replace some of the fossil fuels traditionally used in the brick making process. ... Mixed MSW of Khulna City contains a very little amount of tyre as only 0.5 percent ... Considering three resoling the life time of a tyre can be increase from 15 to .... can be described in a flow chart shown below where dealers are in first phase. In.
M Alamgir, QS Hossain, QH Bari, IM Rafizul, KMM Hasan, G Sarkar & MK Howlader (Eds.) ISBN: 978-984-33-0761-3, Vol. 1, pp.371-376
Proceedings of the International Conference on Solid Waste Management Technical, Environmental and Socio-economical Contexts - WasteSafe 2009 9 to 10 November 2009, Khulna, Bangladesh
Where Do the Used Tyres Go? A Case Study S. M. K. Uddin, Q. H. Bari, and S. M. Moniruzzaman Department of Civil Engineering, Khulna University of Engineering &Technology (KUET) Khulna 9203, Bangladesh ABSTRACT The proper disposal of used tyres in many cities is a big headache of the Solid Waste Management (SWM) authority in different countries. The situation might be different in Bangladesh. Old tyres are used in various ways for non-vehicular purposes. These tyres in due course may be return to the waste stream for subsequent treatment or environmentally safe disposal. Used tyres can beneficially replace some of the fossil fuels traditionally used in the brick making process. An attempt has been taken to look at the scenario of further utilization and disposal of used tyre in Khulna, the third largest city of Bangladesh. In this paper, the inherent utilization of old tyres are explained through intensive collection of data from the users and producers of old tyres products. The experimental results reveals that, (i) The tyres are used for different purposes in environmental sound process like production of dock fenders, washer, bucket, gasket, belt for rice mill shoe sole etc; (ii) There is a practice of using old tyres in brick kiln as a fuel by which energy is recovered, and (iii) Recycling and reusing of old or waste tyres are creating some job opportunities to the people of this city.
INTRODUCTION The mountain of used tyres has grown dramatically during the last decades due to the increased number of vehicles. The proper disposal of used tyres in many cities of different country is a big headache of the SWM authority. The tyres can cause significant environmental pressure through the life cycle if their extensive natures of reuse or recycling options are not utilized. Old tyres are also used in their original form for non-vehicle purposes. Examples include the use of tyres as dock fenders, washer, bucket, gasket, belt for rice mill etc. These tyres will, in due course, be returned to the waste stream for subsequent treatment or environmentally safe disposal. Used tyres can beneficially replace some of the fossil fuels traditionally used in the brick making process. Four kilns in the UK have received full authorization to burn tyres with a combined capacity of over 100,000 tones. The high energy content of tyres initiated several applications of post-consumed tyres for energy recovery. For example, many worn out tyres are used as a supplemental fuel in cement kilns (Pieter 2001). Search of new alternative usages including as aggregate in flexible concrete and different disposal methods are going on (Olivaresa and Barluengab 2004). It would be nice to look at the scenario of the used tyre in Khulna, the third largest city of Bangladesh. It may imply the situation of whole Bangladesh. Usually the old tyres are used in different ways in Khulna city. In this paper, the inherent utilization of old tyres are explained through intensive collection of data from the users and producers of old tyres products.
Practices in Khulna The used tyres have certain monitory value to a group of people of the society. It can be seen that the existence of tyres (as rubber) in any disposal point of mixed municipal solid waste (MSW) is unusual. Mixed MSW of Khulna City contains a very little amount of tyre as only 0.5 percent including all rubber by weight (WasteSafe 2005). This indicates that the people do not throw or dispose away the tyre directly. They try to utilize it in any possible way. The tyre selling shop in Khulna collect new tyres from dealers located in Dhaka. Among those Indian & Chinese companies are in top due to their lesser cost. Vehicle owners and different offices collect tyre from different tyre selling shops. After use of 15 to 18 months they either resole the tyre for reuse or sell it to the tyre repairing shops or garages. In case of government offices they store the old tyre for long time and then sell it through tender/bid
process. Recycling Factory owner, secondary product maker, owner of garages and brickfields are usually bid to buy those old tyres. Then they either resole it or use for other purposes.
