Reverse Osmosis & Bottled Water Filtration

Reverse Osmosis is one of the more common methods of purifying water for the bottled water industry. So what exactly is it and how does it work ?

But before we get into specifics we need to back up a step and get a water analysis done of the source or the supply that you intend to use. This is done by carefully sterilising a 1 liter bottle (including the cap) with jik/bleach then thoroughly rinsing the bottle with the source water. The bottle must now be filled to the brim, tightly sealed and placed in a dark but cool container. A full water analysis will include a detailed list of bacterial contents and if this is the case the water sample must arrive in the testing laboratory no more than 6 hours after it has been decanted A Tuesday, Wednesday or Thursday is best for this. E-maill us if you need a sample Analysis request Form.

The results of the water analysis will determine the method of water filtration and pre-treatment that will be required. Without this crucial step it becomes a guessing game and bad guesses can be very expensive later. The analysis should then be interpreted by a water professional as the results are given in chemical terms and the presence of different chemicals act as indicators of other issues. eg Just because the water is brown in colour doesnt mean that it is just dirt that is discolouring it .See Water Analysis Sample below

Common Filtration Elements Used in Purifying Water for Bottling Purposes

Some common elements of a bottled water purification process would be a sediment removal element, flocculation, softener (for harder waters), iron or Hydrogen Sulphide (rotten egg smell) removal , chlorination, activated carbon to remove the chlorine & other elements, reverse osmosis to purify the water , ozonation used as a sterilizer , storage facility and lastly UV to kill any bacteria in the supply tanks.As you can see this can be quite complicated and I get into this in depth in documents that can be found in our Reference Section

For the small operation or home bottling facility of which you are likely to be just one of some 3000 operating country wide you will probably be able to use a booster - pump based domestic reverse osmosis system and advanced membrane.Reverse osmosis is simply the seperation of chemical elements from water using water pressure to force the water through very finely woven membrane grids which filter to 1/1000 000th of a mm. The removed elements are flushed to the drain and the pure water is then stored in a tank
From Left to right below are some common elements of a filtration system . A 20 inch pre-carbon filter, a water softener and regenerating brine tank, light commercial R.O unit capable of 1200 liters per day & a domestic R.O system with a booster.

In a domestic R.O system the tank is a pressurised steel tank of a capacity of 12, 14 or 77 liters. Alternatively a 500 to 1000 liter plastic drum can be connected by a float valve. Domestic R.O units can supply pure water in the quantities of 200 , 300, 400 or 500 liters per 24 hour period depending on the water pressure and the membrane rating. Light commercial units start at 1200 liter per day capacity and upwards.These units operate at a maximum of 6 bars of feed water pressure. Higher than this and an inline pressure reducer has to be installed.

If you are going to use an R.O for health and particularly business, then stay away from "the cheap and nasty" systems on the market. Rather choose a unit designed for SA conditions. After your first leak or client complaint the "cheapy" can suddenly become a very expensive disaster for you. Expect to pay around R3800 to R4500 for a good quality standard Domestic Unit. These units can also be connected to icemakers, modern fridges with dispensers and a multitude of taps and appliances. A good supplier will be able to offer you excellent advice & support from their technical team .Our Reference Section has some detailed explanations on these processes and practical ways to set-up a small bottling line

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