PRESENTATION BY:

VOSKULA RAJESH

M.PHARM.CEUTICES 1YEAR

ROLL NO:256212880033

WATER TREATMENT BY REVERSE OSMOSIS AND DEMINERALISATION

PLANT

MALLA REDDY COLLEGE OF PHARMACY

Abstract:

Reverse Osmosis (RO) is a membrane based process technology to

purify water by separating the dissolved solids from feed stream

resulting in permeate and reject stream for a wide range of applications

in domestic as well as industrial applications. It is seen from literature

review that RO technology is used to remove dissolved solids, colour,

organic contaminants, and nitrate from feed stream. Hence RO

technology used in the treatment of water and hazardous waste,

separation processes in the food, beverage and paper industry, as well

as recovery of organic and inorganic materials from chemical processes

as an alternative method .

Introduction: Reverse Osmosis (RO) is a process that uses semipermeable spiral wound

membranes to separate and remove dissolved solids, organic,

pyrogens,submicron colloidal matter, color, nitrate and bacteria from water.

Feed water is delivered under pressure through the semi permeable

membrane, where water permeates the minute pores of the membrane and is

delivered as purified water called permeate water. Impurities in the water are

concentrated in the reject stream and flushed to the drain is called reject

water. These membranes are semi-permeable and reject the salt ions while

letting the water molecules pass. The materials used for RO membranes are

made of cellulose acetate, and other polymers.

Scope of Reverse Osmosis:The process has also been applied to treat municipal wastewater. Since

conventional municipal treatment processes do not remove dissolved

solids, but RO process is used for the removal of dissolved solids. RO is

increasingly used as a separation technique in chemical and

environmental engineering for the removal of organics and organic

pollutants present in wastewater. It is seen from literature review that

Reverse Osmosis (RO) processes have been widely used for separation

and concentration (recovery) of solutes in many fields.

Treatment options for ReverseOsmosis: In India, distillery uses various forms of primary,

secondary and tertiary treatments of wastewater. The units processes used are

screening and equalization, followed by biomethanation. Fertiirrigation and

biocomposting with sugarcane pressmud are the most widely used options for

effluent disposal.In case of grain based distillery the treatment given is by way

of DWGS separation, incineration and biomethanation. The process streams

that can be recycled are namely, thin slop and process condensate.Thin slop

contain high TDS, high temperature and contain carbohydrates, organic acids,

dead yeast cells etc. which may have an impact on the fermentation process.

Reverse Osmosis Process Description:

The RO process is simple in design consisting of feed,permeate and reject

stream. For feed water it is necessary to provide pretreatment in order to remove

inorganic solids and suspended solid and using high pressure pump given feed

through semi permeable membrane. Depending upon the permeate where it is

used necessary post treatment is given..

Schematic Diagram of the RO Process:

Difference b/w osmosis and reverse osmosis:

REVERSE OSMOSIS:

REVERSE OSMOSIS:

Reverse Osmosis Requisites:

An RO desalination plant essentially consists of four major systems:

(a) Pretreatment system,

(b) Highpressure pumps,

(c) Membrane systems, and

(d) Post-treatment.

Pre-treatment system is provided to remove all suspended solids so that

salt precipitation or microbial growth does not occur on the membranes.

Pre-treatment may involve conventional methods like a chemical feed

followed by coagulation/ flocculation/sedimentation, and sand filtration or

membrane processes i.e micro filtration (MF) and ultra filtration (UF).

The pressure ranges from 17 to 27 bar for brackish water, and from 52 to

69 bar for seawater. Membrane systems consist of a pressure vessel and a

semi-permeable membrane inside that permits the feed water to pass

through it.

Basic components common of a Reverse Osmosis System:

Cold Water Line Valve:   Valve that fits onto the cold water supply line. The valve has a tube that attaches to the inlet side of the RO pre filter.

Pre-Filter (s): Water from the cold water supply line enters the Reverse Osmosis Pre Filter first. There may be more than one pre-filter used in a Reverse Osmosis system. The most commonly used pre-filters are sediment filters. These are used to remove sand silt, dirt and other sediment.

Additionally, carbon filters may be used to remove chlorine, which can have a negative effect on TFC (thin film composite) & TFM (thin film material) membranes.

Flow Restrictor:   Water flow through the RO membrane is regulated by a flow control. There are many different styles of flow controls. This device maintains the flow rate required to obtain the highest quality drinking water (based on the gallon capacity of the membrane). It also helps maintain pressure on the inlet side of the membrane. Without the flow control very little drinking water would be produced because all the incoming tap water would take the path of least resistance and simply flow down the drain line. The flow control is located in the RO drain line tubing.

Storage Tank:   The standard RO storage tank holds up to 2.5 gallons of water. A bladder inside the tank keeps water pressurized in the tank when it is full.

Faucet:   The RO unit uses its own faucet in areas where required by plumbing codes an air-gap faucet is generally used.

