Practice of Used Tyre Resoling: Is it a Solution or a Problem?

Transcription

1 M Alamgir, QH Bari, IM Rafizul, SMT Islam, G Sarkar & MK Howlader (Eds.) ISBN: , pp. 121 (1-6) Proceedings of the WasteSafe nd International Conference on Solid Waste Management in the Developing Countries February 2011, Khulna, Bangladesh Practice of Used Tyre Resoling: Is it a Solution or a Problem? Quazi H. Bari* and S. M. Kamal Uddin Department of Civil Engineering, Khulna University of Engineering and Technology, Khulna 9203 Bangladesh * qhbari@yahoo.com ABSTRACT In the present study an attempt has been taken to look at the scenario of tyre resoling in Khulna, the third largest city of Bangladesh. This paper presents the resoling patterns of old tyres in addition to its pros and cons that are explained through intensive collection of data from the producers and users. The detail methodology of resoling practiced in the local factories, including utilization of all types of used tyres and used resoled tyres are also discussed. Study results show that, (i) Total four number tyre-resoling factories are identified in Khulna which are creating a job market, providing the vehicle owner having tyres at a low cost and retarding frequent entry of new tyres in the market, (ii) Depending upon the physical condition, an old tyre can retread for single time or resoled not more than two times extending its reuse time for five to six months in each process, (iii) Although resoling of old or waste tyres are advantageous to some extent, the probabilities of the failure of these tyres in use for vehicular purposes should be evaluated. It can be said that resoling process is playing a significant role in reducing environmental threats related to tyres as it s a potential manner of recycle and reuse.. INTRODUCTION Future living standards of the human being and the quality of environment essentially depend on the management policies for solid wastes. Generation and pilling of used tyres are also included in the solid waste stream. The quantity of used tyres has been increasing dramatically during the last decades due to the increased number of vehicles. The increasing rate of used tyres and solid waste generation, limited landfill space and more stringent environmental regulations for new landfill sites and incinerators have increased the waste disposal fees in different countries of the world, especially in the developed countries. Therefore, municipalities are under deep pressure to find sustainable and cost-effective waste management policies. The present waste management hierarchy emphasizes reduce, reuse, recycle, recover and stable residue. In proper management of used tyres the options: reuse, recycle, and recover can effectively be applied. A detail on tyre recycling and their effective utilization for non-vehicle purposes in the Khulna city of Bangladesh has been reported (Uddin & Bari 2009, MDNR 2008). Search of new alternative usages including as aggregate in flexible concrete and different disposal methods are going on (Olivaresa and Barluengab 2004). There is another option exists to reuse the tyres through resoling. The appleability and probabilities of the failure of these resoled tyres in use for vehicular purposes needs proper evaluation. However, the resoling of used tyres has been going on in local small factories for further reuse in the vehicles. An attempt has been taken to look at the scenario of resoling of the used tyre in Khulna, the third largest city of Bangladesh. It may imply the situation of whole Bangladesh. In this paper, the resoling patterns of old tyres are explained through intensive collection of data from the producers and users. The detail methodology of resoling practiced in the local factories is discussed.

2 METHODOLOGY To achieve the desired goal of the research the total program was divided in different scheme so as to manage the work & schedule effectively. As the study was based on the data from field survey in the Khulna city area, initially a questionnaire survey form was prepared and oriented targeting the resoling shop owner & manager group that focuses the pattern of tyre resoling, its quantity, users, different size etc. Table 1 shows the different size of tyre, their use pattern, present market price of new tyre as well as resoled one. After detail survey collected data was tabulated and analyzed on the office desk. It was found that the people doing tyre resoling practically do not have clear idea in all of its technological aspects, and some of the owner does not have any educational background but are doing the same for business. Finally benefits & disadvantages of tyre resoling were closely & critically compared considering social, environmental & economical point of view. Table 1: Size, use pattern and cost of tyre Size of tyre Type of tyre Used Vehicle Avg. cost* of new tyre ( in tk. / pcs) Cost* of resoling ( tk. / pcs) X 20 T1 Bus, Truck X20 T2 Do X20 T3 Do X16 T4 Mini Bus X16 T5 Mini Bus X15 T6 Micro X16 T7 Micro X8 T8 Three wheeler * Present market price of retailer, November, 2010 TYRE-RESOLING FACTORY Establishment of tyre resoling factory is not new in the city and it has found that people in this area were engaged in it since the decade of 1980, where they initially developed their own resoling mechanism only for smallest sized tyre. And now they are using up to date technologies like as re treading which also called cold form. A total of four tyre-resoling industries are identified in Khulna, three of which resole the tyre i.e. hot process and only one retread old tyre. Among them one factory has made their setup ready for re treading and will go in production from next year. However, there are three to twelve workers in each industry. Depending upon the physical condition, an old tyre can retread or resole not more than two times. Each resoling extend the service time of the tyre four to five months i.e gives additional lives for tyre. The user, dealers of new tyres and the owner of resoling industry usually evaluate the tyre by its service month. So here the useful lifecycle is also presented on the basis of service month. Table 2: Resoling pattern of different industry located in Khulna city ize of Tyre Type of Tyre Require amount of rubber (kg) Nos. of tyre resoled per months in factory Factory Factory1 Factory2 Factory4 3 (12) (7) (6) (3) X 20 T Nil Nil 9.00X20 T Nil 8.25X20 T Nil 7.50X16 T Nil 7.00X16 T Nil Nil 7.00X15 T Nil Nil Nil 6.50X16 T Nil Nil Nil 4.00X8 T

