生活污水、畜禽饲养场污水以及制革、洗毛、屠宰业和医院等排出的废水，常含有各种病原体，如病毒、病菌、寄生虫。水体受到病原体的污染会传播疾病，如血吸虫病、霍乱、伤寒、痢疾、病毒性肝炎等。历史上流行的瘟疫，有的就是水媒型传染病。如1848年和1854年英国两次霍乱流行，死亡万余人；1892年德国汉堡霍乱流行，死亡750余人，均是水污染引起的。
Domestic sewage, livestock and poultry farm sewage and waste water discharged from tannery, wool washing, slaughtering and hospitals often contain various pathogens, such as viruses, pathogens and parasites. Water contaminated by pathogens can spread diseases such as schistosomiasis, cholera, typhoid, dysentery, viral hepatitis, etc. Some of the plagues prevalent in history are water-borne infectious diseases. For example, the two cholera epidemics in Britain in 1848 and 1854 resulted in more than 10,000 deaths; in Hamburg, Germany, in 1892, more than 750 deaths were caused by water pollution.
受病原体污染后的水体，微生物激增，其中许多是致病菌、病虫卵和病毒，它们往往与其他细菌和大肠杆菌共存，所以通常规定用细菌总数和大肠杆菌指数及菌值数为病原体污染的直接指标。病原体污染的特点是：⑴数量大；⑵分布广；⑶存活时间较长；⑷繁殖速度快；⑸易产生抗药性，很难绝灭；⑹传统的二级生化污水处理及加氯消毒后，某些病原微生物、病毒仍能大量存活。常见的混凝、沉淀、过滤、消毒处理能够去除水中99%以上病毒，如出水浊度大于0.5度时，仍会伴随病毒的穿透。病原体污染物可通过多种途径进入水体，一旦条件适合，就会引起人体疾病。

In water contaminated by pathogens, microorganisms proliferate rapidly, many of which are pathogenic bacteria, pest eggs and viruses. They often coexist with other bacteria and Escherichia coli. Therefore, it is usually stipulated that the total number of bacteria, the index of Escherichia coli and the number of cangzhou.89ix.comshiyanjiw.89ix.comshoubanhulu.07858.netdianbiaox.37ix.com.cnzengbaiji.37ix.com.cn

yawenzhim.37ix.com.cnbacteria are the direct indicators of pathogen contamination. Pathogen contamination is characterized by: (1) large number; (2) wide distribution; (3) long survival time; (4) rapid reproduction; (2) easy to produce drug resistance, it is difficult to exterminate; (2) traditional secondary biochemical wastewater treatment and chlorination disinfection, some pathogenic microorganisms and viruses can still survive in large numbers. Common coagulation, precipitation, filtration and disinfection treatment can remove more than 99% of the virus in water. If the turbidity of the effluent is greater than 0.5 degrees, the virus will still penetrate. Pathogenic pollutants can enter the water through many ways. Once the conditions are suitable, they will cause human diseases.