Requierdly Controlled Aeration Process Of Oxidation Ditch For Denitrification And Its Application In Municipal Waterwater Treatment Plant

The fresh water resources per capita in China are already quite low. At the same time, population growth and economic development has led to increments of sewage discharge yearly. The emission of large volume of wastewater containing nitrogen, phosphorus and chemical oxygen demand (COD) of high concentration exacerbates the phenomenon of water pollution and further aggravates the shortage of water resources. Building urban sewage treatment plant is an important way to solve the pollution problem. However, sewage treatment is major energy consuming industries, both construction costs and operating costs are exorbitant, which directly affects the effectiveness of Water pollution control. Aeration system which is accounting for more than 50% of the total power consumption is the largest energy consumption in wastewater treatment plant. This paper combined experimental testing and engineering application, researching the new requierdly controlled aeration process of oxidation ditch for denitrification to improve compliance rate of effluent ammonia and sewage treatment efficiency by control aeration rate on demand, which can also save power consumption and operating cost of the plant.Oxygenation capacity of aerators has a significant impact on the performance of aerator systems. Contrast on oxygenation capacity of the surface aeration system and blasting aeration system were investigated and verified through experimental study. The results show:both oxygenation capacity and oxygen utilization efficiency of mechanical aeration system are much lower than blasting aeration system. Consuming same energy, blasting aeration system can provide more oxygen to aeration tank, on this basis, this paper investigated the traditional methods and principle of aeration control, proposed NH4+-N-based intelligent aeration control strategy, solving shortcoming such as large DO concentration fluctuation, poor microbial treatment environmental, low effluent compliance rate and high energy consumption.Taking the surface aeration system and blasting aeration system sewage of an treatment plant in Fujian province city as example, investing and analyzing the capacity and energy consumption of two aeration systems:replaced its surface aeration system in oxidation ditch process to blasting aeration system, The result of investigation by analyzing the effluent quality and power consumption showed that 3.08 million Yuan can be saved for the plant one year; use NH4+-N-based intelligent aeration control strategy on the blasting aeration system, The effect of intelligent aeration control was investigated by analyzing energy saving of blower aeration and nullity of the effluent water, the result showed that the DO of aerobic tank was stably controlled, the treatment effect of biological systems was improved and the average specific energy consumption of every month were decreased by 13.32% On the promise of that effluent compliance rate were 100% and treatment quantity was essentially unchanged.Aeration control strategy has a dual purpose of improving the biological treatment system performance and preventing excessive aeration to save operating cost.