Composting of Organic Wastes for Use in Agriculture

Abstract

Present research work was aimed at developing a system for recycling and utilization of compost derived from kitchen wastes for soil amendment to improve plant growth. Treatment of kitchen waste with a consortium of fast degrading microbes was done. Various parameters were monitored to check the degradation. Kitchen waste was collected from Thapar University, hostel mess and kinnow peels were collected from fruit shop at Thapar University, Patiala. Composting of kitchen waste and kinnow peels was done in pits and plastic tubs respectively using a consortium of microbes, comprising Bacillus subtilis (NA 15), Paenibacillus polymyxa, Saccharomyces cerevisiae and Trichoderma reesei (MTCC 164). Using this consortium, various parameters such as pH, EC, organic carbon, nitrogen, reducing sugar, ash content and volatile solids were monitored at different intervals for 90 days. The carbon content was reduced to 36.31% from 69.03% in 56 days of composting while in case of kinnow peels it reduced to 48%. Simultaneously there was a drop in C: N ratio, optimum C: N ratio was obtained in just 56 days while in the case of kinnow peels the C: N ratio dropped to optimum range of 27.09 in 42 days. Loss in moisture content was monitored in kitchen waste, which reduced from 55.5% to 21.1% over the period of 90 days. On the other hand moisture content in kinnow peels dropped to 18.5%. Reducing sugar yield was observed to have an increasing trend to 65.4 mg/mL from 3 mg/mL while in case of kinnow peels it increased to 107.3 mg/mL from 8 mg/mL. The total nitrogen values tend to increase from 0.063% on day 0 to 2.15% in 90 days of composting. Also the kinnow peels showed the trend, where the nitrogen content increased from 0.057% to 3.66%. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and FTIR was done to check the physical and chemical properties of the treated and untreated biomass. Bio-efficacy trials of the compost prepared from kitchen waste and kinnow peels was checked for its effect on plant growth in pots using brinjal and ladyfinger respectively. Soil to compost ratio was maintained as 3:1 in pots and their performance was compared to plants growing in soil without addition of compost. Physico-chemical test for soil like pH, total carbon, and total nitrogen was checked to evaluate the efficiency of the compost followed by destructive analysis in which biomass produced, root and shoot length along with germination index was analyzed. The Germination Index in case of brinjal with compost was 70 % and in case of ladyfinger it was 66 %. Thus as compared to control the plants grown with compost were much healthier.