Title of Invention	A PROCESS FOR THE MANUFACTURE OF WET BLUE CHROME TANNED HIDE WITH NO DISCHARGE OF LIQUID EFFLUENT OR TOXIC SOLID WASTE
Abstract	A process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste comprises the steps of taking the composite spent liquors obtained from the liming, deliming and pickling operations to an Internal ETP; treating the said composite liquors with a culture of microorganisms, such as herein described, producing bacterial proteases (en/ymes) and bringing the pH to 8 . 5 to 9 . 5. Thereafter, the resultant is recycled for the soaking operation; the spent liquor, obtained after the soaking operation, is evaporated to dryness. The chrome is recovered from the spent liquor, obtained after the chrome tanning and finishing operation, in a CRP, for re-use, the supernatant liquor, after such recovery, being reused for the pickling operation, The wash liquor obtained before deliming and a part of the wash liquor obtained after deliming is taken for carrying out the liming operation. The left over part of the wash liquor obtained after deliming together with tannery spillages and yard cleaning water are taken to an Extemal ETP for treatment and evaporation to dryness. Biogas is generated from the fleshings, by methanisation, to serve as a fuel.

Title of Invention

A PROCESS FOR THE MANUFACTURE OF WET BLUE CHROME TANNED HIDE WITH NO DISCHARGE OF LIQUID EFFLUENT OR TOXIC SOLID WASTE

Abstract

A process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste comprises the steps of taking the composite spent liquors obtained from the liming, deliming and pickling operations to an Internal ETP; treating the said composite liquors with a culture of microorganisms, such as herein described, producing bacterial proteases (en/ymes) and bringing the pH to 8 . 5 to 9 . 5. Thereafter, the resultant is recycled for the soaking operation; the spent liquor, obtained after the soaking operation, is evaporated to dryness. The chrome is recovered from the spent liquor, obtained after the chrome tanning and finishing operation, in a CRP, for re-use, the supernatant liquor, after such recovery, being reused for the pickling operation, The wash liquor obtained before deliming and a part of the wash liquor obtained after deliming is taken for carrying out the liming operation. The left over part of the wash liquor obtained after deliming together with tannery spillages and yard cleaning water are taken to an Extemal ETP for treatment and evaporation to dryness. Biogas is generated from the fleshings, by methanisation, to serve as a fuel.

