Saudi professor produces biogas from animal and plant waste

AHMED Saeed Mohammed Qashash, a teaching member at the University of Al-Baha, has made the first biogas digester, producing organic fertilizers and biogas.

This scientific concept aims at re-using organic leftovers from crops and livestock waste in an economical and safe way to protect the environment from pollution. This concept allows the production of the methane gas in a new and renewable source of energy.

Dr. Qashash said that the bio-digester produces biogas from organic waste through the fermentation of these residues, isolating them from air in the middle of a 90 percent aqueous environment in a tank underground. The size of the tank varies depending on the purpose of the unit; it ranges from several cubic meters to several thousands cubic meters.

When the conditions of temperature, acidity and ingredients balance are on point, the bacteria will disband the organic materials into organic acids and be transformed into methane in the form of tiny bubbles that goes up, mixed with carbon dioxide gas.

Dr. Qashash told Al-Arabiya that cattle waste is one of the best types used in



the production of this gas, followed by sheep, birds and camel wastes, in addition to farm waste emanating from agricultural crops such as wheat, corn, wasted fruits and leftovers in fruit and vegetable shops.

He explained that the waste of one cow per day produces the equivalent of 1,200 liters of gas, while the waste of one chicken produces only nine liters. He added that this gas is used directly for cooking, lighting, heating and cooling, operating internal combustion machines such as irrigation machines, mills and agricultural machinery. It can also produce electric power generators with this biogas.

One cubic meter of biogas can run a machine with one horse power for two hours. It can also run an agricultural tractor that weighs three tons for almost a distance of three kilometers, a six feet refrigerator for six hours, a 60-cm poultry heater for two hours and lighting a 100-watt bulb for six hours.

Dr. Qashash added that gas extraction starts one month after the beginning of the natural fermentation process. When there is no more oxygen available, the fermenting molecules start to produce natural gas.