Sewage is a concept that feels familiar to everyone but seems far from life, but in fact, sewage is very close to all of us.

There are many sewage pipes distributed below the city where we live, and sewage is generated almost every day in our daily lives. So what is sewage?

The more official definition of sewage is the discharge of water from daily life and production that has been contaminated to a certain extent and has lost its original function of use. From this, it can be seen that the concept of sewage is still very broad.

There are many sources of sewage, which can also be defined as liquid or water discharged from residential facilities, commercial or industrial areas mixed with groundwater, surface water, blizzards, etc. carrying waste.

According to the source of sewage, it can be roughly divided into four categories.

Category 1: Industrial wastewater

Wastewater from manufacturing, mining, and industrial production activities, including runoff leachate from industrial or commercial storage and processing, as well as other non domestic wastewater.

Category 2: Domestic sewage

Sewage from residential, office buildings, government agencies or similar sources; Sanitary sewage; Sewer wastewater, including industrial wastewater mixed with domestic sewage in the sewer system.

Category 3: Commercial wastewater

Non toxic and harmless wastewater from commercial facilities with certain components exceeding domestic sewage. Such as catering wastewater. Laundry wastewater, animal husbandry wastewater, etc.

Four types: surface runoff

From rainwater, snow water, highway drainage, water from urban and industrial areas, etc., surface runoff does not seep into the soil, but enters groundwater along streets and land.