Study On Purification Method And Device Of Dispersed Domestic Sewage

In this paper,according to the characteristics of intermittent discharge and large change of discharge volume of the decentralized domestic sewage,the treatment process suitable for the decentralized domestic sewage is designed and the purification device is made.After the purification device is made,the device is operated and debugged to achieve the purpose of stable and efficient removal of organic matter,nitrogen and phosphorus,and provide a feasible construction for the decentralized domestic sewage treatment Discuss the plan.In this experiment,based on activated sludge process and biological membrane,the main process was designed and the integrated device was made.The main body of the design device is a transparent cylinder with a bottom diameter of 200 mm and a height of 1500 mm.The main cylinder is divided into anaerobic area and aerobic area from bottom to top.The sewage enters the anaerobic area at the bottom of the device along the water inlet pipe and then flows into the aerobic area.The anaerobic area is composed of anaerobic sludge and column suspended packing.The aerobic area is composed of a small amount of sludge and column suspended packing.A submersible pump is set above the packing in the aerobic area Return the effluent from the aerobic area to the bottom anaerobic area.The up and down combined process designed in this experiment has the advantages of small floor area,simple operation and maintenance,etc.The continuous water inlet experiment and the intermittent water inlet experiment were carried out to test the operation effect of the device.It was found that the purification effect of the continuous influent experimental device was better,and the removal rate of TP and ammonia nitrogen needed to be improved under the condition of intermittent inflow.Therefore,by adjusting the aeration rate to increase the do in the aerobic zone,adjusting the A /O ratio of the device and optimizing the packing,under the condition that the total amount of intermittent water inflow is 45 L,the performance optimization experiment of intermittent water outflow is carried out.After the optimization,the long-term operation test is carried out to test the stability of the device’s water outflow the conclusion is as follows:(1)The DO of the aerobic area in the unit increases from 3mg/L to 4mg/L,the purification effect of the sewage is obviously improved,and the average removal rates of COD,TP and ammonia nitrogen are increased by 4.3%,5.1% and 6.3%,respectively.(2)When A/O ratio is 2:3,the ammonia nitrogen value of effluent is the lowest.Compared with A/O ratio of 1:1,the removal efficiency of COD,ammonia nitrogen and TP are increased by 1%,1.8% and 2.1% respectively.(3)The efficiency of phosphorus removal was improved by 7.5% when sponge iron packing was added to the anaerobic area and aerobic area of the unit.The phosphorus removal efficiency is increased by 7.5%,the average efficiency of TP is up to 92% after the sponge iron packing is added,and the effluent COD,TP and ammonia nitrogen all reached the first-level A emission standard.(4)The long-term stability experiment was carried out after the optimization of the device.For one consecutive month,the total daily intermittent inlet water was 30 L,COD inlet water index was 196～273mg/L,TP was 3.1～4.6mg/L,and ammonia nitrogen was 20.1～33.5mg/L.When the COD,TP,and ammonia nitrogen from the device could all meet the discharge standard of urban sewage grade A.According to the results of this experiment,the optimized decentralized sewage treatment device has good effect on the treatment of decentralized sewage.Compared with the traditional sewage purification device,it has the advantages of high purification efficiency,strong impact resistance,simple operation and maintenance,and has good stability and application.