Promoting the use of discarded pneumatic rubber tyres to upgrade the ecology of our environment

Antony Santiago

The one page advertisement on recycling rubber tyres (New Straits Times dated July 10, 2007) carried the message that an estimated one billion tyres per year had nowhere to go. The advertisement also says that seven billion discarded rubber tyres are at present available for recycling by a patented process of delinking the chemical bonds that raw latex undergoes in the tyre manufacturing process. The chemicals used in the process are not mentioned but rumor has it that the chemicals used are water soluble and will damage aquatic life. This could be why developed nations are not setting up factories for recycling tyres even though they produce the greatest number of discarded tyres and can use the science and technology of delinking to do the same recycling.

More recently, an article in the New Straits Times dated December 13, 2007 reported that a German engineering company by the name of Intec Micro Powder AG had concluded a memorandum of understanding with a newly formed company called Intec Malaysia Sdn Bhd to recycle tyres. Intec Micro develops designs special machinery and equipment in the field of industrial tyre recycling. The company uses a deep cooling technique to cool the tyres to minus 195.8 degrees C which makes the vulcanized rubber brittle causing it to be pulverized more easily to generate rubber powder which is then used to .

These two technical processes of recycling discarded tyres have not been assessed as to their impact on the environment or whether they are environmentally friendly.

Are there any environmentally sound solutions to take care of the problem of the growing mounds, hills and mountains of discarded tyres?

The writer would like to propose eco-friendly methods of using discarded tyres based on successful experiments in using discarded tyres that are cut and assembled before using them as improvised containers for growing plants and for ecocycling wastes.

The writer who is a researcher in plant science, plant breeding and agriculture and completed his PhD at the University of Singapore in 1974 recalls observing village folk on their own initiative and common sense filling discarded tyres with earth and growing garden plants in them, under crops of fruit trees. Following their example he took the opportunity to conduct research in his home garden in Kuala Lumpur and found to his dismay that the soil in the tyres got water logged and too wet for plants to flourish. At about the same time he observed a tyre technician cut the belly part of the tyre with relative ease using a kitchen knife soaked in water which he then sold to cobblers who used them for mending the soles of shoes which had worn out.

This observation helped the writer to successfully use cut tyres to grow plants and to compost soil. Plants that grew well using this technique included vegetables, ornamental and herbaceous plants, shrubs, climbers and small trees such as papayas, tapioca and small ornamental palms.

His experiments were very successful and encouraged him to write articles in the New Straits Times under a personal column called Green Acres as well as in the Agroforestry Journal, a publication of the Centre for Agroforestry based in Nairobi, Kenya. The positive feedback from readers in other parts of the world suggested that the writer was on the right track.

The writer moved his residence to Petaling Jaya and is continuing his experiments there with discarded tyres donated by Dunlop Industries Malaysia and is getting satisfactory results as before.

Today after more than 30 years experience of growing plants in tyres the writer is confident that the ecocycling of tyres by growing plants in them has a great future in improving the ecology of our planet and would like to promote it as a garden culture of modern civilization. There are many other possibilities to conduct experiments on the use of cut parts of discarded tyres which include road barriers filled with ornamental plants and the like. It is hoped that the setting up of an ecocyling garden will encourage researchers in gardening and landscaping around the world to experiment and implement successful applications of using discarded tyres for useful purposes.

Growing plants in improvised containers of discarded rubber tyres will help avoid the mistake of recycling them using environmentally harmful means and solve the problem of the mounting number of discarded pneumatic tyres which in the humid tropics holds rain water and provides breeding grounds for a wide range of species of disease carrying mosquitoes. There is no need to recycle discarded tyres as suggested in the advertisement which could potentially pollute the waterways of our environment but instead ecocyle them as suggested. We should encourage the development of new tyre cutting methods and produce a variety of tyre parts for a variety of uses to improve our natural environment and produce a cultured landscape and garden environment for all of us to enjoy for the present and the future.

Transforming Urban Waste Products into Gardening Aids in the Humid Tropics

Antony Santiago

A wide variety of urban waste products are available for transforming into gardening aids in the humid tropics where countries such as Malaysia are situated. Every household produces kitchen and garden wastes which are packed in plastic bags and dumped on the roadside for the urban authorities to transport to the many land fills scattered around urban areas. Similarly discarded half shells of coconuts are available by the lorry load from wet markets and factories producing copra. Then there are worn out tyres which are piled up in front of automobile workshops which create and unpleasant sight and are difficult to dispose.

The writer was interested in using these urban wastes and conducted a series of experiments to transform them into raw materials to aid gardening and to study the potential for developing new urban practices and industries that favour the environment.