3 All types of tyre such as truck, bus, and motor driven three- wheeler tyre are recycled by tyre recycling industry in Khalishpur. Owners give these old tyres to recycling industry to convert into new recycled tyres. Recycling is done by several steps shown in the flow chart in figure 1. In each steps old tyres are treated in different process which are discussed in short below. Collection: This is the first stage of the flow chart, here the factory owner tries to collect old tyre from individuals & organizations. Generally they try to participate at different office tender though they follow different policy for collecting tyre. For instance, they try to make good relation with individual vehicle owner & its driver so that they can have priority of buying old tyres from them. Again they give incentive to the individual tyre repairing shops for supplying old tyres and getting order from individual vehicle owner. Selection: In this stage tyres (fig 2b) are separated in different category with visual inspection. At this stage they assure which could be resoled for more than one time. Depending on it they fix up the cost of tyre. Cutting & reshaping: Worn tyres are usually damaged in different ways (fig 2 b). It can have holes on the surface or it may lost is shape also. At this stage old tyres are cut (fig 2 c) into regular round shapes manually with some sort of blades and holes are repaired & treated if any. Surface preparation: Here surface of the tyre is shreds by mechanical cutter (fig. 2d) to make it rough so that raw rubber can be pasted on the surface easily. Leveling & rubber pasting: After preparing the surface some sorts of chemical is used to wet ( fig 2e) the surface before raw rubber is pasted ( fig 2f) on the surface manually. Raw rubber of 2-5mm thick is used in layers for a desired degree of thickness and volume. Moulding & heating: Now tyre is placed in the dice of its size. Afterwards applying heat and pressure moulding is done mechanically to produce new tread on the surface of old tyre as per design of dice (fig 2 g & ). Usually heating is done through steam using boiler of desired capacity. It was then heated for a particular time before releasing from dice. Then it is placed in open air for cooling. Finally it is ready for delivery to the market. Fig 1: Flow Chart of tyre resoling 3

4 Table 3: Service month of new & resoled tyre Type of Tyre Service time of a new tyre (month) T T T T T T T T Service time of a resoled tyre (month) 5-6 BENEFITS In the present study the pros and cons of the practice of tyre resoling were critically observed including its subtle impact in any aspect related to social, economical and more importantly environmental issues. Study reveals the following benefits- Firstly tyre resoling is a method by which it is possible to increase the service life of old & worn tyres. In the study it is found that the used tyre can be reuse by resoling for at least two times depending upon its condition. Secondly it has some social impact as the resoling factories are creating some sorts of job market. After that it can be possible to reduce the total volume of waste generation with respect to time, i.e. waste will come to environment in a lower rate. In addition, another advantage of tyre resoling is that it allays the total import volume of new tyre and its entry rate in the market. Furthermore vehicle owners are getting a secondary option to run their vehicle with lesser expensive tyre thus the expense of vehicle owner for tyre is reduced by a considerable amount. Table 2 shows the average cost of new tyre available in the market and the cost of resoling. It is found that resoling is cost effective to the user. Service time of different types of tyre is shown in table 3. If a used tyre is resoled for at least 2 times then the same tyre will give additional 10 months of service in an average. Considering data for T1 type of tyre, additional cost for recycle is =2200*2=4400 tk and it will give additional 10 month service and some salvage value after that period which is tk. On the other hand if it is replaced, it will cost at least 23,500 tk and give 18 month of service. In that case replacement will give the owner some salvage values, which are 800 to 1000 for T1 type tyre. By applying engineering economy its benefit- cost ratio can be easily calculated. CONCLUSIONS The results show that (i) Total four number tyre-resoling factories are identified in Khulna. There are three to twelve both skilled and unskilled workers in each factory. Used tyres are usually resoled in tyreresoling factory for further reuse in vehicular purposes. (ii) Depending upon the physical condition, an old tyre can retread or resoled not more than three times. After each resoling the tyre can be utilized for four to five months. (iii) Although resoling of old or waste tyres are creating some job opportunities to the people of this city, the probabilities of the failure of these tyres in use for vehicular purposes should be evaluated. 4

5 REFERENCES Uddin S.M.K., Q.H. Bari & S.M. Moniruzzaman (2009) Where Do the Used Tyres Go? A Case Study. Scenario of Solid Waste Management Program of Selected Municipalities in Bangladesh. In Proceedings of the International Conference on Solid Waste Management, WsateSafe, 9 10 November, KUET, Khulna, Bangladesh. pp Davis, M. L and Cornwell D. A Introduction to Environmental Engineering. McGraw Hill, Boston, pp MDNR (2008) Management of Scrap Tires. Missouri Department of Natural Resources, Solid Waste Management Program, Jefferson City, MO, Olivaresa F. H. and Barluengab G. (2004) Fire performance of recycled rubber-filled high-strength concrete. Cement and Concrete Research, Pergamon, Pieter, J. H. van Beukering, and Janseen, M. A. 2001, Trade and recycling of used tyres in Western and Eastern Europe Resources, Conservation and Recycling, Elsivier Vol. 33, pp a) Pile of collected tyre b) Tyre selected for resoling (left one for single resole and for other two its double) c) Manual cut of old rubber coat from surface d) Surface roughing by mechanical device 5

6 e) Wetting of surface by chemical f) Pasting of rubber g) Tyre ready for moulding h) Completed tyre in dice after heating Fig 2: Figure of tyre resoling procedure 6