Water Pumps & Treatment News

Well Disinfection: Why Does My Water Turn Cloudy Sometimes?

At EDS Pumps & Water Treatment Ltd., we know that, even though bacteria are invisible to the naked eye, they can build up to the point where people will notice a sudden cloudiness to their water. That is why we offer a selection of water treatment services for well disinfection.

Why Does My Water Turn Cloudy Sometimes?

Cloudy water is caused by the biofilm sloughing off the plumbing. Best practices dictate that you have your water tested periodically for the presence of bacteria. Well owners become concerned about the number of bacteria in their water; one time it may be low — 10 cfu (colony forming units) — at which point they may “shock” their well. When they retest the water after a couple of weeks, they find the bacteria count has risen to 300 cfu. This is very common when using chlorine (bleach) to disinfect your well.

Well Disinfection

When you chlorinate, or “shock”, a well with sodium or calcium hypochlorite (liquid or granular bleach), it dissolves in water and forms hypochlorous acid and a hypochlorite ion. We use the ion to oxidize metals like iron and manganese to turn them into a solid and filter them out of the water. We use the hypochlorous acid to destroy the bacteria in the water. The pH of the water will determine if we have a predominance of the ion or the acid, so the lower the pH of the water, the more acid we have to take care of the bacteria. That is why it is very important to make sure the water that we are adding the chlorine to is below a pH of 7.0. We usually have to lower the well water pH by adding an acid such as citric acid, acetic acid (vinegar), or something stronger. Once we get it to the correct level of between 5.5 and 6.5, we add the CORRECT amount of chlorine. I say CORRECT amount of chlorine because household bleach is 5.25% chlorine. The other 94.75% are buffers and fillers which RAISE the pH of the water and therefore neutralize the ability of the hypochlorous acid to kill the bacteria! In order to have the best shot at eradicating the bacteria in your well, the water has to be on the acidic side and have a concentration of between 50-200ppm (parts per million). It is usually left in this state for up to 24 hours before it is flushed out.

Well Disinfection Mistakes to Avoid

If the well owner shocked their well once and had little effect on the bacteria, they usually would add a bunch of chlorine the second time thinking that will surely get rid of the bacteria. This is WRONG. All that chlorine has raised the water pH and now there is almost no hypochlorous acid to kill those critters. There are plenty of the hypochlorite ions to precipitate out the metals but little else is going on. So, once this chlorine is flushed out of the water, new food sources such as iron, manganese and other nutrients are drawn into the well where the bacteria are now thriving because a lot of the competition has been eliminated and an abundant food source now exists. Life for the bacteria is great! Bacteria double in population every 20 minutes, so when you sample the water a few days or weeks after the last chlorination, you’ll find the CFU’s even higher!

Chlorinating Well Water

Chlorinating is more complex than commonly thought. It needs careful pre-treatment and measurement to be effective and it should be done by a water treatment professional. ADDING AN ACID TO CHLORINE IS DANGEROUS! It could form chlorine gas if the water pH is too acidic (below 5.0).  Even if all of this is done correctly, bacteria can still return because it may have existed in that aquifer for the last 20,000 years and no amount of disinfecting will change that situation.

Well Disinfection Services from EDS Pumps & Water Treatment Ltd.

Have a Certified Water Treatment Specialist check your water. If you need a disinfectant device or process, they can guide you towards the right solution for your particular needs. Water that has too much iron, manganese or hardness needs to be pretreated before you can use a device like an Ultraviolet Sterilizer, which can significantly add to the cost and maintenance.

At EDS Pumps & Water Treatment Ltd., we have the most Certified Water Treatment Specialists in the province on staff. Contact EDS Pumps & Water Treatment Ltd. at 604-534-1115 for more information regarding well disinfection.