San Angelo - Step Closer To Treated Wastewater

The Water Advisory Board unanimously recommended Wednesday for the city to begin pilot testing a membrane filtration system. Membrane treatment is one step in reclaiming effluent for direct potable reuse

reclaim treated wastewater for drinking.

The Water Advisory Board unanimously recommended Wednesday for the city to begin pilot testing a membrane filtration system. Membrane treatment is one step in reclaiming effluent for direct potable reuse.

The City Council must approve the item for pilot testing to begin.

The first phase of the proposed wastewater reuse project, which could yield 9 million gallons of water per day, is estimated to cost $136.7 million.

"If San Angelo decides to move forward with this project, it's not just a project you want to do halfway," said Ellen McDonald, principal at Alan Plummer Associates, Inc., the firm that was hired by the city to examine wastewater reclamation options for San Angelo. "There needs to be a commitment to do it and to do it right."

The commitment could include added staffing to operate the membrane treatment system, which is more sophisticated than the conventional water treatment system, McDonald said.

The city will continue to seek funding from the state for the project. City staff has not yet established how the proposed project will be funded, said Bill Riley, director of water utilities for the city.

BECOMING AN EFFLUENT CITY

When consultants at Alan Plummer began looking at options to reuse San Angelo's treated effluent, they considered an option the firm recommended in a 2006 study for the city.

At that time, McDonald said, direct potable reuse was not seen as technologically feasible, so consultants recommended that San Angelo discharge its treated wastewater into Twin Buttes Reservoir.

That was an option in the 2015 study, McDonald said, as was the option to discharge the effluent into Lake Nasworthy.

Some cities, such as Abilene, choose to discharge treated wastewater in a body of water because that can be a final step in treating the wastewater.

Cities such as Big Spring and Wichita Falls, however, choose not to discharge the water because of concerns over evaporation, water quality and water rights.

"You're essentially dirtying up the (treated wastewater)," McDonald said.

McDonald recommended that San Angelo officials opt for direct potable reuse.

In this process, the city would pull water from the existing wastewater treatment plant for advanced water treatment — which is where the membrane filtration system comes in.

From there, the treated wastewater would go through the city's conventional water treatment plant, then be delivered to customers along with existing drinking water supplies.

The pilot test is projected to cost more than $1 million, McDonald said, which is part of the $136.7 million estimated for the first phase of the project.

From this initial cost, the price per thousand gallons of water is $4.84, she said.

The second phase, which could add 3 mgd of water, is estimated at $16.6 million, she said.

Running the potable reuse system for a 50-year life cycle, which includes replacement of parts, McDonald said, could cost the city a total $314.2 million.

The cost per thousand gallons of water over the span of the life cycle is about $1.87, McDonald said.

"Unfortunately, that's just what it's costing to develop these sources," said Scott Hibbs, president of Enprotec/Hibbs & Todd, Inc., an Abilene-based engineering firm that is working with Alan Plummer on the project.

Hibbs said other large-scale water projects in Midland and Abilene cost about the same.

"It looks like a big number, but if you look at the Hickory (Aquifer project) costs, it's about the same," he said.

Source: Standard Times

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Taxonomy

• Water Treatment & Control
• Waste Water Treatments
• Purification