Co-digestion to support low temperature anaerobic pretreatment of municipal sewage in a UASB–digester

• Published in: Bioresource technology Vol. 148; pp. 560 - 566
• Main Authors: Zhang, Lei, Hendrickx, Tim L.G., Kampman, Christel, Temmink, Hardy, Zeeman, Grietje
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01-11-2013; Elsevier
• Subjects: Anaerobiosis; Applied sciences; Biodegradation, Environmental; Biological and medical sciences; Biological Oxygen Demand Analysis; Bioreactors; Bioreactors - microbiology; Biotechnology; Cities; Co-digestion; Digesters; domestic waste-water; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; High soluble COD fraction; Low temperature; Methane; Methane - metabolism; Methods. Procedures. Technologies; Municipal sewage; Netherlands; Pilots; Pollution; Pretreatment; reactors; Recycled; Sewage; Sewage - microbiology; Sludge; Temperature; UASB reactors; UASB–digester; Various methods and equipments; Wastewaters; Water Purification - instrumentation; Water Purification - methods; Water treatment and pollution; Netherlands; UASB–digester; High soluble COD fraction; Municipal sewage; Co-digestion; Low temperature; UASB―digester; Anaerobe; Solubility; Upflow anaerobic sludge blanket reactor; Digestion; Pretreatment; Municipal scope; Waste water
• DOI: 10.1016/j.biortech.2013.09.013
• EISSN: 1873-2976
• ISSN: 0960-8524

•Co-digestion enhances direct anaerobic treatment of low temperature sewage.•Soluble sewage COD removal efficiency of the system improved due to co-digestion.•Co-digestion tripled specific methanogenic activity of UASB and of digester sludge.•Additional advantage of co-digestion is improved suspended COD capture in the UASB.
The aim of this work was to demonstrate that co-digestion improves soluble sewage COD removal efficiency in treatment of low temperature municipal sewage by a UASB–digester system. A pilot scale UASB–digester system was applied to treat real municipal sewage, and glucose was chosen as a model co-substrate. Co-substrate was added in the sludge digester to produce additional methanogenic biomass, which was continuously recycled to inoculate the UASB reactor. Soluble sewage COD removal efficiency increased from 6 to 23%, which was similar to its biological methane potential (BMP). Specific methanogenic activity of the UASB and of the digester sludge at 15°C tripled to a value respectively of 43 and 39mg CH4–COD/(gVSSd). Methane production in the UASB reactor increased by more than 90% due to its doubled methanogenic capacity. Therefore, co-digestion is a suitable approach to support a UASB–digester for pretreatment of low temperature municipal sewage.