This paper described the mechanism of anaerobic microbe purifying wastewater, and at the same time, pilot plant research was made to investigate the operating characters of UASB (up-flow anaerobic sludge blanket) dealing with starch wastewater at ambient temperature. Result showed that the UASB reactor is in order when UASB start-up and steady running when the temperature is above 20℃.Set-up mode of UASB was bred sludge by self. The seed sludge was made up of digestion sludge from a municipal wastewater treatment plant and anaerobic sludge from the UASB reactor of brewhouse, and the proportion was 5:1. The seed sludge concentra- tion was 15kgVSS/m3. After seeding, the UASB reactor was operating. The sludge had spent 128 days from foremost relax flocculate to granular sludge. The diameters of granular sludge generally range from 1 to 2.5mm. Most of the granular sludge was sphericity. The wet specific gravity of the granular sludge was found to be 1.04g/cm3. The VSS/SS of granular sludge was above 0.7.The maximum specific methanogenic activity was 128 mL CH4/(gVSS· d). The granular sludge had high methanogenic activity and good settleability.After granulation, the effectiveness of UASB reactor had been improvement. The volumetric COD loading rate reached to 6.5kgCOD/m3d. COD removal efficiency was above 90%. In four day's impact load experiment, the volumetric COD loading rate had been increased from 6.5 kgCOD/ (m3·d) to 11.9 kgCOD/ (m3·d) with a lowering of COD removal efficiency to 82.3%. Under this condition the UASB reactor could still be normal operation.
|