Why Do We Need RO Water Purifier at Home And Office

Date: August 23, 2022, Category: Water & Health

Why Do We Need RO Water Purifier at Home And Office

RO water purifier is the most advanced technology for purifying drinking water. To ensure 100% safe and mineralized drinking water as well as free from virus, bacteria, algal and harmful heavy elements, then Reverse Osmosis – RO water purifier is a must. Let’s discuss the whole scenario-

Is natural water safe?

Water from natural sources is a solution to various matters. Water and soil are mixed everywhere in nature. Most of the elements of soil can be found in water as dissolved matters, insoluble substances, and microorganisms. The majority of these are hazardous to human health.

Natural Water

Common Water Borne Diseases and Responsible Microorganisms:

Diseases Microorganisms
Diarrhoea, Dysentery (Often Bloody or Profuse), Stomach cramp Rotavirus, Escherichia Coli, Shigella, Salmonella, Campylobacter, Entamoeba histolytica,
Abdominal Pain, Gastroenteritis, Ulcer Helicobacter pylori, Campylobacter, Cryptosporidium
Urinary Tract Infection (UTI), acute respiratory tract infection (ARI) Escherichia Coli
Tonsillitis, Otitis media, Sinusitis, Pneumonia Meningitis Streptococcus, Pneumococcus
Conjunctivitis, Boil, Cellulitis, Septicemia Staphylococcus
Cholera Vibrio cholerae
Dermatitis (skin infection), Corneal Ulceration Pseudomonas
Tuberculosis Mycobacterium tuberculosis
Central nervous system InfectionsPulmonary Infection Nocardia asteroides
Anthrax Bacillus anthracis

Common Chronic Diseases and Responsible Contaminant (Substance)

Diseases Substances
Nerve Diseases (Alzheimer, Encephalopathy, Dementia, Stroke, Memory loss, etc.) Aluminum, Manganese, Mercury, Lead 
Kidney Diseases (Cyst & Renal stone) Copper, Nickel, Arsenic, Cadmium, Phosphate, Potassium, Calcium,
Lung Diseases (Tumor, asthma or hypoxemia) Nitrate, Lead, Cadmium, Silicon
Cardiovascular Diseases (Blue baby Syndrome) Sodium, Nitrate,
Liver Diseases (Fatty Liver, Gall Bladder stone) Lead, Cadmium, Carbon-di-Oxide, Cobalt, Mercury
Hair Follicle disease (Hair Loss) Chlorine, Fluorine
Deformity Disorder (Growth Retardation) Lead, Cadmium
Cancer (Carcinoma, Sarcoma, Malignancy) Lead, Cadmium, Chromium, Arsenic

The human body is consist of 68 – 72% of water and medical science also found that the direct or indirect cause of maximum diseases of human is contaminated water. Contaminated water by mentioned substances or microorganisms is not acceptable anyway. So, it is important to ensure safe water to be healthy.

Wrong Thinking About Natural Water

  • Most people consider the water from tube-well or waterfall as safe potable water. But, these sources may be contaminated by various hazardous substances and microorganisms.
  • People also think that boiling the water at 1000 C temperature is safe. But, by boiling the water dissolved or insoluble substances can’t be removed; and some microorganisms may not be killed in this way.
  • Chemicalization (Halogenation or ozonation) is another commonly known system of water purification. But, chemicals contamination is also hazardous to the human body. Besides this, measuring the optimum amount of chemical to kill existing microorganisms in water, is too difficult. Disproportion to the required amount resulting in the existence of live micro-organisms or creates acute toxicity to human health.

All of these procedures aren’t appropriate ways of water purification due to the possible existence of contaminants (substances) and microorganisms in water.

So, filtration is the only way to make the water safe (contamination and micro-organisms free). After filtration safe water must be preserved in such a reservoir that is free from air contact and also must be food grade maintained. Scientifically procedure air pressure tank is used to protect from any type of contaminations after making safe water.

Water Quality Testing

electrolyzer water test

Water quality parameters are Total Dissolved Solids (TDS), Electric Conductivity (EC), pH, Total Coliform, hardness, undissolved heavy solids (Fe, As, Cr, Cd, Pb, etc.) and Turbidity, etc.

TDS Level of water can be measured byTDS meter as mg/L or ppm (particles per million) unit and pH can be determined by pH meter or pH value table. In order to justify if the water safe or not, all other parameters of water can be tested in the chemical laboratory. But laboratory testing is expensive.



