SpecificationGrey WaterSewage Water
DefinitionGrey water is the waste water that drains from washing machines, kitchen, bathtubs and bathroom (shower).Sewage water also known as blackwater, is wastewater from toilets and bathrooms that contains faeces and urine. It contains high levels of pathogens and oil & grease contamination.
Contamination LevelGrey water contains low levels of contaminants, thus making it easier to treat.Sewage water contains higher level of contamination due to presence of disease-carrying bacteria.
Reuse ApplicationsRecycled grey water is used in irrigation, flushing toilets, cleaning cars & floors and constructed wetlands.Recycled black water can only be used as plant fertilizer.
Type of ContaminationUsually contaminated with chemicals and no sewage.Highly contaminated with sewage content rich in organic matter and nutrients.
SourceBathrooms, shower or washing machinesKitchen sinks & toilets
TreatmentSand filtration and controlled wetlands can treat such wastewater.Biological, chemical and Disinfection treatment processes are required.