RO Unit from NEWater

At NEWater our company designs and manufactures the different sizes of high-quality RO Units. Then show the people living in areas where natural water sources or not abundant are still able to live a healthy lifestyle and consume fresh and clean water.

NEWater’s RO Units are commonly used as filtration devices to remove any form of dissolved solids contaminants and impurities including large molecules and ions from the water being treated. This is done by applying pressure to the water with the use of pumps. The water once pressurized is able to pass through the semipermeable membrane and overcome its osmotic pressure. The water passes through and the impurities are retained which are either stored or removed from the device. Other voluntary water treatment techniques may also be employed after reverse osmosis these include UV filtration and carbon filtration to remove unwanted odors, tastes, and microbial pathogens.

Send an email regarding our RO Units and an answer will be delivered within 24 hours from our dedicated customer service!

The Ultimate FAQ Guide for

RO Unit.

In this guide, you will find all information you’re looking for about RO Unit.

Whether you want to learn about features, components, working principles, benefits, or quality verification – you will find all information right here.

Keep reading to learn more.

➣What Is RO Unit?

A reverse osmosis unit is a water treatment process that removes undesired contaminants.

These contaminants can be salts or total dissolved solids.

➣Which Components Make RO Unit?

There are five basic components of an RO system;

• Semi-permeable Membranes And Other Pressure Vessels.

The composition of membrane elements depends on the type of intake water and the clarity of the product water.

Besides, the design of each membrane depends on the specific contaminants to be removed.

The size of the task i.e. municipal, commercial or industrial dictates the size and quantity of membranes to be used in the RO unit.

• Reverse Osmosis Skid.

RO systems can be made durable by mounting all components on a powder-coated, carbon steel frame.

It is resistant to heavy vibrations caused by high-pressure pumps.

They also ensure that the lifespan of the unit is elongated.

• Cartridge Filter.

Cartridge filters in RO systems prevent large particles that would otherwise damage the membrane from coming anywhere close to it.

The most common is five microns spun polypropylene filters but can vary when you request.

The cartridge is enclosed in a casing that is durable and can withstand pressures from the main feed pump.

• Reverse Osmosis High-pressure Pump.

In a commercial and industrial setting, the rejection rate of the RO system is very low without the help of high-pressure pumps.

The pump must be matched with the number of membranes and their sizes.

Normally, the higher intake pumps power ratings, the higher the contaminants rejection and the product water recovery rates.

• Control Panel.

The control panel allows human control over the RO system processes.

Advanced PLCs or solid-state microprocessors may be used depending on how robust the controls have to be.

These controls can be used to control several systems simultaneously, making RO units a one-man water production plant.

Other components can also be built onto the RO unit.

A containerized system can be used to house the RO skid.

Other supplementary skids can be attached to reverse osmosis units for various tasks;

• Cleaning of membranes,
• Pretreatment of raw water,
• Chemical dosing into the system,
• Post-treatment etc.

➣How Does RO Unit Work?

Raw water has pollutants such as bacteria, viruses, microorganisms, and dissolved solids.

Reverse osmosis works by removing these unwanted pollutants from water and forcing the treated water through a semipermeable membrane.

The process flushes out pollutants to produce more pure water.

RO unit uses high-pressure pumps to pressurize the concentrated side of the RO system and push water through the membrane.

The pressure depends on the number of contaminants in the feed water.

Then, the rejected water and permeate or product water flows in a different direction.

This helps in maintaining the membrane clean and reduces the buildup of contaminants.

This filtration process increases the life span of the system and reduces the need of cleaning the membrane.

➣What Are The Key Features Of the RO Unit?

Some of the key features are:

• Mineral Losses.

The RO process eliminates essential minerals needed in the body.

The RO unit chosen should minimize these losses.

• Process Of Purification.

Most RO units use a couple of filtration systems.

Some integrate the features of RO, UV, UF, TDS management, and turbidity in a single unit system.

The increase in the number of stages of water filtration increases the permeates purity.

Some RO systems have automatic flush timers to allow non-stop purification.

It also increases the shelf life of the membrane filter.

• Increased Rates Of Water Recovery.

This examines the amount of water wasted due to RO purification.

Efficient RO units have higher recovery with low wastage.

• Capacity Of Storage And Purification.

The rate of water purification through the RO unit determines the capacity of the storage used.

• Requirements For Size And Special Plumbing.

The size of the RO system should be able to fit in its designated area.

You should also check if the RO system requires special plumbing.

This is to match the inlet and outlet water pressure requirements.

• Maintenance Cost.

Other than the initial cost of purchase and installation, you should also look at the cost of maintaining the RO unit.

You should also keep in mind the warranty period and any after-sale service by the brand vendors.

