NZ626503B - Tannery process with effluent recycling - Google Patents
Tannery process with effluent recyclingInfo
- Publication number
- NZ626503B NZ626503B NZ626503A NZ62650314A NZ626503B NZ 626503 B NZ626503 B NZ 626503B NZ 626503 A NZ626503 A NZ 626503A NZ 62650314 A NZ62650314 A NZ 62650314A NZ 626503 B NZ626503 B NZ 626503B
- Authority
- NZ
- New Zealand
- Prior art keywords
- effluent
- procedure
- liming
- recycling
- drum
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 155
- 238000004064 recycling Methods 0.000 title claims abstract description 43
- VYZAMTAEIAYCRO-UHFFFAOYSA-N chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 32
- 238000002791 soaking Methods 0.000 claims abstract description 31
- 238000004043 dyeing Methods 0.000 claims abstract description 28
- 230000003472 neutralizing Effects 0.000 claims abstract description 26
- 238000005554 pickling Methods 0.000 claims abstract description 26
- 238000001914 filtration Methods 0.000 claims abstract description 18
- 239000002910 solid waste Substances 0.000 claims description 19
- 239000002699 waste material Substances 0.000 claims description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 9
- 239000000126 substance Substances 0.000 abstract description 10
- 239000000463 material Substances 0.000 abstract description 9
- 239000002351 wastewater Substances 0.000 abstract 5
- 239000000203 mixture Substances 0.000 description 34
- 238000007599 discharging Methods 0.000 description 17
- 239000003795 chemical substances by application Substances 0.000 description 15
- 230000000875 corresponding Effects 0.000 description 15
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 8
- 235000015450 Tilia cordata Nutrition 0.000 description 8
- 235000011941 Tilia x europaea Nutrition 0.000 description 8
- 239000011651 chromium Substances 0.000 description 8
- 239000004571 lime Substances 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 238000000354 decomposition reaction Methods 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 6
- 239000002253 acid Substances 0.000 description 6
- 238000005237 degreasing agent Methods 0.000 description 6
- 239000003925 fat Substances 0.000 description 6
- BDAGIHXWWSANSR-UHFFFAOYSA-N formic acid Chemical compound OC=O BDAGIHXWWSANSR-UHFFFAOYSA-N 0.000 description 6
- 239000011780 sodium chloride Substances 0.000 description 6
- 229910052804 chromium Inorganic materials 0.000 description 5
- 239000000975 dye Substances 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 239000010985 leather Substances 0.000 description 5
- 150000003839 salts Chemical class 0.000 description 5
- 102000004190 Enzymes Human genes 0.000 description 4
- 108090000790 Enzymes Proteins 0.000 description 4
- UIIMBOGNXHQVGW-UHFFFAOYSA-M NaHCO3 Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 4
- GRVFOGOEDUUMBP-UHFFFAOYSA-N Sodium sulfide Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 description 4
- 239000000843 powder Substances 0.000 description 4
- 102000004169 proteins and genes Human genes 0.000 description 4
- 108090000623 proteins and genes Proteins 0.000 description 4
- 229910052979 sodium sulfide Inorganic materials 0.000 description 4
- 210000003491 Skin Anatomy 0.000 description 3
- HLBBKKJFGFRGMU-UHFFFAOYSA-M Sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 description 3
- 239000004280 Sodium formate Substances 0.000 description 3
- QTBSBXVTEAMEQO-UHFFFAOYSA-N acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 3
- 230000001105 regulatory Effects 0.000 description 3
- 235000019254 sodium formate Nutrition 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 238000005406 washing Methods 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-N HCl Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 2
- HYHCSLBZRBJJCH-UHFFFAOYSA-M Sodium hydrosulfide Chemical compound [Na+].[SH-] HYHCSLBZRBJJCH-UHFFFAOYSA-M 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid Chemical compound OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 2
- 239000003513 alkali Substances 0.000 description 2
- -1 alkalis Chemical class 0.000 description 2
- 150000001412 amines Chemical class 0.000 description 2
- 150000003863 ammonium salts Chemical class 0.000 description 2
- 230000000844 anti-bacterial Effects 0.000 description 2
- 239000003899 bactericide agent Substances 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000003344 environmental pollutant Substances 0.000 description 2
- 235000019253 formic acid Nutrition 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 230000001264 neutralization Effects 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 231100000719 pollutant Toxicity 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 239000002425 soil liming agent Substances 0.000 description 2
- 150000004763 sulfides Chemical class 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N Ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 210000004369 Blood Anatomy 0.000 description 1
- 102000011782 Keratins Human genes 0.000 description 1
- 108010076876 Keratins Proteins 0.000 description 1
- 102000001621 Mucoproteins Human genes 0.000 description 1
- 108010093825 Mucoproteins Proteins 0.000 description 1
- 231100000614 Poison Toxicity 0.000 description 1
