The drought burns on in Texas. The state's water plan calls for construction of new reservoirs, desalination plants, pipelines and greater conservation and recycling of water to make the water supply in Texas sustainable, and Texans are doing it. Direct recycling of wastewater is about to begin in Big Spring, Texas. No other state is taking such bold action to secure their future, but without a reliable potable water supply there is no future.
The earth has a fixed amount of land and water. All the water that ever was or will be on earth is here right now. More than 97% of the Earth’s water is within the in oceans. The remaining 2.8% is the water within the land masses, as groundwater, rivers, streams, lakes, and within the ice caps and glaciers (over 77% of fresh water is currently frozen and according to climate scientists a significant portion of that may melt). Only a tiny fraction of water falls as rain each year to make the rivers flow, recharge lakes and groundwater. Precipitation does not fall uniformly- there are wet locations and arid locations within a country or region and rainfall varies from year to year and over time as climate changes. Water availability is determined by the weather, climate and the variable length of different parts of the water cycle. Texas has suffered a long drought.
As the demand for water grows in our population centers, we are straining to meet the demand. Even in generally water rich areas there are limits to the availability of water and United States has slowly and quietly begun to address the availability of water by recycling the water indirectly. In the United States municipal wastewater represents a significant potential source of reclaimed water, an estimated 32 billion gallons of water a day (121 million m3/day) is treated in wastewater treatment plants throughout the country. Currently, National Research Council Water Science & Technology Board estimates that only about 7% to 8 % of this municipal waste water is reused, but a third of this water could be reused.(NRC Water Science & Technology Board titled Water Reuse: Potential for Expanding the Nation’s Water Supply Through Reuse of Municipal Wastewater)
Direct water recycling is reusing treated wastewater for beneficial purposes such as agricultural and landscape irrigation, industrial processes, toilet flushing, and replenishing a ground water basin (referred to as ground water recharge) and less commonly returning the water directly to reservoirs. Many of the existing projects that recycle waste water avoid the negative emotional response of drinking water from wastewater treatment plants by either using the water for irrigation and municipal irrigation (golf courses in Arizona) or by treatment and then supplementing river flow, reservoirs or groundwater.
Since 1978, the upper Occoquan Sewage Authority here in Virginia has been discharging recycled water into a stream above Occoquan Reservoir, one of the two potable water supply sources for Fairfax County, Virginia. Recycled water has been part of the Occoquan supply for 34 years supplying Fairfax, parts of Prince William and Loudoun counties with water. Noman M. Cole, Jr developed the Occoquan Watershed Policy in 1971 that specified the type of waste treatment practices that would be adopted on a basin-wide scale, and provided for an on-going program of water quality monitoring to measure the success (or failure) of the wastewater treatment. This resulted in the construction of the Upper Occoquan Service Authority, UOSA, advanced wastewater treatment plant with tertiary treatment to replace the eleven small secondary treatment plants and the creation of the Occoquan Watershed Laboratory to monitor water quality.
For 30 years Los Angeles County has recycled the water from wastewater treatments plants. This water from both secondary and tertiary treated wastewater is discharged into spreading basins to recharge groundwater. Groundwater recharge can be done by surface spreading or direct injection wells. California guidelines recommend spreading over injection because of concerns about water quality and potential health hazards. The groundwater is then mixed with other fresh water supplies for delivery to customers. Many of the existing projects that recycle waste water avoid the negative emotional response of drinking water from wastewater treatment plants (the Toilet to Tap Yuck factor) by either using the water for irrigation and municipal irrigation or by treatment and then supplementing river flow, reservoirs or groundwater.
In Texas they are taking it even further. The population of Texas is expected to double in the next 50 years and several cities in Texas have been forced by the population growth, the extended drought and extreme heat of the past several years to address their water supply and sustainability problems head on. Cities in Texas currently use reclaimed water for power plant cooling, argument stream flow, and to irrigate golf courses and landscapes. Now, the city of Big Spring is the first in the nation to make the direct leap to piping completely treated wastewater to a drinking water treatment plant.
The Colorado River Municipal Water District in Big Spring, Texas is finishing construction on a $14 million wastewater recycling plant. Previously, Big Spring discharged its wastewater into a creek, which passed it through a wetland area that processed it naturally, making the wastewater potable again. The water recycling plant will short circuit that process, fully treating the wastewater and produce approximately 1.8 million gallons per day of raw water and piping it directly back into the town's water treatment plant where it will be blended with other raw water from the reservoirs for treatment and distribution.
This is a huge and unprecedented step. The Texas Commission on Environmental Quality and EPA have lagged behind Big Spring, failing to develop guidance regulations on direct water reuse. Texas law strictly prohibits interconnection between reclaimed water and potable water systems, though both Big Spring and Brownwood Texas have received permission to build water reuse plants connected to the water treatment plants. In addition the Texas Commission on Environmental Quality has funded a study to develop a resource document that can assist in planning future direct potable reuse projects in the state. No other community has ever bridged the emotional gap of direct water reuse before and Big Spring will shortly be followed by Brownwood. Texas leads the way into the future.