Clean safe drinking water for your wellbeing

FAQ


What is Ionisation?

In respect to the information on this web site, the term ionisation refers to a process of forming ions. An ion is simply an atom that has gained or lost an electron. As today's science understands it, atoms are made up of three parts. Protons and neutrons make up the nucleus and electrons which circle the nucleus in multiple layers, depending upon how many electrons there are.

Positive and Negative charged ions

Ideally atoms are balanced as there is the same number of electrons and protons. However, it is possible to throw off or gain electrons orbiting the nucleus. Loss of an electron will lead to a positively charged atom, gaining an electron creates a negatively charged atom. Those charged atoms are called ions. Negatively charged ions are known as an anion due to its attraction to anodes (positively charged electrode). A positively charged ion, which has fewer electrons than protons, is known as a cation due to its attraction to cathodes (negatively charged electrode).

Converting an atom or molecule into an ion

Ionisation is the physical process of converting an atom or molecule into an ion by changing the difference between the number of protons and electrons. This process works slightly differently depending on whether a cation or anion is being produced.

Energy Release

A positive electric charge is produced when an electron bound to an atom or molecule absorbs enough energy from an external source to escape from the electric potential barrier that originally confined it. The amount of energy required being equal to the Ionisation potential.A negative electric charge is produced when a free electron collides with an atom and is subsequently caught inside the electric potential barrier, releasing any excess energy.

Metal

Metals are electrically interesting materials because of their electron configuration. In solid conductive metal, a large population of electrons is mobile or "free". These electrons are bound to the metal lattice but not to any individual atom. Still, the overall number of electrons matches the number of protons of the nuclei. In other words, even though the electrons are not too closely bound to the nuclei, their number is always balanced with the protons, in line with our earlier statement.

Electron behaviour

Even without an external electric field applied, these electrons move about randomly due to thermal energy but on average, there is zero net current within the metal. Given an imaginary plane through which the wire passes, the number of electrons moving from one side to the other in any period of time is exactly equal to the number passing in the opposite direction.

How ions are dispersed

The moment an electrical potential - voltage - is applied, the net current in the metal is not zero anymore since the movement of the free electrons now takes a preferred direction, i.e. towards the anode. When an electrical current is passed through a piece of metal immersed in water, the electrons flow through the circuit. As they leave the conductor (the metal) to travel through the water, atoms dislodge from the metal along with the electrons. The atoms, which are missing electrons, are known as ions, which disperse throughout the water.

Trihalomethanes

Chlorination of water

Chlorine (hypochlorite) is added to drinking water in many countries as a disinfectant to prevent infectious diseases. It has proved to be an enormously successful healthcare measure, doubtlessly preventing widespread illness and death. In 1974, it was found that chlorination of water resulted in the formation of many volatile organic chlorinated compounds from reactions of chlorine with organic matter in the water. Read more from the Greenpeace "Body of Evidence" document

Presence of by-products in drinking water

Most of these by-products are called trihalomethanes (THM) and include chloroform which is known to cause cancer in animals. Chemical analysis of chlorinated water samples has since detected hundreds of other nonvolatile chlorinated substances which only occur at trace levels (less than 1ppb) much lower than levels of THMs, but are also toxic. Extracts of chlorinated by-products from drinking water have been shown to be genotoxic in a wide range of in vitro assays using bacterial, rodent and human cells (Wilcox and Williamson 1986). Over the last 20 years since the discovery of THMs in drinking water, many epidemiology studies have been conducted to investigate whether cancer risk is elevated in humans as a result of chlorination by-products in drinking water (Zieler et al. 1988, Cantor 1994).

Why do we treat tepid loops and cooling towers as flow through, although they are really recirculating systems?

Getting the right ion levels

The volume of water in a recirculation system such as a pool is large in relation to the water losses and we have high ion attrition rates in proportion to water loss. In other words, very little water is lost in the system; however we have a relatively high loss of ions. This is due to the ions being absorbed by the concrete, the filtration system, backwashing, binding to dirt and also bather loading. So ion loss and water loss is disproportional. However, once the correct ion level in the water is achieved for recirculation systems, the micro-processor based circuitry's parameters are adjusted to maintain this level with the minimum of fuss and operator intervention. Any change in these parameters will take some time for the readjustment of the system and the response of the body of water to the new ion deposition rate.

Cooling Towers

However, in a cooling tower we lose a lot of water but not as many ions. As the water evaporates, no ions are lost.The removal of water droplets through the fan removes both water and ions, so this doesn't change the ion concentration. Therefore, the ion loss is proportional to the water loss in the system.

Tepid water loops

The same principle applies to a tepid water loop; the ion attrition rate is very low. Water flow fluctuations over a broad range are commonplace in these applications. So this means that any make up water - if not dosed before entering the system - will lower the ion concentration and any ionisation equipment in the in the loop would have to quickly respond to that change.

However, due to these huge variations in operating conditions in cooling towers and tepid water loops, it becomes impossible to install a unit into the loop itself, i.e., as a recirculation application. The readjustment time of recirculation systems described above is too long for the quickly changing ion concentration which makes it impossible to find a valid set point for the adjustment of the circuitry.

Flow Through System

Another way to explain this is that due to the significant amount of make up water on one hand and water loss on the other, the tepid loop as well as the cooling tower can be seen as a black box, where water enters on one side and comes out on the other. Even though there is a recirculation component in the black box, the system overall behaves like a flow through application. Therefore the only possible location of ionisation equipment that can guarantee an accurate ion concentration is the make up line