Study on Recycling Byproduct Salts from Waste Treatment as Disinfection Materials

Abstract

CaCl 2 , NaCl, and other byproducts generated by waste treatment are landfilled as fly ash. Cl − dissolved in leachate is discharged to public water, which has an impact on agriculture and marine resources. Therefore, concentrate and dry salt (hereafter referred to as by-product salt) are generated by desalting treatment fa-cilities. This study was conducted on the possibility of recycling by-product salt as a disinfection material for wastewater treatment by generating NaClO and other compounds from it by electrolysis. As a result, a mix-ture liquid (hereafter referred to as eco hypochlorite) of NaClO and KClO with an effective chlorine concentration of above 5 , 000 mg/L was generated by a diaphragm-free electrolysis method with the concentration of salt water at 3 % and Ca 2 + at 30 mg/L. In the sterilization capacity test of eco hypochlorite, it was con-firmed that its capacity is equal to or greater than that of industrial NaClO. According to the feasibility study, when the amount of dried by-product salt is more than 0 . 5 t/day (equivalent to the amount of by-product salt generated from a city of 100 , 000 people) and recycled as disinfection material in a sewage treatment facility, it will provide economic merits to both the source (final disposal site) and the user (sewage).