Don’t let biofouling slow the flow

Three-quarters of wells in some parts of Alberta have biofouling problems

Nothing makes a real estate deal go south faster than the discovery that the water well is no good.

Recently Troy Niemans of Titan Water Systems was performing a well test for a real estate transaction and discovered a problem that nearly cancelled the sale.

“The sellers had stated that the well produced six gallons of water per minute, but when we tested it, the yield was less than two gallons per minute,” said Niemans. “Drilling a new well or installing a cistern can be expensive, and the buyer was preparing to back out of the deal.”

After looking up the water well drilling report, which confirmed the well was producing six gallons per minute when first drilled, Niemans suspected biofouling could be causing the problem. Biofouling is caused by the accumulation of bacteria on well casing, equipment, pump intakes, and other surfaces. Microbes form a type of biofilm slime that can plug up the aquifer and well components, decreasing the water flow into the well. When the slime is particularly thick, sediments also adhere to it, worsening the problem.

The seller had Titan shock-chlorinate the water system, and also pull the pump and air-clean the well, followed by chlorinated flushing. A large amount of sediment and slime were removed from the well in this process.

“After we finished, we retested the well and it was again producing six gallons per minute,” said Niemans. “The seller and the buyer were both overjoyed.”

“Biofouling is a significant problem in Alberta water wells,” said Shawn Elgert, an agricultural water engineer with Alberta Agriculture and Forestry. “Some studies have shown as many as three-quarters of wells in certain regions have significant amounts of biofouling. It’s not in itself a health problem, but slime can decrease water flow and promote corrosion of metal well parts.”

Three signs of biofouling are decreased flow rate; increased rust-colour stains (in sinks, toilets, dishwashers, and washing machines — or on laundry); and water that smells like rotten eggs or has a metallic taste.

Regular maintenance can prevent bacteria growth and increase a well’s lifespan, but if you let the slime get out of hand more aggressive action by a licensed water well contractor may be necessary. In addition to other regular maintenance, well owners should check for slimy deposits on the toilet tank (or the pump and drop pipe if the pump is pulled). Also note any changes in the colour, odour, or taste of the water. Regular shock-chlorination will keep bacteria buildup in check. Reducing the pumping rate can also help slow the rate of the biofouling.

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