Ken Williamson, Agricultural Engineering Technologist, Alberta Agriculture, Red Deer
Something that always surprises me is how many people in rural areas use and drink water from dugouts without treating it. Many times there is no treatment or filtering dome at all. Other times, there is treatment equipment installed but it is not working or has been by passed. Two surveys, one in Saskatchewan and one Alberta suggested that at least two thirds of the people using dugout water in their homes do not disinfect it. When you consider that a sample of surface water will often have a bacteria plate count of several thousand per millilitre, it is amazing that more people donšt get sick.At the very least, this water should be disinfected and filtered. Simple chlorination and filtration systems have been used for many years. The most basic of these systems includes:
This basic system can be modified to suit a variety of situations. Pellet chlorinators can be used to dispense the chlorine. Additional chemical feed pumps can be used to add settling agents such as alum to remove suspended sediment and colour. Extra equipment such as water softeners can also be added as required.
A properly installed and maintained disinfection system will provide a fair degree of protection from water borne disease and will make major aesthetic improvements to the water.
Chlorination systems do have their downsides though. They are costly and do require maintenance. the minimum cost of a simple system is about $2,500 and it is not uncommon for a more deluxe system to cost $6,000. Maintenance is a chronic problem. The chemical feed mixtures mist be checked and adjusted. Chemical feed pumps need to be serviced regularly, retention tanks must be flushed, and filters backwashed. Activated carbon filters have a limited life. The granular activated carbon in them must be changed annually. Even with the strong chlorine solution going into the filter they do become populated with bacteria. Activate carbon also has the ability to remove some potentially hazardous substances from the water. These substances include things such as naturally produced algae toxins and by-products of chlorination like chloroform. The older the carbon gets the less likely it is to remove these hazards.
As far as drinking water is concerned my recommendation is that nay dugout water should be distilled, even if it has been run through the best filtration system.