An Effluent Treatment Plant (ETP) is a process for treating waste water in textile, chemical, and pharmaceutical industries, where the water is contaminated to an extreme. Some of the many pollutants that can be treated by it include organic and inorganic matter, oil, grease, heavy metals, suspended particles, and much more. By using it, fresh water is not unnecessarily used for production purposes or commercial activities. It is an effective way to prevent water pollution.

Industrial wastewater contains different pollutants and is often more variable, concentrated, and toxic. The nature of the design, construction and operations are also different.

The aim of effluent treatment is to enable wastewater to dispose safely, without being a danger to public health and without polluting water sources. Increasingly another important aim is to reuse treated wastewater. A treatment system consists of a combination of unit processes to reduce wastewater contaminants to acceptable level.

Preliminary treatment,sedimentation,biological treatment,disinfection and sludge treatment are important stages of a treatment plant. Biological treatment is to transfer dissolved organic content from soluble form to suspended matter in the form of cell biomass.

Aerobic and anaerobic processes will be used depending on the effluent characteristics. Process selection depends on factors such as effectiveness in removing particular contaminant, sludge generation, complexity, energy requirements, construction costs and operation & maintenance costs.

Zero liquid discharge system consists of additional advanced systems consisting of membrane system and evaporation plants.