Ozone applications Swimming pool water
| Water quality can be improved eminently and costs can be saved on the long term when ozone is applied for swimming pool water treatment. |
Swimming pool water pollutants
Swimming pool water polluntion is mainly caused by swimmers. This makes it a very dynamic pollution, which is dependent on the number and types of swimmers. Swimming pool pollutants can be divided up into three groups: microorganisms, undissolved pollutants and dissolved pollutants.
Each swimmer carries a large number of microorganisms, such as bacteria, fungi and viruses. Many of these microorganisms may be pathogenic and can cause disease.
Undissolved pollutants mainly consist of visible floating particles, such as hairs and skin flakes, but also of colloidal particles, such as skin tissues and soap remains.
Dissolved pollutants can consist of urine, sweat, eye fluids and saliva. Sweat and urine contain water, but also ammonia, ureum, kreatine, kreatinine and amino acids. When these substances are dissolved in water, they cannot harm swimmers. However, when these compounds react with chlorine in swimming pool water, incomplete oxidation can cause chloramine formation. This causes the so-called chlorine-scent, which irritates the eyes and respiratory system. In a number of cases, stable compounds can be formed, which can only be removed from swimming pool water by water refresment [13,14].
Essential parts of water treatment systems
Generally, water treatment systems for swimming pool water consist of filtration, oxidation, disinfection and refreshment . The conventional purification process is shown in figure 1. Raw pollutants, such as hairs and plasters are removed from water by filters. Smaller, undissolved particles are removed by sand filtration. To improve this removal system, coagulation may be applied. This makes the smallest undissolved particles easier to remove. Dissolved particles are removed by oxidation by the disinfectant. The disinfectant also deactivates the microorganisms. Substances that cannot be decomposed must be gradually removed by water refreshment.
Figure 1: conventional swimming pool water treatment system
Additional water treatment technique: ozone
Figure 2: global rates of removal of various species of algae by slow sand filtration and slow sand filtration combined with ozonization . (parameters: hight sand bed: 0,9 m; particle size: 0,5-1,2 mm; filtration speed: 10 m/h)
Increasing coagulant efficiency
Figure 3: turbidity removal by aluminum polychloride, with and without (various concentrations of) ozone in the Seine (France)
Benefits of ozone application
These are the main benefits of ozonisation: