Water Treatment

Approaches

These issues are controversial and highly politicized: water treatment is not simply a problem for engineers. Some approaches to water treatment do focus on chemical and biological concerns—on treatment as purification. Policy work, however, generally frames water treatment problems as matters of governance, rather than of scarcity. These discussions are influenced by social science research [Page 991]advocating integrated or holistic approaches where water treatment does not stand in isolation from clean water supplies, water management, or diverse social and cultural practices.

Purification-focused approaches situate water treatment within larger public water systems. Water from ground or surface sources is modified to create “safe” or “useful” water that is then piped to homes and businesses. Water treatment processes mainly entail filtration and decontamination but can also encompass biological treatment or desalination.

Public water treatment processes commonly begin with chemical coagulation and sedimentation—the forming of solids that settle on the bottom of tanks. Sand or gravel filtration then removes suspended solids that may interfere with disinfection. Chlorine or, increasingly, UV light or ozone is employed to neutralize bacteria and viruses. The water is then tested according to standards, such as those provided by the Safe Drinking Water Act, which regulates all public systems in the United States. Organized around measures of quality based on particulate counts of problematic substances, this approach tends to frame water treatment as a technical problem of whether plant design, operation, and performance meet standards and demand while also managing costs.

There have been significant shifts toward more holistic approaches to water treatment in policy and environmental studies. Water quality is seen today more as an environmental problem than just a chemical or biological one. Integrated water resource management, for example, involves considering multiple uses and environmental protection along with the supply and purification process. Tying safe water to clean sources, integrated models mark shifts from treatment for use to reducing source water pollution and from plant management to broader water governance issues. If there is increasing agreement in defining water treatment problems more inclusively, the challenges of addressing them are fraught with disagreement. Solutions, especially those involving the redistribution of responsibility to nongovernmental actors, are at the center of intense debate over the compatibility of market forms with environmental goals and improved access. The control of water treatment systems is at stake in many struggles over whether water is a public or tradable good, a right or resource.

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