Inventing and Refining Sustainable Technologies and Services

ABSTRACT

Egypt (and most of the Arab Countries) is located in an arid zone very poor in forest coverage. This has made Egypt and the whole region on the top of countries, relying on the importation of wood and wood products for the satisfaction of their needs. This is an unsustainable situation. Meanwhile, millions of tons of agricultural residues are being annually burned. This practice is not only environment-unfriendly, but also an irresponsible wasteful approach to a wealth of lignocellulosic resources. The agricultural residues could be subdivided into three main categories; (a) residues of annual field crops, such as wheat and cotton: (b) products of pruning of fruit trees, such as date palms and olive trees; and (c) products of the natural flora, such as the common reed. At the present time there are available data only on the amounts of the residues of the annual field crops. This data reveals that these residues are annually available with great amounts in the Arab world amounting to 273 million tons (dry weight). These residues display certain characteristics, which make them a real asset in the endogenous development of local communities, such as: ease of availability for members of local communities, renewability and cheapness in cost and ease of processing, the existence of traditional knowledge and experience of their utilization on the grass-root level, etc.

A methodology of propagation of industrial use of agricultural residues has been worked out proceeding from the main concept: rediscovering of local materials meaning the direction of thinking and imagination to find contemporary uses for these materials. This may represent an important mechanism: both for the endogenous development of local communities and for the building of endogenous scientific and technological capabilities of the country at large. Three examples are given: the industrial use of the date palm leaves' midribs as an example of how to germinate technology, the use of cotton stalks in particleboard manufacture as an example of the proactive approach for the solution of an environmental problem and the use of products of pruning of fruit trees as an application of the principle of the whole resource use. Therefore, the agricultural residues could serve as a material base for an industrial revolution, which begins from the village.

Keywords: agricultural residues, annual field crops, date palm leaves' midrib, products of pruning, industrial use.

▲ Top

1. INTRODUCTION

Egypt , and most of the Arab countries, are located in an arid zone very poor in forest coverage. The percentage of the area covered with forest, to the overall area ranges between 0.002% for Egypt , 0.3% for Libya , 0.7% Saudi Arabia , 3.5% Syria , 4.5% Tunisia and 22.3% for Sudan [15]. This has made Egypt and the whole region on the top of the countries, relying on the importation of wood and wood products for the satisfaction of their need. But this situation is unsustainable! The consumer associations and environmental movements like Milieudefensie, Natuur & Milieu and Green peace [I], for example, were able to exert great pressures for the preservation of forests. This has led to the reduction of the rate of cutting of wood leading to less availability of wood in the international markets and the increase of its prices [12]. It is projected that the cost of importation of wood in the fisal year 2001/2002 for Egypt will approach 4 billion L.E. [10]. This figure will increase in future when the wood- producing countries follow the objective ofsustainable harvesting [14].

The agricultural residues are a new term, associated with market rationality putting emphasis only on the primary products of renewable material resources. Perhaps until the end of the nineteenth century the traditional way of life, in the Egyptian village was based on subsistence economy. The renewable material resources were totally used without residues. The uses of the secondary products of the date palm give an eloquent example in this concern [3, 4]. The cotton stalks were used - and are still in many villages - for baking of bread in rural ovens and so on. With the drastic change of the way of life in Egypt and the whole area, many agricultural residues became redundant. The burning of these residues became a common practice in the Egyptian village: both for the clearing of the field for the cultivation of the next crop and as a mean for struggle against certain insects such as the cotton boll pink worm residing in the unopened bolls in the cotton stalks after harvesting of cotton fibers. In autumn 1999, when Egypt was bidding farewell to the last century of the second millennium, people in many govemorates in Lower Egypt and especially in Cairo were stunned by the phenomenon of the "Black Cloud" causing health disorders for many of us. One of its main causes is thought to be: the burning of millions of tons of cotton stalks and rice straw!

