| In recent years,the problem of low C/N in city sewage seriously affect the water quality of sewage treatment plant,most of the sewage treatment plant by adding sodium acetate and other things as carbon source to ensure the removal of nitrogen,this will not only increase the operating costs,but also has many drawbacks.Therefore,it is particularly important to find new ways to solve this problem.Many schools try to solve the problem by improving the process and finding new carbon sources.This paper mainly studies the SBR technology,which also called sequencing batch reactor,testing from the two aspects.One is to reform the process,namely: the influence of the influent water on the nitrogen removal was studied by changing the influent number.The other one is study on the dosage of hydrolytic acidification liquid as carbon source on nitrogen and phosphorus removal effect.Take step-feed style,can make full use of carbon source in sewage,so as to achieve the purpose of efficient nitrogen removal.As the most widely used technology in sewage wastewater treatment,activated sludge technique has produced lots of waste activated sludge,while the expenses of waste activated sludge disposal take a more larger proportion in sewage plant operation costs,it even caused damage to the environment.In this paper,hydrolysis acidification liquid is used as carbon source to save cost and improve nitrogen removal efficiency.The full text includes the following three parts:(1)Before the experiment,each parameter of SBR process is optimized so that it can run in the optimum state.After the optimization,a comparative experiment was conducted between step-feed SBR and conventional SBR process.The experiment was completed under the same experimental conditions.The experiments showed that: the average total nitrogen effluent concentration of step-feed SBR reached 11.62mg/L,the removal rate of total nitrogen was 9.04% higher than conventional SBR process;The removal efficiency of COD and ammonia nitrogen was as well as conventional SBR process,and reached 85%,93.5%.This result proved that the step-feed SBR has better treatment effect on nitrogen removal on the basis of small scale experiment.(2)Through the pilot experiment of simulation experiment,further verify the experiment results.The experiments showed that: the average total nitrogen effluent concentration of step-feed SBR reached 13.11mg/L,the removal rate of total nitrogen was2.02% higher than conventional SBR process;The removal efficiency of COD andammonia nitrogen was as well as conventional SBR process,and reached 88.83%,97.98%.This result proved that the step-feed SBR has better treatment effect on nitrogen removal on the basis of small scale experiment.(3)After hydrolysis and acidification of the excess sludge in the water plant as an additional carbon source to compare with sodium acetate was used as a carbon source.By comparing the different ratio of hydrolysis acidizing fluid and sewage,the optimum amount of hydrolysis acidification liquid was determined by the effect of nitrogen addition,and the dosage of sodium acetate was obtained by calculation.After comparison experiment and calculation: the optimum ratio of hydrolysis acidizing fluid and sewage is1:70,and the dosage of sodium acetate was 38.34mg/L.In the same conditions,no additional carbon source,hydrolysis acidification solution and sodium acetate were put into the SBR system to carry on the contrast experiment.The result is:comparing with the non carbon source,the removal rate of TN,COD and ammonia nitrogen increased by13.94%,5.87%,1.93% after adding the hydrolysis acidification liquid,but lower than that of sodium acetate.Nevertheless,it still has to meet the sewage discharge standard.It can be concluded that the hydrolysis acidification liquid can be used as a carbon source.In summary: whether step-feed SBR process section or adding hydrolysis acidification liquid as carbon source can help to enhance the effect of nitrogen removal. |
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