The pH of water is an important parameter to justify usability. It is a measurement of the acid-base equilibrium (0 to 6.9 acidic and 7.1 to 14 alkali). Mathematically calculated by negative common logarithm {pH = − log (H+)} of the hydrogen ion activity in a solution. In dilute solutions, the hydrogen ion activity is approximately equal to the hydrogen ion concentration. By drinking the water of Low pH causing acidity and high pH causing tingling symptoms and burning sensation or toxicity. The pH of safe potable water should be within the range of 6.5-8.5.

TDS (Total Dissolved Solids)


TDS of water means Total dissolved solids (as ions) in water. TDS meter is capable to indicate the dissolved ion density of water but unable to detect insoluble substances and microorganisms. If we can deduct TDS – minimum 97% then we can guess all other solutes already been deducted and that is safe water.

In spite of some limitations, usually, TDS and pH are commonly used parameters to justify the Water quality. Generally dissolved ions are tinier than any other insoluble substances or microorganisms. It can be assumed that TDS reduction (removing TDS) by membrane filtration refers to the rejection of larger particles as well as heavy metals and microorganisms also. So, if the TDS level of water is reduced 97% by any filtration system then it is considered that, maximum insoluble substances and microorganisms are also removed from the water.

So, as a preventive measure against infection or toxicity, medical science recommended applying the best filtration water purification technologies i.e. RO Water Purification in the daily life of human beings.

Currently, there are different types of water purifiers available. All water purifier in Bangladesh have different technical specifications with certain basic requirements, but people need the best water purifier for safe water

Applicability of specific water purifiers depends on water quality, water source, water pressure, amount of daily water requirement and available space. The general person as a customer may be confused to select an appropriate water purifier. In order to relieve the confusion of every valuable customer, ULTIMA has developed a detail featured article about the “Selection Criteria” of the Best water purifier in the market of Bangladesh.

We have to read carefully the following article at least a single time prior to buying a water purifier for our home, business center or office. ULTIMA’s cordial effort may be helpful for buying the best water purifier. We hope that after reading this article buyer will get a strong concept on selecting the best water purifier for domestic or official use.

Now, ULTIMA recommended knowing deeply, about the best water purifier for domestic or official use. Let first we have to know, about water purification technologies.

Water Filtration Technologies

  • Disinfection technologies (Boiling, Chemicalization and electromagnetic radiation)
  • Filtration technologies (by Porous Membrane)
    • Non-Electrical 
    • Electrical

Common Disinfection Technologies

  1. Boiling
  2. Chemicalization
  3. UV Radiation


Overcome thermotolerance of microorganisms at 1000 C or 2120F through boiling water using thermal effect by the Fuel energy

Limitations of Boiling

  • Inability to kill some microorganisms (Such as Clostridium)
  • Inability to remove dissolved ions, insoluble substances, and cadaver of microorganisms
  • Possibilities of fire explosion accidents
  • High fuel energy consumption
  • The high amount of system loss due to pure water vaporization


Halogenations or Ozonation, sometimes used in municipal or community water treatment plants.

Limitations of Chemicalization

  • Harmful chemical contamination (Longtime halogen contamination in drinking water is one of the causes of cancer)
  • Inability to remove cadaver, dissolved ions, and insoluble substances

UV Radiation

Electromagnetic Radiation by Ultra Violet (UV) ray

Limitations of UV Radiation

  • Not useful for turbid water (only applicable for transparent water)
  • Inability to remove cadaver, dissolved ions, and insoluble substances

Due to the limitations of the mentioned disinfection procedures, these are not recommended for purifying the water. But, the tube of the ultra-violate ray may be used as an adjacent device with RO membrane to ensure double-layer protection against microorganisms infection and polishing safe water.

Water Filtration Technologies

Filtration is the water purification systems mean chemical-free technologies lead to separation of solutes from water through a semi-permeable membrane with tiny pores. The function of the membrane is obstructing to pass through the substances and microorganisms from water, which are larger than the pores of the membrane to make safe water.

Non-Electrical Filtration Systems

  1. Ceramic Filtration (CF)
  2. MICRO Filtration (MF)        
  3. ULTRA Filtration (UF)

There is no fundamental difference between CF, MF, and UF. All of these filtration systems are separate based on structural size and pore size of cartridges or membrane for size exclusion or particle capture. Filter with smaller pore size is better than others.

