Aeration Energy-saving Technologies In High Ammonia Wastewater Treatment Using The Advanced A/O Process

Aeration,which is the main energy consumption in biological wastewater treatment,is obviously becoming a key and significant technical problem as a concern in the water treatment industry.For the two main functions of the aeration,it was researched that(1)the aeration oxygen demand(BCOD,Biological-treatment Chemical Oxygen Demand)and the calculation of oxygen supply energy consumption expressed by the power consumption per BCOD removed(kWh·kgBCOD-1),and(2)the minimum mixing energy consumption to meet the mixing requirement that maintains activated sludge in suspension.Firstly,for accurate plant design and management,two new process design concepts was proposed,to Advance A/O Process treating high ammonia wastewater as an example.The two concepts were(1)BCOD and(2)the power consumption per BCOD and their calculation methods were provided respectively.With the concepts,the power consumption per BCOD of four treatment plants that treated the salinomycin and tryptophan production wastewater(5,500 m3·d-1),the penicillin production wastewater(10,000 m3·d-1),the monosodium glutamate wastewater(1,500 m3·d-1)and the methanol and urea production wastewater(7,200 m3·d-1),were 1.29、0.73、1.92 and 2.45 kWh.kgBCOD-1,respectively,which showed good stability.Secondly,the parameters such as COD,TKN,NH3-N,NOx-N,DO,BCOD and power consumption per BCOD in the biological treatment process were analyzed.The result reveals that the main aeration energy-saving technologies are improvement of the transformation rate from ammonia to nitrogen and control of DO concentration steep rise point.Thirdly,through on-site investigation,on-site testing and CFD(Computational Fluid Dynamics)simulation method,the research discovers that the minimum mixing energy consumption is existed in aeration tanks to maintain the activated sludge in suspension.Under a low treatment load,for the mixing energy consumption playing a major role,the mixing energy consumption is required to meet in design and operation management and only decreasing the mixing energy consumption can plants save energy.Fourthly,for decreasing the mixing energy,the change for HS(High Shear)aerators arrangement from even to linear and the special spiral-type plug flow type generated by HS aerator conduce to reduce the minimum aeration intensity to 15 m3·min-1·1000m-3.