Multi-Substrate Anaerobic Co-Digestion of Citrus Pulp, Lawn Grass, and Chicken Manure-A Batch Study

摘要

Anaerobic digestion of organic waste is a promising alternative to landfilling and is being encouraged by current policies in India. However, nutritional imbalance of single waste as a substrate in anaerobic digestion is limiting the effective degradation in biogas production. Co-digestion of multiple organic wastes where the digestion of two or more substrates is carried out in a single digester is a promising method to enhance the nutritional balance. The present study investigated the possibilities of improving biogas production with co-digestion of citrus pulp (CP), lawn grass (LG), and chicken manure (CM) based on the total solid loading (TS %). The design of experiments and analysis of the co-digestion effect were carried out with central composite design (CCD) and response surface methodology (RSM), respectively. Biogas production was found to vary more with respect to total solid loading (TS %) than C/N ratio of the co-digestion mix. The low influence of C/N ratio may be due to prevalence of optimal C/N ratio of 16-33 in all co-digestion mixes. The adopted central composite design-response surface methodology (CCD-RSM) led to maximum biogas production of 688 mL at CP of 0.28 (TS %), LG of 9.4 (TS %), and CM of 4 (TS %). The CCD-RSM is a suitable approach to maximize the biogas production in multi-substrate anaerobic co-digestion. (c) 2019 American Institute of Chemical Engineers Environ Prog, 38:e13146, 2019