Common Water Problems
Whether fed from a municipal source, a borehole, a river, or the ocean, all water supplies contain dissolved mineral salts, microbiological contaminants and other materials. The amounts present determine the final analysis of the water, and ultimately whether the water is suitable for its intended application.
In order to provide quality water for domestic and industrial use, the impurities that exceed acceptable levels have to be identified. Water treatment equipment should never be installed without a water analysis.
In this section, we discuss common water problems, how to identify them, the affects they can have on drinking and process water, and the most effective ways we can treat them.
Bacteria and Viruses
The human body contains certain amounts of coliform and E. coli bacteria. In normal concentrations, these bacteria are not harmful.
Most E. coli are harmless. Some strains, however, may cause illness such as diarrhea, cramps, nausea, headaches or other symptoms. The presence of E. coli or fecal coliform in a drinking water sample may indicate human or animal fecal contamination.
Flourides in water can be harmful to humans and animals, depending on the concentration. Excess amounts of flouride in the water can cause a condition known as ‘endemic dental flourosis’ during the period of tooth formation. This condition leads to dark brown staining of teeth. Conversely, low concentrations of flouride (such as those found in most toothpastes) help protect against tooth decay.
The most effective way to remove flouride is using Reverse Osmosis.
Iron & Manganese
Iron is a problem usually associated with borehole water supplies. Iron can be found in 2 states. Water containing ‘Ferrous’ iron is usually clear when it comes out of the ground, but becomes cloudy or red when it comes into contact with air, converting the iron to its ‘Ferric’ state. Traces of ferric iron can often be seen through the red stains found on basins, baths, toilets and staining on laundry.
Manganese is usually found in the same water supplies as iron. Even small concentrations of manganese can cause brown or black stains to appear.
Specialized iron removal filters can be used to remove iron & manganese from water supplies.
In most water supplies, the presence of excessive nitrate levels is as a result of pollution by organic matter. Usually, excessive nitrates are only found in borehole supplies. An example would be where a borehole and a septic tank are too close to one another.
Concentration of nitrates in excess of 10 ppm in drinking water supplies can cause cyanosis (blue baby). Cyanosis results on a poisoning of the blood, decreasing its ability to effectively carry oxygen through the body.
The pH scale is used to express the acidity or alkalinity of water. The pH scale ranges from 0 to 14. A pH of 7.0 is neutral, indicating a balance between acidity and alkalinity. Values below 7.0 indicate increasing acidic strength. Conversely, values above 7.0 indicate increasing alkaline strength.
Waters with pH below 7.0 tend to cause iron or copper pick-up in piping systems and often lead to staining problems. Blue or green staining will be seen if the piping is copper, and red or brown stains can be expected if the piping is iron. The lower the pH, the greater the tendency of the water to cause corrosion.
Excess acidity in water is treated by neutralizing the acidity the through the addition of alkaline minerals. CWC’s filter systems can be filled with neutralizing media, which slowly dissolves as the water passes over the media bed, adding a small amount of hardness to the water. This additional water hardness may mean that a water softener is recommended.
The ideal pH range is 6.5 - 8.5.
Sodium can be found in almost all water supplies. Low concentrations of sodium have no effect on the taste or quality of drinking water, but as the sodium levels increase, the water will become more corrosive, and the taste will become unpleasant. Usually taste starts becoming apparent at around 500 ppm of sodium.
Sodium can be removed using a Reverse Osmosis process, Deionisation process, or by Distillation.
Excessive levels of sulphates will often lead to a metallic or medicine-like taste, and will act as a laxative. Sulphate removal is usually as a result of a Reverse Osmosis, Deionisation or Distillation process.
Taste & Odours
Tastes and odours are generally considered as the same problem, except for tastes caused by mineral salts. For example, water with high chloride content will have a salty taste but will probably not have any odour. A properly treated water supply should contain no trace of onjectionable taste or odour.
There are a number of tastes and odours that may exist in your water supply. Most often, these are caused by excessive chlorine, but can also include a musty or mouldy smell, or oil, gas or rotten egg odours. For each different type of bad taste or odour there is likely to be a different set of distinct problems and recommendations for treatment.
Chlorine, mouldy or musty tastes and odours can usually be removed using an activated carbon filter. Rotten eggs smells result from traces of hydrogen sulphide in the water, and will usually need to be oxidised or ozonised to effectively remove them.
Total Dissolved Solids
Total Dissolved Solids (TDS) is the name given to the sum of all the mineral compounds dissolved in a water supply. For the most part, TDS is made up of calcium, magnesium and sodium.
High TDS levels can lead to a number of problems, ranging from a salty or brackish taste, to a decrease in the effectiveness of water softeners and other water treatment equipment.
For domestic and most industrial water supplies, the maximum recommended TDS level is 500 ppm. Reverse Osmosis is the most commonly used process for the reduction of Total Dissolved Solids.
Excess hardness is one of the most common water problems on any water supply. While a hard water supply can be used for most domestic applications, it is unsuitable for industrial use. Using hard water can result in:
- Excess use of detergents and other cleaning chemicals.
- Scale build-up on heating elements and in industrial heating and cooling systems.
- Reduced lifespan of heating systems.
- Higher electrical costs.
- White deposits on glass, vehicles and other smooth surfaces in contact with water.
Whilst there are a number of scale removal systems available, hard water can be most effectively treated using an ion exchange water softeners. Water softeners use an ion exchange process to remove the majority of calcium and magnesium ions from the water supply. During the exchange process, the calcium and magnesium ions are replaced by sodium ions, generated from a sodium chloride/water solution (brine) made in the system’s brine tank.
For domestic purposes, the recommended hardness levels are 120-200 ppm. For industrial purposes, hardness should not exceed 50ppm.