Performance of selected organic wastes for available technologies for biogas, Kisumu City Kenya

Over years in cities to villages, inadequate and improper disposal of solid wastes exists, especially in Kenya (Africa) that lead to human and animal dumpsite scavenging, health problems, bad smell and unsightliness. The study tested performance of feacal, food and market (vegetables, fruits, tubers, cereals and green maize cobs) wastes for technologies or equipments available for biogas production (Fixed Dome Bio-Digester - FDBD, Flexible Structure Bio-Digester - FSBD, and Simple Ordinary Drum Bio - Digesters -SODBD) within Kisumu City/County. Only FDBD had known design parameter standards. The market waste were pre-prepared by chopping to sizes with own water content. Little water was added to food waste but feacal matter needed less water than 1:1 ratio used for cow dung; all were mixed to porridge consistency. The SODBD (1m3) produced gas in small quantities with high CO2 content. Match box lighting test at an outlet valve tube (25mm) was only positive for the market wastes. The 2.4 m3 FSBD and FDBD produced gas at 56% and 65% (within standards) from market waste and feacal matter feed stocks. The market waste thus suggested a natural co-generation bio-material. Need therefore arises for determining key parameters (for example caloric value, density and ratios) for feedstock in singular or mixed proportions for the digester systems size design. Manual preparation process here informs systems design automation, performance and management of the bio digesters. The available technology and bio material for biogas production is hence an option in managing particular city wastes but with digester design tailored to Bio material or mixture parameter characteristics for improvement of gas production.