Study On The Optimized Running And Cleaning Of The CMF-S System

Accoring to the system optimization, mathematical statistics and water treatmenttheories we practiced lots of experiments via the continuous micro-filtrationsubmersed (CMF-S) whose scale reaches72m3/d. By studying the optimizedoperation, chemical cleaning and the influence of pre-chlorination we propose theoptimized scheme for the reclaimed water plant running under different workingconditions. On the premise of the effluent water quality, we practice to reduce theoperation expense and slow down the pollution rate of miro-filtration system.Firstly, we ascertain the best working conditions (working period, air wash andwater flush) of CMF-S system under different water treatment scales of both summerand winter, using the orthogonal test method. The result shows that the optimizedworking conditions increase the water production rate to2.7~4.5percent, anddecrease the backwash cost to20.93~37.21persent. Besides, the polluting rate ofCMF-s is depreciated to4.5~30.2percent, which is good to reduse the operation cost,improve the water production and depreciate the membrane pollution.Secondly, the pre-chlorination test is to study the influence on the treatment effect,the specific flux and the organic compound molecular weight distribution of CMF-Ssystem influent and effluent. Based on the membrane pollution of different workingconditions, we propose the best dose of pre-cholorination. The test shows that the bestpre-chlorination concentration is4~5mg/L. Besides, the pre-chlorination have a goodremoval of organic compound whose molecular weight is below4kDa and above50kDa.Thirdly, the continuous running test is to apply the achievements to the reclaimedwater plant production. Compare the optimized result with the former on the aspect ofmembrane pollution rate, water treatment effect, operation cost, and the chemicalcleaning period. The test shows that the optimized result depreciates the pollution rateto9.38percent, increases the water production to1.76percent and decreases thebackwash cost to24.44percent. This test proves the feasibility of period extension.Besides, we studied the CIP cleaning. By analyseing the surface of the membrane andthe TOC test and atomic absorption method, we can conclude that the materials whichcause the membrane pollution are organic compound and scaling substance. Besides, we find that the chlorine cleaning is better than the acid cleaning to recovery themembrane water permeability. However, the acid cleaning is better for removal of themetal contamination.Finally, based on the former achievements, we propose the scheme for optimizedrunning and build the optimized model. According to different water treatment scale,water conditions and so on, we ensure the best dose of PAC and chlorination and theoperation period, which decreases the running cost and depreciates the pollution rate.Compared with the former running condition, the optimized one decreases theoperation cost to6.41%~19.53%, improves the backwash efficiency to3.67%~13.15%, and the water production to37.21%. Besides, the chemical cleaningperiod is prolonged, which is economic.