Author: Asadu Christian Oluchukwu
Department: Chemical Engineering
Affiliation: Nnamdi Azikiwe University Awka
Biofertilizer was produced in this study by composting mixtures of sawdust and urine, sawdust and sewage sludge and sawdust and cow dung respectively. Pilot scale study was performed with containers made of polyethylene (PET) as the composter sequel to selection of a mixture with high yield of Nitrogen. In this study, the mixtures of organic waste were composted at different weight ratios (2:1, 4:1, 6:1 and 8:1). Turning over was done once every week for aeration. Temperature was monitored at different depths daily. Other parameters such as N, C, organic matter, pH and heavy metals were determined at the end of the composting. The results of the study showed that a mixture of sawdust and sewage at a ratio of 6:1 gave a higher percentage of Nitrogen. Organic matter and fixed carbon decreased due to increasing the temperature. Highest temperature obtained was 59.5oC after 25 days. Also, the temperature of some of the compost decreased slightly at day 30 due to maturity of the compost. The heavy metal content of all the composts decreased to world health organisation acceptable standards established by United State Environmental Protection Agency 2004 (2800mg/l for Zn, 300mg/l for Pb, 1500mg/l for Cu, 1200mg/l for Cr and 39mg/l for Cd). The optimization results gave a mixture of sawdust and sewage at a weight ratio of 5:1 for 22.5 days at moisture of 45% as the optimum condition for the manufacture of bio fertilizer. The results indicated that co-composting of sewage and sawdust is a reliable and simple method for the production of biofertilizer. The design considerations and equipment selection were also covered.
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Tags: Asadu Christian Oluchukwu, Biofertilizer, Compositing Mixture, Containers, Cow Dung, Heavy Metals, Nitrogen, Nnamdi Azikiwe University, Organic Matter, Organic Waste, Polyethylene, saw dust, Sewage Sludge, Urine