biological alternating process: real application results and metabolic uncoupling mechanism.
abstract: The biological solution proposed to reduce the wasted sludge production is based on a process of alternating phases realized in a specific reactor (alternate cycles in sludge line (ACSL)) where a quote of the recycle sludge is treated and sent back to the main activated sludge process. The ACSL process was applied in two urban wastewater treatment plants (WWTPs). The reduction was tested by changing the hydraulic retention time and the conditions of oxidation reduction potential. The main mechanism of the process is recognized in the metabolic uncoupling. In fact, an increase in the specific oxygen uptake rate in the biological reactors was recorded (up to 20 mg/g VSS/h), which was stimulated by the fasting condition in the ACSL. The process is able to reduce the observed sludge yield on average of 25-30% with final average values reaching 0.179 kg VSS/kg chemical oxygen demand (COD) for WWTP1 and 0.117 kg VSS/kg COD for WWTP2.
authors.affiliation: a Dipartimento SIMAU, Facoltà di Ingegneria , Università Politecnica delle Marche , Via Brecce Bianche, 12, 60100 Ancona , Italy.
authors.forename: Anna Laura
authors.initials: AL
authors.lastname: Eusebi
authors.forename: Paolo
authors.initials: P
authors.lastname: Battistoni
mesh_terms: D057919:Biological Oxygen Demand Analysis / Q000379:methods*; D019149:Bioreactors / Q000382:microbiology*; D003198:Computer Simulation; D008954:Models, Biological; D012722:Sewage / Q000382:microbiology*; D062065:Wastewater / Q000382:microbiology*; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: alternating phases; heterotrophic yield; metabolic uncoupling; sludge reduction; specific oxygen uptake rate