Tyre-Resoling Used tyre is usually resold in tyre-resoling factory for further reuse. There are four tyre-resoling factory are identified in Khulna. Depending upon the physical condition, an old tyre can retread or resoled consecutively not more than two times. After each re-soling the tyre can be utilized for four to five months. The user, dealers of new tyres and the owner of resoling factory usually evaluate the tyre life by its service month. Considering three resoling the life time of a tyre can be increase from 15 to 25 months or 18 to 28 months depending on other factors mainly the mileage and road condition. Resoling information of a factory located in Khalishpur of Khulna city is presented in Table 1. Mostly eight types (T1 to T8) tyres for truck, bus, mini bus, and motor driven three-wheeler, etc. are available in Bangladesh as shown in Table 1. All types of tyre are resoled by the tyre resoling factory. Resoling is done by several steps. These steps are: (a) cutting into regular shapes; (b) rubber is pasted in layers using octane on the surface manually; (c) finally heating and molding is done to have a finished resoled tyre. An amount of new and specific rubber is needed for each type of tyre as mention in Table1. The cost of resoling is varied according to tyre type. Highest resoled tyre by the factory is type T4 tyre mainly used in minibus. The factory resoled 200 to 220 number T4 type tyres per month with cost ranged 1200 to 1400 taka/tyre. Total number of resoled tyre by the factory is found to be 535 to 615 per months. About 12 workers are employed in this factory. The total employed workers in this factory plus other identified three factories are 28. Table1 Resoling information of a factory located at Khalishpur of Khulna city Size of Tyre (Type)
Used Vehicle
Cost of resoling (Tk)
Require amount of rubber (kg)
Number of tyre resoled per months
1000x20 (T1) 900x20 (T2) 825x20 (T3) 750x16 (T4) 700x16 (T5) 700x15 (T6) 650x16 (T7) 400x8 (T8)
Bus, Truck Do Do Mini Bus Mini Bus Micro Bus Micro Bus Three wheeler
2200-2300 2000-2200 1700-1900 1200-1400 1100-1300 1100-1300 1100-1200 250-300
12.5-13.5 11.0-12.5 10.0-11.5 5.0-6.5 4.5-5.5 4.5-5.5 4.5-5.0 1.0-1.5
10-15 65-70 50-60 200-220 30-35 30-35 25-30 125-150
New Product from Old Tyre During recycling specially as resoling a huge amount of tyre dust is produced from cutting process. The tyre dust also has some sort of salvage value. This dust is used in local shoe sole factory as a raw material. The factory owner sells it at a cost of 5-6 taka/kg. When a tyre become unfit for further resoling, it also has some sort of use. Worn tyres are also collected by two shops in Khulna City. They collect all tyres except three wheeler tyre. The used or resoled vehicle tyres are utilized for different purposes. The tyres can be utilized in the same form or can be cut in different shape for specific usages. Specific use and price of some new products made from the used tyres such as cross belt, flat belt, gasket, coupling, mountain, washer, and bucket are listed in Table 2. The pile of old tires usually seen on the roadside shop in the country is shown in Figure 1a. Table 2 Details of new products made from used tyres
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Sl no.
Product name
Use of the product
Unit
Cost in taka.
1.
Cross Belt
3 pc
5.00
2. 2. 3. 4.
Flat Belt Gasket Coupling Mountain
feet 1pc 1pc 1 set (4pc)
6.00 1.00 6.00 30.00
5. 6.
Washer Bucket
Rice mill Shallow pump motor Rice mill For pipe joint Gear box Bus, truck, private car, motor cycle Generator, pump Tube well
1 pc 1 pc
15.00 15.00 WasteSafe 2009
The appearance of new products made from tyres is illustrated in Figure 1b. The products are sold at comparatively low price compared to new one.
