Plastic Pipe used in reverse osmosis project helps provide El Paso Area Residents with clean water

WASHINGTON, D.C., June 6, 2001 - A competitive price won the attention of a Texas engineering firm to High Density Polyethylene (HDPE) pipe. A superior performance won its loyalty. Seven miles of 20-inch diameter HDPE pipe - nearly 37,000 feet - was specified for the El Paso County Water Authority Reverse Osmosis Treatment Project. The pipeline carries drinking water to a reverse osmosis plant from four 250 horse power vertical turbine wells that pump 1,000 gallons per minute with 400 feet of total dynamic head. It's the second-largest reverse osmosis system in the state of Texas. The project's engineer chose HDPE pipe when the project was being specified two years ago because it was about $5 less per foot than an alternative material. He said even though the prices have since evened out, his first choice in pipe material is clear. "After using HDPE pipe for this project, I would use it any time in the future for water projects," says David Goodrum, district manager for ECO Resources, a utility management company. "The wells are always turning on and shutting off. And the high pressure of emergency shut offs is immense. Other types of pipe can't handle that pressure. With HDPE, there's very little water hammer. The pipe absorbs that pressure, and you can't feel it back at the plant." What the customers of the El Paso Water Authority feel is the extra money in their pockets. The heat-fused joints in the HDPE pipe have zero leakage. No leaks mean no waste. And no waste means customers are only paying for the water that comes out of their faucets, not the water that leaks through a faulty joint. Technicians from a Texas-based PPI member company were responsible for heat-fusing all seven miles of the pipe in the field.

"Every municipality allows (budgets) for leaks," says the firm's district manager for El Paso. "And it's not just the leaks, but the material that's literally sucked and siphoned into the pipe through the cracks in other kinds of pipe. But with HDPE, the pipe won't come apart. When the pipe is joined, two pieces of pipe are now one. Then three pieces become one, and so on. The heat-fused joints are as strong or stronger than the pipe itself." The El Paso Water Authority serves about 12,000 people in a 91-square mile area just east of the city. The job superintendent was Gilbert Zuniga, a contractor from Camino Contracting, Inc., also based in Texas. He's worked with HDPE pipe for several years and understands the benefits of its use. It took just three months to heat-fuse all seven miles of plastic tubing into one continuous 36,960-foot length of HDPE pipe. "Another reason I like it is because the maintenance is so low," Zuniga said. "If the pieces are fused together properly, there's virtually no maintenance whatsoever. The down time is zero. And the flexibility of the pipe is another huge benefit. When you run into something like an 8-inch high-pressure gas line, it can be touch-and-go when you're trying to fit water pipes around that. But the flexibility of the HDPE and the ability to perform the in-ground fusion, it makes the job so much easier." And that's more good news for the citizens near El Paso.

Before this system was installed, the solidity rate in the drinking water was about 1,600 parts per million (ppm). The Environmental Protection Agency (EPA) requires a maximum of 1,000 ppm. Something had to be done quickly. "Construction went very smoothly," Goodrum said. "What made things so quick and easy was that every one of our high-pressure tests with the HDPE pipe passed on the first go. No leakage. We have to provide state-compliant drinking water to our citizens. And we didn't have a choice. This was the only way we could efficiently do that without entering into a wholesale water purchasing agreement with someone." The new reverse osmosis plant will remove about 90 percent of the solids in the water supply. That will exceed the EPA requirements by plenty. In a reverse osmosis system, the goal is not to separate the pure water from the salt and other contaminants. When the natural osmotic flow is reversed, water from the salt solution is forced through a membrane in the opposite direction by application of pressure. Through this process, pure water can be produced by screening out the solids. This project's plant was designed to process 4 million gallons of water per day and is expandable to 8 million gallons per day. For the El Paso Water Authority, that's no mirage.