WATER FILTRATION 101
Water is fast becoming a major issue in Bali and across Indonesia. As the water level drops in the ground the contaminants become more concentrated and more noticeable. Do you get staining, does our cold or hot water smell (rotten eggs)? Most of you reading this, probably have some issue like this.
What many people do not realize that there are un-seen dangers, even if your water seems clean.
City water, piped to your house (PDAM) … Although most supplies seem clean, the water contains high concentrations of chlorine and due to the age of the pipes often has a lot of dirt and sediment (rust) which foul your pipes, systems and taps.
Bore (well) water … As the water leaches through the soil, it collects hundreds of different contaminants. Pesticides from the rice fields, heavy metals (Lead, Chromium and Iron) Dissolved organic matter, minerals and in the worst-case scenario fetal mater from contaminated rivers or a septic tank positioned nearby.
These contaminants, although not always noticeable, do have varied affects upon our health. Even if you are not drinking the water, many of the chemicals and heavy metals are readily absorbed through the skin. For example, Chlorine is absorbed 5 times faster through the skin than by ingesting. To make matters worse. As the water passes through the shower head it atomizes. This causes any heavy metals and bacterial pathogens to become airborne and thus be inhaled.
There are three basic water filtration approaches:
- A) Point Of Use (POU)Potable water
- B) Whole house point of entry (POE). Clean or Potable
- C) Water Softener / Mineral Reduction
For all types, initial water quality is the main issue. Many retail outlets will sell a system, which often as not will do an effective job, but these systems may only provide adequate filtration with complication later or can be total overkill, at the customers expense (Rp).
For most households, this water is supplied via municipal water (PDAM) or from Bore water. Each supply comes with its own problems. This water is then pumped directly into the house or via a storage tank, either tower or ground. For POE systems, analyzing the system design is crucial in providing the most effective yet economic solutions.
Filters, POU and POE are basically designed to remove standard contaminants.
Sediment – Dirty water. Grit, Sand, mud, rust, organic etc.
- Heavy Metals and Chemicals – Iron, Lead, Mercury, Arsenic, Sulfur, Chlorine, Pesticides
- Minerals – Calcium and other stray minerals that cause fouling
- Bacterial – E coli, Coliform
A water test is always advised. Point Of Use (Potable water) under sink or stand alone. Below, WE have listed the standard systems in price order.
Fine filtration. Cartridge type (Sponge or pleated) for the removal of sediment only, where the water is chemical and bacteria free.
Double Cartridge. Fine filtration plus Activated carbon for Heavy metal and Chemical removal. Water deemed to be bacteria free.
Ultra Violet. (UV) Water passes through a cylinder with a UV light source. The UV light sterilizes the water, preventing the bacteria from multiplying but does not kill the bacteria. The water is safe for drinking but unless placed close to the tap, may re-infect. The water has to go through fine filtration first (type b) to prevent bacterial shielding. It is imperative that flow rates are matched to the UV capacity. Something that is not often done here. This system is relatively cheap and is also can be sized for large flow rates (The price does jump quiet significantly) but must be checked and cleaned on a regular basis with approximately a 1-year globe life expectancy. Obviously, the unit requires electricity, but the wattage is relatively low (Size 0.5 gpm – 48 gpm)
Ultra-Filtration. (UF). Water is passed through a Ultra Fine capillary filter. The filter is so fine that it is actually able to remove all bacteria, viruses and cysts. The smart H2O UF filter is a pre-assembled unit with 3 stages of pre filtration, a UF filter and a final clean carbon filter. A water Alkalizing unit may be added if required. The system can be placed below or above counter and comes with a separate tap (So you know that you can drink the water) and is capable of 2 liters/min more than enough to fill your aqua bottles and wash your veggies. Requires no electricity. (A monthly backwash is required with little water wastage)
3M Smart Filter. This slim-line self-contained under counter system, uses fine and activated pre filtration in combination with an Ultra Fine filter to removes 99.9% of all known Bacteria, viruses and cysts. The system again comes with a separate tap and is capable of up to 9 liters per min, uses no electricity and has the no water wastage.
Reverse Osmosis. (RO): WE actually do not advocate the use of RO, unless there are no other alternatives. (Saline water) The water is passed under pressure through a semwe permeable membrane. The membrane is so fine that it removes everything from the water including all minerals and even salt. Unfortunately, this creates DEAD water, which when drunk actually leaches the minerals and salts from your body rather than supplementing. If the water is used for drinking (rather than just washing) WE highly recommend the use of a re-mineralization product. At a domestic level the system is only capable of small flows, requires constant backwashing (Water wastage.) and requires a electrical booster pump.
Even with Chlorine laced PDAM water, WE always advocate a belt and braces approach and would include a bacteria kill system for any drinking water supply.
With the exception of RO, none of the systems are capable of removing Calcium (Minerals) so, depending on water quality, fouling may occur. Minerals are perfectly safe for human consumption with any excess minerals being passed straight though the body.
Whole House Filtration (POE) In general household water does not need to be of a potable quality. The systems are used to remove heavy metals and chemicals that are readily absorbed through the skin (Absorption through the skin is usually higher than absorption through the gullet), Bad odors and reduce mineral levels which cause fouling and, in some cases, itching.
