Wastewater classification

The first is classified according to the chemical properties of the main pollutants contained in industrial wastewater. The inorganic wastewater is mainly containing inorganic pollutants, and the organic wastewater is mainly containing organic pollutants. For example, electroplating wastewater and mineral processing wastewater are inorganic wastewater; food or petroleum processing wastewater is organic wastewater.

The second is classified according to the products and processing objects of industrial enterprises, such as metallurgical wastewater, papermaking wastewater, coking gas wastewater, metal pickling wastewater, chemical fertilizer wastewater, textile printing and dyeing wastewater, dye wastewater, tanning wastewater, pesticide wastewater, power station wastewater Wait.

The third is classified according to the main components of pollutants in wastewater, such as acidic wastewater, alkaline wastewater, cyanide wastewater, chromium wastewater, cadmium wastewater, mercury wastewater, phenol wastewater, aldehyde wastewater, and oily wastewater , Sulfur-containing wastewater, organic phosphorus wastewater and radioactive wastewater, etc.

The first two classifications do not involve the main components of pollutants contained in wastewater, nor can they indicate the hazards of wastewater. The third classification method clearly points out the main pollutants in the wastewater and can indicate the certain hazards of the wastewater.

In addition, starting from the difficulty of wastewater treatment and the hazard of wastewater, the main pollutants in wastewater are classified into three categories: the first category is waste heat, which is mainly from cooling water, which can be reused; the second category is conventional pollution Substances, that is, non-obviously toxic and easily biodegradable substances, including biodegradable organic matter, compounds that can be used as bionutrients, and suspended solids; the third category is toxic pollutants, which are toxic but not easily biodegradable Substances, including heavy metals, toxic compounds and organic compounds that are not easily biodegradable, etc.

In fact, one type of industry can discharge several different types of wastewater, and one type of wastewater will have different pollutants and different pollution effects. For example, dye factories discharge both acidic wastewater and alkaline wastewater. Due to the differences in fabrics and dyes in textile printing and dyeing wastewater, the pollutants and pollution effects will be very different. Even the wastewater discharged from a set of production equipment may contain several pollutants at the same time. For example, the top oil vapor condensed water of the distillation, cracking, coking, and superposition equipment of an oil refinery contains phenol, oil, and sulfide. In different industrial enterprises, although the products, raw materials and processing processes are completely different, they may also discharge wastewater of similar nature. For example, oil refineries, chemical plants, and coking and gas plants may all have oily and phenol-containing wastewater discharged.