- VXMKYRQZQXVKGB-CWWHNZPOSA-N Tannin Chemical compound O([C@H]1[C@H]([C@@H]2OC(=O)C3=CC(O)=C(O)C(O)=C3C3=C(O)C(O)=C(O)C=C3C(=O)O[C@H]([C@H]2O)O1)O)C(=O)C1=CC(O)=C(O)C(O)=C1 VXMKYRQZQXVKGB-CWWHNZPOSA-N 0.000 description 1
- 210000000051 Wattle Anatomy 0.000 description 1
- CVTZKFWZDBJAHE-UHFFFAOYSA-N [N].N Chemical compound [N].N CVTZKFWZDBJAHE-UHFFFAOYSA-N 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- QGZKDVFQNNGYKY-UHFFFAOYSA-N ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 239000002610 basifying agent Substances 0.000 description 1
- 238000006065 biodegradation reaction Methods 0.000 description 1
- 239000008280 blood Substances 0.000 description 1
- 230000005591 charge neutralization Effects 0.000 description 1
- 150000001844 chromium Chemical class 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- QGBSISYHAICWAH-UHFFFAOYSA-N cyanoguanidine Chemical compound NC(N)=NC#N QGBSISYHAICWAH-UHFFFAOYSA-N 0.000 description 1
- 230000003247 decreasing Effects 0.000 description 1
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 description 1
- 235000019525 fullness Nutrition 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000011068 load Methods 0.000 description 1
- 235000013372 meat Nutrition 0.000 description 1
- 244000005700 microbiome Species 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 238000006386 neutralization reaction Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000003921 oil Substances 0.000 description 1
- 235000019198 oils Nutrition 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 230000003449 preventive Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
- 230000035943 smell Effects 0.000 description 1
- 239000001187 sodium carbonate Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 235000018553 tannin Nutrition 0.000 description 1
- 229920001864 tannin Polymers 0.000 description 1
- 239000001648 tannin Substances 0.000 description 1
- 235000015112 vegetable and seed oil Nutrition 0.000 description 1
- 239000008158 vegetable oil Substances 0.000 description 1
- 230000004584 weight gain Effects 0.000 description 1
- 235000019786 weight gain Nutrition 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
- C02F1/004—Processes for the treatment of water whereby the filtration technique is of importance using large scale industrial sized filters
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/22—Nature of the water, waste water, sewage or sludge to be treated from the processing of animals, e.g. poultry, fish, or parts thereof
- C02F2103/24—Nature of the water, waste water, sewage or sludge to be treated from the processing of animals, e.g. poultry, fish, or parts thereof from tanneries
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/04—Flow arrangements
- C02F2301/046—Recirculation with an external loop
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2303/00—Specific treatment goals
- C02F2303/24—Separation of coarse particles, e.g. by using sieves or screens
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C1/00—Chemical treatment prior to tanning
- C14C1/04—Soaking
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C1/00—Chemical treatment prior to tanning
- C14C1/06—Facilitating unhairing, e.g. by painting, by liming
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C1/00—Chemical treatment prior to tanning
- C14C1/08—Deliming; Bating; Pickling; Degreasing
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
- C14C3/02—Chemical tanning
- C14C3/04—Mineral tanning
- C14C3/06—Mineral tanning using chromium compounds
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
- C14C3/02—Chemical tanning
- C14C3/08—Chemical tanning by organic agents
- C14C3/22—Chemical tanning by organic agents using polymerisation products
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
- C14C3/02—Chemical tanning
- C14C3/28—Multi-step processes
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C3/00—Tanning; Compositions for tanning
- C14C3/32—Recovering tanning agents from leather
-
- C—CHEMISTRY; METALLURGY
- C14—SKINS; HIDES; PELTS; LEATHER
- C14C—CHEMICAL TREATMENT OF HIDES, SKINS OR LEATHER, e.g. TANNING, IMPREGNATING, FINISHING; APPARATUS THEREFOR; COMPOSITIONS FOR TANNING
- C14C9/00—Impregnating leather for preserving, waterproofing, making resistant to heat or similar purposes
- C14C9/02—Impregnating leather for preserving, waterproofing, making resistant to heat or similar purposes using fatty or oily materials, e.g. fat liquoring
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/152—Water filtration
Abstract
Industrial tanning process recycles tanning wastewater. Recyclying includes collecting, filtering and seperating of effluent material. Recycling is carried out after each step. Steps may include soaking, liming, re-liming, de-liming bating, pickling chrome tanning, re-tanning, neutralizing, and dyeing. The wastewater from each step is processed separately from the other steps and the recycled wastewater is reused for the same tanning step it was effluent of, after adding additional chemicals as required. ng. The wastewater from each step is processed separately from the other steps and the recycled wastewater is reused for the same tanning step it was effluent of, after adding additional chemicals as required.
