According to the outline of the "14th Five-Year Plan", by 2025, the proportion of surface water reaching or superior to Class III water will reach 85%. Three types of water bodies refer to a class of water quality standards in surface water environment, which are defined as water bodies with good water quality and certain pollution, but not exceeding the national standards. This kind of water body is mainly suitable for general industrial water, domestic water, agricultural water and fishery water. The following will introduce the relevant contents of the three types of water bodies in detail from three aspects.
Three types of water bodies refer to water bodies with good water quality and certain pollution, but not exceeding the national standards. Its specific standards: the content of main pollutants in water is lower than the limit stipulated by national standards, including dissolved oxygen, ammonia nitrogen, total phosphorus, five-day biochemical oxygen demand, permanganate index, volatile phenol, arsenic, mercury, chromium (hexavalent), total coliform and other indicators.
Sensory indexes such as color, smell and taste of water and physical and chemical indexes such as pH value meet the requirements of national water quality standards. The sanitary indexes of water meet the requirements of national water quality standards and can ensure the healthy drinking demand of human beings.
Pollution sources and pollutants of three types of water bodies
Industrial wastewater: Industrial wastewater is one of the main pollution sources of three types of water bodies, including process wastewater, equipment cleaning wastewater, ground washing wastewater and waste heat wastewater. These wastewater contain a lot of pollutants, such as organic matter, heavy metals, ammonia nitrogen and sulfate.
Domestic sewage: Domestic sewage contains a lot of pollutants such as organic matter, ammonia nitrogen and phosphate, which is another major pollution source of the three types of water bodies. Agricultural sewage: Agricultural sewage contains a lot of pollutants such as organic matter, ammonia nitrogen and phosphorus, which mainly comes from farmland irrigation and animal husbandry wastewater.
Other pollution sources: Other pollution sources include municipal garbage, pesticides and fertilizers. These pollutants will enter the water body with natural factors such as rainfall, causing certain pollution to the three types of water bodies.