Research On Optimizing The Process Of Lingqiao Water Treatment Plant

Relying on the Shanghai Pudong Veolia Water Company-Lingqiao Works andbased on the present conditions of Lingqiao WTP, by means of on-site simulation andfull-scale test the project has optimized the performances of coagulation,sedimentation and the filtration for two product systems combined the advancedparticle counting technology with conventional monitoring method.The raw water turbidity of Chenhang reservoir was an important influencingfactor on the flocculants (PAC) dosage. As to the on-site source water from theYangtze, the flocculants dosage can be influenced by the raw water quality. Thepreoxidation of Cl₂ combined with KMnO₄ can be regard as an emergencycountermeasure to deal with the deterioration of the raw waterIt was not significant to the effects of the prechlorination on Chenhangreservoir's source water in the coagulation process, however, for the on-site sourcewater, chloramine can help the flocculation. The chorine dosage should be determinedin the range of 3～4 times of the ammonia concentration in the raw water when it ishigher than 5mg/L for ensuring both an effective disinfection and the best enhancingcoagulation.Both the on-site simulation test and the full-scale test on Chenhang filtrationsystem showed that the filtration cycle was determined by the filtrate's quality ratherthan the water head loss in summer Therefore, it is reasonable to use the filtrate'sturbidity and particle counting to judge the length of filtration cycle and it's backwash.In addition, 8m/h is an optimal filtration rate for the actual filter's configuration,which can make a full use of the whole depth of the sands and the loading available.The feasible filtration cycle is about 96h, which will save 500 m³ of filtered watermonthly for a single filter, while 6000 m³ can be saved monthly for the whole system.The research shows that as a new measurement in water treatment plant, particlecounting can be used as a water quality monitor in the main treatment processes. Itsadvantage of accuracy and sensitivity can assist the conventional water qualitymonitoring methods in improving the routine monitoring of water quality and guarantee the treated water quality.