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How chlorine works in water

Water is one of the most powerful and reactive elements on earth. It consists of one oxygen molecule and two hydrogen molecules that form an angle of 105 degrees. This arrangement of H²O results in a polar molecule because it contains positive and negative electrons. This creates an extremely strong connection between the molecules known as hydrogen bonding, which is what holds water together and gives it a ‘skin’ at the surface.

Water is the ‘universal solvent’ and can contain small amounts of dissolved minerals. It can erode and dissolve rock and sand, and is also capable of absorbing and precipitating minerals as needed. Water will always naturally seek a balance. Further, water is an active chemical that reacts with salts to form bases and with certain metal oxides to form acids. One of its key characteristics is its ability to absorb and transport all types of detritus—including contaminant waste from humans and animals. As a result, water can unknowingly be a holder of disease causing bacteria and viruses.
It can also harbour chlorine-resistant protozoa such as cryptosporidium (crypto).

Outdoor pools are subject to an onslaught from the surrounding environment (e.g. dust, dirt, pollen, plant materials, and insects) as well as contamination from wildlife (e.g. birds, waterfowl, and other vagrant wildlife). Indoor pools are not subject to the same constituents; however, the biggest challenge for all types of pools is the fact that people enter the water.

Swimmer contamination is the largest opposition to keeping pools clean, safe, and sanitary. Humans carry a lot of ‘stuff’ that can slough off and be absorbed into the water. Even the cleanest of persons still carry millions of bacteria on his/her body. Here is a list of some:

• 38,000 micro-organisms released with clearing the nose;
• 100 million to 1 billion organisms from one spit of saliva in the pool;
• 938 mL (33 fl oz) of perspiration released in the pool per hour;
• 5 million organisms shed from a single handwashing;
• one tenth of a gram of fecal material on showered swimmers; and
• every time a swimmer enters the pool millions of contaminate particles are shed. It is for this reason that chlorine plays a key role in the disinfection
  of pools.