Description
TANNERY PROCESS WITH EFFLUENT RECYCLING
Cross-Reference to Related Application
This application claims priority benefits from Chinese Patent
Application No. 201310689868.2 having a filing date of December 23, 2013,
from Chinese Patent Application No. 201410051333.7 having a filing date of
February 17, 2014, and from US Patent Application No. 14/220,871 having a
filing date of 20 March 2014.
Field of the Invention
The present invention relates to relates to the recycling of effluent
emitted from an industrial tanning operation.
Background of the Invention
Large quantities of chemical materials, such as acids, alkalis, salt,
sulfides, lime, chrome tanning agents, fat-liquoring agents, and dyes, are used in
the tanning process, a considerable part of which flow into the effluents.
Tannery effluents mainly come from the preparation process, tanning process,
and other wet-processing processes. The discharge of effluents from the soaking
to dyeing procedures accounts for more than 90% of the total discharge of
effluent from the whole tanning process. These effluents are a complex
composition containing large quantities of poisonous and harmful substances,
including lime, salts, fat, ammonia and nitrogen-based compounds, protein,
sulfides, chromium salt, dyes, hair, hide trimmings, and dirt. The effluents
contain very high Biochemical Oxygen Demand (BOD) and Chemical Oxygen
Demand (COD) values. Due to the great variety of pollutants involved, the great
range in the coefficient of variation for the quality and quantity of water, and
their fetid smell, effluents from tanning factories are difficult to treat.
With the development of environmental protection equipment, the
technology for treating tannery effluents has advanced (see Table 1). However,
the cost of operating the treatment technology is still high and its efficiency is
low. As a result, pollution from tannery is still not effectively controlled.
Table 1: Current Technology for Treating Tannery Effluent
Technical
Technology Technical Advantage
Deficiency
Conventional Removal Rates: Requires a high
activated sludge BOD > 90% quality effluent; is
process not applicable to
COD ≈ 60%-80%
shock load; require
Chromaticity ≈ 50% - 90%
a large amount of
S ≈ 85% - 98%
power; is expensive
to install; requires a
large area; not
effective at
removing ammonia
nitrogen
Technical
Technology Technical Advantage
Deficiency
Biological Removal Rates: Blockages are likely
contact oxidation and maintenance is
BOD ≈ 95%
process difficult; the entire
COD ≈ 92%
system must be
S ≈ 98%
stopped when
performing
maintenance.
Oxidation ditch Removal Rates: The treatment effect
BOD > 95% is not stable; can
only be used in
S ≈ 99% - 100%
warm weather
Suspended solids ≈ 75%.
climates.
Bi-layer biofilter Removal Rates: A suitable reflux
ratio needs to be
BOD ≈ 98%
determined; suitable
COD ≈ 90%
filter materials are
Cr (III) > 96%
required; very
S ≈ 96%
expensive.
Suspended solids ≈ 95%
SBR process Removal Rates: Very expensive; can
only be deployed at
COD ≈ 93.3%
a small scale; its
S ≈ 99.0%
efficiency is low;
Cr (III)≈ 99.4%.
maintenance is
Suspended solids ≈ 90.3%
difficult.
Currently, some companies’ recycle tannery effluents. However they
only recycle effluents using a short procedure (see Table 1), which has a limited
effect in reducing the discharge of effluents, the economy of chemical materials,
and the reduction of production cost. It is a complicated and difficult problem to
recycle all the effluents from of all the procedures associated with the tanning
process. Some of the problems associated with the above technologies include:
the weight gain rate of limed pelt and the yield of wet-blue drop by 1.5% - 3.5%,
and the shrinkage temperature drops by 1.5°C - 3.5°C. Furthermore, the above
processes will damage the grain side of the wet-blue, making the grain side
rough and its color dark. This rougher surfaces results in the finished leather
failing to meet the requirements of some performance indexes.
Summary of the Invention
[0005a] In accordance with a first aspect of the invention, there is provided
a process for achieving near-zero emissions of tannery effluent comprising the
steps of:
(a) recycling an effluent in a soaking procedure, wherein said recycling of
said effluent comprises:
(i) collecting said effluent after said soaking procedure from a paddle-
tumbler or drum into a soaking procedure waste pool;
(ii) filtering solid wastes out of said effluent;
(iii) adding fresh water to said effluent; and
(iv) returning said effluent to said tumbler or drum;
(b) recycling an effluent in a liming procedure;
(c) recycling an effluent in a re-liming procedure;
(d) recycling an effluent in a de-liming bating procedure;
(e) recycling an effluent in a pickling chrome tanning procedure;
(f) recycling an effluent from a re-tanning procedure;
(g) recycling an effluent in a neutralizing procedure;
(h) recycling an effluent in a dyeing procedure.
