Effectiveness of the pretreatment methods on mesophilic anaerobic co-digestion of fruit, food and vegetable waste

Abstract

Pretreatment of the fruit, food and vegetable waste materials could enhance the biogas generation in a shorter time along with waste reduction. The aim of the present work was to assess the effectiveness of alkaline, hydrothermal, thermal and ultrasonication pretreatment of fruit, food, and vegetable waste with cow dung for the mesophilic anaerobic co-digestion. The mesophilic anaerobic co-digestion of fruit food and vegetable waste as single substrate with cow dung were performed in a laboratory scale 1L batch digester for 30 days at 40 ± 2 oC temperature. Obtained result show that pretreatment process has enhanced the biogas and biomethane production by 35 % and 44.4 % with 19.89 % TS and 17.30 % VS removal in case of ultrasonication pretreatment (100.45 ml biogas/gVS and 27.92 ml CH4/gVS,), while slight increase is found with thermal and hydrothermal pretreatment as compared to untreated FFVW. The biogas production is enhanced by 35%, 20.4%, 5%, 6% and biomethane production are enhanced by 44.4%, 22%, 11%, 9.8% in the case of ultrasonication, alkaline, thermal and hydrothermal pretreatment process, respectively. The stable mesophilic anaerobic co-digestion operation was achieved and impacts of the different pretreatment methods on the biogas yield and net energy recovery along with viability of anaerobic co-digestion have been explored.