RO plants

Reverse Osmosis Plants/RO Plants

Reverse osmosis is the process of forcing a solvent from a region of high solute concentration through a membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration when no external pressure is applied. The membrane here is semipermeable, meaning it allows the passage of solvent but not of solute.

To illustrate, imagine a semi permeable membrane with fresh water on one side and a concentrated aqueous solution on the other side. If normal osmosis takes place, the fresh water will cross the membrane to dilute the concentrated solution. In reverse osmosis, pressure is exerted on the side with the concentrated solution to force the water molecules across the membrane to the fresh water side.

The membranes used for reverse osmosis systems have a dense polymer barrier layer in which separation takes place. Since Reverse Osmosis does not occur naturally, it must be created by applying pressure to the high solids water in order to force it through the membrane, with pressures from 8 - 14 bar for fresh and brackish water, and 40 - 70 bar for seawater, which has around 24 bar (350 psi) natural osmotic pressure which must be overcome.

Design Considerations for RO Plant

Covalence EnviroTech RO Plants work on the Crossflow Filtration method, which takes the feed water and uses a percentage of it as a wash or reject stream, removing the solids during the filtration process.

The product flow of an RO Plant is mainly a function of temperature and pressure. System recovery (product divided by feed) is limited by the characteristics of the feed water and can be controlled through the use of recycle stream. Product quality is based on a percentage of dissolved solids fed to the membrane. There should be an economic balance between product quality and system recovery. High recoveries increase concentration of dissolved solids in the system which degrades quality, but high recoveries make the system work more efficiently and decrease waste.

Reverse Osmosis Plants do not deliver to service all of the water that is fed to them. During operation, some of the incoming water is used to wash down the membrane, and only part becomes finished product water. Purified water is referred to as product and wastewater is referred to as concentrate, or reject. The percent of water delivered as product is called the recovery, and depends upon the membrane and on total RO Plant design considerations.

Pretreatment – Reverse Osmosis Plants

The feed water, depending on its source, may contain various concentrations of suspended solids and dissolved matter. Suspended solids may consist of inorganic particles, colloidal particles and biological impurities such as microorganisms and algae. Dissolved matter may consist of highly soluble salts, such as chlorides, and sparingly soluble salts, such as carbonates, sulfates, and silica.

During the Reverse Osmosis process, the volume of feed water decreases, and the concentration of suspended particles and dissolved ions increases. Suspended particles may settle on the membrane surface, thus blocking feed channels and increasing pressure drop across the system. Sparingly soluble salts may precipitate from the concentrate stream, create scale on the membrane surface, and result in lower water permeability through the RO membranes. This process of formation of a deposited layer on a membrane surface is called membrane fouling and results in performance decline of the RO system. The objective of the feed water pretreatment process is to improve the quality of the feed water to the level which would result in reliable operation of the RO membranes. Based on the raw water quality, the pretreatment process for RO Plants may consist of all or some of the following treatment steps:
  • Clarification followed by Sand Filtration for Turbidity removal
  • Water disinfection with chlorine
  • Hardness reduction by Softening
  • Addition of scale inhibitor
  • Reduction of free chlorine using sodium bisulfite/ Activated carbon filters
  • Final removal of suspended particles using cartridge filters
We Offer a wide range of Reverse Osmosis Plants [RO Plants]

Industrial Reverse Osmosis Plants/ Industrial RO Systems

We manufacture a wide Range of industrial Reverse Osmosis Plants to cater the stringent process requirements. Our industrial reverse osmosis Plants are carefully customized and configured to suit the individual requirement of the output water, which varies from normal drinking application to the specific usage, such as food Processing, pharmaceuticals and boiler feeding requirement.

These systems come standard with pre-filters, chemical dosing and Antiscalant dosing. Customization is available on all our units based on individual water application and customer needs.
  • 4" & 8" TFC spiral wound membranes
  • FRP membrane housings
  • Epoxy painted steel frame
  • SS High Pressure Piping
  • Stainless steel High Pressure Multi-stage pumps
  • 20 & 5 micron cartridge filter
  • Low & High pressure switches
  • Glycerin filled pressure gauges
  • Permeate & concentrate flow meters
  • PLC/Microprocessor based Controllers
  • Outlet Conductivity meter
These Industrial RO Systems are available in the Flow Ranges from 1 M3/Hr Product Water Capacity and above. Standard Ranges are available in Multiples of 1 M3/Hr up to 10 M3/Hr.

Higher flow Rates from 10 M3/Hr to 100 M3/Hr and above are custom-built as per Customers requirement with extensive pre-filtration units to suit the most aggressive waters.

