Category: Water, Wastewater & Storm water
A New Sodium Hypochlorite Generation System Using Ion-exchange Membrane Electrolysis technology was developed for drinking water disinfection, which was mainly composed of three parts: the electrolyzer, salt water preparation device and the reactor, where chlorine and sodium hydroxide respectively formed in the anode and cathode chamber can produce sodium hypochlorite.
Laboratory tests were done under realizable operation conditions to observe the operation effects of membrane electrolytic sodium hypochlorite generation device, from three aspects: membrane material, the brine quality into the anode, the water quality into the cathode. At the same time, the effects on the operation results were studied whether the electrolyte was heated or not. The results showed that the concentration of available chlorine of sodium hypochlorite solution produced by the new system increased by 3 times, while the salt consumption reduced by more than half, compared with the traditional non-diaphragm generation system. The production of available chlorine and the power consumption are mainly affected by the ion-exchange membrane, while the variances of the salt consumption and cell voltage are not obvious.
Then, the sodium hypochlorite solution produced by the new generation system is compared with the solution produced by non-diaphragm generation system, and the commercially available solution. The results indicate that the new system can generate high-quality disinfectant with near neutral pH, low total dissolved solids (TDS) and low chlorate. After disinfection by the high-quality sodium hypochlorite, pH value only rises by 0.03, while TDS rises by 0.1mg/L. The forming amount of trihalomethanes (THMs) decreases by 60.4% when the new disinfection system is adopted. The above mentioned and operation cost calculation results show that the new system possesses good application prospect in water disinfection.
Yannan Jia– China Institute of Water Resources and Hydropower Research, Beijing