SUSTAINABLE MANAGEMENT OF COW DUNG FROM SLAUGHTER HOUSES

Abstract

Large amount of cattle dung are generated daily from slaughter houses which are not only of environmental concern due to methane emission but also present a significant health risk if not adequately managed.  In this study, cow dung obtained from slaughter house was anaerobically digested and its composition evaluated.8 kg of the collected cow dung was mixed with water using a mechanical stirrer set at a speed of 150 rpm to form slurry before pouring it into a laboratory scale digester affixed with stirrer, inlet and outlet ports and temperature detector. The set up was left for 3days for microbial activation to take place, before daily stirring.  Average weekly temperature of the slurry inside the digester tank was observed. Biogas produced was collected in a rubber tube and trapped with activated charcoal dissolved in 500 ml of carbon disulphide (CS₂) for 120 minutes in an open air. The liquid filtrate was then analysed using a Gas Chromatography. The optimum temperature was observed at 36.5 ^OC. The digestion temperature variation was between 0.5 to 2 ^OC. Methane bacteria worked best in the temperature ranges between 34 and 37 ^OC. After the liquefaction process, 30 cm³ of biogas was generated. Out of which, methane occupied 25.002 cm³ (83.34 %), carbon dioxide 4.467 cm³ (14.89 %), nitrogen 0.468cm³ (1.56 %) while carbon monoxide generated was 0.063 cm³ (0.21 %). The result clearly show that methane has the highest yield, the energy contained in methane can be used as domestic gas.Cow dung is an excellent substrate for biogas production in anaerobic digesters instead of indiscriminate disposal. Bio-digestion of cow dung is a viable and sustainable solution to the problem of waste pollution, disposal, control and management.