types of water purification systems
There are many types of water purification systems for home use advertised in the market, employing different techniques of water filtration. There are many home utility appliances like storage water purifiers, faucet filters, and countertop distillers which employ these technologies. To make an informed purchase most suitable for your needs, one must take a look at the advantages and disadvantages each filtration technique has to offer;
This type of water purifiers usually employs 5-7 stages of purification, using semi-permeable membrane to pass the water through, and filter out hard water, heavy metal impurities and gastrointestinal disease causing pathogens. The water will taste sweeter and bad odor would be removed. They usually have a durable lifespan of 6-8 years, have a lower maintenance cost, and repairable parts are readily available in the market too.
Since the semi-permeable membranes in RO purifiers use very tiny pores to ensure undesirable elements cannot pass through, it makes this process very slow, while making it difficult to function well with the regular tap water pressure. Hence they require electricity to pump with water through with increased pressure. These membranes are sensitive to chlorine as well, many a times they need to be coated with a layer of carbon filters to avoid damage. The biggest drawback in this filter system is that during the process of removing Total Dissolved Salts (TDS) and other impurities, it can reject upto 75% of the water-input, even if clean water is supplied into the system to be purified. Such low efficiency can make it an undesirable choice, especially in regions which face shortage of water supply. This also makes the time required to collect a required amount of water significantly longer.
Ultra Filtration (UF)
This process drains the pathogenic microbes from the water using a fibrous membrane, similar to what RO systems use. It is a simple physical straining process and doesn’t require chemicals or any electricity to operate; the biggest advantage of this purifier. The membrane uses larger pores than that of RO filters, hence can work well with water from normal tap pressure.
The simple drain-and-clean mechanism of UF filters require them to be cleaned very often, but can be easily cleaned manually, flushing all the dirt trapped. The larger pores can successfully block pathogens, but are ineffective on hard water, dissolved pesticides and other fine metal sediments.
Ultra-Violet Disinfection (UV)
Their unique technology tackles the DNA of the pathogens present in the water, disabling and killing them. These are natural and very efficient filterswhich don’t require any chemicals, don’t alter the pH balance of the water, and consequently consume low electricity. Also, they don’t produce any waste, and manual cleaning and maintenance required is minimum.
The primary feature missing from these water purifiers is that they can’t filter out salts and metals from the water, and usually require clean water to be passed through. Hence UV systems are most successful when combined with RO systems.
These water purifiers use the simplest of technology, by passing the inlet water through layers of sediment filters using gravity and normal tap water pressure. All suspended dirt and sand particles are easily filtered out, and carbon filters can remove any bad odor and chlorine dissolved in the water too.
It is a simple straining process which remains ineffective on fine metal particles line lead and arsenic. They also don’t affect the TDS level of water, or remove any harmful microbes.
Hybrid Filters or Multistage Purification
Most Water Purifiers available in Indian the market employs more than one technology to make it suitable for wider masses and more diverse needs, like the RO+UV or RO+UV+UF water filters. While the RO components clear the hard water, UV and UF make sure the scope of water borne diseases is eliminated. Definitely hybrid filters ensure a higher level of purity.
Many a times, such complex systems are not required. If your water is supplied by municipal corporations, it is fairly clean and UV or UF can be a good enough choice. RO systems are best suited for purifying water from bore wells. If your water supply is a mix of both, only then you are positively required to opt for a hybrid system.
For whatever water purifier you may select, be sure to always check for TDS regulators to be present in the purifier systems. The higher the TDS, the harder the water is. The TDS regulator must be adjusted with the quality of water supplied to ensure that the purifier is not only removing the bad salts and hard metals, but also retaining the natural minerals in the water. These days there are many advances RO water purifier with mineralizers that can add back some of the essential nutrients that get filtered in the RO process.
Most water purifier sale reps can help you determine the TDS levels in your water with a small handheld TDS meter, which can also be bought online. In case such facilities are not available, it is helpful to remember that RO water is best suited for ground water or water from borewells. UV+UF filters work sufficiently well with municipal supplied water. If you get a mix of both, get hard water supply at timesor in doubt, it is safest to go for RO or RO+ (UV+UF) models to cater all needs.