The absence of free elemental oxygen, the state of not requiring or damage by the absence of free elemental oxygen

A mixture of urine, faeces and flush water along with anal cleansing water (if water is used for cleansing) and/or dry cleansing materials. Black water contains the pathogens of faeces and the nutrients of urine that are diluted in the flush water.

A geographical area defined by topography from where all runoff water drains into a reservoir. Often used as a synonym for watershed and river basin.

A system used to collect, treat, discharge, and/or reclaim wastewater from large user groups (i.e. municipal and city level applications).

For onsite sanitation, it includes a) the toilet, b) the onsite sanitation technology that the toilet discharges to and c) the second stage technology (if anything) that the onsite sanitation technology is then connected to (e.g. soak pit or sewer)

Used to describe the flow of faecal sludge, effluent and wastewater between sanitation technologies and the illegal practice of using or returning faecal sludge, effluent or wastewater to the environment, without full treatment.

The methods by which the treatment plant output products (which should be now reduced-risk materials) derived from a sanitation system are ultimately returned to the environment. Where there is an end-use for the product, they can be applied or used.

A facility where domestic wastewater (both black and grey water) is treated close to the source at community or institutional scale to allow for safe local reuse or disposal of generated effluent

The supernatant liquid discharged from a septic tank. The liquid separated out from the septage is also referred as effluent.

A place, amenity, or piece of equipment provided for a particular purpose.

The settled contents of pit latrines and septic tanks. It differs from sludge produced in municipal wastewater treatment plants. The characteristics of faecal sludge can differ widely from household to household, city to city, and country to country. The physical, chemical and biological qualities of faecal sludge are influenced by the duration of storage, temperature, soil condition, and intrusion of groundwater or surface water in septic tanks or pits, performance of septic tanks, and tank emptying technology and pattern.

A facility where the septage and/or faecal sludge is received (by vacuum trucks or otherwise) as an input and gets fully treated to allow for safe reuse or disposal of generated output (both solid and liquid).

The total volume of water generated from washing food, clothes and dishware, as well as from bathing, but not from toilets. It may contain traces of excreta (e.g., from washing diapers) and, therefore, also pathogens. Grey water accounts for approximately 65% of the wastewater produced in households with flush toilets.

A facility where interventions are done at the receiving waterbody (like lakes, ponds and rivers) and/or open drains/nullahs itself for rejuvenation of the receiving water bodies.

A facility (it may include user interface as well) that, in absence of sewerage network, collects and fully/partially treats the black water to allow for safe reuse or disposal of generated effluent.

The semi-solid matter emptied from septic tanks or similar onsite systems. It has an offensive odour, appearance and high concentration of BOD, COD and TSS etc.

A water-tight single-storied tank in which sewage is retained long enough to permit sedimentation and digestion

Sewage is untreated wastewater which contains faeces and urine, this wastewater gets conveyed through the sewerage system. Generally, grey water from the kitchen and bathroom also becomes part of sewage.

The network which transports sewage from one place to another (eg: house to treatment plant)

Faecal sludge that has undergone a treatment process and has successfully been converted into a product that is safe for end-use.

Wastewater that has undergone a treatment process and has successfully been converted into a product that is safe for end-use.

Any significant accumulation of water, both natural and manmade (i.e. surface water)