Full Text	This invention relates to a process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste. Conventionally, hide is soaked twice in fresh water. This results in the use of double the volume of the soak-liquor than that required in the process according to this invention. Besides, the soak-liquor obtained in the conventional process contains a very high amount of total dissolved solid (TOS) and is usually sent for solar evaporation. However, the high amount of TDS makes solar evaporation difficult. Conventionally, liming is done in fresh water, in higher water-floats. The waste liquor from liming contains sodium sulphide , lime and protein waste which are very difficlult to treat Conventionally, reliming is done in fresh water with additions of chemicals including caustic soda/soda ash. 'I'he process according to this invention dispenses with the reliming operation. Conventionally, deliming is done in higher water-floats, making effluent treatment difficult. In the process according to this invention, the deliming is done in dry-float. The disadvantages of the known processes used in the tanning industry are: a. On an average a tannery consumes 25 litres of water for tanning one kg. of raw hide up to wet blue. This volume depletes scarce water resources of the country. b. The percentage of chemicals used is directJy proportional to the volume of water used in the process. Accordingly, the consumption of chemicals is also high. c. The conventional tannery generates solid waste which contains every chemical discharge, from chrome, salt, calcium, sulphide to organic matters. This renders safe management and beneficial disposal of the solid waste difficult. d. While the appropriate authority has stipulated 2100 Mg/litre as the permissible level of TDS, a vast majority of the tanneries fmd this difficult to adhere to, creating an uncertain future for them. c. Effluent treatment plants (ICl Ps) of tanneries are monitored by Govemment and this poses several problems to tannery units especially in rnceting various requirements laid down for such EIPs. ()n the other hand, this invention has the following advantages: a. The water consumption is as low as 2. 5 litres for processing 1 kg. of raw hide into wet blue tanned hide, which is a ten time reduction compared to the conventional consumption of water. b. The use of the process according to this invention results in a 30 % of saving in basic chemicals, such as, sodium sulphide, lime and chromium sulphate, This invention ensures the total use of all the above chemicals as against only 70% offtake of the conventional system. Other than the cost saving of 30% , the constituents of the solid waste is also correspondingly reduced. c. The process according to this invention generates waste which is free from chrome sulphide and salt making it possible for beneficially using it for agriculture, since the basic ingredients are only organic matter and some amount of calcium and ammonia. d. As there is no liquid effluent discharge, the question of TDS does not arise. This is a substantial achievement inasmuch as the TDS of 2100 mg./litre stipulated by the appropriate authority is virtually impossible in a conventional tannery, e. As there is no liquid effluent or toxic solid waste discharge, the question of monitoring ETPs by Government does not arise, f An important consideration is that the quality of leather is greatly enhanced. Various other features of this invention will be discernible from the following further description. The process, according to this invention, for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste comprises the steps of taking the composite spent liquors obtained from the liming, deliming and pickling operations to an Internal ETP; treating the said composite liquors with a culture of microorganisms, such as herein described, producing bacterial proteases (enzymes) and bringing the pH to 8.5 to 9 . 5 and, thereafter, recycling the same for the soaking operation; evaporating the spent liquor, obtained after the soaking operation, to dryness; recovering the chrome from the spent liquor, obtained after the chrome tanning and finishing operation, in a CRP, for re-use, the supernatant liquor, after such recovery, being reused for the pickling operation; taking the wash liquor obtained before deliming and a part of the wash liquor obtained after deliming for carrying out the liming operation; taking the left over part of the wash liquor obtained after deliming together with tannery spillages and yard cleaning water to an External ETP for treatment and evaporation to dryness; and generating biogas from the fleshings, by methanisation, to serve as a fuel. EXAMPLE The composite spent liquors which are obtained after the liming, deliming and pickling operations are taken to an In-Plant Effluent Treatment Plant (Internal ETP). The Internal ElV is an effluent treatment plant which is located within the boundary of the tannery yard or the leather processing area, so that the treated effluents can be recycled for leather processing; unlike the conventional external External Effluent IVeatment Plant (External EIT) where treated liquors are not taken back for leather processing, but let out into public waterways. In the Internal ETP, the composite spent liquors aforesaid are treated with microorganisms producing bacterial proteases (enzymes) and the pH is brought to a value of 8.5 suited for soaking of raw hides. The enzymes digest the unwanted unstructured proteins of the hide. The composite liquors treated as above in the Internal ETP are thus recycled for the soaking of raw hide, Thus, what would ordinarily have been discharged from the tannery into the External EIP is recycled for hide treatment. On the other hand, the spent liquor obtained after soaking is evaporated by solar evaporation or by known mechanical means, so much so nothing is left as liquid effluent after the soaking, liming, deliming and pickling operations. So also the spent liquor from the chrome tanning operation and subsequent finishing is taken to the chrome recovery plant (CRP) where the chrome content is totally recovered and reused in the tannery. The supernatant liquid is taken for the pickling operation. The CRP contains a collection sump, a reactor and a stirrer. The spent liquor remaining after the chrome tanning process, is taken through pipes to the collection sump. From the sump, the spent liquor is pumped to the reactor in which magnesium oxide is added to obtain a chrome precipitate. 1 his precipitate is taken to the stirrer wherein sulphuric acid is added during stirring. The output is "recovered chrome" which is re-used for chrome tanning. The supernatant liquor, which is chrome-free clear liquor formed in the upper part of the reactor is reused for pickling. 1 hus nothing is left as a liquid effluent after the chrome tanning operation. Washing of the hide is done at two stages, one before deliming and one after deliming , Ihe entire before deliming wash liquor is mixed with 50% of the after deliming wash liquor and re-used for liming. The left-over 50% of the after deliming wash liquor together with tannery spillages and yard cleaning water are taken to a small l!.xtemal IllV and treated. Being of very small volume, this liquid is solar evaporated to dryness. I'he tannery spillages and yard cleaning water along with 50% of after delime washing liquor taken to the small External ETP is treated in the following manner.: (i) primary settling (ii) aeration (iii) secondary settling (iv) solar evaporation 1 annery spillages refer to water that might be spilled while conveying hides from one process location to another. Yard cleaning water refers to water used for cleaning processing machines such as tanning drums, paddles and fleshing machines; and water used for cleaning the tannery floor. Fleshing is a bye-product of the tanning industry, when producing wet blue leather from raw hide. Since fleshing is a proteinous matter, biogas is produced by methanisation of fleshing. The biogas thus produced is used as fuel for the generation of heat involved in mechanical evaporation (to which reference has been made herein) and other tannery operations. An example of a known mechanical evaporator is one made of coiled pipes. We Claim: 1. A process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste comprising the steps of taking the composite spent liquors obtained from the liming, deliming and pickling operations to an Internal EIP; treating the said composite liquors with a culture of microorganisms, such as herein described, producing bacterial proteases (enzymes) and bringing the pH to 8 . 5 to 9 . 5 and, thereafter, recycling the same for the soaking operation; evaporating the spent liquor, obtained after the soaking operation, to dryness; recovering the chrome from the spent liquor, obtained after the chrome tanning and finishing operation, in a CRP, for re-use, the supernatant liquor, after such recovery, being re-used for the pickling operation; taking the wash liquor obtained before deliming and a part of the wash liquor obtained after deliming for carrying out the liming operation; taking the left over part of the wash liquor obtained after deliming together with tannery spillages and yard cleaning water to an External ETP for treatment and evaporation to dryness; and generating biogas from the fleshings, by methanisation, to serve as a fuel. 2. A process as claimed in Claim 1 wherein evaporation is carried out by solar or mechanical means. 3. A process as claimed in Claim 1 or Claim 2 wherein the chrome is recovered in the CRP by addition of magnesium oxide to obtain a chrome precipitate which is treated with sulphuric acid to recover chrome. 4. A process as claimed in any one of the preceding Claims wherein the left over part of the wash liquor obtained after deliming , the tannery spillages and yard cleaning water are treated in the External ETP by primary settling, aeration and secondary setding, before evaporation. 5. A process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste substantially as herein described with reference to, and as illustrated by, the Example. 6. Wet blue chrome tanned hide whenever manufactured by a process as claimed in any one of the preceding Claims.

