Study On Piggery Wastewater Treatment With SBR Pocess

With the development of the livestock industry, the pollution of which has been more serious these years, and the piggery wastewater is the in the head of front. Pig farming is a low-profit industry. It's too hard to find an economical and efficient way to dispose the piggery wastewater. To solve this problem, the author investigation on the working process in the pig farm, and find that the prime problem of wastewater treatment is to remove the high concentration of NH₃—N. The author study the traditional and the new way of removing NH₃—N process. The nitrification/ denitrification and the shortcut nitrification/denitrification were used in the piggery wastewater treatment with SBR. There was finally a good result of the experiment.After the investigation on the local pig farm, it was known that the piggery wastewater mostly came from the piggery washing wastewater. It contains high concentration of SS(3000⁵000mg/l), COD(8000¹0000mg/l), NH₃—N(800 1000mg/l). The local treat process is: Barrier—Sediment—Anaerobic—Contact oxidation—Oxidation pool. Because of the low remove rate on NH₃—N in Contact oxidation process, the final out water can't reach the local drainage standard.The SBR was used to replace the Contact oxidation process in the experiment. Under the best procedure (Inflow.15min — Anaerobic.2h —Aerobic4h— Anaerobic.2h —Aerobic4h—Sediment.0.5h—outflow.0.5h—stop.45min), alternate nitrification/ denitrification process was used to remove nitrogen. Control DO: between 1—3mg/l, pH: above 7.0, sludge age: 20days. The removal rate of COD is about 70% and which of the NH3—N is about 98%.. The oxygen demand of the system is about 4—5 times than which the traditional active sludge treatment. About 72mg alkalinity (count by CaCO₃) was needed per liter of wastewater. If the temperature below 15℃,the remove rates of NH₃—N will drop, and the rates is about 50% when which is below 10°C. The nitrification will stop when the temperature is below 10℃.The result of the experiment show that the nitrification/ denitrification process need large more oxygen and alkalinity. It's not suitable for the economical demand of the piggery wastewater treatment. There is also a contravention about the carbon remove in nitrification and carbon demand in denitrifiation.The advanced SBR experiment shows that it is possible to achieve the shortcut nitrification/ denitrification in one reactor in one time by reconstructing, and which use baffle to form one aerobic area and two anaerobic areas. Under the same...