To have a successful garden it is essential that one has the right type of soil conditions, proper aeration and irrigation and the desired type of environment for the plants grown. All these conditions may be provided by using kitchen and garden waste, coconut shells and tyres for growing the plants in containers.

Tyres

In 1985 the writer went to Holland to present a paper at a conference on horticulture in Wageningen. There he took the opportunity to visit Leiden where he saw ornamental plants grown both in Wageningen and Leiden in large tub-like containers in the urban environment.

The author then remembered that village folk in Malaysia who did the same thing with discarded tyres while others improvised a variety of discarded containers to be used for growing plants. These improvised containers included discarded kerosene tins, oil cans, pails and spittoons.

On his return to Kuala Lumpur, Malaysia he observed at a tyre vendor’s store where a tyre mechanic working on cutting worn and discarded tyres to sell as scrap rubber to cobblers who would use the material to fix on to soles of shoes. He had cut the belly part of the tyre with relative ease with a kitchen knife dipped into a pail of water in order to make the act of cutting easier.

These observations gave him the idea of improvising worn and discarded rubber tyres for use as containers for composting soil and making suitable soil mixtures and growing garden plants around his home in Bukit Bandaraya, Kuala Lumpur, Malaysia. After successfully using tyres as aids for soil composting and growing many types of garden plants in tyres the writer feels worn and discarded tyres can be put to better use instead of filling already overcrowded landfills.

Cutting the tyre into several useful parts for gardening use

A pneumatic tyre meant to fit the wheels of a vehicle may be considered to have three parts namely the rim, the belly and the tread. When the rim and the belly of one side of the tyre is cut, this results in a tyre pan . When both sides are cut in the same way the tyre results in a tyre ring. The tyre pans and tyre rings are stacked one over the other to improvise the containers. When the tyre rings alone are stacked one over the other the result is a container suitable for soil composting. Garden waste including grass clippings, weeds and kitchen waste are laid in alternate layers within the container for soil composting waste Subsequently the next tyre will have the rim and belly removed to produce a tyre ring which will be then placed on the tyre pan. Subsequent tyre rings are stacked according to the desired height.

The tyre stack which can be anything from one tyre to seven or eight tyres high and can be used as a container for composting or for growing plants.

The cut rims of tyres can be also tied with with nylon rope to result in wicker like balls which can be lashed to each other to make bigger wicker like balls that can be rolled into shallow seas for growing algae and to protect the young of inhabitants of the sea from predation for eventual harvest by man for food.

There are many other possibilities to conduct experiments on the use of cut parts of discarded tyres which include road barriers filled with ornamental plants and the like.

Kitchen and Garden Waste

According to one American professor by the name Edgar Henderson of the University of Missouri most of the cultivated plants in Central America were grown near dump heaps of the farming communities there. Professor Henderson in his book entitled Introgressive Hybridization explained how the natives of Papua New Guinea grew food crops such as sweet potatoes, yams and tapioca in dump heaps.

The same is true of farming communities in Malaysia and Indonesia who grow banana and papaya trees near dump heaps. In other communities, female members would grow vegetables near the kitchen where they could easily water them and provide nutrients in the form of kitchen waste such as egg shells and onion peelings.

In preparing a soil mixture made out of kitchen waste such as fish innards, scales, shrimp shells, papaya skin, washings and garden waste such as leaves, grass and twigs are thrown into a tyre stack and a layer of soil put on top of it in the ratio of 30% waste and 70% soil. These layers are added on over time until it reaches a height of five to six stacks of tyres which can then be left to stand over three months. Water can be added during dry months and urea crystals may be added on the top most layer from time to time. After three months, the compost should have sufficiently settled to be used as planting material. No other fertilizer or soil needs to be added for this perfect soil mixture.

Coconut Shells

Used coconut shells that have been stripped of its husk and the inner pulp used up as food what remains will be empty half shells. These will make excellent soil aeration devices during the dry season and water retention devices during the wet season.

One half shell will have eyes or holes which would have served as the exit points for the germination of the coconut seedlings while the other half shell has a closed wall. Two half shells with holes are put close together to resemble a ball while another two half shells with a closed wall are cupped one on top and one below the ball. This forms a single unit of the device which looks like a ball made out of four coconut shells which are full of air. These devices are placed 20 centimeters below the soil and placed 20 centimeters apart from each other in a trough. The saplings are placed on top of the devices and then covered with soil.

Air is needed in the soil for biological processes to work whereas water is needed by the plants for photosynthesis. This device provides both. During the dry season the devices are full of air. During the wet season, the air is driven out of the device and in its place is filled with rain water.