This document discusses emerging trends in waste water treatment practices, including converting effluents into value-added products rather than just treating them. It provides several case studies on technologies that reduce or eliminate waste, such as a titanium dioxide process that operates on a zero discharge basis and technologies being developed to convert carbon dioxide into useful products. The document also discusses technologies for using waste materials like municipal waste, copper slag, and phospho-gypsum in cement production and describes processes developed to reduce water usage in denim processing and generate biohydrogen from waste.

1. EMERGING TREND IN
WASTE WATER TREATMENT PRACTICES
Mr.N.S.VENKATARAMAN,
Director
Nandini Consultancy Centre Pvt.Ltd.,
Chennai
Website: www.nandinichemical.com
9th November 2013

2. EMERGING TREND IN WASTE
WATER TREATMENT
PRACTICES
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3. EMERGING TREND
 To avoid waste generation at all by
modifying
the
existing
technology,
developing new technology and discarding
the effluent prone technology.
 Convert the effluent to value added
products, instead of merely treating the
effluent away.
 There are plenty of things to be gained by
pollution control and profit is one of them.
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4. CASE STUDY OF
TITANIUM DIOXIDE TECHNOLOGY
The
sulphate
route
process
technology
generates ferrous sulphate and free sulphuric
acid as effluent, which is the old process.
Later on, the chloride route process technology
was developed, which operates on zero
discharge basis. The emissions are recirculated
in the process.
Now, sulphate route process is steadily giving
way to chloride route process.
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5. UTILISATION OF CARBON DIOXIDE GAS
Carbon dioxide is emitted in large quantity by
several projects including cement plants and
thermal power plants.
Carbon dioxide contributes to global warming
There is huge international concerns about the
global warming effects of carbon dioxide that call
for measures to mitigate the emission of carbon
dioxide.
Now, steps have been taken to convert carbon
dioxide to useful products in multiple ways.
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6. PRODUCTS UNDER DEVELOPMENT
BASED ON CARBON DIOXIDE
 Converting CO2
hydrogen, methanol/
­into
dimethyl ether /gasoline
 Conversion CO2 into polymers
 Conversion of CO2 into polycarbonate
 Pilot plant from carbon dioxide to ethanol
 Formic acid from CO2
 Succinic acid from CO2
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7. PRODUCTS UNDER DEVELOPMENT
BASED ON CARBON DIOXIDE
Polyol from CO2
Carbon dioxide to isobutanol
Acrylate from carbon di oxide
CO2 refrigerant (R744)
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8. BURNING MUNICIPAL WASTE
IN CEMENT KILN
Technology developed by ACC Ltd
Waste material may consist of paint sludge, sludge from
effluent treatment plants and cotton wastes (from
cleaning oily surfaces). Expired goods—medicines, foods
and other FMCG products
Burning municipal waste in cement kilns is better than
destroying them in incinerators or using them as landfill.
This is because the temperature inside a cement kiln can
go as high as 2,000 degree celsius at the main burner.
Furthermore, the emissions out of the kilns do not get
influenced by the burning of these waste materials.
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9. USE OF COPPER SLAG
IN CEMENT PRODUCTION
Technology developed by
Holcim, Singapore
India produces large amount of copper slag from
copper smelters, which are not well used.
Copper slag can be used in cement production, which is
a well established technology abroad
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10. COMMON SALT FREE
TANNING TECHNOLOGY
Technology developed by
Central Leather Research Institute (CLRI)
Percolation of salt water has the risk of contaminating the
soil and ground water.
The Central Leather Research Institute (CSIR – CLRI) has
developed a common salt free tanning technology, adding
economic and environmental benefits to leather making.
This technology not only eliminates the usage of salt in
the tanning process but also shortens the tanning process
by avoiding the steps of acidification and basification.
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11. WASTE WATER REDUCTION
IN DENIM PROCESSING
Technology developed by Clariant
2,900 gallons of water are required to produce one pair of
blue jeans
The new technology reduces the water consumption by
upto 92%, prevents approximately 63% of cotton waste and
saves up to 30% of the required energy.
In the conventional denim indigo dyeing process, the fabric
passes through a line of 10 to 14 vats, depending on the
equipment used.
Clariant’s Advanced Denim concept (Denim-Ox process)
brings this sequence down to four and its Pad/Sizing
Ox reduces this further to just one vat.
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12. BIO HYDROGEN & BIO PLASTICS
FROM WASTE
Technology developed by – IICT, Hyderabad
Bio hydrogen can be generated from wastewater by
dark fermentation and bio electricity can be obtained
through microbial fuel cells (MFC).
IICT, Hyderabad have been operating a 50 litre
capacity reactor to produce bio hydrogen and
bio plastics under a project funded by the Ministry of
Non Renewable Energy.
Now, the plan is to scale up the process for
producing bio hydrogen in a 10,000 litre capacity
reactor.
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13. PHOSPHO GYPSUM
India produces large quantity of phospho gypsum
from phosphoric acid plants, which largely remain
unutilized, causing disposal problems.
Every tonne of phosphoric acid production,
4.5 tonnes of phospho gypsum is generated as
by product. Phospho gypsum production in India is
around 7.1 million tonnes per annum.
Several projects can be set up for making gypsum
wallboard and ceilings that can reduce the need for
cement / river bed sand to some extent. This is well
established practice in developed countries.
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