November 2015: The UN Environment Programme (UNEP) has released a report that presents municipalities with a valuation methodology for pricing the costs and benefits of wastewater treatment. The report, titled ‘Economic Valuation of Wastewater: The Cost of Action and the Cost of No Action,’ finds that wastewater collection, treatment, disposal or safe use – for example, for irrigation – can provide environmental and health benefits. It proposes a methodology to provide an estimation of the value of these benefits, comparing the financial costs of collection and treatment, with the environmental and health costs of releasing untreated wastewater.

The authors note that the environmental and health costs to society of releasing untreated wastewater include diarrhea-related diseases, skin problems and cancer, while the environmental costs can include disruption of aquatic ecosystems, loss of recreational opportunities in polluted areas, and increased greenhouse gas emissions. Excess phosphorus and nitrogen in waterways can stimulate the growth of algae, causing eutrophication and reducing biodiversity. Yet, managing wastewater is typically perceived only as a cost.

The authors address the financial costs of investing in wastewater treatment, including the construction costs of pipelines, and of annual operating costs of treatment systems. Their examples are based on case studies from Australia, Belgium, South Africa and Taiwan, among others.

They conclude that valuation of the benefits of wastewater treatment is necessary to justify the substantial investment that will be needed to address the challenge. They recommend: collecting domestic sewage and storm water in separate networks; encouraging water reuse; considering technologies with lower investment and maintenance costs in developing countries; and continuing to quantify the externalities associated with wastewater treatment and reuse.

The report is based on study by the Global Programme of Action for the Protection of the Marine Environment from Land-based Activities (GPA), the Global Wastewater Initiative (GWI), the UN University (UNU), and the International Water Management Institute (IWMI). [Publication: Economic Valuation of Wastewater: The Cost of Action and the Cost of No Action] [GPA Web Page]