2003-Waste Water Treatment in Leather Industry
-
Upload
harshitha-alisha -
Category
Documents
-
view
157 -
download
6
Transcript of 2003-Waste Water Treatment in Leather Industry
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 1/16
Designed by TheTemplateMart.com
WASTE WATER
TREATMENT IN LEATHER INDUSTRY
PRESENTATION
BY:
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 2/16
INTRODUCTION
Tannery wastes rank among the heaviest and most
polluting of all industrial wastes.
Characteristics-- disagreeable appearance, a bad smell,
and a high degree of intractability.
Animal skins consist of three layers:
The epidermis (cuticle or outer layer)
Layer of fatty tissue &
The inner layer, corium.
Tanning process objective: strip off the two outer layers
-- subject the corium to the action of agents -- from a
semi-solid protein to the tough insoluble mass --
LEATHER .
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 3/16
action of tanning agents
Corium undergoes atransformation (corium becomes insoluble in water,
tough, flexible and highly durable)
Main tanning process:
vegetable tanning process : sole, harness etcchrome tanning process: glove & garment leather.
miscellaneous tanning process ( Alum, oil etc):
furs, chamois etc.
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 4/16
TANNING-PROCESS
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 5/16
WASTEWATER CONTAINS:
Salts (Cl), fat, protein, preservatives (soaking);
Lime and ammonium salts, ammonia, protein
(hair), and sulphides (fleshing, trimming, bating);
Chromium(salts) and polyphenolic compounds
(tanning);
Dye and solvent chemicals (wet-finishing).
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 6/16
CHARACTERSTICS OF TANNERY
WASTES Heavy-- Large amount of suspended matter (hairs,
particles of flesh, suspended particles of lime and calciumcarbonate).
Ability to form a lime mortar inside receiving sewer (
lime calcium carbonate).
CO2
decomposition of organic matter
Vegetable tanneries high colour -- spent tan liquors.
Chrome tanneries color absent
Chrome tannery -- intermittent discharges --highly
insoluble, inorganic solids, low in pH value, and contain
considerable chromium (moderately toxic).
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 7/16
WASTEWATER TREATMENT
Physical treatment (mechanical treatment) screening,
filtering, grease removal, settling, sedimentation etc.
Physico-chemical treatment coagulation with
chemicals, followed by sedimentation.
Biological treatment sand filters and trickling filters.
Sludge handling.
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 8/16
STORAGE AND SEDIMENTATION
Beam house
scrub house
BY PASS
Dry weather operation Tan yard
waste
RIVER
FIG: FLOW DIAGRAM OF TANNERY WASTE TREATMENT PLANT
Settling basin
Settling basin
Pump Sump
Sludge
lagoon
Tan
liquor
storage
lagoon
Man hoi
Man hoi
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 9/16
Tannery waste treatment processes -- storage, sedimentation,
and regulated discharge.
The plant, designed for 200,000 gallons of waste per day-- 2
earthen settling basins, each of 500,000 gallons capacity--operated -- fill and draw units --24hour period.
The weaker waste -- discharged directly & stronger wastes
(intermittent wastes) are settled and subjected to regulated
discharge.
To eliminate a larger portion of BOD & to reduce the amount
of colour -- effluent vegetable tan liquors--separate lagoons
&discharged --periods of high water in the stream.
A separate lagoon for the spent tan liquors --storage for 200
days of normal tannery output. During low stream flow, the scrub house or bleaching wastes
will also be put in the spent tan lagoon to ensure a minimum of
colour in the waste discharge.
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 10/16
CHEMICAL PRECIPITATION
Degree of treatment -- plain sedimentation is insufficient --
coagulation by the addition of chemicals. Coagulants --sulphuric acid, carbon dioxide from flue gas, alum,
and iron salts.
Mechanical flocculation -- part of the treatment.
Alum probably --longest history of use-- tried by several tanneries --
auxiliary to sedimentation during period of low stream flow.
Flue gas -- elimination of caustic lime in tannery waste
Iron salts -- either alone or conjugation with lime.
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 11/16
TRICKLING FILTER PROCESS
A schematic cross-section of thecontact face of the bed media in a trickling filter
Tohelp protectyour privacy, PowerPointprevented thisexternalpicturefrom being automatically downloaded.To download and display thispicture,click Optionsin the MessageBar, and then click Enableexternalcontent.
Tohelp protectyour privacy, PowerPointprevented thisexternalpicturefrom being automatically downloaded. Todownload and display thispicture, click Optionsin theMessageBar, and then click Enableexternalcontent.
A typical complete
trickling filter system
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 12/16
SLUDGE DISPOSAL
All methods -- tannery waste treatment -- sedimentation,
with or without the addition of chemicals -- formidablequantities of sludge (5-10%).
Disposal --sludge in an acceptable --difficult problem.
Common practice -- discharge sludge -- low lying areas
of waste land / to specially prepared sludge lagoons(feasible only if sufficient land area can be provided).
A thick sludge -- a smaller area-- thick tannery sludge ---
difficult to pump.
More satisfactory method of sludge disposal -- provisionof drying beds of sand and cinders, with or without under
drains.
Vacuum filters -- dewatering tannery sludge¶s.
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 13/16
PREVENTION OF WASTE
PRODUCTION Water conservation:
A reduction of water
Re-use of wastewater
Curing hides and skins:
Reduction of the use of salt for preservation
Chilling without salt
Radiation by electron beam or gamma rays.
Biodegradable preservatives (insecticides) should be
used instead of derivatives of chlorinated aromatic
hydrocarbons
Beamhouse processes:
Hair saving methods -- degraded keratin
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 14/16
Tanning: Aluminium, zirconium, titanium and iron are might
be used as substitutes for chromium salts
Finishing:Reduction of volatile organic compounds (VOC) --
aqueous finishes for base and middle finishing coatings.
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 15/16
REFERENCES
Rudolfs W., (2006). Industrial Wastes, Their Disposal
and Treatment. Agrobios (India). pp:148-171.
Mahopathra P.K., (2006). Environmental Biotechnology.,
I.K.International Publishing House Pvt. Ltd. pp:101-147. http://www.fao.org/wairdocs
5/12/2018 2003-Waste Water Treatment in Leather Industry - slidepdf.com
http://slidepdf.com/reader/full/2003-waste-water-treatment-in-leather-industry 16/16