Commercial RO Systems / Institutional RO Systems

One of our most popular series, the Commercial RO usually comes in standard Models. These Commercial RO Systems can be customized to add Multimedia Filters & Activated carbon Filters, Water softeners, Antiscalant Dosing Systems, and UV sterilizers.

These systems are used to purify water and remove salts and other impurities. It is also capable of rejecting bacteria The Main features of these RO Plants are
  • Powder coated frame
  • 20 & 5 micron sediment pre-filter
  • Stainless Steel Multistage High pressure pump
  • FRP pressure vessel
  • Product and Reject Flow Meters
  • Low & High pressure switch
  • High rejection TFC membranes
  • Heavy duty high pressure tubing
These Commercial/Institutional RO Systems are available in following Flow Ranges:
  • 50 LPH RO Plants
  • 100 LPH RO Plants
  • 200 LPH RO Plants
  • 500 LPH RO Plants
  • 750 LPH RO Plants

Containerized RO Plants

Containerized Reverse Osmosis Plants / Containerized Desalination Plants/Containerized Ultra filtration Plants Covalence EnviroTech supplies a host of water treatment in a containerized version. From ultra filtration to brackish water plants to Desalination Plants. Covalence EnviroTech provides an affordable, plug-and-play desalination solution that can be commissioned in a short period. Our ready-to-use containerized desalination plants can produce up to 1000 m3/day of drinking water.

The Plant is housed in a standard 20 or 40 ft container. The containers can be insulated on request. The Plant comes with pre-piped and pre cabled connections [plug and play]. Remote Monitoring Option also available with GSM connectivity Benefits of Covalence EnviroTech Containerized Plants
  • Plug and Play Unit
  • Minimum civil construction required
  • Small footprint
  • High quality components
  • High recovery
  • High TDS Rejection
  • Easy Spare parts availability as standard Components are used
  • Modular in design
  • Low energy and chemical consumption
  • Quick Installation
  • Off shore Applications
  • Armed Services Camps
  • Construction Sites
  • Mining Operations
  • Resorts

Mineral Water Plants/Packaged Drinking Water Plants

As people become more health conscious, the demand for bottled water is increasing at a rapid rate. Bottled water provides easy transportability and assured water quality.

With our several years of experience in the Water Treatment Field, we have developed comprehensive, economically viable packages, such that the capital outlay is optimized. Our packages are offered in modules so that they can be upgraded at a later date as the demand increases. Typically a Packaged Drinking water Plant may consist of:
  • Water Treatment Plant
  • Packaging Plant
The Water Treatment Plant consists of One or All oft the below mentioned pocess:

Chlorine/Hypochlorite Dosing System
Chlorine/Hypo chlorite dosing system is done in the raw water for disinfection / oxidation of iron and manganese (if present) in the water before filtration. sodium hypo chlorite reacts with water to form hypo chlorite acids which acts as disinfecting agent.

PRESSURE SAND FILTER Raw Water is first filtered by filtration unit in series prior to feeding the RO Plant. Pressure Sand Filter unit is provided for removal of Suspended Matters & Turbidity from raw water.

Basic Natural water may contain Colour, Odour, Chlorine & Organics in different proportion, which is undesirable for potable application, and hence, it is necessary to remove the same from water. The Activated Carbon Filter removes Chlorine, Odour, & Colour, Pesticides, Organics and In organics Impurities while passing the water through Carbon Bed.

The Chlorinated water may oxidize the membrane and to avoid the same precautionary we provide Sodium Meta BiSulphite dosing system

The hardness salts of Calcium & Magnesium are likely to be precipitated if concentration exceeds its solubility limit & it may faults the membranes resulting into scaling which ultimately leads to poor treated water quality from RO System. To prevent this Antiscalant dosing (scale inhibitor) dosing system is provided.

Micron Cartridge Filter having Series of filtration with the 20 Micron, 10 Micron, 5 Micron, 1 Micron, 0.45 Micron & 0.2 Micron Cartridge. This is a Consumable Cartridge and should replace it after Days of operation. This for Extra Safety of Product water as it comes through series of filtration and there are some chances of slippages of particles, which can be arrested through the Cartridges

For Reverse Osmosis Process to take place feed pressure of water need to be raised. For this purpose a Vertical Multistage Centrifugal High Pressure Pump in S.S construction is provided R.O. System requires operating pressure of about 14-16 kg/cm^2 . High-pressure pump is fitted with S.S. discharge pipe work with necessary control valves. Necessary instruments like a High Pressure Switch, Pressure Gauge and re-circulation valves are provided for safer operation of system.

