pacts of their practices and the importance of striving for full accountability for one’s impacts on society and the environment.

Both financial and economic perspectives are needed when assessing water supply. If a region’s water authority cannot afford a project, even one with net benefits to society, it will not get built. Subsidies are sometimes provided by local, state, or federal agencies to offset the financial costs for demonstration of new technologies or for projects with broad economic benefits that cannot be captured in an individual utility’s rate structure. For example, the Metropolitan Water District of Southern California has offered a $250 per acre-foot subsidy ($767 per million gallons; $200 per thousand m3) for up to 25 years for local water development to reduce the region’s dependence on imported Colorado River water. The Bureau of Reclamation’s Title XVI has also been a source of subsidies for water reuse projects since 1992 (see Box 9-1). Traditional water supplies may also receive subsidies.

FACTORS AFFECTING THE FINANCIAL COSTS OF WATER REUSE PROJECTS

Whether reclaimed water is used for nonpotable or potable uses, there are several factors that affect the costs of a water reuse program. These include the location of a reclaimed water source (i.e., the wastewater treatment facility), treatment infrastructure, plant influent water quality, customer use requirements, transmission and pumping, timing and storage needs, energy requirements, concentrate disposal, permitting, and financing costs.

Size and Location

In most cases, reclaimed water systems originate at a municipal wastewater treatment plant. Wastewater treatment plants are typically constructed at lower elevations and within close proximity to a point of discharge such as a river, lake, or ocean. As a result, there are pumping costs to bring reclaimed water to the customers or to the water treatment plant, which is typically sited at higher elevations. In U.S. cities, wastewater treatment plants have evolved into large-scale facilities serving extensive areas. This has provided economies of scale and equitable service, minimized impacts on nearby land uses, and centralized technical management.

BOX 9-1
Federal Subsidies for Water Reuse Through the Title XVI Program

The Title XVI program was originally launched in 1992 in the Reclamation Projects Authorization and Adjustment Act (Public Law 102-575). The act directed the Secretary of Interior “to undertake a program to investigate and identify opportunities for reclamation and reuse of municipal, industrial, domestic, and agricultural wastewater, and naturally impaired ground and surface waters” and to support, “the design and construction of demonstration and permanent facilities to reclaim and reuse wastewater.” The act also directed the Secretary “to conduct research, including desalting, for the reclamation of wastewater and naturally impaired ground and surface waters.” The original act authorized cost sharing for three feasibility studies and for the construction of five reuse projects, including three in Southern California, and the act has since been amended to authorize additional projects. Title XVI has been administered through the Bureau of Reclamation.

As of November 2010, approximately $531 million has been appropriated for Title XVI projects, mostly in California, including $135 million from the American Recovery and Reinvestment Act of 2009. Unless specified by Congress, federal funding support is limited to projects in the 17 western continental states. The program has generally provided cost sharing for up to 25 percent of the total project costs, with a project maximum of $20 million. These funds historically have helped reuse projects move forward more quickly than they might have otherwise. Of the 53 authorized projects, 42 have received some funding and 16 have either been completed or have reached the maximum cost-shared funding limit. Three additional projects have received at least 80 percent of their authorized funding. As of the end of 2010, the program had a $630 million backlog for projects that have been authorized and are awaiting appropriations, a significant increase from the $354 million backlog in 2006 (Cody and Carter, 2010). Considering this growing backlog, the recent Congressional Research Service report by Cody and Carter (2010) examined program priorities and the federal role in supporting reuse.

Centralized treatment facilities have been preferred throughout history, but the analysis of benefits changes when one thinks of a wastewater treatment system as a source of water instead of a location for disposal of water. Multiple smaller, decentralized plants could provide several advantages as reuse systems because the location



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement