供水管网水样R2A培养基细菌总数测定及其影响因素探究

Influencing Factors and Determination of Total Bacterial Count of Water Samples on R2A Medium in Water Supply Distribution System

满足饮用水卫生标准的城市给水处理厂净水在输送过程中受到污染,致使管网水中细菌的重新生长和繁殖,从而导致饮用水水质存在安全隐患。以南方某城市管网为研究对象,运用Exp Assoc模型对管网水中细菌菌落总数与细菌出现概率进行模拟,并探讨了管网水的温度、浊度、余氯三个常规指标与水样细菌总数之间的关系。结果表明Exp Assoc模型可以较好地模拟管网水中细菌菌落总数和细菌出现概率的关系,相关系数R2均大于0.97。水温与管网水细菌菌落总数呈正相关关系;管网水高浊度与细菌出现频率亦存在正相关性。余氯对管网水细菌存在水平确实存在影响,当余氯量小于1.0 mg/L时,细菌出现率为100%;当余氯量大于1.0 mg/L时,细菌的出现与余氯值并不相关,呈随机分布状态。

Clean water from the water treatment plants could be polluted during transportation, which leads to the regrowth of bacteria and the potential risk of drinking water safety. The temperature, turbidity, residual chlorine and the total bacterial count of water samples on R2A medium in the water supply distribution system （WSDS） of some southern city were investigated and the total bacterial count of water samples on R2A medium in WSDS and the bacterial appearance probability were fitted by ExpAssoc model. In the same time, influence factors were also discussed. The results indicate that the ExpAssoc model can fit well the relationship between the total bacterial count and the bacterial occurrence probability and the correlation coefficients are greater than 0. 97. Additionally, the total bacterial count of water samples on R2A medium in WSDS is positively correlated with the temperature; high turbidity has a positive correlation with the high bacterial probability of bacteria in WSDS; the residual chlorine indeed has an effect on the bacterial count of water samples in WSDS; when the residual chlorine content is below 1.0 mg/L, the bacteria occurrence rate is of 100%. However, occurrence of bacteria dose not correlated with residual chlorine and shows a random distribution when the residual chlorine more than 1.0 mg/L.