Reverse Osmosis System rejects 97 – 99 % of total dissolved solids by the principle of `Osmosis’. This system consists of a R.O. Module assembly mounted on Structural Skid. High pressure rating FRP Pressure Vessel (Pressure Tubes) are fitted on the skid which houses spirally wound membrane elements in series.

In RO System feed soften water is divided into two streams viz Product & Reject water. Product water is treated water having lesser TDS. Reject water is highly concentrated water, which is not to be used for any purpose but drained. Followed Filtered water at elevated pressure is first feed to Pressure Vessel; treated water is collected in center core tube. Treated water from each membrane is collected jointly in a common product water storage tank and reject is drained.

For safe operation of system following instruments are provided on the Panel.

  • Feed & Reject Pressure Gauge: to indicate respective pressure of R.O.System.
  • Feed & Reject Flow Indicator: to indicate respective flow of R.O.System.
  • T.D.S Meter: to measure TDS of Raw & Treated water. 
  • High Pressure Switch: for tripping HPP in case of excessive feed  pressure
  • Time Totaliser: for counting working hours of H.P Pump/ R.O.System.
Treated water from R.O. System are collected in S.S. constructed storage tank of appropriate capacity. The tank is fitted with S.S. pipe work & isolation valves and suitable type of level indicator.

ABSOLUTE MICRON CARTRIDGE FILTERS: (MCF) - Removing the Micro Biological Growth
During storage, atmospheric or any other contamination may take place in treated water. Hence, after passing water from R.O. System & after Storage, water is once again passed through a micron cartridge filters. This is a S.S.316 Vessel, internally Electro polished fitted with internally with P.P Pleated micron cartridge elements having absolute ratings of 1.0 micron & 0.2 microns which removes all bacterial impurities present in the water and make the water free of particulates.

With follow treatments treated water is free from all the micro-biological impurities like Bacteria, Virus, etc. it may redevelop again in water during prolonged storage. For dis-infection of water is essential for Reverse Osmosis Application before Filling & Sealing in bottle. Hence, a online Ultra Violet Sterilizer is require for disinfections of Treated water before filling in pre-cleaned PET Bottles. The water to be disinfected, is passed through U.V.System, which consists of U.V.Tubes which radiates high intensity Ultra Violet Rays, which in turn kills the micro organisms. This systems consists of a S.S finished surface housing with Ultraviolet Lamps fitted in it. The water to be treated is surroundings this tubes during treatment. An electrical system is provided for production of high voltage required for U.V.Rays generation and Operating Life of U.V.Lamps.

OZONE GENERATOR: (OZONE) - Generate the Ozone Gas
Though R.O. System rejects all the micro – organisms like bacterial & virus and even after passing through MCF & U.V.System it may redevelop in packed bottles over a period of time. Hence, it is necessary to disinfect R.O.Product water prior to bottling filling. This is very much essential to ensure good Mineral Water Quality as per the standards. This Ozone Generator use for the Final Treated Water to make Oxygen Rich water and it removes the Bacteriological growth and also provide you the Shelf Life of your Packed Bottle water unless it open for some period of time. Also this Ozonated water can add some taste in to your Treated water.

The Packaging unit consists of one or All of the mentioned process:

Bottle Manufacturing by PET Blowing Machine:
For manufacturing of PET Bottles for Different sizes and available in Semi and Automatic Operation up to 3600 Bottles per hour.

Rinsing - Filling – Capping – Sealing Machine:
 The bottles are fed into the machine which automatically rinses, fills and screws the cap on it. Caps are stamped with the date of manufacture and expiry before being put into the hopper for screwing on to the bottle.

In this section the labels and the neck sleeve are to be manually put on the bottles which will then pass through the shrink tunnels and onto packing conveyer.

Final Packing:
This could be in cartons - done manually - and no machines have been provided for it.

These Packing Machines come in both versions: Fully Automatic as well as Semi Automatic.

Fully Automatic Machines are with in feed Air Conveyor which gives higher production rate with no change parts for different sizes of bottles. Such machines are Mechanical operated with Cam Drive and pneumatic operation for accuracy of Washing and Filling. 

Semi Automatic Machines are with Manual washing with Turn Tables and rest activity of Filling and Capping are fully automatic operation. Both options have Shrink Tunnel for labeling application.

Covalence EnviroTech offers Complete Turnkey Plants as per the Customer's Requirements. We have Affiliations with leading Machinery manufacturers and have executed such Projects worldwide.
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