Unification of Waste Management from Fish and Vegetable Markets Through Anaerobic Co-digestion

A considerable quantity of waste is being generated from fish markets and harbors of coastal regions in India. Presently, there is no systematic and sustainable ways of disposal which leads to unscientific handling and dumping in landfills. Upon considering the bottlenecks associated with the anaerobic digestion of fish waste (FW) as sole substrate, co-digestion with vegetable wastes (VW) could be an effective alternative to mitigate the problem along with simultaneous treatment of two different waste streams. In this study, an attempt has been made to examine the co-digestion efficiency of FW with VW for which three trials viz., T1 (mono-digestion of VW), T2 (mono-digestion of FW) and T3 (co-digestion of VW and FW) were conducted to analyze the biomethane production potential, degree of biodegradability and pH stability. From the obtained results co-digestion was found to yield 463 +/- 6.73 L/kg VSfed of biomethane which is 24.13% and 22.32% higher as compared to VW (373 +/- 4.94 L/kg VSfed) and FW (378 +/- 4.55 L/kg VSfed) respectively. Maximum biodegradability based on organic carbon destruction was found to be 70% in co-digestion followed by mono-digestion of VW (58.8%) and FW (64%). Prevalence of acidification and ammonification in mono-digestion of VW and FW were reflected by physiological pH of 5.4 +/- 0.41 and 8.3 +/- 0.32 respectively. In co-digestion process pH was observed to be 7.3 +/- 0.70 that indicated high stability and thus enhanced the biomethane yield. Co-digestion of these organic wastes could enhance the efficiency of methane production and therefore presents a unified waste management option.