Low temperature thermo-chemical pretreatment of dairy waste activated sludge for anaerobic digestion process

• Published in: Bioresource technology 2012-01, Vol.103 (1), p.415-424
• Main Authors: Uma Rani, R., Adish Kumar, S., Kaliappan, S., Yeom, Ick-Tae, Rajesh Banu, J.
• Format: Article
• Language: English
• Subjects: Alkalies - chemistry; Anaerobic digestion; Anaerobic processes; Anaerobiosis; Applied sciences; Biodegradability; Biofuel production; Biofuels - analysis; Biogas; Biological and medical sciences; Biological treatment of sewage sludges and wastes; Bioreactors - microbiology; Biotechnology; Biotechnology - methods; Carbohydrates - analysis; Cold Temperature; Crack opening displacement; Dairying; Energy; Environment and pollution; Exact sciences and technology; Fatty Acids, Volatile - analysis; Fundamental and applied biological sciences. Psychology; Hydrogen-Ion Concentration; Industrial applications and implications. Economical aspects; Kinetics; Methane - analysis; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Models, Chemical; Pollution; Pretreatment; Proteins - analysis; Reactors; Reduction; Sewage - microbiology; Sludge; Solubility; Solubilization; Thermo-chemical pretreatment; Time Factors; Volatilization; Waste activated sludge; Waste Disposal, Fluid; Wastes
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2011.09.124

► Low temperature thermo-chemical pretreatment of dairy sludge was studied. ► COD solubilization, SS reduction were found to be 23% and 22%, at 60°C for pH 12. ► Pretreatment with anaerobic digestion led to 80.5%, 117% of TS and SS reduction. ► Pretreatment of sludge leads to an improvement in biogas production of 103%. An investigation into the influence of low temperature thermo-chemical pretreatment on sludge reduction in a semi-continuous anaerobic reactor was performed. Firstly, effect of sludge pretreatment was evaluated by COD solubilization, suspended solids reduction and biogas production. At optimized condition (60°C with pH 12), COD solubilization, suspended solids, reduction and biogas production was 23%, 22% and 51% higher than the control, respectively. Secondly, semi-continuous process performance was studied in a lab-scale semi-continuous anaerobic reactor (5L), with 4L working volume. With three operated SRTs, the SRT of 15days was found to be most appropriate for economic operation of the reactor. Combining pretreatment with anaerobic digestion led to 80.5%, 117% and 90.4% of TS, SS and VS reduction respectively, with an improvement of 103% in biogas production. Thus, low temperature thermo-chemical can play an important role in reducing sludge production.