Page 103 - U4SSC KPIs Verification Manual - A guide for verifiers

Dimension Environment
Sub-Dimension Environment

Category Water and Sanitation
KPI Name Wastewater Treatment
KPI No. EN: EN: WS: 4C Type: Core Type: Sustainable

Definition / Percentage of wastewater receiving treatment (Primary, Secondary, Tertiary)
Description

Rationale / Improvement of water treatment reduces the incidence of a variety of waterborne
Interpretation / diseases. A reliable wastewater treatment system is a major indicator of the level of
Benchmarking local development and of community health. Water pollution from human waste is
less of a problem in countries that can afford to treat sewage and wastewater.
Water pollution can be minimized with adequate investment in treatment systems.
The percentage of wastewater treated is an indicator of water quality management.
All forms of treatment include treatment to permit water release into water
resources of different levels of environmental sensitivity. They are:
i Primary treatment which screen and sediment sewage to remove grosser debris.
ii Secondary treatment which reduce Biological Oxygen Demand (BOD10) to
acceptable levels by microbial oxidation using activated sludge or a trickle filter.
iii Tertiary treatment which reduces BOD still further through micro straining or
filtering, the microbial removal of phosphates and nitrates, and disinfection using
chlorine or ozone.
An improving trend and higher values are considered positive.

Source NOTE – FAO, Wastewater Treatment. Retrieved from <http:// www .fao .org/ docrep/
t0551e/ t0551e05 .htm>
Methodology Calculate as:

Numerator: Total amount of wastewater that has undergone (primary /secondary /
tertiary) treatment (ℓ).
Denominator: Total amount of wastewater collected (ℓ).

Multiply by 100.
Unit Percentage
Data Sources This information is usually known by municipal authorities and is available from the
/ Relevant main water supply and treatment companies.
Databases

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