Experimental Study On The Ultrasonic Enhanced Sodium Hypochlorite Water Depth Treatment Technology

Water resource shortage has already become important obstacle for the sustainable development of society and economy. Reclaimed water reuse can reduce the sewage discharge, and improve water environment. And it also alleviates the shortage of water resources and reduce the cost of water. It has a broad application prospect. As a final processing unit of reclaimed water reuse, disinfection has an irreplaceable role in reclaimed water quality security and hygiene safety particularly.Paper use deep treatment effluent of a sewage treatment plant in Jinan as the research object. Through laboratory static test, the research was carried on ultrasonic enhanced sodium hypochlorite disinfection test, inspecting sodium hypochlorite disinfection, ultrasonic treatment and coordination treatment effect. Coordinated operation process parameters was determined, carrying out process feasibility analysis. The main research conclusions are as follows:Sodium hypochlorite has good disinfection effect on reclaimed water. For the test samples, when the chlorine dosage and the contact time reached respectivly to 50 mg/L and 30 min or 40 mg/L and 120 min, e.coli number and amount of total residual chlorine can meet the regulations of "the reclaimed water quality standards "(SL368-2006) and "the cities sewage recycling of mixed water water quality "(GB/T 18920-2002). For test samples, the regression equation of the CrT values and the inactivated rate of e.coli is:y=1.63541n(x) -7.9848. The regression correlation coefficient R2 is 0.7124; When the removal rate of e.coli is less than 3 CFU/L, CRT value is 1500 mg.min/L, namely disinfectant dosing 50 mg/L and disinfection contact 30 min can meet the standard requirements.Ultrasonic treatment has certain removal efficiency on e.coli and organic matter. When ultrasonic density and ultrasonic action time reached respectivly to 0.75 w/mL and 30 min, the e.coli number is 6×105 CFU/L after ultrasonic treatment and e.coli removal rate is 85%, but can't meet the regulations of "the reclaimed water quality standards "(SL368-2006) and "the cities sewage recycling of mixed water water quality" (GB/T 18920-2002). Ultrasonic treatment should not be used alone, and it is suitable for combination with other disinfection technology.Ultrasonic treatment can effectively strengthen the effect of sodium hypochlorite disinfection on reclaimed water. Ultrasonic treatment can reduce the amount of sodium hypochlorite dosing and disinfection contact time, disinfection costs, ensuring the safety of reclaimed water reuse. The main factors that influences the synergy disinfection effect influence degree is:sodium hypochlorite dosing quantity> contact disinfection time> ultrasonic action time> ultrasonic power. The optimum parameters combination of collaborative disinfection process is:ultrasonic density and ultrasonic action time is respectivly 0.75 w/mL and 4 min, and sodium hypochlorite dosing quantity and contact disinfection time is respectivly 40 mg/L and 30 min. Disinfection effect can meet the regulations of "the reclaimed water quality standards "(SL368-2006) and "the cities sewage recycling of mixed water water quality" (GB/T 18920-2002).