The burning of agricultural residues m Egypt, and the whole Arab region, should be look at not only as an environment-unfriendly practice, but also as an irresponsible wasteful approach to a wealth of lignocellulosic resources our country, and the whole area, is most in need of. In light of the acute scarcity of forest coverage in the whole region we have to accept the challenge of realization of substituting, to the maximum, of our needs of wood and wood products by products, made from agricultural residues. This challenge may stimulate an industrial revolution in its own right, based on the industrial use of agricultural residues.

2. CLASSIFICATIONS AND AVAILABILITY OF AGRICULTURAL RESIDUES.

The agricultural residues could be classified to three main categories: (a) residues of annual field crops; (b) products of pruning of fruit trees and (c) products of natural flora, such as the common reed, miscanthus, water hyacinth, etc. There are relatively available data on the availability of agricultural residues of annual field crops, whereas data is almost absent on the other forms of agricultural residues.

Table 1 gives an estimation of the air-dry weight of residues of some main field crops in the Arab region. It is clear from this table that these agricultural residues are annually available with big quantities amounting to » 18 million tons in Egypt and ^ 273 million tons in the whole Arab region! [9], This table gives us a good idea on the relative significance of these residues. Barley straw is ranked first (% 136 million tons), followed by wheat straw (=s56 million tons), then maize (^45 million tons, groundnut shells (=3.5 million tons), cotton stalks (^3.3 million tons), etc. This table gives as well a good picture of the wide range of variation between the Arab countries, as far as the crop pattern is concerned. This points to the significance of planning of R&D efforts, directed to the industrial use of agricultural residues, with the objective of the realization of intergration of these efforts in the Arab region. For example, Egypt could take the lead in cotton stalks industrial use, Tunisia in barley and wheat straw, etc.

▲ Top

3. SIGNIFICANCE OF AGRICULTURAL RESIDUES

3.1 The agricultural residues are easily accessible for people without necessarily the intervention of the government or transnationals. They are simply on the surface of the earth (or river) and don't need suffisticated equipment for their extraction.

3.2 The agricultural residues are available in highly dispersed form. Each local community in rural areas has its own share of these residues.

3.3 Each local community has its own technical heritage, associated with innovative uses of its agricultural residues for the satisfaction of the needs of its members, (e.g., the use of palm midribs in roofing, door making and fencing, the use of cotton stalks for baking of bread, etc.) This means that when you proceed with the use of agricultural residues you are not beginning from zero, but from the familiarity with, and the stock of knowledge and technical heritage on, the locally available agricultural residues.

3.4 The agricultural residues are annually renewable material resources. Therefore, they have a very strong availability potential as compared, for example, with timber. Besides, they are extremely cheap in most cases. Their cost in most cases is confined to the cost of their transportation and processing until the site of industrial utilization. Besides, due to their biodegradability and/or bulky character, they should be processed as near as possible to the field. Therefore, their prices are safe from the fluctuation of prices in the national and international markets.

3.5 The industrial use of the agricultural residues provides a very practical environment-friendly mean for the preservation of the environment in rural areas, where these residues are produced. Therefore, you could avoid fire, occurring, for example, in unpruned palm gardens. You need not bum cotton stalks or use pesticides to combat against the pink worm.

3.6 The industrial use of agricultural residues improves the resource of agriculture. Farmers could sell their primary products, as well as their secondary products. i.e. agricultural residues.

From the aforementioned it could be concluded that the agricultural residues could be an essential mean for the endogenous development of local communities in many rural areas, especially in the South.

4. A METHODOLOGY FOR THE PROPAGATION OF INDUSTRIAL USE OF AGRICULTURAL RESIDUES.

The suggested methodology proceeds from the main concept: rediscovery of local materials meaning the direction of thinking and imagination to find contemporary uses for these materials. This may represent an important mean for the development of local communities and the building of endogenous scientific and technological capabilities along the path of applied research on the industrial use of these materials. This methodology includes the following steps.