Drain line:   This line runs from the outlet end of the Reverse Osmosis membrane housing to the drain. This line is used to dispose of the impurities and contaminants found in the incoming water source (tap water). The flow control is also installed in this line.

Membrane Characteristics: The membrane should be inexpensive, have longer and stable life.

Membrane should be easily manufactured with good salt rejection i.e. Slightly

permeable to salt.

They should have high water flux i.e highly permeable to water and less susceptible

to fouling.

They should permit the flow of large amounts of water through the membrane

relative to the volume they occupy.

The membrane should chemically, physically and thermally stable in saline waters.

They need to be strong enough to withstand high pressures and variable feed water

quality

TYPES OF MEMBRANES:

Advantages of RO Process:Following are the advantages of the RO process that make it attractive for

dilute aqueous wastewater treatment include:

RO systems are simple to design and operate, have low maintenance

requirements, and are modular in nature, making expansion of the systems

easy.

Both inorganic and organic pollutants can be removed simultaneously by

RO membrane processes.

RO systems allow recovery/recycle of waste process streams with no effect

on the material being recovered.

RO systems require less energy as compared to other technology.

Advantages of reverse osmosis:

The modular structure of the RO proces increases flexibility in building

desalination plants within a wide range of capacities.

The specific energy requirement is significantly low 3- 9.4 kW h/m3 product.

The process is electrically driven hence it is readily adaptable to powering by

solar panels.

Treatment (as well as many others) to produce high quality product water that can

be reused or discharged.

Applications of Reverse Osmosis: This technology has advantage of a

membrane based process where concentration and separation is

achieved without a change of state and without use of chemicals or

thermal energy, thus making the process energy efficient and ideally

suited for recovery applications. The bibliographic review shows

applicability of RO system for treating effluents from beverage

industry, distillery spent wash, ground water treatment, recovery of

phenol compounds, and reclamation of wastewater and sea water

reverse osmosis (SWRO) treatment indicating efficiency and

applicability of RO technology.

Marketed systems of reverse osmosis:

1)Culligan Reverse Osmosis Products

G3 / G3+ Reverse Osmosis System: This flexible system is sized to provide high-quality reverse osmosis water for large applications from 18 to over 200* gallons per minute. The G3 can be a fully integrated part of your Culligan Matrix Solution.

2)G2 Reverse Osmosis System

MARKETED REVERSE OSMOSIS MACHINES:

• M2 Reverse Osmosis System

• E2 Reverse Osmosis System

MARKETED REVERSE OSMOSIS MACHINES:

G1 Reverse Osmosis System

M1 Reverse Osmosis System

DEMINERALISZATION PLANT: Demineralization is the process of removing mineral salts from water

by using the ion exchange process. Demineralised water is water

completely free (or almost) of dissolved minerals as a result of one of

the following processes :

Distillation.

Deionization.

Membrane filtration (reverse osmosis or nanofiltration).

Electrodialysis.

Or other technologies.

Principle :Raw water is passed via two small polystyrene bead

filled (ion exchange resins) beds.

While the cations get exchanged with hydrogen ions in

first bed.

The anions are exchanged with hydroxyl ions, in the

second one.

Process :In the context of water purification, ion-exchange is a rapid and

reversible process in which impurity ions present in the water

are replaced by ions released by an ion-exchange resin.

The impurity ions are taken up by the resin, which must be

periodically regenerated to restore it to the original ionic form.

An ion is an atom or group of atoms with an electric charge.

Positively-charged ions are called cations and are usually

metals; negatively-charged ions are called anions and are

usually non-metals.

SCHEMATIC DIAGRAM OF DM:

The following ions are widely found in raw waters :Cations:Calcium (Ca2+)Magnesium (Mg2+)Sodium (Na+)Potassium (K+)

Anions:Chloride ( Cl-)Bicarbonate (HCO3-)Nitrate (NO3-)Carbonate (CO32-)

DM TANKS:

DM PLANT. CAPACITY: 2 X 15 M3/HR:

Ion Exchange Resins : There are two basic types of resin –

1)Cation-exchange resins.

2) Anion-exchange resins.

Cation exchange resins will release Hydrogen (H+) ions or

other positively charged ions in exchange for impurity cations present

in the water. Anion exchange resins will release hydroxyl (OH-) ions

or other negatively charged ions in exchange for impurity anions

present in the water.

The application of ion-exchange to water treatment and purification

There are three ways in which ion-exchange technology can be used in water treatment and purification :

First, cation-exchange resins alone can be employed to soften water by base exchange.

Secondly, anion-exchange resins alone can be used for organic scavenging or nitrate removal.

Thirdly, combinations of cation-exchange and anion-exchange resins can be used to remove virtually all the ionic impurities present in the feedwater, a process known as deionization. Water deionizers purification process results in water of exceptionally high quality.

Deionization : For many laboratory and industrial applications, high-purity

water which is essentially free from ionic contaminants is required.