➣How Much Does RO Unit Cost?

Most commercial RO units’ costs range from $1000 to $10,000.

For domestic RO units, the price ranges from $200 to $10,000 depending on the type of system used.

The cost of RO units varies due to various reasons;

• System Type.

The type of RO system dictates the size.

The bigger the size the most expensive it will be.

Countertop RO systems range between $300 and $500.

Under Sink (tankless) units cost $300 to $600.

The Under Sink (with tank) will cost $200 to $600.

The whole Home RO system will cost between $1,500 and $10,000

• System Efficiency.

 This is the measure of how quickly the RO unit produces filtered water against the quantity of water lost in the process.

The pure water to reject water ratio will also affect the cost of the RO unit.

Besides, the 1:4 ratio systems waste more water and are thus cheap to buy but costly in the long run.

Modern RO systems have improved ratios of up to 1:2 or 1:1.

These systems cost around $100 to $200 more than the traditional units.

They are cost-effective in the long run.

• Filtration Stages.

RO units will cost more if the number of filtration stages is above average.

Most systems have four filtration stages; pre-sediment filter, carbon filter, semi-permeable membrane, and the post-filter.

These systems remove more than 99% of TDS from water.

Under-sink and whole house RO units have more stages of up to 10 or 12 stages.

Every extra stage implies an extra filter and thus the total cost of the RO is also increased.

• Brand.

Leading sellers of RO units over the decades have proven to be reliable.

These brands will set their products at premiums prices since they have a strong customer fanbase.

On the other hand, emerging manufacturers might sell legitimate products but at lower prices since they need to prove themselves.

You should ensure that these manufacturers have the right certification and the system has a good warranty.

• Certifications.

Certified RO systems cost more because the customer understands that they are reliable.

For RO units, NSF/ANSI 58 certification is the most sort after certification.

It is the national standard for all RO systems.

It shows that the RO system has been tested and deemed effective in terms of efficiency, structural integrity, contaminant removal, and the material used.

• Additional Features.

These features include a pump to boost water pressure

They increase water production capacity, efficiency, and flow rate.

They also minimize the quantity of wastewater to be drained.

Other add-ons include;

• Remineralization stage for balancing water pH and increasing its alkalinity.
• Modular design for ease of replacing membranes or filters.

They also prevent the accumulation of germs in the Ron system.

➣Is Water From RO Unit Safe To Drink?

Yes, water for the RO unit is safe for drinking.

The RO system removes almost all the harmful dissolved contaminants for water.

Despite removing all the minerals, it uses remineralization add-ons to compensate for the removed mineral.

This makes the water purer and safer than it was before.

Back to the guide ⇪

➣Which Types Of Reverse Osmosis Filter Are There?

Sediment filters: they reduce particles like specks of dust, dust, and rust

Carbon filters: they remove volatile organic compounds, chlorine among other contaminants that may bring bad water taste or odor.

 They reduce the concentration of the organic in the RO feed water.

Also, they remove oxidants from raw water.

They cannot remove suspended solids or bacteria.

The influent water requirement for carbon filters is; 5 NTU turbidity, less than 10 ppm free chlorine, and less than 5 ppm TOC.

You must backwash the filters regularly to remove suspended solids that accumulate on the filter surface.

Semi-permeable membrane: they remove 99% of the total dissolved solids (TDS).

Multimedia pressure filters: they reduce turbidity and colloids in the raw water.

They remove particles that are as small as 10 microns in size.

The addition of coagulant in the filter influents stream improves the size of particles removed to about 1 or 2 microns.

Besides, they have an efficiency of removing particles of about 50% for particle sizes of 10 to 15 microns.

The turbidity of influent in the pretreatment system of the RO unit is limited to 10 NTU.

Higher turbidity results in the backwash of filters.

High-efficiency filters: they are designed to remove turbidity and SDI in water.

Initially, they were used in cooling towers to reduce the suspended solids concentration.

There are two types of High-efficiency filters designs;

• Top-over-bottom Design.

They rely on the tangential flow across the media surface to affect the filtration process.

The raw water enters the media in a tangent.

It creates turbulence over the bed.

The tangential force takes off suspended solids on the media surface.

Also, they operate in low flow rates with higher backwash rates.

The backwash time is about 5 minutes.

• Vortex Design.

They use centrifugal forces to rotate raw water over the surface of the media in a cross-flow way.

Larger particles are collected on the sidewalls of the filter tank.

They operate at high flow rates.

Backwash flow is usually lowered and requires about 4 – 8 minutes of backwash time.

Back to the guide ⇪

➣Is RO Unit Water Acidic Or Alkaline?

The RO water is supposed to be dead (i.e., neutral) water.

That is to say without minerals.

