Rinse water Recovery System-METAPure for recovery and reuse of electroplating rinse water.

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Rinse water Recovery System-METAPurefor recovery
and reuse of electroplating rinse water.

• Pure Tech India,
• A-5, Trec step, Thuvakudi, Trichy -620 015
• Telephone[phone] Telefax 00 91-431
  250 1100
• E-Mail contact_at_puretechindia.com website
  www.puretechindia.com

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Electroplating processes and various chemicals
used
S. No Plating process Major chemicals used
1 Cadmium plating Cadmium Oxide, Sodium Cyanide, Sodium Hydroxide
2 Zinc plating Zinc Oxide, Sodium Cyanide, Sodium Hydroxide
3 Copper plating Copper Cyanide, Sodium Cyanide, Sodium Hydroxide
4 Nickel plating Nickel Sulphate, Nickel Chloride, Boric Acid
5 Chromium plating High speed self regulating salt (Chromium sulphate, Chromic Acid)
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Important Contributors in a Electroplating
Effluent Generation
Component Function Effluent Contribution/Remarks
Plating Bath Main component primarily responsible for plating. Contains bath chemicals. Bath is not drained at all except for some unavoidable circumstances generally not seen.
Plating Rinse Removes excess coating material. Major contributor of effluent. Contains primarily bath chemicals with some environmental contaminants.
Acid Bath and Rinse To clean materials of rust. Bath and rinse becomes unusable after a particular period of operation. Main contaminants include rust material with some dust particles.
Alkali Bath and Rinse To clean materials of rust preventive solutions, oil and grease for better plating efficiency. Bath and rinse becomes unusable after a particular period of operation. Main contaminants include oil and grease, rust preventive solution.
Floor Washings Spillovers from plating, rinse, acid and alkali tanks. All effluents listed above in small quantities with water used for floor washing.
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Treatment processes available

• Chemical treatment using
• Sulphuric Acid (pH reduction for chromium
  conversion)
• Sodium Bisulphite (used for converting hexavalent
  to trivalent Chromium)
• Sodium Hypo (Cyanide Oxidation)
• Lime/ Caustic (neutralization)
• Polyelectrolyte (flocculation)
• Clarification (solid- liquid separation) and
• Solid sludge separation.
• Membrane based physical/physiochemical processes.

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Conventional Treatment
Electroplating Effluent
Oxidation/ Reduction/ Neutralization
Neutralization
Precipitation
Flocculation (Polyelectrolyte)
Waste water discharge
Clarification
Sludge Storage
NOTE Cyanide waste Oxidation Chromium
Waste Reduction Acid/Alkali Waste Neutralization
Dewatering
Disposal
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Membrane Systems

• An Overview

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Filtration Types and Comparison

• Normal Filtration Cross-
  flow Filtration
• Normal Filtration Water with contaminants pass
  in direction perpendicular to filter media. The
  contaminants will choke the pores of the filter
  media.
• Cross- flow Filtration Water with contaminants
  pass in direction parallel to the filter media.
  The Outlet from this filtration will have two
  streams coming out. The concentrate stream will
  carry along with it the contaminants. The
  filtered water will come out of a separate
  outlet. The frequency of filter media getting
  choked is very low when compared to normal
  filtration.

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Cross- flow Membrane Processes
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Specific advantages of membrane based treatment
systems

• Compact and less space occupying.
• Marginal chemical consumption (needed in case of
  pH correction).
• Skid mounted systems.
• Very low sludge generation.
• Very low electricity consumption.
• Requires little/ no civil construction.
• Separated water is ideally suitable for high
  quality rinse and bath top up.