  Ceramic Filtration (CF) Micro-Filtration (UF) ULTRA Filtration (UF)
The standard pore size of the membrane 0.3 – 0.8 micron 0.1 micron 0.01 micron
Capable to remove Some particulates and colloids Some particulates, colloids, fungus and algae Some particulates, colloids,  fungus, algae, and bacteria
Unable to remove Fungus, algae, bacteria, Virus, Ions and Molecular substances Bacteria, Virus, Ions and Molecular substances Virus, Ions and Molecular substances

Electrical Filtration Systems

  1. Multi or Nano Filtration (NF)         
  2. Hyper Filtration (RO: Reverse osmosis) 

Multi or Nano Filtration (NF)

It is an electrical water filtering process by a porous (0.001 micron) membrane capable to remove maximum polyvalent ions and micro-organisms and preserve cations by an electronic collector of positive charge which absorbs harmful substances with a negative charge. Multidimensional research is now underway about this filtration system and it is still now commercially unavailable.

Hyper Filtration- (RO: Reverse osmosis)

Reverse osmosis (RO) is a water purification process through the tiniest porous (0.0001 microns) membrane utilizing external pressure electric booster pump against normal osmotic pressure. The membrane allows only water to pass through with some monovalent ions. Larger matters than 0.0001 microns must be rejected by this membrane. It works as a reducer of TDS as well as insoluble substances and microorganisms from water.

Comparison between Nano Filtration and Hyper (RO) filtration Systems:

  NANO Filtration Hyper Filtration (RO)
The standard pore size of the membrane 0.001 micron 0.0001 micron
Capable to remove Particulates, colloids, fungus, algae, bacteria, Virus, Multivalent Ions, large  molecular substances Particulates, colloids, fungus, algae, bacteria, Virus, Ions, All molecular substances
Unable to remove Monovalent Ions, Some tiny molecular substances Very few amounts (2-3%) of monovalent Ions which are tiny in size. 

Note: Except halogens most of the tinier monovalent Ions, are positive to human health. An extra activated carbon stage (T33) is used after RO membrane stage in a RO water purifier toabsorb existing halogens. So,these few amount (3%) of monovalent Ions consisted water is considered as safe potable water. But these ions should be removed for the medicine production purpose in pharmaceutical industries with following some process.

Available Water Purifier In Bangladesh

  1. UV water purifier: Using disinfection technology by electromagnetic radiation
  2. CF water purifier: Using membrane with pore size of 0.3- 0.8 micron
  3. UF water purifier: Using membrane with pore size of 0.01 micron
  4. RO water purifier: Using membrane with pore size of 0.0001 micron
    • Combined (RO + UV) water purifier: Using membrane with a pore size of 0.0001 microns with disinfection technology by electromagnetic radiation

Latest water purifier

RO Water purifier

The first commercial RO water treatment plant was built in 1960. This technology is now recognized by the Public Health and Safety organization – NSFAmerican National Standards Institute(ANSI)Environmental Protection Agency (EPA). It is certified by the International organization for Standardization (ISO) 9001: 2008and also appreciated by the World Health Organization (WHO). As a result, the RO filtration method is applying worldwide as the latest water purifying technology due to the highest effectivity which is commercially known as RO water Purifier.

RO Water Purifier

This purifier consists of RO membrane. Standardpore size of RO membrane is 0.0001 micron. So that, it is capable to capture maximum substances from water. It is the main component (stage) of RO Water purifier.

In order to increase the longevity of RO Membrane until the highest tentative period, multiple additional stages have to adjust asPre RO stages.

Commonly Used Pre RO Stages Are

  • PP Membrane (Sediment Filter)
  • GAC (Granular Activated Carbon) Filter
  • CTO (Chlorine Taste and Odor: Activated Carbon) Filter

To make the water mineral-rich and increase the pH level of potable purified water by RO membrane some additional stages may be adjusted as post RO stages

Commonly Used Post RO Stages Are

  • Mineral and Alkaline cartridge
  • T33(Activated Carbon)
  • UV filter  

Required stages for an RO water purifier depend on the water quality of the source. RO water purifier generally consisted of 6 to 10 stages including RO membrane.

PP Membrane (Sediment Filter)

This is a porous membrane made from melt-blown polypropylene (one kind of thermoplastic) known as a sediment filter. It is mainly used as the first stage of RO water purifier for remove insoluble particles (Soil, Sand, Scales, organic wastes. etc.) from water.

