Water Treatment

By Reverse Osmosis Only 2.5% of the earth's water is fresh water usable by human beings,the remaining 97.5% is sea water , While worldwide there is ever-increasing consumption of water with its diversified uses, shortages of "useable water" have been becoming a more and more serious problem.

WATER TREATMENT BY MEMBRANE SEPARATION TECHNOLOGY

Membrane separation processes in current use include:

Reverse osmosis

is capable of separating even ions and organic substances, which are the smallest solutes in aqueous solutions.

FEATURES OF REVERSE OSMOSIS

What is Reverse Osmosis ?

Reverse Osmosis (RO) is a modern process technology to purify water for a wide range of applications, including semiconductors, food processing, biotechnology, pharmaceuticals, power generation, seawater desalting, and municipal drinking water. From initial experiments conducted in the 1950’s, which produced a few drops per hour, the reverse osmosis industry has today resulted in combined worldwide production in excess of 1.7 billion gallons per day. With demand for pure water ever increasing, the growth of the reverse osmosis industry is poised to continue growing well into the current century. This section will provide historical background on the development of RO, and introduce the concepts of osmosis and semi-permeable membranes.

In Reverse Osmosis

The water moves to the salty side of the membrane until equilibrium is achieved. Application of an external pressure to the salt solution side equal to the osmotic pressure will also cause equilibrium. Additional pressure will raise the chemical potential of the water in the salt solution and cause a solvent flow to the pure waterside, because it now has a lower chemical potential. This phenomenon is called Reverse Osmosis.

Applications

Water utilities,Food and Beverages,Tube and Micro Circuit manufacturing,Pharmaceuticals,Hotels & Resorts,Hospitals,Mineral Water Processors,Power Generation,Domestic Applications,Electronic Component manufacturing,Semi conductors

Reverse Osmosis Elements

The Reverse Osmosis elements are of the following configuration :

Hollow Fine Fibres The hollow fine fibre RO membranes are the fibres bound in cylindrical bundle.
They provide large surface area. Feed water passes through the walls of fibre and passes through the bore. Brine or the concentrate is rejected through the Brine outlet.

Spiral wound

In spiral wound configuration, the RO membrane is spirally wound around a permeate collector tube. The pressure vessel can house a number of elements with necessary seals and inter connector contaminants remain on the outside surface

Tubular

Tubular membranes are housed in the inner surface of support tube. An appropriate number of membrane tubes are connected in parallel within a modular container with manifolds, which provide connectors for feed permeate and concentrate.
Pressurized water flows through the tube and permeate passes through the tubular membrane along the entire length.
(Because of Spiral Wound construction, it has resistivity against immediate fouling in element and easy cleaning process by membrane cleaning chemicals with wide application from low salinity water to high salinity sea water. Nowadays, spiral wound membrane is used widely).
Water Egypt and Globe Well Design the Rverse Osmosis /Desalination to get maximum efficiancy from the system ,With easy operation The material of construction of the system may be Fiber glass reinforced plastic, Stainless steel ,PVC,etc…as suit to your requirement.

Water Egypt and Globe Well REVERSE OSMOSIS SYSTEM

is designed in very wide range,i.e. for Home application, Hotel Application and Industries,with wide production capacity.

Reverse Osmosis need:

pre treatment The pretreatment of water is required to remove the Dissolved, Foreign, Organic and Biological impurities. Dissolved impurities include Calcium, Magnesium, Silica, etc. which can damage the porosity and Brine channels of membrane element. Foreign impurities like Suspended Solids, Turbidity, etc. can damage the porosity and Brine channels of membrane element. Organic impurities like Oil & Grease and Biological impurities like Algae, Fungus and harmful Bacteria, that can grow by multiple effect in the empty space in the membrane element because of stagnant water present in the element, can damage the element physically.

Usually, the pretreatment includes the following :

Softening, Acid dosing, Suitable antiscalant dosing, etc. Pressure Sand Filteration, Micron Filteration, Coagulant dosing, etc. Activated Carbon, Chlorination - Dechlorination, Sterilisation, etc.

post treatment

The post treatment for RO treated water is necessary and require some sort of treatment which can enable to use the RO treated water for process, drinking purpose, etc. Most effective post treatment for industries, drinking purpose and general use may vary depending on the raw water quality and the type of application. Softening, degassification, dealkalisation, demineralisation, Mixed bed deionisation, Chlorination or Sterilisation are the types of post treatment usually applicable to RO treated water.

GW RO Reverse Osmosis

is proving to be the most cost effective means of producing pure potable water from seawater with total dissolved solids of up to 50,000 part per million. Water Egypt and Globe Well design based on a comprehensive feed water analysis report, temperature and pressure data, ensures that client's requirements are met and the World Health Organization Guidelines for water quality are not violated.
By using computer aided design and modeling techniques, Water Egypt and Globe Well is capable of selecting the best permeator design for any given application .By using the spiral wound membrane.
This is done with great care taking into consideration optimum performance and system economics.

PROCESS DESCRIPTION

The raw water is pumped from the raw water storage tank using the filter feed pumps (it can be pumped direct from the well).
Chlorine is added to the incoming raw water to overcome contamination and prevent biological growth.
During operation, the treated raw water enters the pressure filter in which solids adhere to the media while the filtered water passes through.
The filtered raw water is then dechlorinated by the addition of Sodium Bisulphite.
At the RO unit, sulfuric acid is added upstream of the cartridge filter to adjust the feed water pH., The pH adjustment of the feed water is essential to prevent the formation of calcium carbonate scale.
Scale inhibitor is injected in order to inhibit the precipitation of the sparingly soluble salts, which are present in the feed water.
The chemically adjusted feed water is then passed through 5 micron cartridge filters for the protection of the RO membranes and high pressure pump, where particles greater than 5 microns are removed.
Downstream of the cartridge filters, low-pressure safety switch is fitted to the high-pressure pump to protect the pump from running dry.
Water is then fed from the inlet manifold to the high-pressure pump.
Various system pressures are monitored on pressure gauges.
The pressurized water enters RO modules where the desalinated water (product) flow passes through, as permeate and the remain is rejected as concentrated water (Brine).
Brine flow of the RO unit is controlled through a manual control valve, which then passes through the concentrate flow meter before leaving the plant.
Predictably, the amount of carbon dioxide in the post treatment stage is considerably high, This is mainly due to the addition of sulfuric acid in the pretreatment stage and its impact on the bicarbonates in the feed water.
Sodium hydroxide is injected in the permeate stream leaving the RO unit so as to adjust the pH to the required level.
The RO product water is disinfected by injection of sodium hypochlorite.

DESIGN PARAMETERS

Water Egypt and Globe Well design parameters depending on the following: Feedwater total dissolved solid Operating temperature Operating Pressure Salt Rejection (nominal) Conversion rate (nominal)

STANDARD SPECIFICATION

OPTIONAL SUPPLY AND ACCESSORIES :

OPERATION AND MAINTENANCE

Water Egypt and Globe Well have the capabilty and experience to operate all types of water purification and treatment plant, under contract with the client

TRAINING

Training can vary from simple operating handbooks, to a comprehensive site training to suit the client's specific needs.

SERVICE

Water Egypt and Globe Well skilled engineers are available to assist with desalination projects, from inspection through to commissioning of the plants.
The company has facilities for both on and off site training of operators in the control, data logging, operation and servicing of all types of plants.