Wastewater is a common designation for any water that in one or another way has been affected in quality by human influence.

Wastewater is a common designation for any water that in one or another way has been affected in quality by human influence and which is transported through a combined or separate sewer system.

Wastewater contains a broad spectrum of waste of organic or inorganic origin that can be discharged from different sources. These sources can be e.g. domestic residences, commercial properties, industry, agriculture as well as surface run-off and infiltrated water in the sewer system. These different sources are commonly divided into three categories:

Domestic wastewater
Water which is contaminated by use and normally discharged from WC, showers, baths, bidets, wash basins, sinks and floor gullies.

Trade effluent
Wastewater discharge resulting wholly or in part from any industrial or commercial activity.

Surface water
Water from precipitation which as not seeped into the ground and which is discharged to the drain or sewer system directly form the ground or from exterior building surfaces

The terms black and grey water is sometimes also used to describe wastewater. The term black water describes wastewater which contains faecal matter and urine. Wastewater without the content of faecal matter or urine is on the other hand referred to as grey water. Grey water comprises 50-80% of residential wastewater

Wastewater encompasses a wide range of potential contaminants of inorganic or organic origin. Below is a partial list of wastewater constituents:

  • Bacteria, viruses, prions and parasitic worms.
  • Organic particles such as faeces, hairs, food, vomit, paper fibres, plant material, humus, etc.
  • Soluble organic material such as urea, fruit sugars, soluble proteins , pharmaceuticals etc.
  • Inorganic particles such as sand, grit, metal particles, ceramics, etc.
  • Soluble inorganic material such as ammonia, road-salt, sea-salt, hydrogen sulphide, heavy metals etc.
  • Macro-solids such as sanitary napkins, nappies/diapers, condoms, needles, children's toys, dead pets etc.
  • Gases such as hydrogen sulphide, carbon dioxide, methane, etc.
  • Emulsions such as paints, adhesives, mayonnaise, hair colorants, emulsified oils, etc.
  • Toxins such as pesticides, poisons, herbicides, etc.