The performance of the PP membrane depends on the fineness of its pore size.PP with finer (Lower) pore size considered a better one and takes a higher price than others. Generally, finer porous PP is high in weight within minimum space. Weight varies according to length.

Commercially Available PP In Bangladesh:

  • Length:

Regular size: 10″ & 20″
Customized size: 5″, 6″, 8″ etc.

  • Pore size:

General: 5 microns, 1 micron and 0.45 micron

  • Weight:

Length 10″: 75, 80, 100, 125 and 150 gram
Length 20″: 150, 160, 200, 250 and 300 gram

Note: PP of regular size is available in public market. But, customized size of any stage is only available at responsible distributor company. For this reason, regular size PP is preferable. Prior to buy a RO water purifier, we have to determine which purifier contains regular sized and finest porous PP. Finest in Bangladesh: 0.45 micron pore size with 150 gram (10″) & 300 gram (20″)

Activated Carbon Filters

Carbon Filters

Active carbon is produced from raw organic materials, such as coconut shells or coal. Heat, in the absence of oxygen, is used to increase (activate) the surface area of the carbon.

A grading system is applicable for the quality judgment of coconut shell carbon. Iodine number is a widely used parameter to assess the quality of activated carbon for estimation about it’s simplicity, rapid absorbent quality, surface area, and porosity. The iodine number is defined as the milligrams of iodine absorbed by one gram refers to the absorption of halogens

Three types of activated carbon filters are used for water purify as additional stages with RO water purifier.

GAC: Granular Activated Carbon

Carbon Filters

GAC removes particularly certain-dissolved organic chemicals. However, other chemicals, like iron and nitrate do not attract the carbon and are not removed by GAC, but this filter is also capable to remove fumes and some objectionable odors of water.

CTO Membrane

Chlorine Taste and Odor (CTO) membrane is an activated carbon filter coated by a porous blanket used for absorbing dissolved chlorine, unusual Tastes, and objectionable odors.

T33 Membrane


T33 Membrane Inline Granular Activated Carbon Filter (T33)used to absorbing fumes or halogens, improve the taste of potable water and increasing the bleach of water.

Commercially available activated carbon for GAC CTO and T33 stages in Bangladesh:

  • Coconut shell carbon and coal carbon
  • Grade: Iodine – 300, Iodine – 800, Iodine – 1100, Iodine – 1200
  • Without grading

Note: As iodine number is quality indicator of carbon filter. So, highest iodine number is preferable for carbon filter. Best quality in market of Bangladesh is Iodine – 1200 grade Coconut shell carbon.

Reverse Osmosis (RO) Membrane


RO membrane is the main component of RO water purifier. Standard RO membrane consists of the tiniest pore (0.0001 microns) formed by typically either cellulose acetate or polysulfone coated with aromatic polyamides3. The capability of Membrane (Water filtration rate) rated as GPD (Gallons per day). The membrane of higher GPD considered as powerful. Accuracy and quality depend on uniform reduction quality and higher surface area which increase GPD (gallon per day). But, we have to confirm RO membrane is original (standard).

Power of Commercially Available RO Membrane

  • For residential use: 50, 75, 100 GPD Power
  • For commercial use: 200, 300, 400, 800 GPD Power

Note: Uniform reduction rate 97%-98% makes safe water. 100 GPD Power is the best for domestic use and 200 GPD is suitable for official use.

Booster Pump

Booster Pump

RO water purifier depends on electric power; the booster pump is an adjusted power supply device used to apply external pressure on RO membrane. The power of the booster pump should be matched to the power of RO membrane, otherwise, it results in the defective output.

The capability of the booster pump rated as GPD (Gallons per day). Booster pump of higher GPD considered as more powerful, and quality depends on better performance with longevity.

Power of Booster Pump

  • For residential use: 50, 75, 100 GPD Power
  • For commercial use: 200, 300, 400, 800 GPD Power

Note: Original 100 GPD Power is the best for domestic use and 200 GPD is suitable for official use.

Reservoir Tank

Reservoir Tank

There are three types of reservoir tanks available in the market of Bangladesh.

