| This pilot study mainly includes the following three aspects:①Research on hydrolysis acidification. To solve the high COD concentration as carbon resource shortage and a larger proportion of quantity of industrial waste water, experiment with a baffle hydrolysis acidification reactor to ensure follow-up biochemical processing unit can be efficient operation and the stability of the effluent water reaches the standard.②Optimum control of dissolved oxygen. We took "the miraco bubble aerate system and mechanical plug flow" instead of conventional aeration in oxidation ditch in order to improve the utilization rate of oxygen. At the same time, we increased the depth of oxidation ditch substantially. By adjusting the spatial distribution of dissolved oxygen along the channel length, achieve high efficiency of nitrification and denitrification, and achieve the purpose of saving energy.③The regulatory of oxidation ditch. This paper investigated the removal effect of nitrogen of oxidation ditch at different HRT. And the effect of temperature on oxidation ditch running effect.When the HRT of hydrolysis acidification was1.5h,2h,3h or4h, the average removal efficiencies of NH3-N was4.6%,9.9%,13.5%and9.7%, and the removal efficiencies of COD was-25～60%. The result showed that HRT=3h achieved the highest COD and ammonia nitrogen removal. And BOD5/COD increased from0.33to0.45. And the temperature had a little effect on hydrolytic acidification tank. Although anaerobic microorganisms is more sensitive to temperature than aerobic, but extended solids retention time and improving sludge concentration can remedy adverse effect of low temperature.In oxidation ditch, the effluent of oxidation ditch COD, NH3-N and TN achieved "Cities Sewage Treatment Plant Pollutant Discharged Standard"(GB18918-2002) the center one levels A to discharge the standard when aeration pipes open full. As aeration pipes open half, in the ditch could not form alternating aerobic-anoxic environment because of the high proportion of anoxic zone space and the nitration is restrained. Treatment effect of the system is poor in winter. In the oxidation ditch put a aeration pipe in each tunnel for improved the treatment efficiency and slurry mixing effect. The DO average value is2.2mg/L underwater20cm, and2.12mg/L underwater60cm after increasing the aeration area of oxidation ditch. The removal of COD, NH3-N and TN was all improved, NH3-N and TN increased doubled, COD increased10.7%.It was found that HRT was1Oh or8h can achieve high removal rate of nitrogen when regulated hydraulic retention time of oxidation ditch. The removal rate of NH3-N could reach more than90%, the removal of TN when HRT was8h was higher than1Oh. But the removal of NH3-N and TN was very poor when HRT drop to6h and4h. In consideration of the removal, energy saving and consumption reducing, HRT=8h was suitable.Control the temperature in14～34℃, effluent of COD, NH3-N and TN could get satisfactory control when the temperature is greater than23℃; the removal of COD, NH3-N and TN was dramatic decline, reduced20%-50%, when the temperature is below20℃. But the removal of COD without any big changes when the temperature below. Temperature influence on nitrogen removal efficiency because of the activity of the nitrifying bacteria was inhibited. But it could improve by adjusting the hydraulic load. |
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