The Primary Design Of Wastewater Treatment Plant For 100000 Tons/year Of Starch Production

China is the country that the products of starch is much heavier than others in the world, but along with the starch production process the high concentrated wastewater becomes a serious source of environmental pollution. Therefore paying more attention on treating the wastewater and preserving environment has becamed the most important thing in our citric acid industry. The emissions of wastewater from the production process contain a large number of soluble organic compounds (carbohydrates, fat acid, protein, starch, etc.) which are biodegradable, non-toxic and non-harmful. The workshop designed in this thesis could process 100000 tons starch wastewater. In this design the main raw material is cassava water flow is 900m3/d, COD is 18000～19000 mg/L, BOD quantities is 7000～12000mg/L, pH is 4.0～6.0, the temperature for 22～32℃.The process of wastewater treatment is as follow:the wastewater â†' grill â†' adjustment sedimentation pond â†' anaerobic treatment â†' denitrogenation processing â†' water leakage.In the processing the adjustment sedimentation pond design variable is:Long 20m, extends 5m, deep 6.5m. In the anaerobic process chooses 4 design parameters forcircular UASB upper flow anaerobic sludge beds of which structual variables are as follows:diameter 8m, the deep 12m. In the denitrogenation processing working procedure this design choice uses A/O denitrogenation processing, supposing one aeration tank which has five porch type, the porch extends 10m, single unit aeration tank pond long 5m. In the end the sludge settles through the secondary pond after aerobic process, the purified water discharge from the discharge mouth and the standard of purified water is COD≤200mg/L.