Understanding the Complexities of Water Wells
There are a number of facets concerning the "quality" of well water in rural Alberta and western Canada. A large body of evidence is confirming that the bacterial quality of well water ’does’ deteriorate over time, even with regular treatment of wells. Infiltration of new microorganisms from outside the aquifer and the development of Biofilm (discussed later) inside the aquifer and the entire well/water system, including the pressure tank, water pipes and toilets are important contributors to this deterioration.
"Water Well Quality" can be categorized into 4 areas:
Many aquifers yield water which contains minerals. Calcium carbonate (CaCO3) is the most common mineral, usually referred to as the "hardness" in your water, or the white scale showing up in your tea kettle or humidifier. Other minerals such as Iron (Fe) leave a distinctive taste in the water and magnesium (Mg) even acts as a mild laxative. Tests are available to determine the mineral content in your water. Minerals are normally dealt with successfully by using an array of filter systems, although strong tastes like iron are sometimes difficult to remove totally.
2. Aquifer Characteristics and Flow
Finding water beneath the earth's surface is often viewed as an ’Art’, with "water witching" being one of the more recognized methods of finding water. Drilling is old, proven science/technology. Unfortunately the geological (down hole) understanding of most aquifers has not received much significant attention. The Oil and Gas industry have used imaging, core sampling etc. to understanding their reservoirs. Individual owners of water wells cannot afford to spend tens of thousands of dollars to understand their individual or communal aquifer. With no image / understanding of their water source geology it is often unknown to the well owner if they have:
- Tapped into a very local and tightly defined / sealed aquifer.
- Tapped into a surface aquifer with a geological porosity which allow from very little to high water flow / movement within the water aquifer.
- Tapped into an underground stream which has a significant movement of water.
3. Bacterial / Pathogen Contamination
Almost all wells have some bacterial populations. These microorganisms can be naturally occurring and may have survived in the aquifer for thousands of years or they can be introduced by the well drilling process. Microorganisms can also be introduced by surface water flooding into the wellbore or by surface water seeping into the aquifer through structural pores or fractures.
Five Major Categories of Bacteria:
Iron Reducing BacteriaThis is probably the most common of the well bacteria. In combination with elemental iron in the water, it leaves a red stain throughout the entire water system, from toilet bowls, and sinks, to the washing machine. It can leave the water with a slight red/brown tinge of color, and an unpleasant taste and odor. The iron bacteria feed on iron, so often reduces the wall thickness of iron casings and pipes, sometimes resulting in total collapse after a period of time. Iron bacteria live very deep in the Biofilm, right next to piping where they feed, so it is hard to kill them. Commercial test kits are available to test for iron reducing bacteria.
Sulphur Reducing BacteriaBecoming more recognized in Alberta over the last few years. It is easily identified by the rotten egg/H2S smell and taste. It can make the well water essentially undrinkable when the sulphur bacteria are in high concentrations. Since the bacteria feed on naturally occurring sulphur or sulphate, it can be found anywhere, as sulphur/sulphate exists in most soils and a lot of our geology. It is often more concentrated near coal, sour oil and gas deposits, and is therefore a bigger problem here in Alberta than in other provinces. Commercial test kits are available to test for sulphur reducing bacteria.
Slime BacteriaOften found in combination with the other well bacteria, but can cause problems on its own. It is essentially colorless and tasteless, but shows up in your water and toilet tanks as a layer of slime or gel, floating on the top of the water. There is also a slight red form of the bacterium that grows on the submerged surfaces in the toilet bowl and tank, and any other surfaces beneath the water level. The biggest problem with heavy slime bacteria concentrations is that they can seal off the intakes of submerged pumps. There are extreme examples where pumps have failed and had to be replaced every 6 months due to the slime plugging the intake of the pump. With no water entering and lubricating/cooling the pump, the bearings fail.
Heterotrophic BacteriaMicroorganisms that cannot synthesize their own food and are dependent on organic material as an energy and reproductive source. This is a catchall category for a multitude of other less detrimental/ known bacteria, which are present in aquifers and wells, but are seldom considered a public health threat. They are tracked because they are indicative of the right growing conditions for more harmful bacteria.
PathogensAgents that cause disease, notably living microorganisms such as a bacterium or fungus. The ones most commonly found in wells are contained in a group called ’coliforms’, indicating organisms from "fecal" contamination. The most well known coliform is Ecoli, which can be introduced into the aquifer through surface flooding of the well bore or seepage of fecal contaminated surface water through the pores or fractures, into the aquifer. Ecoli is of great concern because it can kill humans, but there are numerous other coliforms that are of concern, and could be present in wells. Most provinces have testing systems to test for the presence of coliforms in well water, available through their Health or Agriculture departments.
Biofilm is best visualized as the slime on the rocks in a creek or river. Microorganisms / bacteria in water attach themselves to a water/surface interface and immediately start to colonize with multiple other bacteria species. The colony begins to produce a gel like, substance whose purpose is to feed, house and protect the colony (for a full scientific explanation see "Biofilm/Biofouling" on the Biostel Web site). Over time, the array of microorganisms/bacteria and the thickness of the biofilm increase. This biofilm attaches itself solidly to any surface - metal, plastic, glass, ceramic, even human tissue. Utilizing the protection of the biofilm the microorganisms reproduce. Many of the colony members stay in the biofilm. Others free themselves and float into the water (planktonic) to re-colonize downstream on another surface; or, infect those drinking the water. There are instances of pathogenic microorganisms such as Ecoli and Legionella, living and multiplying in potable water systems in cities and towns. Biofilm is very difficult to eliminate because of its protective gel layer and the incalculable dilution factor within the water system. High concentrations of chemicals can have little effect on biofilms, and are often not used because they put the system out of use for significant periods of time, render the water unusable for humans and animals, due to unpalatable taste and odor. Heavy biofilm can decrease the flow rate (in the aquifer, through pipes, and screens) by reducing the void space or openings and creating resistance/friction. Biofilm continually shed live and dead particles into the flow. These dead particles are often visible as black material coming through the taps. Over a period of years it can produce a black hue/color in the water and produce a distinctive and unpleasant odor and taste.
Well Treatment Results!
This September 2008 picture below shows water from a well contaminated with Iron Bacteria near Red Deer, Alberta. The water in the bottle on the left is before treatment; the two bottles in the middle are taken from the flow, as the contaminants were flushed out of the well after treatment and, the bottle on the right, is the water after the complete treatment.
According to the owner the well water is "cleaner than I have ever seen it"!