Water Purifiers: An Everyday Necessity

Bacteria and viruses are not visible to the naked eye but they are the major causes for water borne diseases. Bacteria cause gastro-enteritis, typhoid, cholera, paratyphoid, dysentery and diarrhoea. Virus causes polio, dysentery, gastro-enteritis, and diarrhoea. The type of impurities found in the drinking water coming to your home is mainly due to the source and distribution medium of water. Most common sources of drinking water are piped municipal corporation supply, hand operated water pumps, water tankers, lakes, rivers, bore wells, etc.

Why is Water Purifier Required?

Quality of water is getting deteriorated and contaminated day by day. There are many harmful contaminants that are present in water. These impurities are having an adverse effect on human health.  These include dissolved solids, arsenic, fluoride, antibiotics, micro plastics, rust, pesticides, disease-causing germs and bacteria and heavy metals such as arsenic, lead, iron, fluoride etc. These contaminants are responsible for causing serious health issues like cholera, hepatitis, jaundice, typhoid, and even cancer. These impurities affect the taste and smell of the water as well. Hence, it is important to remove these contaminants from the water, so that your family is provided with water that is free of any smell as well as safe and healthy for consumption.

Which type of water purifier is better for what kind of water?

There are different kinds of water purifiers available in India today. Water purifiers can be from just a simple water filter with filter cartridge element to the more advanced water purifiers using membranes for water filtration followed by sterilisation with UV filter.

• When water is hard and has high contamination, consider RO + UV purifier.
• When water is hard and has low contamination, consider RO purifier.
• When water is soft and has high or low contamination, consider UV purifier.
• If you don’t have installation feasibility for RO, UV water purifiers like running water, optimum water pressure, electricity, consider Gravity based filters
• Gravity based filter is the right purifier for municipality or corporation water, which is already chemically purified, and since this water comes from running water.

 How to find out which type of water purifier you require?

Water contains many dissolved salts, impurities which should be removed before drinking. TDS levels measure the amount of dissolved salts and heavy metals like lead, arsenic, mercury present in water.  The first thing to do is to get your home water tested for the type of pollution it may have. Accordingly you may decide which type of water purifier you need.

By measuring TDS Level in water, you will be able to make sure whether the water you are drinking is pure or impure. The maximum TDS level in water is 500mg/litre. You must make sure that it meets this mentioned level. If you see that the level is exceeding 1000mg/litre, we suggest that you do not drink that water.

 How to check the TDS Level in Water at Home?

The easiest method is digital TDS meter tester to check the TDS of water. You can easily buy a Digital TDS Meter for about Rs.150-200.

Water Purification Technologies & Uses

Reverse Osmosis (RO) Purifiers

Reverse Osmosis (RO) pushes the water molecules from the region of higher TDS level to the region of lower TDS level by applying external pressure with the help of a water pump to reverse the natural flow of water. Water with impurities or high TDS is pumped at high pressure into the RO chamber, this pushes the water molecules across the semi-permeable membrane to the other side while leaving the dissolved solids and other impurities behind. All the dissolved solids and impurities along with some input water, also known as RO waste water, are discharged through a separate outlet. RO purifiers are therefore always recommended for purifying water which has high TDS level.

Ultraviolet (UV) Purification

Ultraviolet or UV purification uses ultraviolet rays for the purification of water. A UV purifier works by throwing high intensity UV rays on the water which kills or inactivates the disease causing bacteria and viruses. However, UV purifiers cannot remove any dissolved or un-dissolved impurities or chemicals from water. Hence, most of the UV purifiers that are available in the market use some form of external sediment pre-filters to remove un-dissolved impurities and activated carbon filter to remove chlorine and some dissolved impurities. Therefore, UV water purifiers are only recommended for areas where the water source has low level of TDS. If the water has low TDS level but it is contaminated with bacteria and viruses and appears muddy, then you can use UF+UV water purifier.

Gravity based Water Purifiers

Water is allowed to flow from a top container to a lower container under the effect of gravity. Gravity-based water purifiers do not use electricity and therefore called non-electrical water purifiers. They typically use activated carbon or UF, which is made up of small carbon granules in order to absorb impurities from the water.

Ultrafiltration (UF)

Ultrafiltration also uses a semi-permeable membrane with much larger pores (appx. 0.01 microns) as compared to RO with very small pores (appx. 0.0001 microns).The advantage of UF purifiers is it can work without electricity because the membrane has much larger pores and water can pass through it naturally using the force of gravity. Which means no external pressure or water pump is required. Since UF purifiers do not hold back any water, there is no wastage of water. But there are some limitations of using UF purifiers, because of the larger pore size, UF can only remove un-dissolved solids and larger impurities. It cannot remove the dissolved solids or reduce the TDS level. So, UF purifiers are not suitable for purification of high TDS water or hard water.

Activated Carbon Filter

These types of filters or purifiers are the simplest to use and provide the most basic water purification. These filters generally comprise of sediment or sediment + activated carbon filters which can remove large and un-dissolved impurities like mud and sand along with some chemicals and microorganisms.

Candle Filters

Ceramic candle filters have 2 stainless steel containers where the upper container is fitted with 1-3 ceramic candles. In the candles, silver powder is impregnated which acts as a strong repellent of the pathogenic bacteria. It is considered the safest conventional water filter as per Consumer VOICE repeated studies.

Comparison of Water Purification Technology at a Glance

Water Purifier Brands Available in Markets

Note: Prices may vary. For latest price, check on amazon.in or flipkart.com.