After several weeks of successful testing, the mixer designed to blend water produced by a new treatment plant with water from the older plant has developed a problem.

“The mixer is not working,” Dennis Spinks, general manager of the Brown County Water Improvement District No. 1, told board members Tuesday. “They’re looking into the situation. It’s back to the drawing board. At first it was working great, but something happened within that time and now. The water is still good, it’s just that the mixer is not doing what it’s designed to do. It’s not meeting the expectations it was bought for. We’re not going to pay for something that’s not working.”

Spinks said the problem developed on the 24th day of a scheduled 30-day test period.

Meanwhile, the older “west” plant continues to provide the high quality treated water required by wholesale customers like the City of Brownwood, Brookesmith Water Supply and the City of Bangs. However, as temperatures rise, demand will increase, and Spinks said he doubts it can produce enough to meet peak summer demand, which could exceed 10 million gallons per day.

“About six mgd is about all we can get out of it,” Spinks said. “We hope to have (the new plant) online before July.”

Meanwhile, the rehabilitation planned for the west plant has been put on hold until September or October.

The new plant utilizes the recently developed membrane filtration process, which becomes more efficient as temperatures rise. Its peak output has been estimated at 12 mgd.