Recycling Treated Wastewater for Drinking Water is Not a Good Alternative to SDS

Some people want Colorado Springs to turn wastewater into drinking water instead of building SDS. The U.S. Bureau of Reclamation studied six options for doing that and rejected all of them because of the cost – twice as much as a pipeline – and because it would be “less desirable from a standpoint of public health protection.”

Reuse is a key part of our strong commitment to conservation, and an important portion of our city’s water supply is provided by treating wastewater for irrigation of public and private properties with nonpotable water. In fact, we pioneered the recycling of treated wastewater for irrigation in the 1960s. Colorado Springs has the second largest nonpotable-water system in Colorado.

An important portion of our city’s water supply is provided by treating wastewater for irrigation of public and private properties with nonpotable water. In fact, we pioneered the recycling of treated wastewater for irrigation in the 1960s. Colorado Springs has the second largest nonpotable-water system in Colorado.

Economic, Environmental Challenges

Water can be reused directly through treatment (recycling) or indirectly through methods like exchanges with other water users. Recycling wastewater directly into drinking water isn’t a good alternative to SDS at this time, for both environmental and financial reasons. Recycling wastewater into drinking water is energy intensive and, therefore, has a big carbon footprint. It generates a large volume of solid waste. And it would be about twice as expensive as our proposed alternative for SDS.

Converting wastewater into drinking water involves a process called reverse osmosis – forcing the wastewater through a thick membrane to remove contaminants. The process is energy intensive, resulting in more greenhouse-gas emissions and a large carbon footprint.

It also generates a large volume of solid waste – the concentrated salts and other contaminants removed from the wastewater. This concentrated brine is too salty for potable use or crop irrigation and too salty to discharge into streams. It has to be stored in evaporation ponds and the resulting salt-laden solid waste eventually will end up in our landfills.

A Better Way

With existing technology, recycling wastewater into drinking water is the less efficient, more expensive and less environmentally desirable than using the water rights we already own to provide water for our future. It would be irresponsible of Colorado Springs to pursue this method of reuse at this time when there’s a better way. Reuse by exchange, as we do today, is smart reuse. Exchange is a way to trade water with other users so water can be used more efficiently without expensive, energy-intensive treatment and without leaving behind potentially harmful waste.