We conducted a study on a model drinking water distribution system to evaluate the impact of nutrient in the form of sodium acetate on the growth and survival of coliform and heterotrophic plate count (HPC) bacteria f...We conducted a study on a model drinking water distribution system to evaluate the impact of nutrient in the form of sodium acetate on the growth and survival of coliform and heterotrophic plate count (HPC) bacteria for a maximum of 21 days residence time of water in pipes. Our results show that, besides the nutrient added and the absence of any additional source of contamination and additional supply of nutrient, there was significant growth of the above mentioned bacteria in the pipes and bottles for a couple of days, after which the bacterial population began to decrease. The results indicate that the bacteria used the nutrient to grow and multiply until the nutrient was totally consumed and became depleted in the bulk water phase, after which the bacterial population reached a near stationary level and subsequently declined. This suggests the death of some of the bacteria and their dead cells were used by other bacteria for growth and survival. Using a detection limit of 3.3 CFU/100 mL for the coliforms, the study shows that after sometime, no bacteria were found in the water phase of the pipe, however, the biofilm in the pipes still harbored some of the bacteria. The results have revealed that the bacteria also have the tendency to move from the water phase to the biofilm since the latter provides a more suitable environment for bacteria to thrive on and grow, thus prolonging their survival in the system.展开更多
采用定量盘法(HPC for Quanti-Tray)与平皿计数法对水中菌落总数进行检测。比较结果显示,两种方法具有相关性,且没有统计学意义上的显著性差异。采用定量盘法测定水中菌落总数具有操作简便、结果容易读取、人为误差少、可以采用与总大...采用定量盘法(HPC for Quanti-Tray)与平皿计数法对水中菌落总数进行检测。比较结果显示,两种方法具有相关性,且没有统计学意义上的显著性差异。采用定量盘法测定水中菌落总数具有操作简便、结果容易读取、人为误差少、可以采用与总大肠菌群酶底物法检测同样的试验平台等优点,满足了实验室检测水中菌落总数的要求。展开更多
文摘We conducted a study on a model drinking water distribution system to evaluate the impact of nutrient in the form of sodium acetate on the growth and survival of coliform and heterotrophic plate count (HPC) bacteria for a maximum of 21 days residence time of water in pipes. Our results show that, besides the nutrient added and the absence of any additional source of contamination and additional supply of nutrient, there was significant growth of the above mentioned bacteria in the pipes and bottles for a couple of days, after which the bacterial population began to decrease. The results indicate that the bacteria used the nutrient to grow and multiply until the nutrient was totally consumed and became depleted in the bulk water phase, after which the bacterial population reached a near stationary level and subsequently declined. This suggests the death of some of the bacteria and their dead cells were used by other bacteria for growth and survival. Using a detection limit of 3.3 CFU/100 mL for the coliforms, the study shows that after sometime, no bacteria were found in the water phase of the pipe, however, the biofilm in the pipes still harbored some of the bacteria. The results have revealed that the bacteria also have the tendency to move from the water phase to the biofilm since the latter provides a more suitable environment for bacteria to thrive on and grow, thus prolonging their survival in the system.
文摘采用定量盘法(HPC for Quanti-Tray)与平皿计数法对水中菌落总数进行检测。比较结果显示,两种方法具有相关性,且没有统计学意义上的显著性差异。采用定量盘法测定水中菌落总数具有操作简便、结果容易读取、人为误差少、可以采用与总大肠菌群酶底物法检测同样的试验平台等优点,满足了实验室检测水中菌落总数的要求。
