Humankind use source of nature in order to increase their condition of life. After this process, source of nature has been decreasing since especially industrial revolution. Wastewater is generated by the use of water in homes, industrial and commercial activities.

Wastewater should be treated because it has harmful for environment. If wastewater originate from homes, it calls domestic wastewater or from industrial originate it calls industrial wastewater. regardless of the wastewater is originated from industrial or homes, it should not discharge to environment without treatment. Domestic wastewaters contain organic pollutants whereas industrial wastewaters contain inorganic pollutants. These organic and inorganic pollutants should not discharge to environment because concentration of these higher than environments. That's why, When wastewater treatment plan design, it consider biological oxygen demand for domestic wastewater. For industrial wastewater this parameter is chemical oxygen demand. Domestic wastewater treatment systems are used when the wastewater is of domestic origin, and industrial wastewater treatment systems are used when the wastewater is of industrial origin.

Domestic Wastewater Treatment (Municipal or Sewage Wastewater)

When domestic wastewater treatment plant designs, it consider population, unit water consumption. Domestic wastewater is turbidity and colourful and it spread out bad smell around to environment. Amount of Oxygen generally is less r in domestic wastewater because of organic pollutants. Sometimes there may be no oxygen in water. That's why dissolved oxygen is important for treatment. It can seen table 1 some parameters in domestic wastewater. Domestic wastewater treatment plant is two system. One of them is package biological treatment, which design for construction sites, holiday villages, recreational facilities, etc.

Industrial Wastewater Treatment Plant

Parameter of pollution of industrial wastewater all the time is not same. Industrial wastewater after the treatment directly can discharge to environment or it can discharge to sewage system after preliminary treatment. Industrial wastewater contains heavy metals such as zinc, nickel, arsenic, cyanide. That's why, it must select system, which treat these heavy metals from water according to legislation of countries.