| The EGSB reactor, in which anaerobic ammonium oxidation, methanogenesis and denitrification were already coupled, and BAF reactor were integrated to develop a new technology of wastewater treatment which made anaerobic ammonium oxidation, methanogenesis and shortcut nitrification-denitrification coupled in a system in the study. Different synthectic wastewaters were treated by the integrated system to demonstrate main effective factors. The results indicated the integrated system is adapted to treat domestic wastewater and high strenth industrial wastewater. It could also save plentiful energy expend by aeration, simultaneity converse a plentiful amount of COD in wastewater to CH4. It could conquer high effluent concentration of NH4+-N in the anaerobic treatment and saved energy and organic substances requirements under the conditions of simultaneous removal of COD and ammonium at high loadings.①Steady shortcut nitrification was achieved in BAF reactors inoculated with aerobic ammonia oxidation bacteria after the start-up operation of 20d. The concentration of NH4+-N and COD in the effluent was below 0.1 mg/L and 30 mg/L respectively, the concentration of NO2--N and NO3--N in the effluent was 45.55 mg/L and 4.18 mg/L respectively under the performance conditions that DO was between 0.8 and 1.2 mg/L, pH was controlled between 7.8 and 8.5, temperature was between 3235℃,influent flux was 13 mL/min, the concentration of ammonium and COD in the inflow was 50 mg/L and 500 mg/L respectively and outer recycle ratio was 200%.②The anaerobic ammonium oxidation, methanogenesis and shortcut nitrification-denitrification were successfully coupled in a system integrating EGSB and BAF reactors without adding NO2--N in the influent. The effluent of EGSB was treated by shortcut nitrification in BAF, while the effluent of BAF recycled to EGSB to provide NO2--N for the later. A synthetic wastewater containing COD of 500 mg/L and NH4+-N of 40 mg/L was treated by the EGSB-BAF integrated system, when different outer recycle ratios were used. The experimental results demonstrated that integrated system gained the best removal effect at the outer recycle ratio of 200%. The concentrations of NH4+-N, NO2--N, NO3--N and COD in the effluent of the system were 1 mg/L, 4.3 mg/L, 2.56 mg/L and 40 mg/L respectively on this recycle ratio condition. The removal loading rates of COD, total nitrogen and ammonium were 1.7718 kg/(m3.d), 0.1368 kg/(m3.d) and 0.1639 kg/(m3.d), respectively. Compared with conventional activated sludge process, EGSB-BAF integrated system saved O2 of 9.1303×10-4 kg/d and COD of 2.9292×10-3 kg/d, simultaneity reclaimed CH4 of 1.03 L/d form the wastewater.③A synthetic wastewater containing COD of 300 mg/L and NH4+-N of 30 mg/L was treated by the EGSB-BAF integrated system.The experimental results demonstrated the concentrations of NH4+-N, NO2--N, NO3--N and COD in the effluent of the system were 1.06 mg/L, 3.4 mg/L, 1.13 mg/L and 18.2 mg/L respectively at the outer recycle ratio of 200%. The removal loading rates of COD, total nitrogen and ammonium were 1.1799 kg/(m3.d),0.1069 kg/(m3.d),0.1246 kg/(m3.d), respectively.The results indicated the integrated system adapted to treat synthetic wastewater on this condition and reached better removal effect.④A synthetic wastewater containing COD of 900 mg/L and NH4+-N of 40 mg/L was treated by the EGSB-BAF integrated system.The experimental results demonstrated the concentrations of NH4+-N, NO2--N, NO3--N and COD in the effluent of the system were 1.07 mg/L, 4.39 mg/L, 1.97 mg/L and 70.47 mg/L respectively at the outer recycle ratio of 200%. The removal loading rates of COD, total nitrogen and ammonium were 3.4571 kg/(m3.d),0.1398 kg/(m3.d),0.1647 kg/(m3.d), respectively. The results indicated the integrated system adapted to treat synthetic wastewater on this condition and reached better removal effect.⑤A synthetic wastewater containing COD of 900 mg/L and NH4+-N of 120 mg/L was treated by the EGSB-BAF integrated system.The experimental results demonstrated the concentrations of NH4+-N, NO2--N, NO3--N and COD in the effluent of the system were 2.05 mg/L, 12.89 mg/L, 2.6 mg/L and 44.08 mg/L respectively at the outer recycle ratio of 200%. The removal loading rates of COD, total nitrogen and ammonium were 3.5633 kg/(m3.d),0.4334 kg/(m3.d),0.4948 kg/(m3.d), respectively. The results indicated the integrated system adapted to treat synthetic wastewater on this condition and reached better removal effect.⑥A synthetic wastewater containing COD of 1200 mg/L and NH4+-N of 120 mg/L was treated by the EGSB-BAF integrated system.The experimental results demonstrated the concentrations of NH4+-N, NO2--N, NO3--N and COD in the effluent of the system were 3.21 mg/L, 10.62 mg/L, 3.04 mg/L and 86.67 mg/L respectively at the outer recycle ratio of 200%. The removal loading rates of COD, total nitrogen and ammonium were 4.6342 kg/(m3.d),0.435 kg/(m3.d),0.4885 kg/(m3.d), respectively. The results indicated the integrated system adapted to treat synthetic wastewater on this condition and reached better removal effect. ⑦The higher the concentration of COD in the inflow was, the lower the activity of anammox bacteria was, and the lower the removal efficiencies of NH4+-N from EGSB was compared the results among test a and test e. The activity of denitrification and methanogenesis in EGSB, denitrification in BAF were enhanced at different extent accompanying the concentration of organics increased. When the integrated system treated wastewater with high concentration of organics, it also could achieve better removal efficiencies, simultaneity saved more energy expend of O2 and organic substances requirements on conditon that the concentration of NH4+-N increased to a certain degree to provide enough NO2--N outer recycling to EGSB by shortcut nitrification process in BAF in order to relieve the competition of interstitial substance between anaerobic ammonium oxidation and denitrification bacteria, and enhance the ability of anaerobic ammonium oxidation.
|
PDF Full Text Request