Anaerobic co-digestion of cheese whey and septage: Effect of substrate and inoculum on biogas production. (15th April 2022)

• Record Type: Journal Article
• Authors: Bella, K.; Venkateswara Rao, P.
• Is Part Of: Journal of environmental management. Volume 308(2022)
• Publication Date: 2022-04-15
• Subjects: Whey wastewater -- Septage -- Anaerobic digestion -- Methane yield -- Inoculum -- Modelling; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2022.114581
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Cheese whey is an industrial waste generated from the cheese processing unit of the dairy industry and requires treatment before its disposal. The present study investigated the possibilities of improving the digestibility from anaerobic digestion of lipid rich dairy by-product, cheese whey using septage as the co-substrate with different inoculum. Biochemical methane potential assays were conducted under mesophilic temperature conditions and results were validated using Modified Gompertz Model. Two sets of BMP tests were done; to assess the individual and combined digestion abilities of septage in anaerobic co-digestion of whey and to assess the ability of 3 inoculum sources (cattle manure, sewage sludge, and acclimatized anaerobic sludge) in the co-digestion process. The results indicated that septage is an excellent co-substrate that has better adaptability with cheese whey and the optimum mix ratio was found as 40:60 (SCW : SSP ). BMP tests were also conducted with inoculum at S/I ratio of 1 and statistical analysis was performed to study the synergistic effect of both co-digestion and inoculum. The tests revealed that the cattle manure resulted in the highest biogas production (342.22mL/gVS) at 60% whey fraction. Modified Gompertz model fitted the experimental data well and identified an increase in lag phase times when whey fraction is increased. Comparatively higher lag phase times ranging from 1.98 to 4.35 days were obtained for sewage sludge inoculated samples. The maximum methane production (Pmax ) was obtained at 60% whey fraction (369.63 ± 4.05mL/gVS) at a very short lag time of 0.76 ± 0.17days for cattle manure inoculated mixture. Graphical abstract: Image 1 Highlights: Co-digestion of cheese whey(CW) and septage(SP) was investigated with and without inoculum addition. Co-digestion helped in higher biochemical methane yield than weighted average of individual substrates. Fraction of cheese whey in co-digestion mix has increased from 40 to 60% with the use of inoculum. Co-digestion of CW and SP with cattle manure as inoculum resulted in higher methane production.