gray water

сточные хозяйственно-бытовые воды

сточные хозяйственные воды

сточные бытовые воды

фановые воды

мор. сточные воды после душа ср. black water

Greywater, sometimes also spelt as graywater, grey water or gray water and also known as sullage, is wastewater generated from processes such as washing dishes, laundry and bathing. Sometimes, the term excludes kitchen wastewater containing significant food residues. It is quite distinct from blackwater in the amount and composition of its chemical and biological contaminants. Greywater gets its name from its appearance and possibly also from its status as being neither fresh (white water from groundwater or potable water), nor heavily polluted (blackwater from feces or other toxic chemicals). From the point of view of treatment and pollution prevention, greywater decomposes much more quickly and is easier to treat and eliminate than blackwater, but is still considered to be a health and pollution hazard if released into the natural environment untreated.

In recent years concerns over dwindling reserves of groundwater and overloaded or costly sewage treatment plants has generated much interest in reusing or recycling greywater, particularly for use in irrigation. However, concerns over potential health and environmental risks means that many jurisdictions demand intensive treatment systems that are so expensive they usually cost more than simply treating and buying the tap water they save. Treatment methods and risks are poorly researched and understood by authorities. Despite this, greywater is often reused for irrigation, illegally or not, in drought zones or areas hit by hose pipe bans, typically by manual bucketting. In the third world, reuse of greywater is often unregulated and is common. At present, the recycling of greywater and its risks are poorly researched compared with its elimination.