The amount of water on the earth’s surface is fairly constant, but in many parts of the developed world we are running out of the right kind of water and our ability to access it. The severe water shortages found in California and the southwestern United States, Australia and even parts of the United Kingdom show that we need new ways to ensure a clean water supply.
One is to produce high-quality water from wastewater, something that is continuously improving. While this could help alleviate the pressure on the water supply, public attitude towards the idea of using water that is recycled from wastewater and other streams for drinking and domestic use is l most important obstacle.
The treatment and reuse of “gray” water (waste from bathrooms, showers, washing machines, etc.) for non-potable uses such as irrigation is already widespread. But as water demand increases and supplies continue to decline, more and more attention is being paid to “black” water, in simple terms, to wastewater.
Technological advances and environmental regulations have made the production of the highest quality water from sewage not only feasible, but increasingly an economic and political necessity. The challenge facing water engineers now is perhaps just as important: convincing the public to accept wastewater recycled in this way for general household consumption.
Public attitudes hard as water
Let’s be clear. Untreated wastewater is a dangerous thing, responsible throughout history (and all too often today for many communities around the world) for more deaths, disease and misery than almost any other cause.
Industrial wastewater treatment is rightfully considered one of the wonders of the modern world. Customers of modern water utility companies expect reliable, high-quality water supply and extraction as a given, to the extent that most have no idea where their water is coming from or going.
In practice, of course, wastewater discharged into the environment from one community has long become the source of water for another downstream community – think Oxford, Reading, London in a chain along the Thames. Urban myths about how many people have already tried a Londoner’s tap water are deeply ingrained and somehow accepted. But when asked directly about the acceptability of recycled wastewater as a direct feed into drinking supplies, attitudes harden.
In a 2008 Oregon State University survey, while the majority supported a specific water recycling proposal in principle, the percentage of people who were fully in agreement with potential applications dropped to just 13% for uses associated with contact or human consumption, approximately 55% for other industrial and municipal uses.
In a 2013 poll for The Guardian newspaper, 63% of respondents said they would drink recycled wastewater, but the context was broader and the question more hypothetical than the Oregon study.
This psychological factor is important: like flying in your ointment, we get discouraged when a problem is at hand. The key is to add steps in the process: drain the treated wastewater into the river before withdrawing it for drinking.
A 2012 study of southern water suggests this approach would be acceptable if quality could be guaranteed. Recent evidence on the prevalence of antibiotic-resistant microbes in treatment plants highlights the need for continuous technical development to combat emerging threats to health and the environment. Other concerns relate to persistent organic pollutants, such as pharmaceuticals, which can be concentrated through repeated recycling of black wastewater.
In an effort to introduce recycled water systems, water engineers face the challenge of addressing real and perceived threats to water quality, distrust of commercial services and government authorities, and a profound fear of contaminated water.