Biological Technology Research For Deep Denitrification In Tiantang River Sewage Purification Plant

In recent years,there are many researches on biological treatment technology with denitrification function at home and abroad.Compared with chemical and physicochemical methods,biological denitrification technology has been paid great attention by the wastewater treatment industry because of its advantages of high efficiency,low investment,low operating cost,good sludge settling performance and so on.Reconstruction and expansion project of Beijing Daxing District Tiantang river sewage treatment plant needs a reconstruction in the first period and a new construction in the second period.The treatment of water in the first period was transformed from 40000 m³/d to 25000m³/d.Prolong the stay time to improve the effect of denitrification.The treatment of water in the second period is 55000 m³/d.The effluent quality standard of the sewage treatment plant is increased from the former national level B standard to the Beijing local standard B.A variety of biochemical processes with nitrogen removal function,experimental data and the characteristics of actual inflow of TianTang River sewage treatment plant are researched and analyzed.After modifying the process design,biochemical treatment process and parameters of the sewage treatment plant are designed.Based on a full investigation of the water quality and analysis of all kinds of biological nitrogen removal processes,research and field experiment of process technology are conducted according to the corresponding standards of Beijing.After the investigation in Planning Bureau and Water Bureau of Daxing District and dozens of factories and residential communities in the upper reaches,the biochemical denitrification process is determined to be a modified A²O process,using the experience of the feasibility study report of the expansion and expansion project of the TianTang River.To ensure the reliability of the technical process route,pilot test is carried out.The experiment shows that modified A²O process only cannot meet the requirement of deep denitrification,and then an"improved A²O+AO"process of denitrification is adjusted and proposed.After optimizing process parameters and increasing the adjustment of parameters,the process is more flexible and more adaptable to the fluctuation of the influent nitrogen concentration.The research results are applied to the preliminary design of the project.After the completion and upgrading of the TianTang River sewage treatment plant,good operation results have been achieved over 1 year.Under the average daily water quantity of 75000m³?the maximum daily water quantity is 82000m³?and in the case of the water quality indicators?TN?reached 78mg/L&?NH₃-N?reached 60mg/L,the treated water and effluent quality meet the design requirements.The success of upgrading and extension project in Beijing Daxing District TianTang River sewage treatment plant has a good reference for the same type process of large and medium sewage treatment plant in Beijing and process design and operation of the B standard for the water quality in Beijing.Good economic,social and environmental benefits have been obtained.