Although high flow cartridge type filters are available, the low initial cost is, more often than not, outweighed by the frequent cartridge replacement cost.
For this reason, rather than using disposable cartridges, we use large media filled pressurized poly tanks. The media, (most common) as listed below, removes the appropriate contaminants and holds them there. Like a swimming pool filter, these tanks are backwashed to waste, which removes the contaminants. Again, like a pool filter, the media has to be replaced (1 -2 years depending on water quality) but this is much more cost effective than cartridge.
There are 2 Back wash systems: Manual. Simple, but relies on the staff remembering to do their job. Automatic. More expensive but it is set and forget.
Back wash waste volumes depend on water quality, type of system and usage. For an average 2 bed family home, the system is back washed every 2-3 days with a water loss of 200-300 liter. The times can be extended but the cost of water lost is offset by the extra pressure (Pump power and electricity) required to push the water through the dirty media. In most cases the water can be flushed to the garden.
Sand (Silika) – For the removal of Grit, Dirt, solid matter
Activated Carbon – For the removal of Chemicals, poisons and heavy metals, such as Chlorine, Sulfur, mercury, Cyanide, Arsenic, Fe, Etc.
(99% of all properties will require this, due to the chemicals and pesticides alike used in rice/other farming)
Feorolite – In Very high Iron (Fe) deposit areas.
Resin – Ion exchange. Reduction in High Iron and Sulfur content plus reduction in Minerals (Calcium, Etc.)
Each of these systems must to be designed to suit the position (Pre or Post tank) the flow rates required
(Match the appropriate pump) and water quality.
Mineral reduction understood (Water Softener)
There are three main household systems that WE condone in Bali.
Salt water softener
The Ion exchange, Salt water softener, uses salt to change the chemical structure and draw out the
Calcium. Salt is placed in a Brine tank, (25 kgs of salt per week average house) is siphoned into the water. This water is then passed through a resin filter (Same type of tank as described above) which removes a good proportion of the calcium. The filter is then back washed as above.
This is the standard domestic softener system used in Bali, with its draw backs being the ongoing cost and maintenance time of replacing the salt and quite high wastage rates. Often the water cannot be used on the garden.
Electronic Water Conditioner (EWC)
A set and forget system. Here the water is modified by a controller (EMF induction) such that the calcium (and other soluble matter) is dissolved out of suspension into solution. These minerals (not visible to the naked eye) then just pass through the system without attaching themselves to the taps, pipes or heating elements etc. The systems do not require any backwash and are actually capable of reducing existing mineral build up, thus increasing energy savings and preventing bacterial growth zones.
Water Filter Bali has teamed up with the 2 foremost innovators in this field. Calclear and Hydrosmart, offering significant gains in capability and capacity with full understanding of the systems application and design parameters and a full service back up
In extreme circumstances, RO systems may be used. As stated earlier, these systems remove everything from the water. Their main application is for the removal of salt, but in some circumstances, they are the preferred solution for removing calcium (Launderettes etc.) or treatment of effluent or gray water. In cases of brackish & sea water there are few alternatives, especially on an industrial scale.
RO systems do have their draw backs. They have a high initial cost; they require high electrical input and have a high waste to supply percentage. In addition, they produce low pH (acidic) dead water. This water can be aggressive to your pipes taps and equipment and is not really suitable for drinking. (Dead water leaches minerals from your body)
For households with a bacterium count or for potable water a few systems are available. Even though you may not drink the water Bacteria may mutate and form dangerous growths on tank inner walls, bathroom walls, sinks and inside the taps.
Those with a initial zero bacteria count, should also consider a bacteria removal system. Although fine now, leaching from your or your neighbors’ septic tank may occur. WE would highly recommend a 6 mthly bacteria check (Rp 125,000 per test in Quantum)
It should also be noted that Filters (Especially active carbon) are the perfect breeding ground for bacteria, so even the smallest count may develop into a major problem
For existing houses. A full household flush is recommended prior to installation of any bacteria kill.
Chlorine dose. We all hate chlorine, but it is a very effective oxidant (Bacteria kill). However, your system is dosed (We have many variations) the chlorine must be removed before it enters your water feed system
- High flow rate Smart H2O UF POE filters are now available. The relatively inexpensive systems require no electricity and have a low discharge to usage rate.
- As with point of use, bacteria shielding and flow rates are the main issue. An average bore pump is capable of 30-50 liters per min (More for distribution pumps) This requires quite a hefty UV system that can cost a lot more than you expect. Again. Re-infection can occur, especially on long pipe runs.
Ozone. Smart Ozone injectors are often used for spa’s or as a secondary system for pools, Ozone is a very efficient oxidizer, and can disinfect high volumes of water at source. Power consumption is low, but system design and placement are very important considerations and may not always be possible.
Silver Ionization. An inline or circulation system. Here we pass a low voltage current between 2 silver anodes, releasing a small amount of silver into the water. The silver cracks the outer shell of the bacteria or viruses effectively killing it. This system is very good for circulating water systems where re-infection is an issue.
Reverse Osmosis. Removes 99.9999 % of all bacteria. Unfortunately, it removes all minerals also. Without re-mineralization, this is also detrimental to your health.