Dear Maya, There are common ...

Dear Maya,

There are common steps to treatment of industrial waste water treatments.Primary, secondary & tertiaryDepending on the type of industry and the nature of its wastes, industries must utilize methods such as those used for advanced treatment of sewage to purify wastewater containing pollutants such as heavy metals and toxic chemicals before it can be discharged. Industries are permitted to discharge directly to receiving waters under the National Pollution Discharge Elimination System (NPDES) permit system or to municipal sewers under the Industrial Pretreatment Program. Pollution prevention programs are very effective in helping industries reduce discharged pollutants, by eliminating them at the source through recycling or through the substitution of safer materials. More and more industries are approaching or attaining zero discharge by cleaning and reusing their water over and over and over.

https://www.researchgate.net/publication/296056670_ENVIRONMENT_MANAGEMENT_AND_ADVANCED_WASTE_TREATMENT_SYSTEM_IN_NITROGENIOUS_FERTILIZERS_PLANT?ev=prf_pub
Read more: http://www.pollutionissues.com/Ve-Z/Wastewater-Treatment.html#ixzz4XoH5CACY