Most people consider any form of recycling to be a good thing. However, as with every great idea, there are usually some unintended consequences when it is put into practice, and this is certainly true of water recycling.
People often recycle, or reuse, wastewater in an attempt to conserve freshwater, which is in short supply. This reuse helps lessen the burden on freshwater resources, but it also can be harmful to humans and the environment.
Water recycling is usually divided into two categories: treated sewage and recaptured rainwater. Citizens usually have very few reservations about using recaptured rainwater, but many feel uneasy about releasing treated sewage into the environment. However, cities across America have been reusing treated water for decades, and in some cases, the practice has been beneficial to local habitats that have inadvertently become dependent on treated sewage for survival.
Although there is some concern regarding how recycled water might hurt the environment, water recycling does have some significant benefits, the most important of which is sustainability. For example, numerous cities use wastewater recycling as a solution to water shortages caused by drought. To create a sustainable water supply that is much more cost effective than extracting salt from seawater or purchasing freshwater elsewhere, these communities extract fresh water from sewage. Many areas of California, which has faced long-standing water scarcity problems, use this method of supplementing the water supply.
Recycled water can also help sustain wildlife habitats and ecosystems. In some locations, wastewater that is released into the environment has become essential to maintaining certain wildlife habitats. For those habitats that have become dependent on treated sewage to survive, protests over wastewater recycling programs could threaten their survival.
Farmers often use recycled water that would otherwise be wasted to irrigate crops. By doing so, they don’t have to rely on water from the environment. However, they must employ proper farm management techniques to maintain soil integrity and mitigate the effects of pathogens and chemicals on crops.
Drawbacks of Recycled Water
Although recycled water benefits some wildlife, it adversely affects many other animals and habitats. According to a recycling proposal prepared by the Sacramento Regional County Sanitation District, diverting previously discarded wastewater from the Sacramento River for the purpose of water recycling would rob endangered salmon and other fish of the water needed to maintain their habitats.
Recycling treated wastewater also threatens human health because this water contains microbial pathogens, including bacteria, protozoa, viruses, and helminthes (which are basically parasites). Although most people don’t become ill from exposure to these pathogens, some do. Proponents assert that as long as people use recycled water for its intended purposes, the likelihood of humans contracting an illness is minimal. Despite this, the risk of exposure to these pathogens is a genuine concern.
A wide range of endocrine disrupting chemicals, or EDCs, are also present in recycled water. These chemicals, which are found in medications, pesticides, heavy metals, and insecticides, have been shown to disrupt proper endocrine system function in animals. However, there is no concrete evidence that low amounts of exposure affect human health. The highest concentration of these contaminants is found in untreated sewage. Yet, small amounts remain in recycled water even after treatment.
Wastewater used for irrigation purposes poses yet another risk. For instance, in agricultural irrigation, treated water can disturb the pH and salinity levels of soil, leading to poor yields and plant toxicity.
To effectively use recycled water while minimizing any risk to the environment, communities must adopt and strictly follow diligent monitoring procedures. The health impact of pharmaceuticals entering the water supply should not be ignored, as they present similar problems to EDCs. While research shows the threat of pharmaceuticals in water to be small, it may be too soon to understand their true impact.
Risk management is of critical importance when it comes to recycled water. It also helps to maintain public confidence in the process. Those in charge of recycling programs must vigilantly protect wildlife and the public.