Study On Improve The Run Organic Load Of Kitchen Waste Anaerobic Digestion In Semi-continuous

Experiment uses kitchen waste which come from student cantee and restaurant. The inoculum taken from a farmers digester outskirts of Chengdu. The test was carried out with a semi-continous feeding reactor under temperature about35℃by increasing organic load gradually to find a maximum organic load of anaerobic digestion.Experiment was divided into two phase, On the first phase, the anaerobic fermentation raw materials use kitchen waste which come from restaurants and the second uses the kitchen waste from the student cafeteria, the result showed that kitchen waste from different sources have a significant impact on the upgrade of the organic load, The process of the fermentation system was normally under the organic load anaerobic about1.0gVS/L.d～1.5gVS/L.d. pH value was maintained at about7.2, VFA concentration was maintained below480mg/L. The ammonia nitrogen and alkalinity level were normal. A variety datas are maintained in the normal range of growth of methane bacteria. The Gas production、methane percentage、per unit mass of VS methane production rate were risen with the rise of experimental organic load at1.5gVS/L.d,10.52L/d、10.20%、0.98L/g respectively. At this point the anaerobic fermentation system is running best, but the anaerobic fermentation system was trended in inbalance when incressing the organic load at1.5gVS/L.d.The second phase of the experiment,, the kitchen waste from the student cafeteria was used. The experimens was operated normaly with amaximum organic load about2.5gVS/L.d organic load, which pH was7.4, VFA was below480mg/L. The ammonia and alkalinity concentrations were higher than before more than2000mg/L and9000mg/L, respectively. The gas production rose to12.63L/d. The methane content dropped to about59.22%, The methane production rate decreased to0.598L/gVS.The system stability was enhanced greatly to ensure the early acidogenic stage transit to the methanogenic phase smoothly.The experimental results show that:①uder the condition of increase organic load gradually the anaerobic digestion systerm using pig manure as substrate can keep balance between acidogenic stage and methanation stage.②in the higher concentration of organic load, methanogenic bacteria requires a longer acclimation time to adapt new environment.③the kitchen waste composition has a huge impact on the system, because of its higher fat content, which can only been operated under lower organic loading, But it is able to access higher unit mass of VS biogas production and methane production rate.