A casestudy on disposal and management system of solid wastes generated from Tannery IndustrialEstate Dhaka (TIED)IntroductionLeatheris a stabilized and imperishable natural fabric of fine texture obtained fromraw (green) or preserved (Salted) hides and skins of animals by tanning throughinvolvement of both mechanical and chemical operations 1.
The conversion of animalouter coverings into leather is practiced by the primitive people from ancienttime, which is now one of the most prime-concerned global industries 2. Theleather industry, well known as user of natural resources is always not onlygiven priority for its economic dominance but also for environmental influenceas it generates pollutant wastes having hazardous impact on environmentaldegradation. For this, the leather industry is now introduced as highlypotential polluter industry unless proper disposal and treatment of generatedwastes is performed 3. The wastes generated by the tanneries are classifiedinto three groups such as solid, liquid and gaseous in nature and are enlistedin the figure I 4, 5.
FigureI: Types of wastes generated from tanneries during leather processing 5Inthe conversion of 1 ton wet salted hides, 500 kg of different chemicals, 40 of water (process and technical water) and2600-11700 kWh energy is consumed but only 200-250 kg of finished leather(grain and embossed split) is achieved containing only 72 kg chemicals insidewhich is only 25.5% of the total raw materials and discharge approximate 600 kgof waste in different forms 3, 6. The tanneries generate around 6 milliontons of solid waste as trimmings (both tanned and un-tanned), fleshing, splits,shaving & buffing dust and sludge (both chrome contained and non-chrome) atan average of 80% in leather processing per annum 7, 8, 9. During beam houseand post tanning operation, most of the solid wastes (trimmings, fleshing,splits and shaving dust) are generated, containing small amount of (2-6% (w/w))non-chrome mineral substance usually dependable on quality of hides/skins,tanning technique and condition process in chemical characteristics. Moreover,useless splits, shaving dust and unnecessary cuttings carry 3-6% (w/w) of fatand about 15% (w/w) of mineral components, including 3.5%-4.
5% (w/w) ofchromium as generatedfrom tanned leather. Sludge from wastewater treatment plant generally bearswater (up to 65% (w/w)), organic materials (30% (w/w)) and chromium (iii) compounds(approximately 2.5% (w/w)) 9.These solid wastes might have limitedimplementation but possess serious environmental problem without safe disposaland treatment 10. Though developed countries are now shifting away from thissector due to high labor cost and environmental risks, leather processing isstill an unavoidable source of earning foreign money and export trade for manydeveloping and under-developed countries 11. In Bangladesh, the leatherindustry is relatively an older industry with an age-old tradition of overseven decades has significant involvement of producing such leather, recognizedfor its superior grain pattern and strong fiber strength worldwide since 194012. According to the annual report of Bangladesh Economic Review of 2017,leather sector (combining leather industry, footwear and leather productsindustries) is ranked second in terms of earning foreign exchange just afterreadymade garments and around 1234 million$ is achieved from this sector in fiscalyear 2016-17 13, 14. To keep this momentum steady, the leather industriessituated in the capital’s Hazaribagh area is shifting to Harindhara village ofHemayetpur Thana under Savar Upazilla over 200 acres land and facilitated withcentral dumping yard, sludge power generating system (SPGS) and Central EffluentTreatment Plant (CETP) which better known as Tannery Industrial Estate Dhaka (TIED)or partially as Savar Leather Park for the purpose of eco-friendly productionfrom April 8, 2017 15.
Figure II: Map of Tannery Industrial Estateat Savar 16Thetanneries how maintain the generated solid wastes with proper utilization oftreatment system to reduce environmental risk at newly shifted area of SavarLeather Park are the highlights of this study by an application ofquestionnaire and focused group discussions. Literature ReviewTheraw hides and skins, used as the raw material of leather industry is mainlycomposition of protein and fat containing amount of 10.5% (w/w) of each groupsand 60% moisture content and high water (both free and bound) 9. Collagen, astructural protein is presented largely among different types of proteins (collagen, elastin, keratin,glycoprotein, albumins and globulins)and accountable to form leather associated with tanning materials 17. Duringleather processing the solid waste generates mostly in beam house 80%, tanning19% and finishing 1 % 18. The nature and amount of solid wasteoriginated from leather processing of one ton hides and skins are listed intable I 10.
