Industrial wastewater treatment describes the processes used for treating wastewater that is produced by industries as an undesirable by-product. After treatment, the treated industrial wastewater (or effluent) may be reused or released to a sanitary sewer or to a surface water in the environment. Most industries produce some wastewater. Recent trends have been to minimize such production or to recycle treated wastewater within the production process.

Bottled water is drinking water (e.g., well water, distilled water, mineral water, or spring water) packaged in PET Bottle or Glass Water Bottles. Bottled water may be carbonated or not. Sizes range from small single serving bottles to large carboys for water coolers. In 2018, a major study conducted across nine countries found that bottled water from 92% of the world's leading brands were contaminated with microplastic particles, with health concerns. Although vessels to bottle and transport water were part of the earliest human civilizations, bottling water began in the United Kingdom with the first water bottling at the Holy Well in 1621.

Sewage treatment, or domestic wastewater treatment, is the process of removing contaminants from household domestic sewage. It includes physical, chemical and biological processes to remove physical, chemical and biological contaminants. Its objective is to produce treated water and a solid waste or sludge suitable for discharge or reuse back into the environment.