Anaerobic Co-Digestion Of Kitchen Waste

In recent years, with the accelerated urbanization and the improvement of living standards in china, it has become an urgent problem facing the pollution of kitchen waste and pig manure to environmental protection departments. Taking the kitchen waste and pig manure as the experimental raw materials, the basic datum of several experimental indexes, such as pH value, total alkalinity, VFA, ammonia-nitrogen, production rate of gas, production rate of methane etc. are obtained under different OLR value at the medium temperature (37℃±1℃) and the stability of the system performance and gas production properties are analyzed in this thesis. Meanwhile, the best operating conditions of anaerobic treatment are found.The experimental results show that the pH value of the digestive system gradually increases from 6.61 to more than 7 as the OLR value increases. Also the concentrations of VFA increase as the OLR value increases, which can accumulate to more than 900mg/L when the OLR value gets to 1.5 g VS/(L·d). The concentration of ammonia-nitrogen fluctuates between 1355-2420mg/L when the OLR value increases from 0.5-1.5 g VS/ (L·d) and the system of anaerobic digestion works steadily within the same OLR value bounds.The amount of the nutrients of C,N and the ratio of C/N are all increased when the OLR increases. The production of the gas of the anaerobic digestion system per day gradually increases from 815mL to 4550mL. The average volume fraction of methane is 0.3582-0.3964 when the OLR value is between 0.5-1.25 g VS/(L·d) and it is below 0.3 when the OLR value is increased to 1.5 g VS/(L·d). The rate of methane production is improved due to the C/N ratio rises and can get to 1968 mL-g-1VS. The average methane production rates are 1376,1556,1523,1111 and 660 mL-g-1VS when the OLR values are 0.5,0.75,1.0,1.25,1.5 g VS/(L·d) respectively.