(a) Pile of old tyre
(b) Varieties of new products made from old tyre Figure 1 Old tyre and its new products
Miscellaneous Utilization Old Intact Tyre There is a greater use of old tyre is in hand carts in the country. Usually two people work drive one hand cart to carry heavy goods through usual narrow roads. They are frequently seen near large bus and truck terminals, river ports, railway stations and wholesale dealer areas. Now-a-days previously used wooden wheels are replaced by the old vehicle wheel with old tyres and tubes. This kind of utilization created many job opportunities in the country. Old Tyres are widely used in boats and barges in crowded ferry route in urban and suburban area of the country as shown in Figure 2a. The tyres are tied on the outside of outer extremities of water vessel to save them from different type of common shocks occur in normal navigation process specially during arrival in to the jetty. Usually a small boat needs 6 to 12 number T6 to T7 type Tyres. Tyre type T2 to T6 are used for larger barge or trawler with different numbers. Large size burnt clay pitcher are widely used to store drinking water in roadside food shops. They use tyres to hold the pitcher safely in position as their bottom is spherical. The tyre provides a soft and durable base for this kind of earthen pitcher as shown in Figure 2b. Some times old tyres are kept in front of a garage as a symbol or signboard of tyre shop. The used rickshaw or bicycle tyres are used as a bottom guard for hand made cane chairs, the local name is Mora. The bottom guard save the bottom part of the Mora from wear and tears during uses and consequently increase their life.
(a) Use in boats to resist impact from other vessel/object WasteSafe 2009
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Tyre heap at brick field
c) Part of tyre stored for selling to brick field owner
d) On-site storage of tyre cut-piece at brick field
Figure 2 Miscellaneous use of old tyre There is a greater scarcity of natural stones used as building material in Bangladesh. As an alternative a larger number of bricks made from clay are burnt in the brick kiln by burning fossil fuels traditionally. A large number of tyres have been beneficially replaced some of the fossil fuels used in the brick making process in Bangladesh. Abidance is available that four kilns in the UK have received full authorization to burn tyres with a combined capacity of over 100,000 tones. It is very difficult to collect data from brick factory regarding tyres burning in the brick field. They think that they are doing an illegal job. For incineration of mixed solid waste the temperature of burning should be above 800 o o C (Davis and Cornwell 1998). The temperature for brick burning in brick kiln is usually above 1100 C (Aziz 1981). Therefore it is safe to burn the tyres for brick burning in Bangladesh. It is expected from this research that there should be immediate permit for tyre burning in brick kiln in absence of any guideline. It will minimize a partial demand of the fuel for brick burning every year which is must as we need a huge number of brick for construction. It will also release the headache of the authority for its final disposal. Search of new alternative usages including as aggregate in flexible concrete and different disposal methods is going on. A project on the strength behavior of tyre dust mixed concrete is going on in the Department of Civil Engineering, KUET. The initial result showed that the mixing of certain percentage of tyre dust highly increase the ductility with a tolerable reduction in compressive strength. This implies their further utilization in shock resisting members of the structure or foundations. EMPLOYMENT GENERATION Recycling of tyres in Khulna city is not only reducing environmental hazards but also creating job opportunity for low income group. Many people involve themselves in each phase of tyre recycling and thereby self employed. There are five tyre resoling factories providing job for around fifty workers. After getting experience from these factories, workers moves towards better factories for higher salary or open another factory in different area. Hence increase the job scope & reduce unemployment rate. It also creates work facilities to surrounding district like Pirojpur, Bagerhat, Satkhira etc. where there are no resoling factories. Some people from those areas have some form agreement with the factories existing in Khulna, for resoling at a reduced price. They collect order for resoling from those areas, resoled from Khulna at the contract rate and thereby continue their business without investment of huge capital. There are a large number of garages in this city area. Two to three numbers of workers work in each garage. In addition, new product making shops also creates some sorts job field. Again some people involve themselves in a business of collecting tyre dust & cut piece and sell those to shoe sole factories & brick filed owner respectively. Thus tyre recycling process has an impact on poverty alleviation of the increasing population through income generation.
