A Study On Black-odorous Water Governance Of Xin He River By Biological Aerated Filter

The black-odorous water is the main content of the national environmental protection inspection.It is also one of the main tasks to improve the quality of the water environment and the livable living environment of the city.Therefore,this study takes the typical black-odorous water Xin he River in Xi’an as the research object.On the basis of comprehensive analysis and evaluation of Xin he river pollution and treatment characteristics,the research team proposed a combined process of fabricated permeable barrier（PB）,anaerobic filter（AF）,biological aerated filter（BAF）and integrated constructed wetland（ICW）.In this paper,the treatment efficiency and influencing factors of core aerated biological filter（BAF）in the combined process were studied.The degradation characteristics of BAF on organic matter and ammonia nitrogen under different working conditions and the operation effect in field test were combined.The test results optimize the BAF design parameters.The main research results are as follows:（1）After one year’s water quality monitoring of the river,the limiting factors affecting water eutrophication of the river were identified on the basis of the monitoring data.Besides,we use the single-factor standard index method,the improved Nemerow index method,and methods of water quality matrix and weight analyzing analyzed the results of water quality of Xi’an municipal wastewater in this study.The characteristics of refractory organic matter were analyzed by means of three-dimensional fluorescence spectroscopy,Fourier Transform Infrared Spectrometer and X-ray photoelectron spectroscopy（XPS）The above analysis shows that the river belongs to the inferior-V water,TP was the limiting factors affecting water eutrophication of the river,SS,COD,NH₃-N,and TN account for a large proportion in the evaluation and were important pollution factors;In different seasons,the BOD₅/COD_Cr of the Xinhe River is less than 0.25,and the soluble microbial metabolites（SMP）and humic acids account for more than 60%of the total amount of fluorescent organic matter in the Xinhe River.The infrared spectrum shows the metal network in water.The content of the combined humus is large,indicating that the organic matter in the Xinhe River is an inert organic substance and is difficult to be biodegraded.（2）The BAF film was started by artificial inoculation.After 15 days of trial test,the maximum removal rates of COD and NH3-N were 68.2%and 76.22%,respectively,and the removal rate was stable.Microscopic examination showed the presence of indicator microorganisms such as worms and rotifers,indicating that the film is successfully started.Exploring the influence of hydraulic load on the treatment effect,and determining the optimal hydraulic load is 0.67 m³（/m²·h）.Under this condition,the gas-water ratio is adjusted to obtain the optimal gas-water ratio of 2:1.The removal characteristics of the filter were studied.The results showed that the COD removal rate reached 45.62%at the depth of 90 cm filter,and the average removal rate of NH₃-N was only 17.42%.In the range of 90¹30 cm,the average removal rate of NH₃-N reached 81.78%.In the pilot test,The maximum removal rate of COD was 75.14%,and the maximum removal rate of NH₃-N was 99.42%.Through the microscopic examination,it was found that there were indicator microorganisms such as worms and rotifers in the water,indicating that the membrane was successfully activated.The average removal rate of COD during operation was 12.20%,and the maximum removal rate was 33.22%.Due to the poor biodegradability of Xinhe River,the refractory COD is relatively large,and the running time is short.The dominant genus with long generation period has not been enriched,showing a low removal rate.The average concentration of NH₃-N influent was 10.65 mg/L,the average effluent concentration was 2.47 mg/L,the average removal rate was 81.54%,the maximum removal rate was 99.32%,and the removal rate was stable above 90%after the operation,due to biodegradable degradation.The organic matter is less,and the autotrophic nitrifying bacteria shows a strong competitive advantage and has excellent removal ability for NH₃-N.（3）Based on the above research results,the design parameters of aerated biological filter in black-odorous water of Xin he River treatment project with a treatment capacity of 15,000 m³/d were optimized,which can be used for the feasibility study and engineering design of black-odorous water treatment in China.