title: [Study on the advanced pre-treatments of reclaimed water used for groundwater recharge].
abstract: To prevent groundwater contamination, pretreatments of reclaimed water are needed before the groundwater recharge. In this study, five treatments, including ultrafiltration (UF), ozonation, magnetic ion exchange (MIEX), UF coupled with ozonation and MIEX coupled with ozonation, were evaluated for their purification efficiencies of the reclaimed water and their influences on the following soil aquifer treatments. For organic matters in the secondary effluents, identified as dissolved organic carbon (DOC) and specific ultraviolet absorbance (SUVA), 20% DOC and 10% SUVA are removed by MIEX treatment with dose of 5 mL x L(-1), while only 10% DOC and no SUVA are removed by UF, but neither of these two pretreatments enhance the purification of soil aquifer treatments. Differently, SUVA of the secondary effluents are removed by 60%-79% by ozonation alone or coupled with UF/MIEX, increasing the biodegradability of the reclaimed water. These pretreatments significantly enhance the removal of organic matters by the following soil aquifer with DOC in the final effluents reducing to 1-2 mg x L(-1). For nitrogen, MIEX can remove 25% NO3(-) -N, and ozonation can remove 72% NH4(+) -N. The soil aquifer treatment could efficiently remove NH4(+) -N to below 0.5 mg x L(-1), while no obvious removal is detected for NO3(-) -N. In conclusion, more attentions should be paid to the organic matters and NO3(-) -N during the pretreatments of reclaimed water. Among all the pretreatments tested here, ozonation coupled with MIEX is capable of increasing the biodegradability of the reclaimed water and removing NO3(-) -N, which is a good choice for the pretreatment of groundwater recharge.
authors.affiliation: Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China. gyt09@mails.tsinghua.edu.cn
authors.forename: Yu-Tuan
authors.initials: YT
authors.lastname: Gao
authors.forename: Xue
authors.initials: X
authors.lastname: Zhang
authors.forename: Xuan
authors.initials: X
authors.lastname: Zhao
authors.forename: Gang
authors.initials: G
authors.lastname: Zhao
mesh_terms: D005374:Filtration / Q000379:methods; D060587:Groundwater / Q000032:analysis*; D007475:Ion Exchange Resins; D010126:Ozone / Q000737:chemistry; D059027:Recycling / Q000191:economics / Q000379:methods; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D014876:Water Pollution / Q000517:prevention & control*; D018508:Water Purification / Q000379:methods*
chemical_list: D007475:Ion Exchange Resins; D014874:Water Pollutants, Chemical; D010126:Ozone