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PROPOSED TYRE RECYCLING PATTERN The tyres in due course are returned to the waste stream for subsequent treatment or environmentally safe disposal. As the old Tyres have a certain level of monitory value, the overall management of old tyre as a part of solid waste does not impose much pressure on the authority. A practical old tyre management diagram for cities and towns of Bangladesh based on the data collected in Khulna can be proposed as diagram shown in Figure 3. It is observed that there exist continuous safe use & management practices of the used & torn tyre. New tyres enter into the market of Khulna through dealers, who collects those from Dhaka where importers imports from India, China etc. These tyres are then absorbed fully by different phases. These phases can be described in a flow chart shown below where dealers are in first phase. In second phase dealers distribute tyres to different tyre selling shops. Individual vehicle owner & different offices like Govt. & NGO’s which uses tyres for their vehicle are in third phases. They buy tyre in retail price from tyre selling shops. These tyres are then used by them for a certain period. Afterwards these are either resoled or totally go to the brick field as a fuel. Companies & offices store used tyres for a certain period and call for tender in order to clear their store which involve inventory control. Here exists a significant management practice. Company’s call open tender for selling their used & worn tyre in a recurring period. Generally owner of resoling factories, tyre repairing shops and even of brick fields bid for the same. On the other hand, individual owner generally resoled their tyre for at least two-times and then sell it to the tyre repairing shops which are in fourth phase. Basically this phase is responsible for safe environmental disposal of worn tyres. These shops generally exist at different locations of city area, beside the main city roads; and help people by pumping air & repairing lick in tyre. Thereby they get well known to the drivers of individual vehicles from whom they buys worn & used tyres directly. And depending upon the condition, they sell tyres to either secondary product maker or resoling factories which are also in the same phase. Some times boat owner (to resist impact), men driven cart (locally called thela gari), etc also collect tyres from them. Dealers of New Tyre
Tyre Selling Shops
Used in Vehicles of Individual Owner / Different offices
Resoling factories (Resoled Tyres)
Raw material to produce resoling rubber (Called as Reclaim)
Tyre repairing Shops / Garages
Secondary product making shops
Different new product
Tyre Dust (Shoe sole maker) Brick field (as fuel)
Secondary product market
Figure 3 Tyre recycling pattern Secondary product maker are doing excellent job. Searching of the background of these people gives amazing information. That is they actually have no technical knowledge & training but depending upon their practice and thereby gathering experience they make different new product from worn tyres as per demand. Sometimes it requires replacing different types of accessories of machines which can be built from tyre such as washer, gasket, bucket etc. If in case of emergency those parts are not available in the market in proper shape & size, people have no other alternative to go except these WasteSafe 2009
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shops. For example, rice mill owners supply the size & shape of flat belt; and order them for the same which is very cheap rather than replacing that by a new one. Thus they are enormously helping to run factories, machines, pumps, vehicles etc. at a cheap cost. These shops generally collect worn tyres from garages (tyre repairing shops). They also bid the tender for worn tyres. Tyre resoling factories are in the phase four. They usually collect old tyre which can be resoled. Here exist a good collaboration in between different garages and factory owners. These factory owner buys resole able worn tyres from garage owner and also gives incentive to influence them for catching the resoling order from individual vehicle owner. Hence maximum of the vehicles comes into their resoling stream. While producing resoled tyre, huge amount of tyre dust & cut piece are produced. They don’t throw these into the open environment rather they sell those. Tyre dust are used for making shoe sole which is a fantastic solution and can be considered as a fifth & final phase in the flow path. These dusts are also used to produce raw material to produce resoling rubber (Called as Reclaim). Huge amount of cut piece are produced in resoling factories & secondary product makers shops. They store it consciously in a safe place and sell it to the brick filed owner after having sufficient amount. Brick field owner some times hire the secondary product makers for cutting the tyres which they directly buys as a full shape tyre. Use in brick field as fuel can be considered as final phase of the flow path.
CONCLUSIONS The results depicts that 1. The tyres are used for different purposes in environmental sound process; 2. Old tyres are resoled to make it fit for reuse in motor vehicle; 3. A number of Tyre is disposed in environmental friendly way such as fuel for brick kiln.
REFERENCES Aziz, M. A. 1981. A Textbook of Engineering Materials. Hafiz Book Center, Dhaka, pp. 31-33 Davis, M. L. and Cornwell D. A. 1998. Introduction to Environmental Engineering. McGraw Hill, Boston, pp. 678-679 Olivaresa, F. H. and Barluengab, G. 2004. Fire performance of recycled rubber-filled high-strength concrete. Cement and Concrete Research, Pergamon, 34 109– 117 Pieter, J.H. van Beukering, and Janssen, M. A. 2001. Trade and recycling of used tyres in Western and Eastern Europe Resources, Conservation and Recycling, Elsevier Vol. 33, pp.235–265 WasteSafe, 2005. Integrated Management and Safe Disposal of Municipal Solid Waste in Least Developed Asian Countries - A Feasibility Study. Department of Civil Engineering, KUET, Bangladesh & Asia Pro Eco Program of the European Commission
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