Efficient removal of organic matters and typical odor substances in rural drinking water using Ozone-BAC-UF combined system to meet new water quality standards in China

Abstract

China has just implemented new drinking water quality standards, canceling the provisions detailed in the previous standards that allowed relatively lenient water quality standards in rural areas, and unifying the water quality requirements for urban and rural areas. In rural areas of China, lakes are important sources of drinking water, but their water typically contain high concentrations of organic pollutants. In addition, removal odorous substances from such sources is challenging. In response to these issues, an ozone-biological activated carbon-ultrafiltration process is proposed and its efficiency in drinking water treatment is explored. The results indicate that O3-BAC pretreatment significantly improved the efficiency of the membrane process in removing organic and odor substances. At an ozone dosage of 2 mg/L, with granular activated carbon as filler and an EBCT of 25 min, the O3-BAC pretreatment allowed removal rates in the membrane system equal to 71.5% of CODMn, 84.2% of UV254, as well as 92.2% and 92.5% of GSM and 2-MIB, respectively, the latter being typical odor compounds. In addition, the function and diversity of the microbial communities in the reactor were evaluated under different pretreatment conditions at different stages: functionally specific microorganisms were enriched in different systems, and some microorganisms contributing to the removal of organic and odorous substances were identified. The effluent from the combined Ozone-BAC-UF process consistently met the new requirements for drinking water in China, implying that the combined system has significant potential for practical applications for drinking water treatment in rural areas.