Valorization of spent mushroom substrate (SMS) along with rice straw as feedstock for efficient bio gasification

Abstract

Wastes generated after mushroom harvesting are known as spent mushroom substrate (SMS) which causes contamination of the environment. Anaerobic digestion is an economical and viable technology used for the management of several types of agricultural wastes, thus generating syngas that has many thermal applications. The current manuscript reports the potential of SMS for anaerobic digestion in five different combinations with rice straw, cattle dung, and bio-digested slurry. The kinetics of the biogasification process occurring in digesters was analyzed by modified Gompertz model. Results showed that maximum biogas (3,12,664 ml) was produced in digester C containing SMS, rice straw, cattle dung, and bio-digested slurry in the ratio of 8:2:1:1 as compared to control (48,968 ml) consisting of only SMS and water in the ratio of 8:2. Evaluation of feedstock for proximate and chemical composition recorded a notable reduction in total solids (TS), volatile solids (VS), cellulose, hemicellulose, lignin content as compared to control. On the other hand, ash content showed a significant increase after anaerobic digestion. Modified Gompertz equation revealed that maximum biogas production potential (P) of 6,150.50 mLg-1 VS with a biogas production rate (Rm) of 134 mLg-1d -1 and lag phase () of 12.80 days was observed in digester C as compared to the control digester A (P= 12.24 mLg-1 VS; Rm = 8.56 mLg-1d -1; =8.80 days). The study demonstrated that the codigesting SMS with rice straw can be successfully implicated for producing biogas as an energy source rather making dumped at the village site for causing pollution.