[0005b] The term ‘comprising’ as used in this specification and claims
means ‘consisting at least in part of’. When interpreting statements in this
specification and claims which include the term ‘comprising’, other features
besides the features prefaced by this term in each statement can also be present.
Related terms such as ‘comprise’ and ‘comprised’ are to be interpreted in a
similar manner.
In one embodiment, the current process performs effluent recycling
in procedures from soaking to dyeing. Apart from normal volatilization and
unavoidable sifting, the recovery rate of the tannery effluent can reach near
100%, which solves the problem of tannery effluent discharge. Furthermore, the
process and equipment is relatively simple and easily applied to existing mass
production processes used in tannery.
In one embodiment of the process for recycling tanning effluent, the
effluent recycling is carried out independently in the soaking, liming, re-liming,
de-liming bating, pickling chrome tanning, re-tanning, neutralizing, and dyeing
procedures.
In the above embodiment the effluent is recycled in each of the eight
steps: (1) the soaking procedure; (2) the liming procedure; (3) the re-liming
procedure; (4) the de-liming bating procedure; (5) the pickling chrome tanning
procedure; (6) the re-tanning procedure; (7) the neutralizing procedure; and (8)
the dyeing procedure. These steps are discussed in greater detail below.
The recycling of the effluent in the soaking procedure involves:
collecting the effluent after each soaking procedure; filtering solid wastes in the
effluent; stirring uniformly; putting the effluent into a soaking drum or paddle-
tumbler for the next soaking procedure; and detecting the number of
microorganisms in the effluent to determine the amount of bactericide to add.
The recycling of the effluent in the liming procedure involves:
collecting the effluent after each liming procedure; filtering solid wastes in the
effluent; stirring the effluent uniformly; and putting the effluent into a liming
drum or paddle-tumbler for the next liming procedure. In the liming procedure,
hair can be filtered.
The recycling of the effluent in the re-liming procedure involves:
collecting the effluent after each re-liming procedure; filtering solid wastes in
the effluent; stirring uniformly; and putting the effluent into a re-liming drum or
paddle-tumbler for the next re-liming procedure.
The recycling of the effluent in the de-liming bating procedure
involves: collecting the effluent after each de-liming bating procedure; filtering
solid wastes in the effluent; stirring uniformly; and putting the effluent into a de-
liming bating drum for the next de-liming bating procedure;
The recycling of the effluent in the pickling chrome tanning procedure
involves: collecting the effluent after each pickling chrome tanning procedure;
filtering solid wastes in the effluent; stirring uniformly; and putting the effluent
into a pickling chrome tanning drum for the next pickling chrome tanning
procedure.
The recycling of the effluent in the re-tanning procedure involves:
collecting the effluent after each re-tanning procedure; filtering solid wastes in
the effluent; stirring uniformly; and putting the effluent into a re-tanning drum
for the next re-tanning procedure;
The recycling of the effluent in neutralizing procedure involves:
collecting the effluent after each neutralizing procedure; filtering solid wastes in
the effluent; stirring uniformly; and putting the effluent into a neutralizing drum
for the next neutralizing procedure;
The recycling of the effluents in the dyeing procedure involves:
collecting the effluent after each dyeing procedure; filtering solid wastes in the
effluent; stirring uniformly; and putting the effluent into a dyeing drum for the
next dyeing procedure.
In the above procedures, equipment, such as a strainer with a 1 mm - 5
mm bore diameter can be used to filter the solid wastes after each procedure.
Apart from normal volatilization and unavoidable sifting, nearly all of the
effluent can be recycled, and when the effluent is insufficient, fresh water can be
added. In the above procedures, most, if not all, of the parts of the effluents can
be recycled. In other words, in a particular setup, the various procedures can be
used alone or in combination with other procedures.
In one embodiment, fleshing and splitting are performed after the
soaking and liming procedures, respectively. The effluents produced during
fleshing and splitting can be collected in corresponding effluent collecting
devices for recycling.
After the soaking, liming, re-liming, de-liming bating, pickling chrome
tanning, re-tanning, neutralizing, and dyeing procedures the conventional water
washing step can be removed. However, if washing with water is necessary or
desired, the effluent produced after water washing also can be recycled.
In general, the soaking effluent can contain, among other things,
soaking agent, NaCl, Na CO , degreasing agent, fats and their decomposition
products, hair, keratin, mucoprotein, meat, blood. Under normal circumstances,
the content of residual degreasing agent in the effluent is usually 15% - 30% of
its initial amount, the content of soaking agent in the effluent is usually 15% -
% of its initial amount, and the content of Na CO in effluents is usually 30%
- 50% of its initial amount.