This is both a good and bad thing.

The water generated is neither harmful nor beneficial.

Dead water, however, is acidic since its pH is less than seven when it is without alkaline elements like calcium and magnesium.

Reverse osmosis filtration systems, however, not only remove contaminants but also ad minerals.

This leaves the water cleaner and healthier than before purification.

The modern-day RO water is, therefore, alkaline due to the remineralization add-ons that are featured in the system.

Back to the guide ⇪

➣How Does RO Unit Compare To UV Water Purifier?

RO units produce more reject water compared to UV purifiers that do not produce any.

Also, RO units remove total dissolved solids while UV purifies do not.

In RO systems, bacteria and viruses are blocked out and flushed out alongside microorganisms.

UV systems, on the other hand, kill bacteria and viruses while retaining their bodies in the permeate.

RO systems take a longer period to purify water while UV systems take less time.

Besides, RO systems improve the taste of water while UV systems do not alter the taste of water.

RO units are more costly compared to UV systems.

Both RO and UV units require electricity to run.

Both units require prefiltration such as sediment filters.

➣How Do You Calculate RO Unit Recovery Rate?

Recovery is the quantity of water being ‘recovered’ as good product water.

Higher recovery indicates less water quantity of concentrate drained while saving more of the product water.

When the recovery is too high for the unit design, it might result in bigger problems caused by scaling and fouling.

The recovery of an RO system depends on the feed water chemistry and the pretreatment of the RO system.

Recovery is calculated as shown and expressed as a percentage.

Back to the guide ⇪

➣How Often Should You Replace RO Units?

Replacement of RO units varies depending on how well you maintain the unit.

Filters must be maintained regularly say, 6 to 9 months depending on the quality of feed water.

You should change the membrane at least every 2 or 3 years.

If you maintain the RO system according to the designed guidelines, the system will last up to 10 to 15 years.

Back to the guide ⇪

➣Do Pressure And Temperature Affect Working Of RO Unit?

Yes, temperature and pressure affect the performance of RO units.

Temperature influences the system flux rate and the rejection rate.

The flux rate is proportional to the water temperature.

Higher temperatures lower the viscosity of water allowing ready flow across the membrane.

The rejection on the other hand decreases with the temperature rise.

This is so because the salts dissolve at higher temperatures.

Temperature changes can be corrected by the operation pressures used.

Higher pressures for cold water and lower pressures for warmer water.

Operating pressure affects the flux and rejection rates directly.

It affects the driving force of water across the membrane.

Higher pressures result in higher water fluxes.

The rejection rate increases while salts’ passage is lowered due to an increase in pressure.

Back to the guide ⇪

➣What Are The Standard Specifications Of the RO Unit?

Some technical requirements of the RO unit are;

1. Proper feedwater pH and pre-filtration.

The quantity of TDS and suspended solids in the water should be controlled within the designed limits.

1. Monitoring the levels of microbiological quality.

The system should be disinfected when the levels of microbiological quality exceed the set parameters.

• Cleaning of the RO unit and disinfection.

The system components should be cleaned mechanically before disinfecting.

You should also test and ensure that the chemicals used in disinfecting the system are removed.

1. You should avoid using ion exchangers and filters downstream of the RO system.
2. Use certified RO systems and test them regularly.

You should also operate within the manufacturer’s guidelines to produce quality water.

Back to the guide ⇪

➣What Are The Benefits Of the RO Unit?

• Reduces the harmful dissolved contaminants from the water.
• It reduces the quantity of sodium in the water.
• Removes the bad taste and odor that may arise due to fouling.
• It is easy to install and maintain RO units.
• It’s very friendly to the environment compared to bottled water.
• RO units have portable designs.
• RO units require limited space for installation.
• RO systems are cheaper compared to bottled water.

Back to the guide ⇪

➣Are There Limitations Of RO Unit?

They are expensive in terms of initial purchasing cost and installation.

RO systems for homes remove most of the water minerals leaving the RO water with an acidic pH.

The purification process of RO units is long.

Back to the guide ⇪

➣What Material Is RO Unit Made Of?

RO membranes are made of synthetic polymers.

RO membranes are made using;

1. Cellulose acetate
2. Polysulfone coated with aromatic polyamides.

Back to the guide ⇪

➣Do RO Units Have Warranty?

Yes, RO units have a warranty.

The warrant varies from one vendor to another ranging between 1 and 2 years of service.

The warranty however does not cover filters and membranes.

The validity of the warrant is dependent on;

1. Regular maintenance and replacement of filters and membrane according to the manufacturing manual.
2. The unit is operated in compliance with the design manual and installation.

The warrant loses its validity due to;

1. Improper storage, installation, maintenance, and operation
2. Inappropriate use of the unit.

• Damages are caused by environmental reasons.

