CONVERSION OF FOOD RESIDUALS TO ORGANIC FERTILIZER AS A STRATEGY FOR INSTITUTIONAL WASTE MANAGEMENT IN FORCADOS, DELTA STATE, NIGERIA

Abstract

Food wastes generated From canteens and restaurants in corporate institutions have potential for attracting pests and rodents, producing odours and unaesthetic surroundings, and promoting the breeding of disease vectors. There is dearth of information on institutional food waste management which incorporates resource recovery mechanism in Nigeria. The objectives of the study therefore, were to determine the nature and amount of food wastes generated, develop a composting strategy and assess its quality for possible use within the company. The food wastes generated were obtained from Shell Petroleum Development Company's canteens. The food wastes were composted and fortified with poultry litter, blood meal, harvested water hyacinth and grass clippings from the lawns as Nitrogen enrichment materials. The composting process was aerobic windrow system, which produced compost within eight weeks. In the process, food wastes, poultry litters and dried grass clippings from the lawn were mixed in the ratio of 1:1:2 on dry weight basis to obtain optimal Carbon: Nitrogen ratio. A weighing scale was used to record the weight of the daily food wastes generated. The composting biomass, compost, leachates and soil were analyzed for pH, temperature, Carbon, Nitrogen, Phosphorus, Potassium and selected heavy metals. The compost was used to grow plantain, a staple food in the environment. The yield of plantain grown on the produced compost was assessed for bunch weight, number of hands and fingers. A similar assessment was done with plantain grown on soil without compost. Descriptive and inferential statistics were used for data analysis. The mean daily generation of food wastes was 1502 ± 0.15 kg. During the composting process the variation in temperature was 28°C to 65°C during dry season and 26°C to 62°C during rainy season. Chemical analysis showed that the matured compost consisted of the following: Carbon, 40.0± 5.5%; Total Kjeldahl Nitrogen, 3.56 ± 5.65%; Total phosphorus, 1.12± 5.53% and Potassium, 2.03 ±12.87%. The C:N ratio was 11.23, an indication of high nitrogen, resulting to fast decomposition of the biomass. The heavy metals (in mg/kg) included Lead (1.40 ± 1.32), Chromium 0.6±7.12), Cadmium (1.1 ±4.52), Zinc (0.55 ± 12.34), Nickel (1.41 ± 6.64) and Copper (0.29 ± 14.11). The leachates contained; biochemical oxygen demand, 138.8 ±3.45 mg/l chemical oxygen demand, 240.5± 5.64 mg/l; Turbidity, 3.22 ±14.72 mg/kg; Dissolved Oxygen, 5.6 ±21.43 mg/l and Iron, 1.39 ± 3.67 mg/l. The Compost had no Clostridium sp; but showed Aspergilus niger and E.coli of low count (1.0 x 10² and 1.0 x 10³). The mean bunch weight of the experimental and control plantain were 7.80 ±1.43 Kg and 6.5 ± 0.95kg respectively (t=2.50, p< 0.05). The number of fingers in the experiment and control plantain were 17.8 ± 1.80 and 15.3± 2.05 respectively (t= 3.19, p < 0.05). The production of Nitrogen-rich organic fertilizer from food residuals for growing plantain is an effective resource recovery strategy, and a way of promoting environmental sanitation.