Reverse osmosis effective for dugout water

BRANDON — About 20 percent of Canadian prairie farms get their water from dugouts, which they’re forced to use because their area does not have access to potable well water.

The typical PFRA dugout has a sand filter between the dugout and the seepage well from which water is pumped. The sand filters out particulates and organic matter and holds onto them so they don’t sneak into the seepage well. That worked when the whole system was new, but the sand filter eventually plugs up, explains Brian Tennant, developer of the Dugouts to RO (reverse osmosis) system for purifying dugout water.

“Once the sand filter plugs, there’s no way to backwash, so now the sand is infected with a high concentration of organic matter.”

Tennant was a plumber in his early years, then bought a pig farm at Kipling, Sask., which he sold after 20 years. He and his wife wanted to stay in Kipling, but didn’t want to give up farm life.

“We found a beautiful farmyard with a beautiful house just outside Kipling. It had been on the market for quite a while. Nobody would buy it because the only water was from a dugout. It had absolutely terrible water. The dugout was in an alkali slough. Cattle had direct access to it for a number of years. It was the worst dugout I’d seen in my life.

“My wife is from a farm, so she understands dugout water. But she refused to move out there because of the water. I told her I’d fix it. I spent the next three or four years making almost no progress with the water quality.”

After 12 years of research and development and trial and error, Tennant finally arrived at a water purification system that takes the worst imaginable dugout water and converts it into pure, clean potable drinking water. He began marketing his Dugout to RO systems last year. He says his system is significantly different from anything else on the market.

“One thing I do that’s different is, I deal with the particulate problem up front. I like to pump water from the middle of the dugout, about one third of the way from the bottom. I’ve found that’s the best water. I use a stainless-steel screen on the intake so I catch all the bigger pieces. This is the hardest part of dealing with a dugout. If you don’t solve the particulate issue, there’s no point is proceeding further.

“When I started, I was only getting three months on a membrane, and they are expensive. What I wanted for my own house was the same thing I wanted for my customers. I wanted a system where I didn’t have to replace things or mess with things. So, the biggest challenge was getting the pre-filtering down pat before water hit the membrane. I have the particulate down to less than five microns before it hits the RO membrane.

“One of my criteria was that I didn’t want chlorine. Chlorine is great for killing E. coli and other bad things, but it also has some negative properties. It’s especially bad in dugout water that has a lot of organic matter. Chlorine does bad things when it interacts with organic matter.”

From the start, Tennant wanted to use reverse osmosis. However, that’s a problem with any surface water because of particulates that plug up the reverse osmosis membrane. It’s not a problem with clean well water. Also, dugout water changes with the season. A person needs to account for everything from algae blooms in late summer to anaerobic water in the winter.

Tennant says the first thing he learned was that he had to inject oxygen into every dugout, either with a windmill or electric aerator. He says he won’t even sell a system unless he oxidizes the dugout.

“Water flows through the RO system, separating good water from bad water. RO technology always has a waste stream. Everyone tries to get their waste stream as small as possible because they don’t want it to look like they’re wasting water. They use antiscalants to soften the water. That’s a pretreatment injected into the water before it enters the RO membranes. But I don’t use any chemicals.

“I take the opposite approach. I look for a large waste stream. That means I’m running the best water through the system, which is more efficient. Waste water goes back to the dugout. I use three or four gallons of dugout water to make one gallon of good water. I have way less problems with membranes this way.”

He says good water then flows through an oversized ultraviolet light that disinfects any E. coli and coliforms. Next, good water is forced through a one-micron absolute filter, which is fine enough to remove any trace of beaver fever, also known as giardiasis. The parasite Giardia lamblia that causes beaver fever can squeeze through a five-micron membrane and can survive the UV light. But the one-micron membrane is tight enough to catch it. Then the good water flows through another UV light so the customer is protected if the first UV light burns out. Good water finally goes into a storage tank.

“It took a lot of research and a lot of trial and error. I worked on this for 12 years, but I finally have it down pat. We have great water, safe water, without chemicals or chlorine.”

The compete Dugout to RO system sells for $16,500 installed. Each system is custom built to match the challenges of each specific situation. The system can be installed in a basement or in the optional insulated shed for an additional $5,000.

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