  1. Lid Consisted Tank: This tank is cheaper than any other tank. Though it is used with some RO water purifier, there is a possibility of contamination by air contact and encroaching insects within a short time. Besides this, this type of reservoir tank becomes dirt periodically due to continuous dust allocation.
  2. Air Tight Tank: This tank is free from air and insect contamination. But it is unable to create sufficient pressure on water flow; so, this doesn’t allow multiple faucet facility.
  3. Air Pressure Tank: This tank is free from re-pollution. It is capable to create enough pressure (unit: PSI) for proper water flow through the faucet. So, this tank allows double faucet installation with RO water purifier.

Example: Nearly 50 PSI required for RO water purifier.

Note: As the reservoir tank is used for preserve purified water after filtration, it should be food grade maintained and capable to protect the purified water from re-pollution. Alongside  ability to create proper pressure for water flow through multiple faucet is important for“drinking and kitchen water solution”. Only air pressure tank is consisted with these qualities. So, Food grade maintained air pressure tank is preferable for domestic and official use.

Mineral and Alkaline Cartridge

Mineral and Alkaline

Generally, RO filtered water is considered as free from micro-organisms and any substances. Purified water is bitter in taste. As the required amount of minerals for human health can be consumed from vegetables, fruits, species, fishes and meats as food ingredients; so, it is not essential from water. But In order to improve the taste of potable water, minerals may be added with purified water.

World Health Organization (WHO) recommended pH level of potable water is within 6.5 – 8.5. Besides this, alkaline water is positively ionized which is beneficial for human health development. For this reason, some health favorable alkaline may be used to increase pH level of potable water.

Note: To enrich water quality we need to add healthy mineral and alkaline cartridge should be added as a post RO stage.  Though mineral and alkaline is rarely found as combined tube in market, But combined tube is preferable.

UV Filter

UV Filter

It is a filtering device depends on electromagnetic radiation using the proper electrical power supply. It is capable to kill micro-organisms from transparent water but unable to remove substances. So this device may use as an extra stage for secondary disinfection. Electricity requirement varies on the measurement of consumption.

Water Faucet

Water Faucet

It is a device for delivering water from a plumbing system made of metal or plastic. Faucet may be compacted with purifiers or portable.

  • Compacted faucet may not convenient for all members of the family. Alongside, if the faucet is tangible for all, children may keep running the faucet unnecessarily several times may cause wastage of purified water.
  • A portable faucet may be installed anywhere in house. But if a faucet is placed at such a place where water can be dropped on the floor; that may cause wet and slippery floors as well as increase the risk of accidental injury for family members.
  • Metal faucet is strong and long-lasting, but there is a possibility of rust allocation on an iron faucet. So stainless steel (alloy) faucet is preferable due to its rust-free specialty. 
  • Single faucet may not be enough for family use. In some purifier extra faucet can be installed. Air pressure tank is a prior condition of using a double faucet.

Note:In order to avoid the risk of accidental injury faucet should be in basin. So portable multiplestainless steel (alloy)faucet is a significant speciality to choice better faucet for family and official use.

Maintenance And Customer Care of RO Water Purifier

Each stage of RO water purifier has different longevity depends on the water quality of source and amount of consumption. Different stages need to change periodically according to water quality. Changing of stages and service support professional installation and friendly customer care are significant issues. Defective installation resulting in ineffective filtration with poor outcomes.Improper Installation systems

Improper Installation Systems

Improper Installation

  • Parallel or bypass installation of any stages resulting in high TDS and substance contamination
  • Air contacted reservoir tank causing re-pollution.

We should avoid improper installation in order to get safe water.

Proper Installation system

Proper Installation system

  • Series Installation of stages
  • Strong wall setup (Ex: Large and rust-free screw)
  • Air pressure reservoir tank to protect the safe water from re-pollution
  • Significantly separate drainage line.

All companies don’t have a customer care service. It rated by using CRM software and service charge.

Key Points to Determine Best RO Water Purifier

  • The pore size of PP (Sediment); i.e. 0.45 micron in best.
  • The efficiency of RO membrane Filter (97%-98% reduction)
  • GPD of RO membrane and Booster Pump
  • Iodine Grade of activated carbon (coconut shell); i.e. GAC, CTO & T33
  • Portability of stainless steel (rust free) faucet with multiple faucet facility
  • Food grade maintenance of air pressure tank.
  • Availability of filter and accessories in the market.
  • Better and friendly customer care services

If we read this article, it may be helpful to make proper decisions to identify the best RO water purifier. Thus the effort of ULTIMA will be successful. Honesty (truthfulness) is the noble and public health safety is the humanitarian Goal of ULTIMA (Your best family friend).


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