2. WHAT IS ZERO LQUID DISCHARGE
Zero Liquid discharge refers to installation of facilities and system which
will enable industrial effluent for absolute recycling of permeate and
converting solute (dissolved organic and in-organic compounds/salts) into
residue in the solid form by adopting method of concentration and thermal
evaporation.
ZLD will be recognized and certified based on two broad parameters that
is, water consumption versus waste water re-used or recycled (permeate)
and corresponding solids recovered (percent total dissolved /suspended
solids in effluents).
3. METHODOLOGY OF ZLD
Segregation of effluent by way of contamination of organic load,
utility waste , sewerage, colour effluent etc .
Pre treatment for TSS and colour removal
Use biological process for BOD/COD reduction
UF RO for TDS reduction and make product water for reuse.
Use evaporation techniques such as Solar evaporation & Thermal
evaporation for reject handling to achieve ZLD.
4. COMPLIANCE
Standards for compliance have been notified under the Environment
Protection Act, 1986.
The notified standards permit industries to discharge the effluents
only after compliance.
However, CPCB and SPCBs / PCCs now, are insisting industries to
reduce water consumption and also take measures to not-to-discharge
effluents.
But, it has been observed that industries are not able to meet all time
compliance standards and as a result, rivers like Ganga, Yamuna and
its tributaries is carrying high pollution load and it is the dilution
available in river water which helps in minimizing pollution load.
Besides compliance , there is need of Corporate Social Responsibility
of corporate and Industries towards our society to give clean
environment , water and protect natural resources .
5. MAJOR CONCERNS…
•Reduce Foot Print
•Quality of water recovered for recycle.
•High Operating Cost due to steam
consumption.
•Frequent scaling and choking of metal tubes
resulting hours lost in capacityutilisation of
plant
11. KEY FEATURES OF PFET(MVRE) TECHNOLOGY
Thermodynamically, the most efficient technique to evaporate
water is to use mechanical vapor thermo compression.
The main components of the PFET system are: vacuum vessel,
evaporative heat transfer surface installed inside the vessel and
vapor recompression fan.
Water boil inside the MVRE vessel ( Under Vacuum) at 60.5 deg.
Vapor is extracted from the evaporation chamber and
compressed by a fan to a pressure of 23 kpa corresponding
temp.63.0 deg.
The vapor, at 63.0 C, is passed back through a heat exchanger
inside the evaporation chamber where it gives up its latent heat,
to the evaporation chamber recirculation brine on the other side
and, in doing so, condenses back to a liquid at 63.0 deg.C.
The Heat of condensate coming out is also used in pre –heating
of feed water.
Once the process is established the only heat which needs to
be supplied to the system is that required to heat the feed water
from 60.5º C to 63.0º C
13. Uniform distribution of Liquid
on the Surface of Polymeric
Heat Exchanger as seen
through Effluent doped with
Dye.
LIQUID DISTRIBUTION ON POLYMERIC HEAT EXCHANGER
23. BENEFITS OF PFET( MVRE) TECHNOLOGY
Arvind Envisol Polymeric Film Evaporation Technology, benefits achieved
includes :
Low cost evaporative surface results into
• large heat transfer surface
• small temperature difference – 2.5 deg.C
• simple, low speed fan as vapor compressor
• low power consumption @ 15 KW per M3 effluent
• Very low steam consumption @ 15 kg. per M3 effluent.
Polymer surface
• Not prone for scaling
• Can be operated in low pH
• corrosion resistant
Smooth surface
• easy cleaning
The major advantage of this technology is huge heat exchanger surface
area can be incorporated into the system at a very low cost.
24. TYPICAL APPLICATION AREAS
Textile industry
Steel and metal industry
Mining industry
Pulp & Paper
Food and Beverage Industry
Landfill leachate
Groundwater remediation
Seawater desalination
Chemical industry
Electronic industry
Power plants
Pharma industry
Fertilizer Industry
Auto Industry
27. 200 KLD Capacity MEE & PFET(MVRE) Operation Cost Comparison
Steam cost taken as Rs. 1.25/-kg. and power cost taken Rs. 6.5/- unit.
Sr. No. Description MEE - 4 effect PFET ( MVRE)- cooncentrate up to 12%
solid
MVRE+Crystallizer for ZLD
1 Steam Consumption 280 kg/KL 15 kg/KL
2 Power Consumption 22 KWH/KL 15 KWH/KL
3 Operating Cost/KL ( Rs. Based On
Steam & Power Consumptions)
500 116 200
4 Operating Cost/Day (Rs.) 100000 23200 40000
5 Savings in Operating Cost /Day (Rs.) NA 76800 60000
6 Annual saving through opex. For 300
working days
Rs. 2.3 Cr. Rs. 1.8 Cr.
7 Cooling Water Requirement High Small Small
8 Cleaning Chemicals Required No chemical required Less (required only for MEE)
9 Avg. Down Time /Day (hrs) 4 0 (for MVRE) 0 (for MVRE)
10 Cleaning waste Generated Yes No Not for MVRE
11 Structure requirement High Medium Medium
12 Foot Print Area High Low Medium
13 Operations Complex Easy for MVRE Easy for MVRE
14 Capital Cost High Less As compared to alone MEE Almost same