Full Text

This invention relates to a process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste.
Conventionally, hide is soaked twice in fresh water. This results in the use of double the volume of the soak-liquor than that required in the process according to this invention. Besides, the soak-liquor obtained in the conventional process contains a very high amount of total dissolved solid (TOS) and is usually sent for solar evaporation. However, the high amount of TDS makes solar evaporation difficult.
Conventionally, liming is done in fresh water, in higher water-floats. The waste liquor from liming contains sodium sulphide , lime and protein waste which are very difficlult to treat
Conventionally, reliming is done in fresh water with additions of chemicals including caustic soda/soda

ash. 'I'he process according to this invention dispenses with the reliming operation.
Conventionally, deliming is done in higher water-floats, making effluent treatment difficult. In the process according to this invention, the deliming is done in dry-float.
The disadvantages of the known processes used in the tanning industry are:
a. On an average a tannery consumes 25 litres of water
for tanning one kg. of raw hide up to wet blue. This
volume depletes scarce water resources of the
country.
b. The percentage of chemicals used is directJy
proportional to the volume of water used in the
process. Accordingly, the consumption of chemicals
is also high.

c. The conventional tannery generates solid waste
which contains every chemical discharge, from
chrome, salt, calcium, sulphide to organic matters.
This renders safe management and beneficial
disposal of the solid waste difficult.
d. While the appropriate authority has stipulated 2100
Mg/litre as the permissible level of TDS, a vast
majority of the tanneries fmd this difficult to adhere
to, creating an uncertain future for them.
c. Effluent treatment plants (ICl Ps) of tanneries are
monitored by Govemment and this poses several problems to tannery units especially in rnceting various requirements laid down for such EIPs.
()n the other hand, this invention has the following advantages:
a. The water consumption is as low as 2. 5 litres for
processing 1 kg. of raw hide into wet blue tanned

hide, which is a ten time reduction compared to the conventional consumption of water.

