Research On Treatment Technology For The Circulation Use Of Railway Scouring Sewage

Based on investigations on status quo of scouring sewage treatment both at home and abroad, depending on systematic analysis on problems and shortcomings of existing treatment technique for circulation use of scouring sewage, we put forward three different treatment schemes for the circulation use of scouring sewage, and according to water quality of various scouring water, through small-scale and pilot-scale experiments in combination with various treatment techniques, the optimum scheme of circulation use and corresponding treatment process are obtained.The small-scale experiment, which is carried out through first mixing washings and then making it coagulate and filter it, reveals that PAC is a quite good coagulant, and that the low-pressure membrane filtration is a quite good mode of filtration. It is shown that the low-pressure membrane filtration process is lower in one-shot project investment, lower in operating cost, and shorter in period for recovery of investment than coagulation process, based on economic analysis for the coagulation process and the low-pressure membrane filtration process.It is shown by Pilot-scale experiment applying the low-pressure membrane filtration process that PAN ultrafiltration membrane is a kind of the best material quality, and that the filtration with PAN ultrafiltration membrane has a certain capacity of disinfection.Through sewage treatment applying ultrafiltration- ultraviolet disinfection process, turbidity of water and such pollutants as suspended mat, grease, bacilli, coliform community can effectively be removed from scouring sewage, and the active ingredient LAS of detergent can partly be remained in treated water, and after sewage treatment, the water quality can meet requirements of circulation use, and treated water can be used to wash clothing and other articles of daily use, without harmful effects on sensitive whiteness and plasticity of washed clothing and other articles, and can also meet hygienic security required for the circulation use of scouring sewage. A comparison of membrane seepage flux and net treated-water production under different hydraulic back washing conditions indicates that the optimum hydraulic back washing condition of ultrafiltration membrane is obtained at back washing 2.0 minutes per 0.5 hour. Under long- term operation condition, the chemical cleaning method with alkaline available for ultrafiltration membrane is the most effective and convenient.