What are the methods for pool water disinfection without using chlorine?

The standard method for maintaining of the pool water is by using chemical substances like chlorine, flocculants, algicid etc. Most of these chemicals are toxic and harmful for the human health. The chlorine products which are mostly used for disinfection of the pool water turn into vapour extremely fast, literally for a several days. That is why it is necessary to put constantly chlorine tabs in the pool water.

To prevent the fast evaporation of the chlorine, the chlorine products producers add to it preservatives and other chemicals. Although they are in small quantities, these preservatives are toxic, because they accumulate in the water. As a result of the constant chlorine adding in the water, the quantity of the preservatives increases and if a man doesn’t change the water very often, there is a danger of harming the human organism.

An unpleasant side effect of the chlorine products used for the disinfection of the pool water is that the chlorine has the ability to combine with the nitrogen contained in the human urine, sweat and some other cosmetic creams and forms chloramines. They cause the unpleasant smell of the chlorine, which is typical for many swimming pools in Bulgaria. Also chloramines cause irritation and redness of the eyes and skin.

Nowadays are developed considerably more healthy methods for the water disinfection, through which the use of chlorine and other chemicals is minimized.

The advantages of these disinfection systems are the following:

• It can be achieved pure water without using chemicals.
• They prevent the unpleasant smell of chlorine and the eye redness.
• Possibility for automatization of the whole pool water disinfection process.
• Predictability of the costs, as there is no need of constantly buying of chemicals for maintaining of the pool water.

The most popular methods for disinfection of the pool water, which replace the use of chlorine completely or partially are salt electrolysis, disinfection with minerals and UV-disinfection.

The salt electrolysis is a process in which with the help of electrical power causes the chemical reaction, as a result of which forms chlorine. For this purpose it is necessary to add to the water minimal quantity of salt, about 4g/liter. The chemical name of the salt is sodium chloride, which through the process of salt electrolysis decomposes into its constituent parts of sodium and chlorine. The thus obtained chlorine begins to act as a powerful disinfectant instantly. Subsequently, the remaining sodium ions combine again with the chlorine to form the salt from which they emerged. So the salt electrolysis represents a closed cycle.

The advantages of the system salt electrolysis:

• Completely avoiding the use and storage of chlorine products.
• The disinfection process realizes completely automatically, which facilitates very much the efforts of pool maintaining. This is a great advantage for swimming pools, which cannot be maintained constantly.
• There is no unpleasant smell of chlorine around the pool, which is typical for the pools maintained with chlorine.
• And one more advantage, which is typical only for the pools equipped with salt electrolysis: the lightly salt water contains minerals and chemical elements, which are very favorable for the human body. It improves the blood circulation, fastens the stroma and the skin becomes softer.

Disadvantages:

• The salt water is very aggressive to metals and causes corrosion. That is why in this case must be used only stainless steel type V4A.

The disinfection through minerals represents a capsule which contains silver and copper ions. The minerals combine with the water cycle through the filter system of the pool. So the silver and copper ions get into the water of the pool and began to act like disinfectants eliminating any microorganisms such as bacteria, algae etc. For example, algae disappear when you deprive its ability to photosynthesize.

The combination of the silver and copper ions with the bacteria and algae has one more positive effect: the size of the particles increases and they can be taken by the filter system and respectively are filtered.

The system can decrease the amount of used chlorine by about 70 %, but it cannot replace it completely.

Advantages:

• The copper ions prevent the appearance of algae.
• The silver ions eliminate the bacteria.
• There is no smell.
• It doesn’t depend on the temperature of the water in the pool.
• Easy mounting.

It is very important not to mix the system for disinfection with minerals and the ionizer. The difference between them is that the ionizer needs electricity.

The system of disinfection through minerals has cartridge, which should be changed every 6 months. If you use the pool only during the summer months, you should change it once a year. Its price is about 180 lv.

System for UV – disinfection

The system for UV – disinfection consists of special lamp, which produces UV- rays with wave-length 253.7 nanometers. It is known that UV-rays with a wave-length between 200 and 300 nanometers have the ability to eliminate pathogenic bacteria and microorganisms.

UV-rays destroy any microorganisms and bacteria as they break their function to reproduce. This process proceeds in the UV- lamp itself.

The system is mounted after the sand filter, in the so-called flow of clean water. With the assistance of the filter pump, the water is pushed to the UV-lamp under pressure, where proceeds the process of disinfection, after which the purified water goes on to the pool.

Advantages:

• It prevents the appearance of chloramines (a waste product that is formed as a result of the reaction of chlorine products with human urine).
• In contrast to the chlorine, it doesn’t cause skin and eye irritation.
• It is environmentally friendly.
• It reduces the use of chlorine and other chemicals up to 80%.
• Compact system with easy assembly.
• It isn’t influenced by the level of pH (acidity) in contrast to the chlorine, which loses its efficiency, when the pH is not within the admissible rate.
• Reasonable price and low cost for operation and maintenance.

The three above-described systems for disinfection of pool water can be combined to achieve excellent hygiene of the water while using minimal amounts of chlorine and other chemical products.