Frequently Asked Questions:
1. How does reverse osmosis (RO) work?
Reverse osmosis known as RO, is a cutting-edge water filtration technique. It is a membrane filtration technique that operates by applying pressure to water and pushing it past the minuscule holes of a membrane that is semi-permeable. When water passes through the finest semi-permeable membrane of our reverse osmosis plant, it is deionized and demineralized. Several pollutants and toxins are held within the water that passes through the membrane, which aids various businesses in processing safer and healthier water.
2. Does your RO plant require regular maintenance?
No, our Reverse Osmosis plant is expertly designed to operate for a very long time. Our semi-permeable membrane allows you to get the required outcomes without stressing about plant upkeep because to its low membrane degradation, high permeate recoveries, and resilience. The plant's architecture has been simplified to need less care from you while still giving you water of top quality.
3. Why are our RO Plants Unique?
We've already established a market position for our RO plants. This accomplishment can be due to their extraordinary efficacy in purifying muddy or saltwater water. Our solution is supported by three key pillars: advancement, expertise, and excellence. Our RO plants employ membrane technique to treat water for both consumption and industrial uses.
4. What distinguishes reverse osmosis from a water filter?
Reverse osmosis varies from standard filters, primarily in terms of filtering efficiency. Unlike RO, which features membrane filtration technique that eliminates dissolved impurities in addition to stubborn dirt, ordinary filters just simply remove insoluble grime and particulates.
5. What benefits does the industrial RO system offer?
Reverse osmosis is a dependable technology, which is why industrial RO water plants are immensely popular. Ionic salts, living and dormant viruses, microbes, organic compounds with a high molecular weight, and suspended particles are all removed. The system is entirely automated, and the water that is drawn from the plant is fit for human consumption.
6. Why reverse osmosis is used in a desalination plant?
Seawater is turned into drinkable water at a desalination plant. The technique, called reverse osmosis, is most frequently used, which includes exerting external pressure to drive seawater across membranes from a highly concentrated region to a low concentration area. Microscopic pores in the seawater membranes permit water particles to flow through while mostly excluding salt and many other pollutants, resulting in the discharge of pure water from the other end. Sea water desalination membrane has higher capacity of membrane with bit more smaller pore size than brackish water membrane and require more pressure than brackish water membrane.
7. What Benefits do Desalination Plants offer?
It can provide an endless, climatically independent, and consistent source of quality water, extending water resources far more than is possible from the water cycle. Where there is no native source of freshwater, it can offer drinking water. As it typically surpasses criteria for quality of water, seawater desalination plants can help alleviate strain on freshwater resources that originate from places that need protection. In middle eastern countries, small island countries, where water sources have gone well below desired level where bore well water is not available, desalination plants are blessings for potable water requirements.
8. What is the principle of REVERSE OSMOSIS (RO)?
Reverse osmosis (RO) is a water filtration technique that makes use of the fundamental osmosis principle, i.e. tendency of water molecules to pass through a membrane from a region of low salt concentration to a region of high salt concentration. Conversely, in a RO system, an external pressure (pressure greater than osmotic pressure) is applied to reverse the flow of water molecules through semipermeable membrane which blocks/retains the unwanted molecules and larger particles, yielding water with high purity.
9. What is the main part, heart of reverse osmosis system RO PLANTS?
The RO module is the heart of the Reverse Osmosis system. The module comprises of the membrane/s employed for the purification process. The pore size of the employed membrane is responsible for purification/desalination/blocking of the unwanted particles.
10. How/what reverse osmosis membrane made out of?
RO membranes are made out of a flat membrane sheet which consists of three layers; a polysulfone layer, a barrier layer made of polyamide, and a polyester support base layer. The polysulfone layer serves as a reinforcement for the barrier layer, which removes salts, pollutants, germs, and viruses from water.
11. Type of reverse osmosis membrane/filters
The type of RO membrane is based on the different needs of the water filtration/purification application. The membranes are classified based on their pore size as; Micro-Filtration (MF), Ultra-Filtration (UF), Nano-Filtration (NF), and Reverse Osmosis (RO) membranes. A graphical illustration of what can flow through various membrane types is shown in the picture below.
