Thermophilic anaerobic acid digestion of biosolids: hydrolysis, acidification, and optimization of retention time of acid digestion. Issue 3 (1st May 2006)

• Record Type: Journal Article
• Authors: Puchajda, Bartek; Oleszkiewicz, Jan
• Is Part Of: Journal of environmental engineering and science. Volume 5:Issue 3(2006)
• Page Start: 187
• Page End: 195
• Publication Date: 2006-05-01
• Subjects: environment; Environmental engineering -- Periodicals; Sanitary engineering -- Periodicals; Environmental engineering -- Canada -- Periodicals; Environnement, Technique de l' -- Périodiques; Technique sanitaire -- Périodiques; Environnement, Technique de l' -- Canada -- Périodiques; Environmental engineering; Sanitary engineering; Canada; Electronic journals; Computer network resources; Periodicals; 628.05
• DOI: 10.1139/s05-038
• Languages: English
• ISSNs: 1496-2551

Abstract

Abstract : The objective of the study was the optimization of the retention time in a thermophilic acid digestion system. To achieve this optimization, acidification index defined as the ratio between acidification rate and hydrolysis rate was used. First-order reaction model developed by Eastman and Ferguson (1981) was used to describe hydrolysis of particulate matter in sludge. The first-order hydrolysis rate constant was found to be 2.36 d –1, and the initial concentration of degradable particulate COD was found to be 10.4 g/L. A model of acid digestion was proposed that included acidogenic biomass growth and decay. The total acidogenic population was estimated and kinetic parameters of acidogenic population were specific growth rate 0.78 d –1, net specific growth rate 0.25 d –1, decay coefficient 0.52 d –1, and observed yield 0.05 mg biomass / mg COD consumed. Based on the acidification index, the optimum retention time in a thermophilic acid digester was 3–3.5 d. Key words : wastewater sludge, biosolids, anaerobic digestion, hydrolysis, acidification, kinetics.