营养物质和氯对饮用水中细菌再生长的影响

Effects of nutrients and chlorine on bacterial regrowth in drinking water

饮用水生物稳定性与水质安全息息相关,控制细菌再生长是保障饮用水生物稳定性的有效措施.为此,以细菌再生长潜力(BRP)为研究方法,采用实验室配水实验,探讨碳、氮、磷3种营养物质以及自由氯对细菌再生长潜力的影响.结果表明,单一营养物质不足时,满足土著细菌生长的碳、氮、磷营养物质质量浓度的临界值分别为250、7和3μg/L,碳、氮、磷对BRP的产率系数分别为2.35×106(R^2=0.99,p<0.05)、9.76×107(R^2=0.91,p<0.05)和1.76×108CFU/μg(R^2=0.91,p<0.05);两种营养物质不足时,相对质量浓度较低的营养物质为BRP主要限制因子,而且可导致其他营养物质支持细菌再生长能力的下降.研究发现随着水中自由氯质量浓度的增加,BRP呈下降趋势,当自由氯质量浓度≥0.50 mg/L,细菌生长得到有效控制,氯削减水中营养物质促进细菌再生长的能力.

The biological stability is closely associated with the safety of drinking water and can be controlled effectively by prohibiting bacterial regrowth. The effects of three main nutrients（ organic carbon,phosphorus,nitrogen） and chlorine on bacterial regrowth in drinking water were investigated using BRP method in lab-scale experiments. The critical values of carbon,nitrogen and phosphorus promoting bacterial growth were 250,7 and 3 μg/L respectively,while the yield values for heterotrophic bacteria of the three nutrients were 2. 35 × 106（ R^2=0.99,p〈0.05）,9.76×107（ R^2= 0.91,p〈0.05） and 1.76×108CFU/μg（ R^2= 0.91,p〈0.05） during the absence of only one kind of nutrient. When two kinds of nutrients were in deficiency,nutrient which was relatively low would be the main BRP limiting factor and decrease the supporting ability of the other nutrients on bacterial regrowth.Moreover,BRP decrease with the increasing amount of free chlorine in drinking water. When the concentration of free chlorine reached 0. 5 mg/L,the growth of bacteria was inhibited obviously. In other words,free chlorine weakened the ability of nutrients supporting bacterial regrowth.