The effluents in the liming and re-liming procedures can contain,
among other things, fats and their decomposition products, salts, lime, a liming
2- - + 2+
agent, S , OH , Na , Ca , protein and its decomposition products, enzymes and
amines. Wherein the content of the residual lime in the effluents is usually 37%
- 55% of its initial amount, and the content of the residual Na S in the liming
effluent is usually 2.4 g/l - 3.2 g/l.
The de-liming bating effluent can contain, among other things,
proteins and their decomposition products, de-liming agent, degreasing agent,
fats and their decomposition products, enzymes and ammonium salts, and
amines. Wherein the content of the residual enzymes in the effluent is usually
% - 50% of its initial amount, the content of the residual ammonium salts in
the effluent is usually 30%-40% of its initial amount.
3+ -
The chrome tanning effluent can contain, among other things, Cr , Cl
, SO , proteins and their decomposition products, oils and fat and their
decomposition products, etc. Wherein the content of the residual Cr is usually
2.8 g/l - 3.2 g/l, the content of the residual Cl is usually 7 g/l - 15 g/l, the
content of the residual acid radical in the effluent is usually 30% - 45% of its
initial amount.
+ 3+
The re-tanning effluent can contain, among other things, Na , Cr and
organic tanning agent.
The neutralizing effluent can contain, among other things, neutral
salts. Chemical materials such as fat-liquoring agents, dyes and dye assistants
are used in the dyeing procedure, except a portion that are absorbed, the vast
majority flow into the effluent. These pollutants are macromolecular organic
matters, have high concentrations, but have slow biodegradation speed. All the
effluents above are normally discharged without disposal. This not only pollutes
the environment, but also is a waste of resources.
In some embodiments, the soaking and liming procedures can use the
same drum or paddle-tumbler. In these embodiments, the soaking and liming
effluents are collected to the collecting device respectively, and the drum or
paddle-tumbler is controlled for discharging the effluents into each collecting
device by the use of valves.
Specifically, when the soaking and liming procedures use the same
drum or paddle-tumbler, a first valve is mounted on the drum or paddle-tumbler
for discharging the soaking effluent into a corresponding effluent collecting
device, while a second valve is mounted on the drum or paddle-tumbler for
discharging the liming effluent into a corresponding effluent collecting device.
When discharging the soaking effluent, the first valve is opened, the second is
closed, and the effluent is discharged into the corresponding effluent collecting
device after passing through a split-flow pipe. When discharging the liming
effluent, the second valve is opened, the first valve is closed, and the effluent is
discharged into the corresponding effluent collecting device after passing
through a split-flow pipe.
Similarly, the de-liming bating and pickling chrome tanning
procedures can also use the same drum. The de-liming bating and pickling
chrome tanning effluents are collected next to the drum respectively and the
drum is controlled for discharging the effluent into each collecting device via
valves. Specifically, when the de-liming bating and pickling chrome tanning
procedures use the same drum, a third valve is mounted on the drum for
discharging the de-liming bating effluent into a corresponding effluent
collecting device, while a fourth valve is mounted on the drum for discharging
the pickling chrome tanning effluent into a corresponding effluent collecting
device. When discharging the de-liming bating effluent, the third valve is
opened, the fourth valve is closed, and effluent is discharged into the
corresponding effluent collecting device after passing through a split-flow pipe.
When discharging the pickling chrome tanning effluent, the third valve is
closed, the fourth valve is opened, and the effluent is discharged into the
corresponding effluent collecting device after passing through a split-flow pipe.
Similarly, the re-tanning, neutralizing and dyeing procedures can also
use the same drum. The re-tanning, neutralizing and dyeing effluents are
collected next to the drum respectively and the drum is controlled for
discharging effluent into each collecting device via valves. Specifically, when
the re-tanning, neutralizing and dyeing procedures use the same drum, a fifth
valve is mounted on the drum for discharging the re-tanning effluent into a
corresponding effluent collecting device, while a sixth valve is mounted on the
drum for discharging the neutralizing effluent into a corresponding effluent
collecting device. At the same time, a seventh valve is mounted on the drum for
discharging the dyeing effluent into a corresponding effluent collecting device.
When discharging the re-tanning effluent, the fifth valve is opened, while the
sixth and seventh valves are closed, and effluent is discharged into the
corresponding effluent collecting device after passing through a split-flow pipe.
When discharging the neutralizing effluent, the sixth valve is opened, the fifth
and seventh valves are closed, and the effluent is discharged into the
corresponding effluent collecting device after passing through a split-flow pipe.
When discharging the dyeing effluent, the fifth and sixth valves are closed, the
seventh valve is opened, and the effluent is discharged into the corresponding
effluent collecting device after passing through a split-flow pipe.
