Rules of anaerobic digestion of cow manure by wet method and the effect of carriers

Experiments were conducted to observe the effects of polypropylene net ball, fiberglass and carbon fiber film carriers on biogas production, pH values, COD removal rate, microorganism and activity of coenzyme F₄₂₀ in the outflow fermented and fermentation rules in the anaerobic condition of 5% cow manure. pH values decreased to the lowest at the third day of fermentation, then increased above 7 at the 7th day of it. Biogas output reached the highest pinnacle at the ninth day of it, then decreased gradually. COD removing happened mainly during 4～8 day of fermentation. The amount of bacteria in the outflow fermented was the highest at the sixth day of it, then decreased to relatively stabilizing level during 12～26 day of it. The activity of coenzyme F₄₂₀ was the same changing rule as the amount of bacteria in the outflow fermented. Polypropylene adhered more anaerobic microbes to its surface, and prolonged pinnacle significantly and increased biogas yield(p<0.05) and reduced significantly outflow of microorganism with outflow of fermented manure(p<0.01).