The Basic Chemistry Of Water Purifiers And Water Filters...

Most of us depend entirely on tap water as the source of pond water. We also drink, cook, wash and bath using this tap water, and the water companies say it is the safest and highest quality and yet the sales of bottled waterhave increased over the years. This reveals something shocking...!

Take a moment and imagine you were a fish trapped in a pond ...

Ornamental fish thrive in water that is clean and pure. Adding chemicals (chlorine, fluoride) to the water is necessary to make it safe or better for human consumption. Fish on the other hand demand water with as few additives as possible. The water companies have a legal responsibility to supply us with water that is safe drinking water. But do they do this? No they do not....

The large boom in the water purifier business means something...

Drinking water quality has improved in the past quarter of a century due to much more tighter standards and policing. There has also been a large number of complex water purifiers. This is because we now have the means of providing our Koi with what they need, via our tap water.

The technology and know-how of howwater purifiers operate has increased, and so too has their throughput and performance. The cost of these units has also been reduced and this increased the demand.

As we start to go through how water purifiers work to produce better quality of source water, we will have to begin thinking at the molecular level, which will definitely involve some grade 11 chemistry --- ouch! (back to the lab guys). If I can understand this chemistry, then so can you!

It is also worth noting that when examining the market for water purifiers, you may be bombarded by various claims and counter-claims. Do not take everything at face value. I am not here to verify these claims or go against them here - I am here to explain how water purifiers work. Furthermore, there is a great deal of commercially sensitive information that manufacturers wish to keep confidential.

So to avoid any law suits I will skip that bit. So rather than explain how individual makes of purifier function work, we will look at the chemistry that all purifiers use in order to produce pure clean water.Different purifiers will use this chemistry in different ways, and it is these different modes of action upon which the various commercial claims are based for each unit on the market.

Alright time for a little chemistry...

Water and the solutes dissolved within it are made up of ions. Ions are essentially atoms that are electrically charged and are the main building blocks for other molecules. The charge may be positive or negative, depending on the type of ion, with every ion having a charge which cannot change.

When electrolysis occurs, which involves the use of two oppositely charged electrodes (negative and positive) to separate out ions in a solution, the positive electrode is called the anode and the negative electrode is called the cathode.

Here negatively charged ions are attracted to the positively charged anode (and are therefore called anions), where as the positively charged cations are attracted to the negative cathode.

Let me take an example of salt (sodium chloride). When salt is added to water it dissolves and then dissociates into two separate ions - a positive sodium ion (or cation, Na+), and a negatively charged chloride ion (or anion, Cl-). So in solution, sodium chloride no longer exists and it's ions are free to move and combine with other ions of an equal and opposite charge.

All the ions can be divided into two groups; the positively charged cations such as calcium, iron, magnesium, sodium (all metals) and the negatively charged anions such as bicarbonate, sulphate, nitrate, carbonate, chloride.

How this chemistry is applied to a water purifier.

There are many common properties between a pond filter and a tap water purifier. Both systems are a function of the quality and type of media that is utilized, as well as ways in which the media are combined, together with the throughput or flow rate of water.

Just as it is key for our mechanical filtration to precede our biological chambers to prevent them from blocking up and thus affecting their performance, so too is a purifier's first media mechanical in its function.

On the face of it, tap water is crystal clear and free from suspended particulate matter. We must ensure that any microscopic debris is prevented from impacting on the purifying media later on.

A typical first cartridge will trap particles down to 20 microns. These usually take the appearance of a tightly-bound spool of white wool. But take a look at it after only a month or so and it will have a muddy red or brown appearance, largely due to the interception of iron. These pre-filters will have to be replaced periodically.

You can read a wide range ofwater usage articles. They discuss the use of water in the house and home ... topics covered include filters, heaters, softeners and water in the garden.