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Reverse Osmosis

• Finest form of filtration

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Osmosis - Reverse Osmosis Illustration
Pressure P
Concentrate
Dilute
Dilute
Concentrate
Semi- Permeable Membrane
Semi- Permeable membrane is one which will allow
only water molecules to pass and not salts. In
the Left diagram, under normal circumstances,
water molecules from dilute solution side will
permeate towards concentrate side to form an
equilibrium.This is Osmosis and the pressure
present is Osmostic pressure. In the right
diagram, when a pressure P is applied in excess
to the normal pressure , water alone is squeezed
into the dilute solution side from the
concentrate solution side. This is Reverse-
Osmosis.
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Typical Reverse Osmosis Membranes
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Reverse Osmosis Process flow diagram
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RO membrane structure
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Separated components applications

• Permeate flow (usable/product water flow)
• Rinse
• Bath top up
• Concentrate flow (Reject flow)-
  
• Bath (if the concentrate contains only salts used
  in the electroplating bath with permissible
  contaminants)

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Reverse Osmosis Membranes Rejection Rates
Solute Symbol Molecular weight Rejection ()
Sodium Fluoride NaF 42 99
Sodium Cyanide NaCN (pH 11) 49 97
Sodium Chloride NaCl 58 99
Silica SiO2 (50 ppm) 60 98
Sodium Bi- Carbonate NaHCo3 84 99
Sodium Nitrate NaNo3 85 97
Magnesium Chloride MgCl2 95 99
Calcium Chloride CaCl2 111 99
Magnesium Sulphate MgSo4 120 gt99
Nickel Sulphate NiSo4 155 gt99
Copper Sulphate CuSo4 160 gt99
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Membrane based Rinse water recovery systems
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Major contaminants and their removal
S .No Contaminant Removal Process
1. pH Correction Acid/ Alkali addition
2. Suspended Solids Stainless Steel Filter Strainer Stainless Steel Bag Filter
3. Microscopic oil particles Activated Carbon Filter
4. Coating Materials IONICS unit using Reverse Osmosis membranes
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Process Flow Diagram
Effluent from electroplating process
Filtration System
Prep Tank
Pump
Acid/ Alkali addition
RO based IONICS Unit
Permeate tank to process
High pressure pump
Reject back to bath/ treatment
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Low flow membrane systems
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High flow membrane systems
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A Typical application in electroplating process
Flow of parts
Stage 1
Stage 2
Stage 3
Stage 4
Spray-Dip-Spray City Water Rinse
High Pressure Rinse
Chemical Cleaner
Phosphate Dip
Flow of parts
Stage 5
Stage 6
Stage 7
Stage 8
Stage 9
DI water
Spray-Dip-Spray City Water Rinse
Spray-Dip-Spray Water Rinse
Spray Water Rinse
Chromate Dip
Spray Rinse
RO
TO WASTE TREATMENT
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RO Process in Nickel Plating
evaporation
RINSE 1
RINSE 2
PLATE
parts
parts
feed
RO
permeate
concentrate
95 recovery
Make-up (Pure water)
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• Benefits
• 70 of rinse water can be recovered and reused
  for Bath Top up and as Rinse water.
• Pollution Problem solved
• The cost of treatment is got back to by way of
  water which can be reused for rinsing process.
• Customers
• Silver Crown Electroplaters 100 and 200 LPH
• Divya Engineering 10 LPH
• Sundaram Fasteners Limited, Chennai 200 LPH

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• Other Electroplating Process related Products
• Desorber Oil water separator for Degreasing
  Baths.
• OleoSepa Desorber, Ultrafiltration System for
  complete oil removal and reuse of Degreasing
  solutions.
• Bag Filtration System For filtering suspended
  solids upto 1 microns for your plating baths.
  Filter media can be offered in Stainless Steel,
  Polypropylene and HDPE wire cloths. Complete unit
  can be fabricated in the above materials.
• RO Plant For removing Total Dissolved Solids in
  water used for bath and rinse for better
  efficiency of plating.

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Thank You

• For Queries, Please contact
• E- Mail contact_at_puretechindia.com
• (Photographs shown are taken from our supplied
  equipments and there are feature additions taking
  place in each new equipment manufactured)