太湖、钱塘江取水口底泥及周边土壤有机物形成消毒副产物的特征研究

底泥、土壤均是水体有机物的重要来源,但目前相关消毒副产物(DBPs)形成方面的研究偏少.本研究以长三角重要水源地太湖、钱塘江取水口的底泥和周边土壤的浸出液为研究对象,探索氯、臭氧+氯、氯胺、臭氧+氯胺4种消毒方式下,三卤甲烷(THMs)、卤代酮(HKs)、卤乙腈(HANs)、卤代硝基甲烷(HNMs)的形成情况.结果表明,太湖、钱塘江取水口的底泥、周边土壤有机物的芳香度均很低(SUVA254(即比紫外吸光值)2),与腐殖质(Sigma)相比,底泥、土壤有机物不是氯消毒中THMs的重要前驱物,但却是HANs特别是HNMs的重要前驱物.相比氯消毒,氯胺消毒能大幅降低土壤、底泥有机物THMs、HKs、HANs、HNMs的生成量,而且也可抑制含溴DBPs的形成.臭氧预处理大幅提高了氯、氯胺消毒中HKs、HNMs的产量,但对THMs、HANs则不一定.太湖、钱塘江的土壤、底泥存在一定的溴污染,但不管是哪种消毒方式,均是HNMs的溴嵌入因子最大.

Formation of disinfection by-products upon disinfection of the organic matter from sediment and surrounding soil of water intake in Tai Lake and Qiantang River

Sediment and soil are important sources of organic matter for surface water. However, little work was carried out on the association with disinfection by-products (DBPs) formation. This study investigated the formation of trihalomethanes (THMs), haloketones (HKs), haloacetonitriles (HANs) and halonitrimethanes (HNMs) upon disinfection (chlorination, ozone-chlorination, chloramination, ozone-chloramination) of the organic matter from sediment and surrounding soil of water intake in Tai Lake and Qiantang River. Results showed that the organic matters from the soil and sediment had low aromaticity (SUVA₂₅₄(specific UV absorbance at 254 nm)<2). Though these organic matters were not the important precursors for THMs during chlorination, they were potent precursors for HANs, especially for HNMs as compared with humic acid (Sigma). Chloramination substantially reduced the yields of THMs, HKs, HANs and HNMs, and inhibited the formation of brominated DBPs compared with chlorination. Treatment of preozonation remarkably increased the production of HKs and HNMs whether for chlorination or chloramination, but this was not certain for THMs and HANs. Certain degree of bromine contamination occurred in the sediment and soil, and the highest bromine substitution factor was observed in HNMs.