TableI: Quantity of generated solid wastes in processing 1 tons of raw hides andskins 10 Sl. No. Name of solid waste Quantity (in kg) 1 Salt from handshaking 80 2 Salt from solar pans (not realized) 220 3 Hair 100 4 Raw hide cutting 40 5 Lime sludge 60 6 Fleshing 120 7 Wet blue trimming (grain splits) 30 8 Chrome splitting 65 9 Chrome shaving dust 95 10 Buffing dust 65 11 Dyed trimming 35 12 Dry sludge from ETP 125 The generated solid wastes of substantial amount from tanneries were dumpedopenly at the roadside when the tanneries in Bangladesh were located in thecapital’s Hazaribagh area that caused hazard both in human health and discomfortin living condition, results environmental calamities 19, 20. Research Methodology Study site and populationThe study was conducted at Tannery Industrial Estate Dhaka which is locatedat Harindhara village of Hemayetpur Thana under SavarUpazilla of the capital, where 155 tanneries are shifting from capital’s HazaribaghThana and 92 tanneries are running their production. Voluntary participation ofleather technologists of 12 tanneries was included in the study.
Study design and samplingA cross sectional study was carriedout to design the study frame work. A pilot study was done before sampling andquestionnaire preparation. The tanneries used as sample in the study wereselected by using random sampling method.Figure III: Conceptualframework of the study Find out solid wastes generating source & generation rate Characterize solid wastes Dumpingwastes Renewable wastes Direct dumping Treated dumping Suitable by-products Treatment cost Treated product’s cost a) Compareboth costs a)Comparison of both costsb) Environmentaleffects b) Influence on economic benefit a) Qualityassessment of dumping processb) Furtherrecommendation for better tannery solid waste management system Data collectionA standardizedstructured open-ended questionnaire was used for the data collection. Thequestionnaire was prepared in English and asked directly translating intoBengali and applied on December 6, 2017 to December 18, 2017. A skilled datacollection team of three members collected the listed data of questionnaireusing face to face interview technique. Permission from the industry authorityand verbal consent from the leather technologists of tanneries were taken inadvance. Respondents had complete liberty not to response to any of thequestions and leave any time during the study.
The interviewer-administeredquestionnaire included the general information of the tannery (number ofworkers, annual turnover, tanning methods and final products), disposal of solidwaste (generation of wastes, kinds of generated wastes, utilization andrecycling of waste, final destination of sludge and other solid waste). Informationon quality assessment & using of dumping yard was collected by approachingfocus group discussion method.Data analysisTo achieve the objective of the study, qualitative method was approachedwith utilization of descriptive analysis, comparative analysis, and costbenefit analytical tools.
In descriptive analysis, the general information ofthe tanneries like ownership, workforce, annual turnover, application oftanning methods, production type and capacity were included that highlighted ageneral overview of tanning, leather production and involvement of people inleather sector of Bangladesh.In comparative analysis, the quantity of generated solid wastes wascompared with the quantity of solid wastes of table I highlighted in literaturereview part by converting the values evolving in processing 100 kg hides andskins. Moreover, treatment technologies of theses wastes were also focused suchas reusable, non-reusable wastes or recyclable, non-recyclable includingdumping procedures and quality assessment of dumping yard.Results and discussion Duringdata collection for the purpose of study assessment using the questionnaire ,it is found from the sample that most of the tanneries are run as Sole Proprietorship (7 tanneries), partnership farms(4 tanneries) and Limited Company (1 tannery) in ownership where 750 workerswork altogether. All types of tanning methods (chrome, vegetable andcombination) are applied to convert the putrescible raw hides and skins intoleather which depends on the quality of raw hides and skins or according to thedesirable properties of leather that buyers want. 6 tanneries from the samplecarry out beam house to finishing operation producing quality wet blue, crustand finished leather, 5 tanneries are involved in beam house and wet backoperations to produce wet blue and crust leather but only 1 tannery perform wetback operation and produce crust leatheras it has newly started its production.