b. The use of the process according to this invention
results in a 30 % of saving in basic chemicals, such
as, sodium sulphide, lime and chromium sulphate,
This invention ensures the total use of all the above
chemicals as against only 70% offtake of the
conventional system. Other than the cost saving of
30% , the constituents of the solid waste is also
correspondingly reduced.
c. The process according to this invention generates
waste which is free from chrome sulphide and salt
making it possible for beneficially using it for
agriculture, since the basic ingredients are only
organic matter and some amount of calcium and
ammonia.
d. As there is no liquid effluent discharge, the question
of TDS does not arise. This is a substantial

achievement inasmuch as the TDS of 2100 mg./litre
stipulated by the appropriate authority is virtually
impossible in a conventional tannery, e. As there is no liquid effluent or toxic solid waste
discharge, the question of monitoring ETPs by
Government does not arise,
f An important consideration is that the quality of
leather is greatly enhanced.
Various other features of this invention will be discernible from the following further description.
The process, according to this invention, for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste comprises the steps of taking the composite spent liquors obtained from the liming, deliming and pickling operations to an Internal ETP; treating the said composite liquors with a culture of microorganisms, such as herein described, producing bacterial proteases (enzymes) and bringing the pH to 8.5 to 9 . 5 and, thereafter, recycling the same for

the soaking operation; evaporating the spent liquor,
obtained after the soaking operation, to dryness;
recovering the chrome from the spent liquor,
obtained after the chrome tanning and finishing
operation, in a CRP, for re-use, the supernatant
liquor, after such recovery, being reused for the
pickling operation; taking the wash liquor obtained
before deliming and a part of the wash liquor
obtained after deliming for carrying out the liming
operation; taking the left over part of the wash
liquor obtained after deliming together with tannery
spillages and yard cleaning water to an External
ETP for treatment and evaporation to dryness; and
generating biogas from the fleshings, by
methanisation, to serve as a fuel.
EXAMPLE
The composite spent liquors which are obtained after the liming, deliming and pickling operations are taken to an In-Plant Effluent Treatment Plant (Internal ETP). The Internal ElV is an effluent treatment plant

which is located within the boundary of the tannery yard or the leather processing area, so that the treated effluents can be recycled for leather processing; unlike the conventional external External Effluent IVeatment Plant (External EIT) where treated liquors are not taken back for leather processing, but let out into public waterways.
In the Internal ETP, the composite spent liquors aforesaid are treated with microorganisms producing bacterial proteases (enzymes) and the pH is brought to a value of 8.5 suited for soaking of raw hides. The enzymes digest the unwanted unstructured proteins of the hide.
The composite liquors treated as above in the Internal ETP are thus recycled for the soaking of raw hide, Thus, what would ordinarily have been discharged from the tannery into the External EIP is recycled for hide treatment.

On the other hand, the spent liquor obtained after soaking is evaporated by solar evaporation or by known mechanical means, so much so nothing is left as liquid effluent after the soaking, liming, deliming and pickling operations.
So also the spent liquor from the chrome tanning operation and subsequent finishing is taken to the chrome recovery plant (CRP) where the chrome content is totally recovered and reused in the tannery. The supernatant liquid is taken for the pickling operation.
The CRP contains a collection sump, a reactor and a stirrer. The spent liquor remaining after the chrome tanning process, is taken through pipes to the collection sump. From the sump, the spent liquor is pumped to the reactor in which magnesium oxide is added to obtain a chrome precipitate. 1 his precipitate is taken to the stirrer wherein sulphuric acid is added during stirring. The output is "recovered chrome" which is re-used for chrome tanning. The supernatant liquor,

which is chrome-free clear liquor formed in the upper part of the reactor is reused for pickling.
1 hus nothing is left as a liquid effluent after the chrome tanning operation.
Washing of the hide is done at two stages, one before deliming and one after deliming , Ihe entire before deliming wash liquor is mixed with 50% of the after deliming wash liquor and re-used for liming.
The left-over 50% of the after deliming wash liquor together with tannery spillages and yard cleaning water are taken to a small l!.xtemal IllV and treated. Being of very small volume, this liquid is solar evaporated to dryness.
I'he tannery spillages and yard cleaning water along with 50% of after delime washing liquor taken to the small External ETP is treated in the following manner.:

