Study On The Particle Counting Method In Water Treatment Plant

With rapid economic development,the living standards of the residents in Guangzhou increases constantly,On the one hand Guangzhou City increases water supply,on the other hand makes higher demands on drinking water quality.How to improve water purifying ability and guarantee qualified chlorinated water have become primary tasks of many water plants when raw water quality changes.This research subject measures raw water changes of Xijiang River for two years with combined beaker coagulation and production experiments.The research also through combined use of particle number with turbidity,p H value,algae content and microbial biomass,etc.,optimizes coagulant dosage,rinsing sink cycle,filtering velocity,etc.of water plants in operation,to ensure reduced operating cost on the basis of qualified chlorinated water.As the research on raw water of Xijiang River shows,water under low turbidity,low temperature and algae contents,traditional indicators change are insignificant while the particle number can intuitively reflect raw water changes.The coagulant dosage experiment shows that,when raw water under the temperature of 20~30?,and the high turbidity of 100~400NTU,alum amount of 45mg/L~55mg/L is reasonable.Under the low temperature and turbidity,it hardly achieves ideal flocculation effect if only alum amount is increased.Thus the adding of coagulant aids within 0~0.5mg/L is suggested,and particle number can reduce by 20% after precipitation.Particles production experiment of sinking water shows that,pulse clarifier has poor resistance to water quality and temperature fluctuation,and that particle counting method can timely change hydraulic condition to ensure flocculation and precipitation effect.When raw water is under high turbidity(inflation of 3.5: 1 and cycle of 60s~70s),and rinsing sink cycle of 18~20h,it will achieve good effect.After the pulse clarifier cleaning,the number of small particles in water after filtration obviously increases.If water inflow reduces by a half,the penetrating phenomenon obviously decreases.The application experiment of particle counting method in the filtering process shows that,initial filtrated water quality is mainly affected by filtering velocity and backwashing strength,and that for ordinary rapid filters,the water quality over-standard phenomenon appears in preliminary filters.Thus Xi Cun water plant is suggested to reduce filtering velocity after backwashing by a half,and adjust backwashing strength to 12/(s· m2)above so that the number of 2~3?m particles in optimized initial filtrated water can reduce to 50 particles/ m L below.In contrast,filters of air and water distribution in the type of “filter plate + long-handle filter head”,has more advantages than filters of air and water distribution in the type of perforated pipe and high resistance,in increasing backwashing strength and reducing the number of particles in initial filtrated water.In brief,high sensitivity of the particle counting method can make up for the shortage of regular testing modes.Thus the method applicable to water treatment process can reflect water quality changes more accurately and timely,and play an important role in securing drinking water.