RO membranes come in a variety of specifications to suit a range of requirements, including treatment of tap water (TW), Brackish Water (BW) and Sea Water (SW). For instance, a RO membrane that uses high pressure and requires a lot of energy to operate is not necessary to clean river water. The UF membrane would be the ideal membrane for such an application because it needs very little energy and will filter out even the smallest viruses and dirt particles in water that has a low salt content. River water that passes through a UF membrane is pure and suitable for drinking.
12. Is there membrane available for effluent treatment?
Yes, depending on the nature of effluent water and the quality of water required post filtration a schematic/system (single pass/double pass RO system) can be devised with combination of different types of membranes to achieve the required purity level.
13. What are the pre-treatment required for reverse osmosis membrane?
For a RO system to function properly and to avoid fouling, scaling, premature RO membrane failure, and frequent cleaning needs, proper pre-treatment employing both mechanical and chemical treatments is essential. Commonly employed RO pre-treatment process/solutions are listed below:
- Multi Media Filtration (MMF)
- Micro-Filtration (MF)
- Anti-Scaling/Scale Inhabitation
- Softening of Water by Ion Exchange
- Organics Removal by Activated Carbon
14. What are post treatment required for reverse osmosis membrane?
The RO product water is soft and slightly acidic (pH 5-6) with minimal alkalinity. Low-alkalinity water is hostile to metal and asbestos-cement pipes and absorbs calcium from pipes coated with mortar. Since they lack nutrients and have no flavour, they are not suited for distribution or drinking. Remineralization of the RO product water is therefore necessary to achieve the following goals:
- a minimum alkalinity of 80 mg/l as CaCO3
- a calcium carbonate precipitation potential (CCPP) of 3-10
- a positive Langelier Index (LSI) (0–0.5).
Appropriate treatment methods include:
- Carbon dioxide dosing followed by filtration via limestone and lime caustic dosage to elevate the pH over the saturation point
- Hydrated lime or calcite and carbon dioxide dosing; dosage of calcium chloride with sodium bicarbonate
15. Can reverse osmosis membrane remove arsenic?
Yes, Reverse Osmosis membranes are capable of removing arsenic. Nevertheless, pre-treatment can sometimes be necessary depending on the qualities of the raw water.
16. Can reverse osmosis remove heavy metal from water?
Yes, heavy metals including Arsenic (As), Chromium (Cr), Iron (Fe), Lead (Pb), and Mercury (Hg) can all be eliminated by reverse osmosis. Reverse osmosis (RO) filtration membranes have pores that are 0.1 nm in size, which is much smaller than the size of heavy metals. Heavy metals can be conveniently filtered out by RO systems due to their remarkably small pore size.
17.What are the limiting conditions for reverse osmosis systems RO systems?
Some of the limitations of RO system are mentioned as follows;
- Chlorine free water is required as RO feed for preventing membrane from spoiling.
- RO membranes are unable to filter out chlorine or other chemical pollutants. In a similar vein, they are unable to stop microbes or particles that are smaller than the membrane's hole sizes.
- Feed water quality should be maintained as per design specifications of the RO membrane. There is no one fit for all solution.
18.What are the different fouling can happen to reverse osmosis membrane?
Depending on the nature of fouling/foulants present in the feed stream, type of fouling is divided into four categories:
a) Inorganic fouling/scaling is the build-up of inorganic precipitates, such as metal hydroxides, on membrane surface or within pore structure.
b) Particle/colloids fouling happens when suspended solids and/or colloidal material stick to a membrane's surface or clogs the membrane's pores.
c) Microbial fouling sometimes also referred as biofouling is the growth of microbes, plants, algae, or other biological pollutants on or inside the pores and surfaces of filter membranes.
d) Organic fouling is defined as the collection of carbon-based material on a filtration membrane.
19.Precautionary measures to avoid reverse osmosis membrane fouling
A regular cleaning and maintenance regime can aid in preventing the accumulation of foulants on the membrane, such as;
- Careful selection of membrane material
- Choice of configuration
- Pre-treatment of raw feed water
- Process Optimization
- Control of Inorganic Salt Solubility
- Regular rinsing of RO membrane
- Use of a disinfectant
- Feed water temperature regulation
- Preventive maintenance
20.How much high pressure requires for reverse osmosis membranes?