Water of this quality can be produced by deionization. The two most

common types of deionization are :

Two-bed deionization.

Mixed-bed deionization. 

Two-bed deionization : The two-bed deionizer consists of two vessels - one containing a

cation-exchange resin in the hydrogen (H+) form and the other containing

an anion resin in the hydroxyl (OH-) form. Water flows through the cation

column, whereupon all the cations are exchanged for hydrogen ions. To

keep the water electrically balanced, for every monovalent cation.

e.g: Ca2+, or Mg2+, two hydrogen ions are exchanged. The same

principle applies when considering anion-exchange. The decationised

water then flows through the anion column. This time, all the negatively

charged ions are exchanged for hydroxide ions which then combine with

the hydrogen ions to form water (H2O).

DM PLANT:

MIXED-BED DEIONIZER: In mixed-bed deionizers the cation-exchange and anion-exchange

resins are intimately mixed and contained in a single pressure vessel.

The thorough mixture of cation-exchangers and anion-exchangers in a

single column makes a mixed-bed deionizer equivalent to a lengthy

series of two-bed plants. As a result, the water quality obtained from a

mixed-bed deionizer is appreciably higher than that produced by a

two-bed plant.

Mixed-bed deionization:

Mini DM Plant Specifications :

Model: eDM-5

Flow rate: 50 to 80 Lit/hr.

Space requirement: very compact- 1 m x 1m

Power: NIL, Min inlet pressure 0.5 kg/cm2

Output TDS: Less that 10 ppm

Output DM Qty.: 500 Lit at 100 ppm TDS

(Best suitable when feed water is corporation water TDS < 100 ppm)

Advantages : Variety of cost effective standard models.

Improved aesthetics and rugged design.

User friendly, low maintenance and easy to install.

Simpler distribution and collection systems.

Quick availability.

Pre dispatch assembly check.

The multiport valves are top mounted as well as side mounted with the

necessary high pressure rating PVC piping.

Single valve operation as compared to the six valves in conventional filters.

Advantages : Each operating step is clearly marked on the valve, thereby eliminating

chances of error in the operating sequence.

Single valve assembly, with its simplified frontal Piping, simpler

distribution collecting systems is Very easy to install.

Rust free.

Less power consumption.

Durable.

Economical.

High shelf life.

APPLICATIONS: Boilers feed water, Textiles, Pharmaceuticals, Chemicals, Breweries,

Swimming pools, Potable Water, Hospitals, Automobile, and   Battery, Fertilizers.

Ion Exchange Plants    - Softener.   - Industrial DM Plant.   - Two Stage & Multi Stage DM Plants.   - Mix Bed Demineraliser.   - De-Gasifiers.   - Cation Polisher.   - Manual/Automatic Plants.   - Pharmaceutical Industry.   - Power Plant.   - Oil & Gas sector.   - Chemical Industries.   - Textile Industries.

Conclusion: Feed Water containing suspended particles,

organic matter as well as inorganic salt may deposit on the membrane

and fouling will occur or damage the membrane because of applied

pressure and size of particles. Therefore the priority to remove these by

way of pretreatment will determine the RO efficiency. Hence RO

membrane performance can be checked to avoid the irreversible

damages to the RO membrane. In fact success of RO system depends

upon efficiency of the pre treatment.

References: *Garud R. M., Kore S. V., Kore V. S., Kulkarni G. S. A Short Review on Process

and Applications of Reverse Osmosis from universal journal of environamental

research and technology. Volume 1;issue 3:233-238.

Bellona, C., J.E. Drewes, P. Xua and G.Amy,(2004):,”Factors affecting the

rejection of organic solutes during NF/RO treatment-a literature review, “Water

Res., 38: 2795-2809.

Bodalo-Santoyo, A., J.L. Gomez-Carrasco, E. Gomez-Gomez, F.Maximo -Martin

and A.M. Hidalgo-Montesinos,(2003):,”Application of reverse osmosis

membrane to reduce pollutants present in industrial waste water ,

“Desalination155: 101-108.

Chian, E., Bruce, W., and Fang, H., (1975):"Removal of Pesticides by

Reverse Osmosis",Environmental Science and Technology, 9- 364.

Craig J. Brown P.Eng Presented by: Phillip J. Simmons PhD, Eco-Tec Inc., ,

Ontario, Canada Presented at the Water Management in Process Industry,

organized by the Lovraj Kumar Memorial Trust, India, November, 2002.

Smith, J.H., Renouf, P.W., Crossen, M., “50 Years in Separate Beds”,

Proceedings of the International Water Conference 1984.

Craig J. Brown P.Eng Presented by: Phillip J. Simmons PhD, Eco-Tec Inc., ,

Ontario, Canada Presented at the Water Management in Process Industry,

organized by the Lovraj Kumar Memorial Trust, India, November, 2002.

I HOPE YOU UNDERTSOOD SOMETHING…..

…..THANQ U