This year the focus of the World Water Day is the symbiosis between water and wastewater. It will grant an opportunity to illustrate how waste water is a valuable resource and how its safe management can be an investment that will benefit humans and ecosystems.
Wastewater is used water. It is divided into 3 major categories of water.
Storm runoff: this is the water that enters via storm drain and is dumped directly into local surface water. It is not treated in any way so any contaminants present are directly entered into the local watershed. Programs such as Yellow Fish Road have been initiated to raise awareness of the threats to our ecosystem caused by indiscriminate dumping into these storm sewers.
Grey Water: This is the waste water from household appliances and sinks. It can be used to irrigate agricultural areas and some recreational areas, such as golf courses, without any danger. This water may contain soaps and cleansers which are easily removed via the interaction with sand and clay during the percolation of this water to the local water table. In arid areas it is common to see waste water pipes carrying gray water draining directly into gardens or yards.
Reclaimed Water: This is the water which has been treated at a sewage treatment plant and can now be reused. It is comprised of not only sewage, but also water from sinks and household appliances as well as industrial discharge which has been processed and then discharged. It can still contain substances which are harmful or toxic to our health and the environment so this water is not recommended for use in agricultural areas producing food products or in recreational areas. It can be used in industrial cooling plants or processes. It can also be further treated to make it cleaner. Some areas actually have developed treatments that can may this water potable again.
If not properly cleaned wastewater can carry disease. It can harm fish and wildlife populations by contributing to oxygen depletion. Recreational use of water can be restricted and drinking water contaminated if harmful substances are not properly removed. The food supply can be reduced if bans on the consumption of shellfish and other aquatic life are issued because of pollution.
In the United States, with the water scarcity in some areas and with conservation being stressed, the reuse of wastewater is becoming increasingly important. This “reclaimed” water use can free up potable water to be used elsewhere. It can supply the water needed for agricultural and industrial use.
In California the use of reclaimed water saves about 5.5 billion gallons of fresh water a year, enough to provide drinking water to 83,000 households. Californians are becoming more supportive of the use of reclaimed water as the severe drought in their part of the world continues.
In Arizona, the city of Tucson, has created a wetland from the backwash of the reclaimed water treatment system. https://www.tucsonaz.gov/water/sweetwater-wetlands-educational-activities . This wetland, constructed with input from the local Audubon society, has re-created a habitat which previously existed in the Santa Cruz River watershed. The Santa Cruz River has had no natural flow since the 1940’s when massive pumping of the groundwater lowered the water table.
In the United Arab Emirates they are boosting public awareness that using reclaimed waste water is a safe effective way to stretch the small fresh water reserves available. Maximum utilization of every drop of water is the end goal.
How can reclaimed water be used?
In Thermoelectric plants
To cool power generation equipment
In Industrial manufacturing if human consumption is not a risk
In Car Washes
Mineral extraction in Mining
With worldwide freshwater resources rapidly dwindling, the use of reclaimed water is now more important than ever. 1 in 6 people on the planet now lack access to safe drinking water and with the world population soaring this situation is only going to get worse. Children are dying every day from water borne diseases caused by the lack of treatment of waste.
This World Water Day, we are reminding everyone that we need to ensure waste water receives adequate treatment and then maximum usage. As time goes on this goal is more and more vital to sustain life on our planet.