Generates as rainwater penetrates through the top of the landfill siteafter landfilland comes into contact with the landfilled waste to extract dissolved substances (COD, TN, etc.)

It is composed of highly toxic organic pollutants, oxynitrides and toxic substances, and acts as a major environmental hazard to the surrounding environment and human body due to the non-degradable substances .

Depending on the type and property of the landfilled waste, the location where advanced chemical treatment facilities are excluded or installed may change.