Process performance of dry, batch anaerobic digestion of sewage sludge: methanogenic seed mixtures

• Published in: Water science and technology Vol. 66; no. 2; pp. 445 - 450
• Main Authors: Szűcs, B Rózsáné, Szántó, G L, Simon, M, Füleky, Gy
• Format: Journal Article
• Language: English
• Published: England IWA Publishing 01.01.2012
• Subjects: Anaerobic digestion; Anaerobic processes; Anaerobic treatment; Anaerobiosis; Biodegradation, Environmental; Degradation; Digestion; Laboratories; Methane; Methane - metabolism; Mixing ratio; Reactors; Sewage; Sewage - microbiology; Sewage sludge; Sludge; Sludge digestion; Sludge drying; Waste Disposal, Fluid - methods
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2012.223

A dry, batch anaerobic digestion (DBAD) process was tested on two sewage sludge types with different methanogenic seed fractions under laboratory conditions. The aim was to indicate optimal sludge:seed mixing ratios and analyse process performance based on degradation rate and reactor-specific methane production. The attained results were compared with the performance of a liquid-state, laboratory-scale stirred reactor (SR). A mixing ratio of at least 1:1.25 (sludge:seed) yielded processes free from significant inhibitions. Further seeding increments resulted in slightly better performances, but much lower sludge fractions treated in the reactors. Compared with the SR process, the DBAD reactors produced comparable degradation rates albeit in a significantly longer process and with somewhat lower reactor-specific methane production rates. These findings indicate that the DBAD method may provide a viable alternative to liquid-state processes if sludge drying is already applied and reactor volume requirements are of importance.