The leathers produced by thesetanneries generally exported to foreign and rest that are tanned without anybuyers order are sold in local market especially for making leather accessoriesresults annual turnover of total 102 million BDT/ sq. ft (8.5 million BDT/ sq.ft in average).Forthe purpose of leather production from raw hides and skins, the tanneriesproducing all types of leathers generate large number of solid wastes. Tanneriesproducing both wet blue and crust generate moderated solid waste and only thetanneries producing crust leather generates less amount of solid wastes.
The quantityof generated solid wastes by the tanneries is enlisted in table II in case ofprocessing 100 kg hides and skins.TableII: Quantity of generated solid wastes in processing 100 kg of raw hides andskins Sl. No. Name of solid waste Generated from Quantity (in kg) 1 Curing salt Desalting 3.1 2 Raw hide/skin trimmings Pre-soaking 8 3 Hairs Liming 2 4 Fat & tallow Liming 2.5 5 Limed fleshing Fleshing 16 6 Limed sludge/trimmings Fleshing 3.
8 7 Bated scuds Bating 0.5 8 Chrome sludge Tanning 1 9 Wet-blue trimming Post tanning 2.3 10 Split Splitting 5 11 Shaving dusts Shaving 7.5 12 Crust trimmings Crust finish 3.4 13 Buffing dusts Finishing 2.5 14 Finishing trimmings Finishing 2 Acomparison between the quantities of generated solid wastes obtained from theface to face interview sessions with the table I is show under a graphicalrepresentation which shows that tanneries generate solid wastes mostly frombeam house operations, moderate amount from wet back and small amount duringfinishing. Figure IV: Comparison betweenquantities (in kg) generated solid wastes evolved per 100 kg wet saltedhide/skin treatment. Thetanneries not only generate a larger amount of solid waste but also dischargesignificant amount of tannery effluent mostly from beam house operation and wetback.
The discharged effluents originated from every stage of 100 kg hides andskins processing are shown in table IIITable III: Effluent originated from every stage of 100 kghide and skin processing Stages Generated Effluent Quantity in liter Treatment technology & utilization Presoaking 200 CETP Soaking 150 CETP Liming 100 CETP Fleshing & Unhairing 20 CETP Washing 60 CETP De-liming 50 CETP Bating 50 CETP Washing 60 CETP Pre-tanning 200 CETP Tanning 80 CETP Samming 5 CETP Wet back 200 CETP Re-tanning & Dyeing 100 CETP Fat-liquoring 150 CETP Top dyeing & Fixing 100 CETP Setting out 2 CETP Vacuum drying 5 CETP Finishing 1 CETP Duringfocused group discussion on the dumping process of these generated solidwastes, it has come out that the generated solid wastes generated from beamhouse process are totally disposed in the dumping whether few of them can beeither reusable or recyclable, meanwhile wastes evolved from wet back andfinishing process are reused as well as recycled in form of variousby-products. The reuse and recyclable solid wastes are enlisted in table IV. Table IV: Treatment technology ofsolid wastes originated from hide/skin processing Wastes Generated from Treatment technology Curing Salt De-salting Reuse Raw hide/skin trimming Pre-soaking Gelatin manufacturing, Toe-cap making Fat & tallow Liming Poultry feed Wet-blue trimming Post tanning Animal feed Splits Splitting Glove leather production Shaving dust Shaving Adhesive making Crust trimming Crust finishing Small leather accessories Buffing dust Finishing Glue production Famished trimming finishing Footwear and other leather goods making ConclusionsWastesthat can neither be reuse nor recycle because of less developed recyclingtechnologies and lacking of any type of recycling factories around TIED. Sincethe TIED is still under construction, the leather technologists highly believedthat government would take necessary steps in case of proper solid wastemanagement system.Study LimitationThoughthe study was conducted quite successfully, some limitation was observed. Dueto less access to the tanneries during data collection, the sample size turnedsmall and resulted less informative. The study may not be able to draw theoverview of solid waste management system but could show a simple sketch.AcknowledgementsThe authors are humbly grateful to Institute of Leather Engineering &Technology (ILET) for providing all facilities, and responsible for any typesof errors and omissions.
