Water treatment by demineralisation

1. WATER TREATMENT BY REVERSE
OSMOSIS AND DEMINERALISATION
PLANT
MALLA REDDY COLLEGE OF PHARMACY
PRESENTATION BY:
VOSKULA RAJESH
M.PHARM.CEUTICES 1YEAR
ROLL NO:256212880033

2. 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 .

3. 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.

4. 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.

5. Treatment options for Reverse
Osmosis:
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.

6. 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..

7. Schematic Diagram of the RO
Process:

9. Difference b/w osmosis and
reverse osmosis:

10. REVERSE OSMOSIS:

11. REVERSE OSMOSIS:

13. 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.

14.  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.

15. 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.

16.  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.

18. 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

19. TYPES OF MEMBRANES:

20. 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.

21. 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.

22. 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.

23. Marketed systems of reverse
osmosis:
1)Culligan Reverse Osmosis Products
G3 / G3+ Reverse Osmosis System:
2)G2 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.

24. MARKETED REVERSE OSMOSIS
MACHINES:
• M2 Reverse Osmosis System
• E2 Reverse Osmosis System

25. MARKETED REVERSE OSMOSIS
MACHINES:
G1 Reverse Osmosis System
M1 Reverse Osmosis System

26. 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.

28. 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.

29. 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.

30. SCHEMATIC DIAGRAM OF DM:

31. 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-)

32. DM TANKS:

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

34. 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.

35. 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.

36. 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.

37. 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).

38. DM PLANT:

39. 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.

40. Mixed-bed deionization:

41. 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)

42. 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.

43. 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.

44. 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.

45. 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.

46. 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.

47.  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.

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SOMETHING…..
…..THANQ U