Indicator 6.3.1 Proportion of domestic and industrial wastewater flows safely treated

Goal 6: Ensure availability and sustainable management of water and sanitation for all

Target 6.3: By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally

Indicator 6.3.1: Proportion of domestic and industrial wastewater flows safely treated

May 2024

Indicators: 6.2.1a, 6.3.2

Senior Manager

Compilation of Environment and Natural Resources Statistics

+254-735-004-401, +254-202-911-000, +254-202-911-001

P.O. Box 30266–00100 GPO NAIROBI.

dps@knbs.or.ke

Definitions:

This indicator measures the volumes of wastewater which are generated through different activities, and the volumes of wastewater which are safely treated before discharge into the environment. Both of these indicators are measured in units of 1000 m³/day, although some data sources may use other units that require conversion. The ratio of the volume treated to the volume generated is taken as the ‘proportion of wastewater flow safely treated’.

Wastewater flows will be classified into industrial, services, and domestic flows, with reference to the International Standard Industrial Classification of All Economic Activities Revision 4 (ISIC). To the extent possible, the proportion of each of these waste streams that is safely treated before discharge to the environment will be calculated.

Concepts:

Total wastewater generation and treatment can be quantified at the national level, and wastewater can also be disaggregated into different types of flows, based on ISIC categories. Domestic wastewater generated by private households, as well as wastewater generated by economic activities covered by ISIC categories, may or may not be pre-treated on premises before discharge to either the sewer for further treatment or directly to the environment The main sources of wastewater include wastewater from households, services and industries, i.e. point sources of one or more pollutant(s) that can be geographically located and represented as a point on a map. Diffused pollution from non-point sources such as runoff from urban and agricultural land can contribute quite significantly to wastewater flows (Figure 1), and therefore its progressive inclusion in the global monitoring framework will be important. Presently, it cannot be monitored at source and its impact on ambient water quality will be monitored under indicator 6.3.2 “Proportion of bodies of water with good ambient water quality”.

Differentiating between the different wastewater streams is important as policy decisions need to be guided by the polluter pays principle. However, wastewater conveyed by combined sewers usually combines both hazardous and non-hazardous substances discharged from different sources, but also runoff and urban stormwater, which cannot be separately tracked and monitored. As a consequence, although the flow of wastewater generated can be disaggregated by sources (domestic, services industrial), the treated wastewater statistics are most commonly disaggregated by type (e.g. urban and industrial) and/or level of treatment (e.g. secondary) rather than by sources.

Total wastewater flows can be classified into three main categories (see ‘disaggregation section’ for details:

• Industrial (ISIC divisions 05-35)
• Services (ISIC divisions 45-96)
• Domestic (private households)

Wastewater treatment can be classified into three main categories (see ‘disaggregation section’ for details:

• Primary
• Secondary
• Tertiary

Where possible, treatment will additionally be classified into either on-premises or off-premises treatment.

Domestic wastewater: Wastewater from residential settlements which originates predominantly from the human metabolism and from household activities.

Industrial (process) wastewater: Water discharged after being used in, or produced by, industrial production processes and which is of no further immediate value to these processes. Where process water recycling systems have been installed, process wastewater is the final discharge from these circuits. To meet quality standards for eventual discharge into public sewers, this process waste-water is understood to be subjected to ex-process in-plant treatment. Cooling water is not considered here. Sanitary wastewater and surface runoff from industries are also excluded here.

Total wastewater generated is the total volume of wastewater generated by economic activities (agriculture, forestry and fishing; mining and quarrying; manufacturing; electricity, gas, steam and air conditioning supply; and other economic activities) and households. Cooling water is excluded.

Urban wastewater: Domestic wastewater or the mixture of domestic wastewater with industrial wastewater and/or runoff rain water.

Wastewater: Wastewater is water which is of no further value to the purpose for which it was used because of its quality, quantity or time of occurrence. Cooling water is not considered here.

Wastewater discharge: The amount of water (in m3) or substance (in kg BOD/d or comparable) added/leached to a water body (Fresh or non-fresh) from a point source.

Wastewater treatment: Process to render wastewater fit to meet applicable environmental standards or other quality norms for recycling or reuse.

percent

Reference is made to the WHO Guidelines for Drinking Water Quality

Water Service Regulatory Board

Administrative from WASREB

2017,2020,2023

2018,2021,2024

Water Service Regulatory Board

Kenya National Bureau of Statistics

Kenya National Bureau of Statistics is mandated to collect,compile,analyze,publish and disseminate official statistics for public use

Wastewater data are crucial to promote strategies for sustainable and safe wastewater use or reuse to the benefit of the world’s population health and the global environment, but also to respond to growing water demands, increasing water pollution loads, and climate change impacts on water resources.

Sustainable Development Goal 6 (SDG 6) is about ensuring the availability and sustainability of water and sanitation for all by 2030. SDG Target 6.3 sets out to improve ambient water quality, which is essential to protecting both ecosystem and human health, by eliminating, minimizing and significantly reducing different streams of pollution into water bodies.

The purpose of monitoring progress using SDG indicator 6.3.1 is to provide necessary and timely information to decision makers and stakeholders to make informed decisions to accelerate progress towards reducing water pollution, minimizing release of hazardous chemicals and increasing wastewater treatment and reuse. The target wording covers wastewater recycling and safe reuse with implication on water use efficiency, although it is not fully addressed by the global indicator and methodology.

SDG indicator 6.3.1 tracks the proportion of wastewater flows from households, services and industrial economic activities that are safely treated at the source or through centralized wastewater treatment plants before being discharged into the environment, out of the total volume of wastewater generated.

There is a relative lack of knowledge about the volumes of wastewater generated and treated, because wastewater statistics are in an early stage of development and not regularly produced or reported. Monitoring is relatively complex, costly, and data are not systematically aggregated to the national level and/or accessible; especially industrial wastewater data which are in general poorly monitored and seldom aggregated at national level.

The amount of wastewater generated is calculated by summing all of the wastewater generated by different economic activities and households. Wastewater flows are expressed in units of 1000 m3/day, although some data sources may use other units that require conversion.

The amount of wastewater safely treated is calculated by summing all of the wastewater flows which receive treatment considered equivalent to secondary treatment or better. This wastewater flow is expressed in units of 1000 m3/day, although some data sources may use other units that require conversion.

The proportion of wastewater flows which are safely treated is calculated as a ratio of the amount of wastewater safely treated to the amount of wastewater generated.

The Kenya National Bureau of Statistics is ISO certified based on 9001:2015 Standard requirements. The processes of compilation, production, publication and dissemination of data, including quality control, are carried out following the methodological framework and standards established by the KNBS, in compliance with the Internationally acceptable standards

The KNBS adheres to Kenya Statistical Quality Assurance Framework (KesQAF) that underlines principles to be assured in managing the statistical production processes and output.

Data consistency and quality checks are conducted through Technical Working Groups (TWGs) before publication and dissemination.

The processes of compilation, production, publication and dissemination of data, including quality control are subjected to a set criteria and standards to ensure conformity.