The above process leads to a reduction of discharge the effluents
which helps alleviate the tanning pollution problem as well as save energy. For
example, the temperature in the later period of the tanning process is around
28°C - 35°C, 3-10°C lower than conventional processes.
Furthermore, the finished leather manufactured by the above process
has a decreased looseness rate, increased compactness and fullness, and meets
the requirements of most performance indexes. Compared with processes using
fresh water, after each procedure, the resulting solid waste material is 5% - 40%
of that produced in process using fresh water, while consumption of chemical
materials can be reduced by 15% - 55%.In one embodiment, the consumption of
chromium powder is reduced by 35% - 65%. The consumption of some
chemical materials can be reduced by more than 90%, and consumption of
certain chemical materials such as salt can be almost entirely eliminated.
Brief Description of the Drawings
is a schematic flowchart showing a recycling process being
used throughout the tanning process.
Detailed Description of Embodiment(s)
illustrates one setup 100 of a near-zero emission tannery.
Soaking procedure 1 using the soaking effluent involves adding (based
on the weight of raw hide and skin ) 200% soaking effluent, 0.7% soaking agent,
0.3% degreasing agent, 0.5% sodium carbonate and 0.1% sodium sulfide. The
mixture then enters a cycle of running for 40 minutes and standing for 40
minutes. The cycle is repeated three times. Then 0.3% bactericide is added. The
mixture is then mixed for 20 minutes and then enters a cycle of running for 3
minutes and standing for 57 minutes. This cycle is repeated overnight before
running for 40 minutes the next day.
The effluent is then discharged and filtered 31 into a soaking effluent
pool where it is stirred uniformly 11. The effluent is pumped out by an alkali-
resistant pump, and returned 21 to soaking drum.
Liming procedure 2 using liming effluent involves adding (based on
the weight of raw hide and skin) 70% liming effluent, 1.0% liming assistant, and
0.15% sodium hydrosulfide. The mixture is then mixed for 30 minutes. Then
1.2% lime is added and the mixture is mixed for 30 minutes before being left to
stand for 30 minutes. Next, 0.5% sodium hydrosulfide is added and the mixture
is mixed for 20 minutes and then left to stand for 20 minutes. The hair is then
filtered out and 0.5% sodium sulfide, 0.8% lime and 0.1% degreasing agent are
added and the mixture enters a cycle of running for 20 minutes and standing for
minutes; this cycle is repeated three times. Next, 20% liming effluent, 0.5%
sodium sulfide, 0.5% liming assistant, and 1.0% lime is added and the mixture
enters a cycle of running for 20 minutes and standing for 20 minutes; this is
repeated 2 times. Then the mixture enters a cycle of mixing for 10 minutes and
standing for 20 minutes; this cycle is repeated 6 times. Next, 80% liming
effluent is added. The mixture then mixes for 10 minutes, before entering a
cycle of running for 5 minutes and standing for 55 minutes; this cycle continues
over night.
After liming procedure 2 is completed, or in some cases during the
procedure, the effluent is discharged and filtered 32 into effluent pool 12. From
effluent pool, the liming effluent is pumped out by an alkali-resistant pump 22
and returned to the liming drum.
Re-liming procedure 3 involves adding (based on the weight of raw
hide and skin) 100% re-liming effluent, 0.8% lime, 0.2% sodium sulfide, 0.4%
liming assistant, and 0.10% sodium hydroxide. The mixture is mixed for 30
minutes and then left to stand for 40 minutes. Then the process enters a cycle of
running for 5 minutes and standing for 55 minutes; this cycle is repeated 6
times. The mixture is then left to sit overnight.
After re-liming procedure 3 is completed, or in some cases during the
procedure, the effluent is discharged and filtered 33 into effluent pool 13. From
effluent pool, the liming effluent is pumped out by an alkali-resistant pump 23
and returned to the re-liming drum.
De-liming bating procedure 4 involves adding (based on the weight of
limed pelt) 100% effluent, 0.2% degreasing agent, 0.6% de-liming agent, 1.2%
ammonium sulfate, 0.2% hydrochloric acid, and 0.3% acetic acid. The mixture
is mixed for 40 minutes and 0.25% bating enzyme is added. Finally the mixture
is mixed for an additional 30 minutes.
After de-liming bating procedure 4 is completed, or in some cases
during the procedure, the effluent is discharged and filtered 34 into effluent pool
14. From effluent pool, the de-liming bating effluent is pumped out by an alkali-
resistant pump 24 and returned to the de-liming bating drum.
