The United Nations has officially designated 2013 as the International Year of Water Cooperation. In response to this global call for action, the Environmental Performance Index (EPI) team is seeking to improve upon its water indicators for the 2014 edition, which will be released in January.

Water-Treatment-with-Aeration-300x200Over the years, we’ve attempted to measure country-level performance on water in a number of ways. To assess performance in terms of water management, early versions of the Environmental Sustainability Index (ESI), the predecessor to the EPI, relied on modeled data on biological oxygen demand (BOD) emissions from the World Bank and crude estimates of national groundwater availability from the Food and Agriculture Organization’s (FAO) Aquastat database. From 2008 to 2010, we partnered directly with the UN Environment Programme’s (UNEP) Global Environment Monitoring System (GEMS)/Water Programme database, GEMStat, to develop a Water Quality Index based on sparse in situ monitoring data for dissolved oxygen, conductivity, pH, nitrogen, and phosphorus. However, we eventually abandoned this measure in the 2012 EPI due to data gaps and questions regarding the longevity of the database.

For the 2014 EPI, we are renewing efforts to both seek new indicators to measure water performance as well as to provide guidance for the ‘next generation’ of water indicators.  On Sept 11-12, we will hold a meeting in Stockholm, Sweden, following World Water Week to bring together experts from around the world to discuss how we might construct credible indicators to better assess performance on water management.

Toward this end, we are also seeking country-level data on wastewater treatment—data that we don’t have, but critically need. Specifically, we are reaching out to youCan you send us your wastewater treatment data or statistics for your country or a country you are knowledgeable about? Please see contact below.

The source for water treatment data usually comes from a country’s national environment reports, statistical bureaus, or other official sources of data. We do not need statistics from international or multilateral agencies such as the FAO, World Bank, or the United Nations—we already have those. For your efforts, we will acknowledge you in the 2014 EPI report.

Please see the definition below for the kinds of water treatment data we are seeking:

Water treatment: Water treatment variables can provide important information about the amount of wastewater or sewage that is treated prior to being discharged. These variables may include: 1) the amount of produced wastewater, 2) the amount of collected [municipal] wastewater, and 3) the amount of treated or untreated [municipal] wastewater.[1] Often, these variables are reported independently in volumetric units, or aggregated together as percentages of one another (e.g., dividing the volume of treated wastewater by the volume of collected wastewater provides the percentage of wastewater treated).

Treated municipal wastewater variables are commonly reported by the type of treatment applied to collected wastewater. These treatment types include primary, secondary and tertiary. Primary treatments involve physical or chemical processes, such as the use of settling or holding tanks, chlorine disinfection, and ozonation. Secondary treatments may involve the use of activated sludge, secondary clarifiers, trickling filters, and settling basin digesters. In addition to a secondary treatment process, tertiary treatments also involve processes to remove or significantly reduce nutrients, such as nitrogen and phosphorous, through membrane filtration (e.g., reverse osmosis), activated carbon, or disinfection, among others. Unless a specific treatment type is provided with the data, it can be assumed that wastewater is treated through a combination of these processes (commonly reported as “at least primary/secondary treated.”)

[1] FAO’s AQUASTAT database provides several useful definitions related to wastewater. Produced municipal wastewater is the “annual volume of domestic, commercial and industrial effluents, and storm water runoff, generated within urban areas. Collected municipal wastewater is “municipal wastewater collected by municipal wastewater sewers or other formal collection systems.” Treated wastewater is “treated wastewater (primary, secondary and tertiary) annually produced by municipal wastewater treatment facilities in the country.” For more information on treatment types, please refer to the “treated municipal wastewater” definition on AQUASTAT’s web page at

For more information, or to get in touch about data, please contact:

Thank you!