(i) primary settling
(ii) aeration
(iii) secondary settling
(iv) solar evaporation
1 annery spillages refer to water that might be spilled while conveying hides from one process location to another.
Yard cleaning water refers to water used for cleaning processing machines such as tanning drums, paddles and fleshing machines; and water used for cleaning the tannery floor.
Fleshing is a bye-product of the tanning industry, when producing wet blue leather from raw hide. Since fleshing is a proteinous matter, biogas is produced by methanisation of fleshing. The biogas thus produced is used as fuel for the generation of heat involved in mechanical evaporation (to which reference has been made herein) and other tannery

operations. An example of a known mechanical evaporator is one made of coiled pipes.

We Claim:
1. A process for the manufacture of wet blue chrome tanned hide with no discharge of liquid effluent or toxic solid waste comprising the steps of taking the composite spent liquors obtained from the liming, deliming and pickling operations to an Internal EIP; treating the said composite liquors with a culture of microorganisms, such as herein described, producing bacterial proteases (enzymes) and bringing the pH to 8 . 5 to 9 . 5 and, thereafter, recycling the same for the soaking operation; evaporating the spent liquor, obtained after the soaking operation, to dryness; recovering the chrome from the spent liquor, obtained after the chrome tanning and finishing operation, in a CRP, for re-use, the supernatant liquor, after such recovery, being re-used for the pickling operation; taking the wash liquor obtained before deliming and

a part of the wash liquor obtained after deliming for carrying out the liming operation; taking the left over part of the wash liquor obtained after deliming together with tannery spillages and yard cleaning water to an External ETP for treatment and evaporation to dryness; and generating biogas from the fleshings, by methanisation, to serve as a fuel.
2. A process as claimed in Claim 1 wherein evaporation
is carried out by solar or mechanical means.
3. A process as claimed in Claim 1 or Claim 2 wherein
the chrome is recovered in the CRP by addition of
magnesium oxide to obtain a chrome precipitate which
is treated with sulphuric acid to recover chrome.
4. A process as claimed in any one of the preceding Claims
wherein the left over part of the wash liquor obtained
after deliming , the tannery spillages and yard cleaning
water are treated in the External ETP by primary

settling, aeration and secondary setding, before evaporation.
5. A process for the manufacture of wet blue chrome
tanned hide with no discharge of liquid effluent or toxic solid waste substantially as herein described with reference to, and as illustrated by, the Example.
6. Wet blue chrome tanned hide whenever manufactured
by a process as claimed in any one of the preceding
Claims.

Documents:

082-mas-2000-abstract.pdf

082-mas-2000-claims filed.pdf

082-mas-2000-claims grand.pdf

082-mas-2000-correspondence other.pdf

082-mas-2000-correspondence po.pdf

082-mas-2000-description complete filed.pdf

082-mas-2000-description complete grand.pdf

082-mas-2000-form 1.pdf

082-mas-2000-form 19.pdf

082-mas-2000-form 26.pdf

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Patent Number

201896

Indian Patent Application Number

82/MAS/2000

PG Journal Number

08/2007

Publication Date

23-Feb-2007

Grant Date

14-Aug-2006

Date of Filing

03-Feb-2000

Name of Patentee

K.K.S.K. LEATHERS PRIVATE LIMITED

Applicant Address

R.N. PUDUR, BHAVANI MAIN ROAD, ERODE 638 005, TAMIL NADU, INDIA

Inventors:

#	Inventor's Name	Inventor's Address
1	KHADER MOHIDEEN MOHAMED HYDER	K.K.S.K. LEATHERS PRIVATE LIMITED, R.N. PUDUR, BHAVANI MAIN ROAD, ERODE 638 005, TAMIL NADU, INDIA
2	KHADER MOHIDEEN AHAMED SHEIK MOHIDEEN	K.K.S.K. LEATHERS PRIVATE LIMITED, R.N. PUDUR, BHAVANI MAIN ROAD, ERODE 638 005, TAMIL NADU, INDIA

PCT International Classification Number

C14B1/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA