“Yuck” Not a Factor in Brownwood Direct Reuse Plan

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The City of Brownwood plans to be a pioneer in the direct use of reclaimed wastewater for drinking water – but public works director David Harris isn’t worried about winning public acceptance for the proposal.

Brownwood, an industrial community of 20,000 near the geographic center of Texas, found direct reuse (sometimes unfortunately called “toilet to tap”) to be its best option for boosting its water supply in the face of a severe drought. Harris notes that contrary to expectation, the challenges are technical and not political. And the technical challenges seem to be resolved.

Harris and other city leaders have spent years communicating effectively with the city’s thought leaders and citizens. Drawing on the resulting bank of goodwill, Harris has made the case for direct reuse in plant tours, news stories, civic club presentations and other venues. Residents seem to accept that there is no cost-effective alternative and that the technology is sound.

The city and most other communities in Brown County take drinking water from Lake Brownwood, a manmade reservoir that has been drawn down to historic low levels in recent dry years. There is no major aquifer in the county and no other cost-effective source to provide an alternate supply. Citizens responded well to a water conservation initiative, cutting usage by 24 percent, but the city still saw a need to shore up its supply.

The city’s regional wastewater treatment plant (4.54 mgd design, 2.5 mgd average) produces high-quality tertiary effluent (<2 mg/L BOD, 0.5 to 1.5 mg/L TSS, 0.1 to 0.3 mg/L ammonia), with no detected fecal coliform. Tests have shown that the water meets primary drinking water standards for all constituents other than nitrate, which stands at 24 mg/L (the federal maximum is 10 mg/L), according to Harris.

Therefore, the city is planning a new water treatment plant to turn the effluent into potable water. Working closely with the Texas Commission on Environmental Quality, the city has designed a plant that uses membrane ultrafiltration and reverse osmosis (RO) in a fully redundant configuration – what the U.S. EPA calls a multiple barrier approach.

“Really, we have designed two water plants in one, but we get credit for one,” says Harris. “We probably don’t really need the RO to meet all the requirements, but we’ve included it for the public relations and the guarantee that we’re going to remove the salts, nitrates, dissolved solids and pharmaceuticals that are in wastewater effluent.”

The plant, estimated to cost between $6 and $8 million, will also use full chlorine disinfection before the filtration stages, along with UV treatment for microconstituents and parasites and an activated carbon process as a final polishing step.

“The system we’re planning is pretty advanced,” Harris says. Because it’s a first-of-its-kind project, the city and the TCEQ have worked collaboratively in a step-by-step manner to create an acceptable design, he notes: “The review is very intense and specific. I expect we will have approval 30 to 90 days from now. Once we get approval for construction, we have approval for the funding already, and our council will have to make the decision to do it or don’t.”

If built, the plant would supply about 30 percent of the city’s water demand. The balance would still come from Lake Brownwood; residents would receive a blend of water from both sources.



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