A RO system requires a minimum of 30 psi to operate properly, but preferably 60 psi. In general, for fresh and brackish water, the pressure requirement is typically 2-17 bar (30-250 psi), whereas for seawater it is 40-70 bar (600-1000 psi).
21.In which industry reverse osmosis membrane can be used?
Reverse Osmosis is very efficient in treating nearly all types of water (brackish, surface and ground) for both large and small flows applications. A few examples of businesses that employs RO water are; Textile, Mining, Pharmaceutical, boiler feed water, food and beverage, metal finishing, and semiconductor production.
22.Is desalination different than reverse osmosis system?
Desalination is a separation technique used to reduce the dissolved salt content of very high saline water like sea water to a usable level. Whereas, RO is one of the separation techniques that can be employed for water desalination. Other notable desalination techniques are; Thermal multi stage flash distillation, Mechanical vapor compression, Electro dialysis, and Ion exchange.
23.Where are desalination plants being used?
Saudi Arabia, United States, Qatar, Bahrain, Kuwait, and the United Arab Emirates are nations chiefly relying on massive desalination of seawater for both domestic and industrial use. Furthermore, micro desalination facilities are also found in textile, leather, food industries, etc.
24. Working principle/ function of desalination plants SEA WATER DESALINATION PLANTS
A desalination plant works by reducing salt concentrations from brackish/seawater intended for human use or recovering salts from water supplies intended for industrial purposes. Desalination plants typically employ one or more of the following techniques for water treatment:
- Reverse Osmosis
- Mechanical Vapor Compression
- Thermal Multistage Flash Distillation
25.Comparison between desalination SEA WATER DESALINATION PLANTS and thermal distillation OF SEA WATER
Desalination is a separation technique used to reduce the dissolved salt content of saline water to a usable level. Whereas, thermal distillation is a process that involves changing saline water into vapor by means of thermal energy (heat). These vapours which are free from minerals, salt and other impurities are then collected and condensed, yielding high purity (> 99%) distilled water.
26.What is the pore size of reverse osmosis membrane?
Reverse osmosis membranes have a pore size ranging from 0.0001 micron (0.1 nm) to 0.001 micron (1 nm).
27.What is the pore size of desalination membranes?
Desalination membranes have a pore size ranging from 1.0 micron (1000 nm) to 2.0 micron (2000 nm).
28.What is the difference between Ion exchange resin and reverse osmosis membrane RO membrane?
Ion exchange is a physio-chemical process that selectively removes salts and contaminants by efficiently exchanging ions of similar electrical charges, whereas reverse osmosis is a physical method in which water is passed through a semi-permeable membrane against a concentration gradient by applying pressure.
29.Is Reverse Osmosis good for environment?
The leftover brine water of RO has just a slightly higher concentration of dissolved inorganics and is free from any sort of chemical/s. Thus, it makes it intrinsically safe for discharge and safe disposal. The carbon footprint of RO plant has just an impact of 2.1 - 3.6 kg CO2/m3 of treated water.
30.Difference between 1 and 2 stage REVERSE OSMOSIS, RO System?
In a single stage RO system, the feed water enters the RO system as one stream and exits the RO as either as permeate water or concentrate (or reject).
In a two-stage system the concentrate from the first RO system becomes the feed water to the second RO system. The permeate water collected from the first stage is combined with permeate water from the second stage. These additional stages aids in enhancing the recovery from the system.
31.What are some applications of REVERSE OSMOSIS, RO plant?
Typical applications of RO plant include:
- Purification of home drinking water
- Desalination of brackish/seawater water to produce drinking water.
- Recovery from wastewater
- Food and beverage processing
- Biomedical separation
- Industrial effluent/process water treatment
- Boiler feed water
32.What are basic components of REVERSE OSMOSIS RO system?
- Line Isolation Valves
- Pre-Filters
- Reverse Osmosis Membrane
- Post-Filters
- Auto Shutoff Valves
- Non-Return Valves
- Flow-Restrictor
- Storage Tank
- Faucet
- Drain Line
