Study Of Combiantion Of Short-cut Nitrification And Ozone Oxidation Under The High Ammonia Concentration Wastewater

With the growing of industrial economy, the nitrogen pollution in water bodies is becoming increasingly serious. There is great significance to develop nitrogen recycling process research in base of sustainable development with reduction, reuse, recycling concept.In this study, a short-cut nitrification process was applied to oxidize ammonia, and then the effluent was oxidized by ozone oxidation, the high concentration of ammonia in wastewater was recycled and translated to industrial raw materials or agricultural fertilizers, at last the nitrogen in wastewater was recovered. Experimental studied the startup and manages of short-cut nitrification, the effort of aeration and sludge age on nitrification process, the water quality control and ozone oxidation of the out fluent of short-cut nitrification impact of instrument. The main conclusions are as follows:1. The temperature was set at 30℃, aeration capacity was set at 0.11m3/h in SBR reactor, and ammonia concentration in inflow water increased gradually. The ammonia removal rate reached 90%, nitrite accumulation rate reached 90% after 31d, and the startup of short-cut nitrification was realized. The pH, DO and OUR were used to monitor the operation as real-time monitoring parameters, which kept short-cut nitrification steadily in SBR system.2. Under sludge age12d, the aeration of 0.14 m3/h had a higher reaction rate of nitrite accumulation than aeration of 0.18m3/h, but the ammonia removal efficiency was decreased. And compared to aeration of 0.14 m3/h, ka and kb were enhanced and the oxidation of NH4+-N was accelerated under aeration of 0.18 m3/h. With increase of sludge age, ka and kb were significantly decreased, but kc was increased, which showed a reduction of nitrite formation and nitrite accumulation rate in system, and the reaction toward to complete nitrification. So the increase of sludge age is disadvantageous to maintain the stability of short-cut nitrification. 3. On the condition of SRT12d, aeration 0.18m3/h, nitrite accumulation rate reached 89%,and maximizing specific consumption rate rate was achieved, ka was up to 43.6×10-3·mgNH4+-N·h-1·mgMLSS-1.4. To get NO2--N:NH4+-N in short-cut nitrification effluent to 1:1,a formation was derived and verified to calculate the reaction time:t=a·b·η·C0/MLSS·ka.5. With ozone oxidation of short-cut nitrification effluent, ammonia concentration remained unchanged, and nitrite nitrogen was oxidation to nitrate nitrogen rapidly during the process. The greater the ozone dosage, the higher rate of oxidation of nitrite nitrogen was got, with the ozone dosage 2.0g/h, the nitrite oxidation rate achieved 74mg NO2--N/h. The greater the ozone dosage were used the smaller total nitrogen loss. High concentrations of ozone molecules were caused by high bicarbonate concentration, which promoted the reaction rate.6. NH4NO3 solution was obtained by short-cut nitrification and ozone oxidation at last. The concentrated liquid or crystal NH4NO3 were got form the solution by further treatment, and then back for industrial or agricultural application.