They sincerely acknowledge all leather technologistswho participated in interviews for the purpose of data collection and MinhazulAbedin, Junior research fellow, SAIST for unconditional support andco-operation.References1Ahmed, S.-“Shoe upper leather and its manufacturing concept”in “Footwear Digest” a quarterly magazine published from FDDI, India, ISSN No.0971-9121 October 2002, Vol-34, pp. i-viii2 FAO World Statistical Compendium for Raw Hides andSkins, Leather and Leather Footwear 191920093 Andrioli, E., Gutterres,M.
-“Evaluation of waste management in tanneries”, XXXIIII IULTCS Congress,November 24th-27th, 2015 Novo Hamburgo/Brazil4 Bio-infoPublications, International Journal of Agriculture Sciences, ISSN: 0975-3710,volume I, Issue 2, 2009. 5 Verheijen, L.A.
H.M.; Wiersema, D.;Hulshoff Pol, L.W.
; De Wit, J.-Management of Waste from Animal Product Processing, InternationalAgriculture Centre Wageningen, the Netherlands, January, 1996 6 Paul,H. L., Antunes, A. P. M.
, Covington, A. D., Evanus P. and Phillips, P. S.(2013): Bangladeshi Leather Industry: An Overview of Recent SustainableDevelopments, SLTC Journal, vol (97): 25-32. 7 Rajamani, S.
Dr.-WorldEnvironmental Update in Leather Sector- Bio-Energy Generation From TanneryEffluent and Solid Wastes, Leather News India, September 2010 8 The EuropeanTanning Industry Sustainable Review, Prepared by COTANCE as a contribution tothe World Summit on Sustainable Development, May 20029 Kanagaraj, J.;Velappen, K.C.; Chandra Babu, N.K.
.; Sadulla, S.-Solid Wastes Generation in TheLeather Industry and Its Utilization For Cleaner Environment-A Review, Journalof Scientific and Industrial Research, 65,2006, 541-548.10 PalanisamyThanikaivelan et al, Recent Trends inLeather Making: Processes, Problems and Pathways, Critical Reviews inEnvironmental Science and Technology, 35:37-79, 2005 11 Khan, W.-LeatherIndustry in Bangladesh: Opportunities and Challenges December 30, 2014),American Journal of Trade and Policy, Vol. 1, No.
3 (2014), page: 117-124. 12 Hasan, M. M. -“Analysis-of-leather-industry-of-Bangladesh”,September 6, 2012.
14 BangladeshEconomic Review, Annual Report 2017, Dhaka Bangladesh. 14 BangladeshExport Promotion Bureau (EPB) (2017), Export Statistics, Dhaka, Bangladesh 15 Bangladesh Tanners Association (BTA), Survey Report 2017,Dhaka, Bangladesh. 16Bangladesh Labor WelfareFoundation report – March 2017 17 McLaughlin,G.
D. & Theis, E.R.
-The chemistryof leather manufacture (Reinhold publishing corporation, New York) 1945, 133. 18 Ramamoorthy,G.; Sehgal, P K & Mahendrakumar-Improved uptake of basic chromium salts intanning operations using keratin hydrdysate, J Soc Leather Technol Chem, 73 (1989) 168-170. 19 UNIDO Expert Team, Technical Report, United NationsIndustrial Development Organization (UNIDO). TF/BGD/05/001, (2005). 20Training Institute for Chemical Industries (TICI), Report on ExistingEnvironmental Status of Hazaribagh. 2005, Dhaka, Bangladesh.