EFFECT OF GAC AND BIOCHAR ON BIOGAS PRODUCTIVITY IN THERMOPHILIC ANAEROBIC DIGESTION OF WHEAT HUSK

Abstract

Anaerobic digestion (AD) of lignocellulosic wastes in India can reduce the pollution and promote efficient harnessing of bioenergy. Carbon-based conducting materials could promote direct interspecies electron transfer (DIET) and make the AD more efficient. This study examines the role of granular activated carbon (GAC) and granular biochar (GBC) in enhancing anaerobic co-digestion (ACoD) efficiency of wheat husk and sewage sludge. GAC and GBC (particle size: 2-5mm) were added separately at five different concentrations: 10, 20, 30, 40, 50 g/linoculum. Biochemical methane potential (BMP) test was conducted under thermophilic condition (55oC). The findings revealed that samples amended with GAC and GBC at 20 g/l dosage had highest biogas yield of 249 and 256 ml/gVSadded, respectively. In both cases, a shorter lag phase was observed compared to the control (no GAC and GBC addition). The GBC amended samples showed relatively stable biogas production throughout 51 days of digestion compared to GAC. The GBC related samples showed consistent results regarding pH, alkalinity, VFAs and soluble chemical oxygen demand (sCOD), unlike GAC samples. This study confirms that conducting materials enhanced AD of lignocellulose is advantageous and should be explored further for different organic wastes and under different operational conditions.