Pickling chrome tanning procedure 5 involves adding (based on the
weight of limed pelt) 90% pickling chrome tanning effluent, adjusting the
effluent to pH 0.7 by adding sulfuric acid and then adding 0.25% mildew
preventive. The mixture is then mixed for 10 minutes and then 0.5% formic acid
is added. The mixture is then mixed for an additional 20 minutes before adding
0.3% sulfuric acid for 3 times at 10 minute intervals. The mixture is then mixed
for 90 minutes before 0.2% fat-liquoring agent is added. The mixture is then
mixed for 30 minutes and allowed to sit 90 minutes before 1.8% chromium
powder is added. The mixture is then mixed for 30 minutes and an additional
2.2% chromium powder is added. The mixture is then mixed for 60 minutes and
then 0.5% sodium formate is added. The mixture is then mixed for 30 minutes
before adding 0.25% basifying agent. The mixture is then mixed for 4 hours
before finally adding 80% pickling chrome tanning effluent, heating to 35°C and
mixing for an additional 3 hours.
After pickling chrome tanning procedure 5 is completed, or in some
cases during the procedure, the effluent is discharged and filtered 35 into
effluent pool 15. From effluent pool, the pickling chrome tanning effluent is
pumped out by an acid-resistant pump 25 and returned to the pickling chrome
tanning drum.
Re-tanning procedure 6 involves adding (based on the weight of
shaved leather) 90% re-tanning effluent, adjusting its pH to 2.5 with sulfuric
acid, regulating the mixtures temperature to 36°C and then adding 0.3% formic
acid. The mixture is then mixed for 30 minutes and then 1.5% acrylic acid re-
tanning agent is added. The mixture is then mixed for another 30 minutes before
1.0% chromium powder and 0.3% fatliquoring agent are added. The mixture is
then mixed 60 minutes and 1.0% fat aldehyde is added. The mixture is then
mixed for 30 minutes and 0.8% sodium formate and 0.2% sodium bicarbonate
are added before the mixture is mixed another 60 minutes. The process then
enters of cycle of running for 10 minutes and standing for 50 minutes; this cycle
is repeated 5 times.
After re-tanning procedure 6 is completed, or in some cases during the
procedure, the effluent is discharged and filtered 36 into effluent pool 16. From
effluent pool, the re-tanning effluent is pumped out by an acid-resistant pump 26
and returned to the re-tanning drum.
Neutralizing procedure 7 involves adding (based on the weight of
shaved leather) 200% neutralizing effluent, regulating temperature to 35°C, and
then adding 2.0% neutralization tannin and 1.5% sodium formate before the
mixture is then mixed for 20 minutes. Next 1.2% sodium bicarbonate and 3.0%
fatliquoring agent are added before the mixture is mixed for 60 minutes while
the pH value is kept between 4.0 and 6.5.
After neutralizing procedure 7 is completed, or in some cases during
the procedure, the effluent is discharged and filtered 37 into effluent pool 17.
From effluent pool, the neutralizing effluent is pumped out by an acid-resistant
pump 27 back into the neutralizing drum.
Dyeing procedure 8 involves adding (based on the weight of shaved
leather) 80% dyeing effluent, regulating the temperature to 30°C, and adding
2.5% acrylic acid re-tanning agent before the mixture is mixed for 20 minutes.
Next 4.0% dicyandiamide re-tanning agent, 1.5% wattle extract, and 2.0%
sulfited vegetable oil are added before the mixture is mixed for 40 minutes.
Finally 2.0% dye and 1.5% composite fatliquoring agent are added before the
mixture is mixed for 60 minutes.
After dyeing procedure 8 is completed, or in some cases during the
procedure, the effluent is discharged and filtered 38 into effluent pool 18. From
effluent pool, the dyeing effluent is pumped out by an acid-resistant pump 28
back into the dyeing drum.
While particular elements, embodiments and applications of the
present invention have been shown and described, it will be understood, that the
invention is not limited thereto since modifications can be made by those skilled
in the art without departing from the scope of the present disclosure, particularly
in light of the foregoing teachings.
Claims (10)
1. A process for recycling an effluent emitted from a tanning operation comprising the steps of: (a) recycling an effluent in a soaking procedure, wherein said recycling of said effluent comprises: (i) collecting said effluent after said soaking procedure from a paddle-tumbler or drum into a soaking procedure waste pool; (ii) filtering solid wastes out of said effluent; (iii) adding fresh water to said effluent; and (iv) returning said effluent to said paddle-tumbler or drum; (b) recycling an effluent in a liming procedure; (c) recycling an effluent in a re-liming procedure; (d) recycling an effluent in a de-liming bating procedure; (e) recycling an effluent in a pickling chrome tanning procedure; (f) recycling an effluent from a re-tanning procedure; (g) recycling an effluent in a neutralizing procedure; (h) recycling an effluent in a dyeing procedure.
2. A process according to claim 1, wherein said step of recycling an effluent in a liming procedure comprises: (i) collecting said effluent after said liming procedure from a liming paddle-tumbler or drum into a liming procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said liming paddle-tumbler or drum.
