Liquefaction of food waste and its impacts on anaerobic biodegradability, energy ratio and economic feasibility

Abstract

In the present study, a new and novel attempt was made to investigate the effect of liquefaction (20–60%) on energy efficient gaseous biofuel recovery and cost during chemo thermo disperser liquefaction of food waste (CTDL). The outcome of the study revealed that rpm (10,000), specific energy input (174 kJ/kg TS), disintegration time (5 min) and energy efficiency of about 11.1 kg SCOD/KWh were considered as optimum in terms of energy and cost. The cost incurred to achieve 20–40% liquefaction was estimated to be 0.0132–0.0168 USD and found to be comparatively very low than the cost incurred (0.0367–0.0547) to achieve 50–60% liquefaction. The biodegradability results showed that a significant increment in biodegradability was achieved (from 0.26 gCOD/gCOD to 0.8 gCOD/gCOD) when the liquefaction was increased from 30 to 40% and an insignificant increment in biodegradability (from 0.8 gCOD/gCOD to 0.84 gCOD/gCOD) was achieved when the liquefaction was increased from 40 to 60%, respectively. The impact of liquefaction on energy balance and cost at tonnage level revealed that 40% liquefaction was considered to be profitable with energy ratio and net profit of about 1.12 and 93 USD/Ton, respectively.