Biological Factors in Water Treatment

Keeping Your Water Healthy and Clean. The key biological elements in maintaining sanitary water are listed below:

Disinfection

- Controlling bacteria and viruses in the water that helps to assure the water will be healthy and safe for swimming.

The process of controlling bacteria and viruses in the water that helps to assure the water will be healthy and safe for swimming is known as disinfection, or sometimes sanitation. Disinfection is not to be confused with the control of algae in the pool water, as algaecides are best used for that purpose.

While a wide variety of methods for disinfecting or sanitizing pools are available in the market, the two most common methods are chlorine and bromine. Over the recent past, other processes have also gained more attention. These include PHMB (biguanide), Ozone and Ionizers. Each has its strengths and weaknesses.

Chlorine

The most widely used sanitizer for pool disinfection is chlorine, and is available in a number of forms. The following table lists the most commonly used forms of chlorine and some of their characteristics.

Note: Regardless of which form of chlorine is used, all produce the same active sanitizer known as “FREE CHLORINE” when added to water. As this active sanitizer begins to work, it can then take several different forms, not all of which are desirable.

Shock Treatment

- The process of super chlorinating or shocking the water to remove bather contaminants that build up over time.

Regardless of which disinfection system is used, the control of bather and other wastes is critical. For example, one active swimmer produces two pints of perpiration per hour in a pool. Perspiration contains a wide range of organic and inorganic contaminants and these will accumulate and combine with chlorine to form the very undesirable combined chlorine form. In bromine systems, although odors and irritation are not a problem with bromamines, the wastes themselves can build up and eventually make water uncomfortable for bathing. The regular removal of these wastes is a must in any system.

The odor that is associated with combined chlorine is often mistakenly referred to as “too much chlorine in the water”, but actually indicates that there is too little. The best way to remove these wastes is with regular oxidation. To destroy these wastes, we use either Super Chlorination or Shock Treatment.

We use the phrase “super chlorination” when referring to the use of a sudden large dose of chlorine to destroy wastes. Conversely, the phrase “shock treatment” refers to the use of non-chlorine type shock. In either case, the goal is to destroy and remove bather waste in addition to preventing formation of combined chlorine or accumulation of irritating waste products.

Algae Control

-Preventative tips for keeping algae from starting.

The final biological factor that must be considered is algae growth. Algae growth is perhaps the most obvious sign of something gone wrong in pool maintenance.

Proper maintenance will not only keep you water looking great, but also allow for easy prevention of algae growth

There are two basic groups of algae:

1. Free-floating types including green algea and mustard algae varieties. These tend to be found throughout the water. While they may cling or settle on surfaces such as walls and floors, they are not usually affixed to them. They tend to color a water body cloudy green or yellow.

2. Black algae is the common name or term given to the dark blue-green algae found growing on pool surfaces. Black algae growth in localized areas such as along one wall, in the deep end, in a corner or around obstacles such as steps indicates an area of pool circulation.

The growth of both types of algae can be easily prevented by using a quality algaecide as part of a regular maintenance program, and by proper circulation. It takes far less algaecide to prevent algae growth from getting started than it will to cure it once it has occurred

The regular use of algaecide is also recommended to prevent problems should a failure of the disinfection program occurs. Due to the volatile nature of chlorine or bromine, these residuals can often be lost very quickly in pools due to equipment or operator error or by heavy rainfall or bather waste demand. If this occurs without an algaecide present, the rapid growth of algae can occur in a few hours. However, if an algeacide is present, it will acti as algae growth prevention until the sanitizer system is functioning normally.