3. A process according to claim 1 or claim 2, wherein said step of recycling an effluent in a re-liming procedure comprises: (i) collecting said effluent after said re-liming procedure from a re-liming paddle-tumbler or drum into a re-liming procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said re-liming paddle-tumbler or drum.
4. A process according to any one of the preceding claims, wherein said step of recycling an effluent in a de-liming bating procedure comprises: (i) collecting said effluent after said de-liming bating procedure from a de-liming bating drum into a de-liming bating procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said de-liming bating drum.
5. A process according to any one of the preceding claims, wherein said step of recycling an effluent in a pickling chrome tanning procedure comprises: (i) collecting said effluent after said pickling chrome tanning procedure from a pickling chrome tanning drum into a pickling chrome tanning procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said pickling chrome tanning drum.
6. A process according to any one of the preceding claims, wherein said step of recycling an effluent from a re-tanning procedure comprises: (i) collecting said effluent after said re-tanning procedure from a re-tanning drum into a re-tanning procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said re-tanning drum.
7. A process according to any one of the preceding claims, wherein said step of (a) recycling an effluent in a neutralizing procedure comprises: (i) collecting said effluent after said neutralizing procedure from a neutralizing drum into a neutralizing procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said neutralizing drum.
8. A process according to any one of the preceding claims, wherein said step of recycling an effluent in a dyeing procedure comprises: (i) collecting said effluent after said dyeing procedure from a dyeing drum into a dyeing procedure waste pool; (ii) filtering solid wastes out of said effluent; and (iii) returning said effluent to said dyeing drum.
9. A process according to claim 1, substantially as herein described with reference to any embodiment disclosed.
10. A process for achieving near-zero emissions of tannery effluent, substantially as herein described with reference to any embodiment shown in the accompanying flowchart.
Applications Claiming Priority (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201310689868.2 | 2013-12-04 | ||
CN201310689868.2A CN104694675A (en) | 2013-12-04 | 2013-12-04 | Novel process for manufacturing leather with simple procedures and equipment |
CN201410051333.7 | 2014-02-15 | ||
CN201410051333.7A CN104843807A (en) | 2014-02-15 | 2014-02-15 | Cycle engineering for realization of tanning waste water near-zero emission |
US14/220,871 US9776887B2 (en) | 2013-12-04 | 2014-03-20 | Tannery process with effluent recycling |
US14/220,871 | 2014-03-20 |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ626503A NZ626503A (en) | 2015-09-25 |
NZ626503B true NZ626503B (en) | 2016-01-06 |
Family
ID=
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11040890B2 (en) | Tannery process with effluent recycling | |
Sivaram et al. | Toxic waste from leather industries | |
Hu et al. | Ecological utilization of leather tannery waste with circular economy model | |
CN102534056B (en) | Tanning production process capable of recycling waste water repeatedly from soaking to dyeing | |
EP3045548B1 (en) | Chromium tanning process with reduced waste discharge | |
Gutterres et al. | Chromium in tannery wastewater | |
Hutton et al. | Water pollution caused by leather industry: a review | |
CN106145530B (en) | Method suede nitre dye wastewater treatment and recycled | |
Murad et al. | Studies on theWaste management syste m of a tannery: an overview | |
AU2009273626A1 (en) | Method of chemical-mechanical treatment of waste waters from operation of tanneries | |
AU2015271965B2 (en) | Tannery process with effluent recycling | |
CN104004866A (en) | Leather preparing technology capable of periodically filtering circulating wastewater | |
Swartz et al. | Water and wastewater management in the tanning and leather finishing industry: Natsurv 10 | |
WO2015081624A1 (en) | Tanning process | |
Awulachew | A review of pollution prevention technology in leather industry | |
WO2015120661A1 (en) | Circulation engineering for achieving near-zero discharge of tanning waste water | |
NZ626503B (en) | Tannery process with effluent recycling | |
Mijaylova Nacheva et al. | Alternative treatment strategy for tannery water reuse and material recovery | |
Sah | Greener approach to leather techniques | |
Madanhire et al. | Investigation of waste management practices and cleaner production application in a tannery: Case study | |
Mocanu et al. | Tanneries wastewater treatment | |
Ramanujam et al. | Wastewater treatment technology for tanning industry | |
Giaccherini | Modelling tannery wastewater treatment to evaluate alternative bioprocesses configurations | |
Crudu et al. | INNOVATIVE MATERIAL-TECHNOLOGY SYSTEM WITH CONTRIBUTION TO INCREASESING ECO-EFFICIENCY OF INDUSTRIAL LEATHER PROCESSING. | |
Chen et al. | Resourceful utilization of tannery wastewater |