Back to the guide ⇪

➣How Do You Verify Quality Of RO Unit?

The quality of the RO units depends on the feed water TDS, percentage of rejection, and percentage of recovery.

The higher the percentage of recovery with a lower percentage of rejection the lower the quality of the RO water.

Back to the guide ⇪

➣Which Contaminants Do RO Units Remove In Water?

Some of these contaminants include:

• Suspended solids
• Microbes
• Organics substances
• Colour
• Metals such as iron, manganese, or aluminum
• Hydrogen Sulfide
• Silica
• Calcium carbonate
• Traces of metals such as barium and strontium
• Flouride
• Salts
• Sediments
• Chlorine
• Arsenic
• Volatile Organic Compounds (VOCs)
• Herbicides and pesticides

Back to the guide ⇪

➣Are RO Units Portable?

RO units are portable.

Under-sink RO system can be installed from one point of use to another.

Back to the guide ⇪

➣Do RO Units Remove Essential Minerals From Water?

Yes, RO systems remove almost all important minerals from water.

These minerals are useful to the human body,

Advanced RO systems, however, have provisions for remineralization add-ons to counter the lost mineral.

This makes these systems robust and beneficial for human consumption.

Back to the guide ⇪

➣How Much Power Does RO Unit Use?

Most RO units run using water pressure.

The electricity is only needed when you use add-ons such as a booster pump and UV lamp.

Standard units do not have either.

RO units with add-ons use electricity in water production.

Most RO systems consume 3 to 10 KWh to produce 1 cubic meter of freshwater.

Back to the guide ⇪

➣Is Water Pretreatment Essential When Using Reverse Osmosis Unit?

Preconditioning of RO feedwater is critical to its operation.

This helps to protect the membranes from fouling and prolong the meantime to failure (MTTF) of the RO unit.

The RO membranes behave like cross water filters.

It is made of a porous material to allow the movement of water across the membrane.

Also, it prevents the passing of 99% of dissolved solids across the membrane.

Most of the dissolved solids are in the unit reject water and are discharged to waste.

These solids continue to accumulate along the surface of the membrane.

Continued accumulation results in membrane blockage which causes losses in the flux rate.

Preventive treatment is done to remove impurities in the water.

The requirements for pretreatment vary from one unit to another.

Besides, the objectives of pretreatment in RO systems are constant across the board.

These are;

1. Maintain the designed flux rate.
2. Minimize the frequency of cleaning the membrane.

• To prolong the useful life of the RO unit.

Back to the guide ⇪

➣Which Type Of Cartridge Filter Does Reverse Osmosis System Use?

There are three common types of cartridge filters used in RO systems.

• Spun-bonded Or Melt-blown.

They are manufactured through thermal means.

It is either through bonding or heat blowing of pure polypropylene microfibers.

This is done so that the outside surface density is lower and increases gradually as you near the center of the filter.

They have high capacity since they can trap contaminants on the whole cross-section of the filter.

• String-wound.

In these filters, a string of polypropylene is wound around the center core of the filter.

They utilize Van der Walls forces to trap small contaminants.

They face difficulties in unloading the particles when the pressure drops are higher.

When using these filters, it is recommended that you use slower flow rates of about 2 to 3 GPM per TIE.

• Pleated.

They are normally used in applications that require higher purity such as pharmaceutical and microelectronics.

Besides, they can have a single-layer construction or be multi-layered.

They are made from polypropylene, polyethersulfone, and borosilicate fiber.

Back to the guide ⇪

➣Does RO Unit Require Chemical Cleaning?

Yes, the RO unit requires chemical cleaning.

Well-designed RO systems have provisions for cleaning skids that help in the cleaning process.

The skid has a chemical tank, solution heater, recirculation pump, drains, hoses among other fittings.

Chemical cleaning agents help in maintaining the RO membrane.

The type and quantity of foulant determine the best cleaning agent.

Acid cleaners are useful in removing deposits of mineral scale.

Hydrogen peroxide is mostly used to correct or prevent biofouling-related problems.

Due to the variety of cleaning agents available, it is recommended that contact the RO unit manufacturer or vendor for effective cleaning.

During operation, you should monitor the RO unit to predict when cleaning of the membrane is needed.

Cleaning is required when the flux rate reduces by 10%.

If you clean the RO unit every month or more, there is a likelihood of;

1. The quality of raw water is changing
2. The pretreatment system has a problem, or

• There are operation-related problems.

Further Reading:

• Reverse Osmosis System
• Reverse Osmosis Drinking Water System
• RO Membrane Filters
• RO Purifier Machine

For all your RO units, contact us now.

Back to the guide ⇪