Any untreated/natural water is comprehended to contain pollutants categorized under Physical, Chemical, and Biological levels. Physical contaminants carry visible impurities like mud/dirt, sediment, or suspended substances. Chemical pollutants include naturally occurring organic chemicals, salts, metals, pesticides, etc., but mineral salts are desirable to some extent. Biological contaminants incorporate microbes like bacteria, viruses, and parasites (cysts).
Physical impurities can be removed mainly using basic pre-filtration techniques commonly used in many water purifiers. Biological contaminants can be extracted using various technologies like UV, ozonation, ultrafiltration, biocidal resins, and allied substances.
However, removing the dissolved chemicals/solids due to their size and complex nature is crucial. While activated carbon can eliminate some organic chemicals and chlorine, it cannot effectively extract heavy metals and pesticides. This is where RO enters the scenario.
Reverse Osmosis (RO) is a sheath separation process in which the water is transferred under high pressure through a semi-permeable membrane. This process extracts excess TDS (Total Dissolved Solids), chemical pollutants like Nitrate, Fluoride, Arsenic, other heavy metals & Pesticides from water to make it innoxious for drinking. About 20-30% of purified water is achieved, and 70-80% water with high impurities collection is drained (‘reject’ or ‘waste’ water).
RO cannot be extensively applicable for all water types due to fundamental technology limitations. Since RO works on very tiny pore-sized layers molecularly separating dissolved chemical impurities, it cannot, by design, specify between so-called ‘good’ and ‘bad’ chemicals. Therefore, it is necessary to use RO technology only for waters where the resulting profits exceed its limitations.
Domains where RO profits are marginal compared to water wastage:
Water below 500 mg/L TDS, more precisely below 200 mg/L TDS, when subjected to RO treatment, leads to potable water with shallow mineral content, which could deplete essential minerals for the body in the long run. This is because the reservoir water below 200 mg/L TDS is likely to spawn less than 70 mg/L of Calcium and Magnesium, both necessary minerals.
However, it must be aimed out that water is not the primary source of minerals or nutrients for humans – food is. More than mineral deficiency, the most substantial reason RO should be shunned in low TDS areas is to prevent water waste as 70-80% of water is drained when RO is used.
For waters between 200-500 mg/L, which can be a passing range where taste and health factors can impact a purchase decision, both RO and other treatment technologies can be utilized as individual taste preferences, and household provisions also matter.
Here, the constrained choice may be to avoid RO because many consumers may still find water adequate in taste up to 500 mg/L TDS unless specific medical conditions (such as diagnosis of kidney stones) exists in a household, which will compel the use of RO even in 200-500 mg/L cases.
Thus, it is necessary to use RO technology in the proper water conditions rather than indiscriminately. The end-consumer must be aware of both the positives and limitations of RO technology and must be instructed to use, as per their household requirements, preferences, and quality of input water.
Bottling India believes in the ‘right product for the right market – that has been its philosophy from inception. One outcome of this philosophy is the strong recommendation for testing each home’s water quality before the purchase decision. Bottling India recommends the suitable model from different models of water purifiers that they make, each with its advantages and underlying technologies.
You can think of living without food at once, but you cannot think of living without water. Pure water for drinking is what we all need, and that is our right as well. But the question here is whether everyone is getting safe and impurities-free water? The answer to this problem is a big no, and the reason behind this is that supply in water does not meet the criteria set for safe water. This is why most of us depend on RO water purifiers to meet our demand for clean and contamination-free water.
While on the other hand, many agencies, institutions, and companies need to acquire safe water for their employees from the commercial RO plant owners. Most probably, that is why the demand for this business is increasing day by day, and we must say that there is no harm in investing in such a business where the risk is not that high.
How does a reverse osmosis system perform?
A reverse osmosis system eliminates sediment and chlorine from water with a prefilter before it forces water through a semipermeable membrane to remove dissolved solids. After water exits the RO layer, it passes through a postfilter to clean the drinking water before entering a dedicated faucet. Reverse osmosis systems have different stages depending on their number of prefilters and post-filters.
Stages of RO Plants
The RO layer is the focal point of a reverse osmosis system, but an RO plant also includes other kinds of filtration. RO systems are built up of 3, 4, or 5 stages of filtration.
Every RO plant contains a debris filter and a carbon filter in addition to the RO layer. The filters are prefilters or post-filters, depending on whether water passes through them before or after it transpires through the layer.
Each type of plant contains one or more of the following filters:
Sediment filter: Decreases particles like dirt, dust, and rust
Carbon filter: Decreases unpredictable organic compounds (VOCs), chlorine, and other impurities that give water a bad taste or odor
Semipermeable layer: Extracts up to 98% of total dissolved solids (TDS)
The only difference between both is that domestic RO water purifiers filter at a much slower rate than industrial ROs. For instance, on average, it takes around 2-4 hours for a RO to fill its tank of approximately 10 liters, whereas, when we talk about a commercial RO plant, it can deliver up to 5000 liters of filtered water every year. We know that the difference is enormous, so such RO plants are used to meet the demand for ample water supply.