4.1 Conduction of tests to determine the physical and mechanical properties of the materials. This is thought to give a new identity to the local material and put it in comparison with the alternative materials in the market. The results of the aforementioned test may be a mean for the promotion of the tested materials in a new contemporary context.

4.2 Development of new products from the local materials and thus opening of new markets for these materials.

4.3 Design of manufacturing processes and machines for the aforementioned products taking into consideration the features of the sociocultural context, where the industrial activity will be conducted.

4.4 Determination of the optimum or appropriate manufacturing process parameters. This necessitates the conduction of applied research to determine the values of these parameters.

4.5 Manufacturing and testing of the machine or equipment prototype and its modification if necessary.

4.6 Establishment of an experimental pilot unit for the new products putting the new industrial activity under test and exposing it: to entrepreneurs to convince them to invest in this new business, to marketing agencies to urge them to find best markets for the new products, and to consumers to accept the material in its new use or application.

4.7 Conduction of technical and economic feasibility studies to establish industrial projects, based on the use of the materials under consideration.

▲ Top

5. EXPERIENCES IN THE INDUSTRIAL USE OF AGRICULTURAL RESIDUES.

5.1 New Avenues for the Use of the Palm Midrib.

The drastic shift in the way of life in many rural areas in Egypt has led to the decay of many traditional uses of the palm midrib (e.g., in roofing, door making, fencing, crate making, etc.) This has led, consequently, to the neglect of pruning of palms. Fig 1, leading to many fire accidents, as well as the drop of the economic value of the palm itself. The tests, conducted by the Centre for Small-Scale Industries has proven that the palm midrib enjoys physical and mechanical properties comparable, with those for known wood species [5], such as spruce and beech. This has led to the finding of new avenues for the use of the palm midrib.

5.1.1 Arabesque from the palm midribs.

The Arabesque (Mashrabiah) handicrafts are a part of our cultural heritage. The Arabesque items are being used in furniture, windows, and partitions (Fig. 2) The drastic increase in the price of imported beech wood, usually used for Arabesque, has led to the shrinkage of demand on Arabesque handicrafts. Therefore, it was thought that the replacement of beech wood by the cheap locally available palm midribs may open the way for the revival of Arabesque handicrafts, especially in rural areas. The Centre for Development of Small-Scale Industries has launched a project on July 2nd, 1995 in the Dakhia oases in the New Valley govemorate to disseminate Arabesque handicrafts using palm midribs as a raw material. A training center was established to train the beneficiaries (Fig. 3), who obtain their lathes on a loan basis and produce at home. The project has made great success turning the poor, especially women, to autonomous producers and entrepreneurs and transforming the idea of use of trees pruning products as a substitute for imported wood into reality. The project opens a great potentiality for dissemination of a new culture of sustainable use of renewable material resources in rural and desert communities in the whole region.

5.1.2 Palm midribs in blockboard.

Due to its full reliance on imported spruce wood, the blockboard industry in Egypt is in a critical situation. Therefore, it was decided to direct research to the use of palm midribs as a substitute for spruce in the core layer of the blockboard. The research results have proved that he palm midrib-core blockboard enjoys physical and mechanical properties comparable (and several of them superior to) those for spruce- core blockboard [2]. Therefore, machines were designed and manufactured for the conversion of palm midribs into strips of uniform cross-section for the core layer. TheCentre has established a pilot factory in El-Kharga, the New Valley govemorate on October 27th, 1993, for the manufacture of palm midrib-core blockboards. This new product has been successfully marketed and used in school furniture in community schools, established all over Upper Egypt by the UNICEF.

5.1.3 Particleboards from palm midribs.

It has been proven that the ratio of utilisation of palm midribs in Arabesque and blockboards does not exceed 40%. Therefore, research was conducted to use these midrib residues in particleboard manufacture. The results have proven that particleboards, manufactured from palm midribs, enjoy physical and mechanical properties satisfying the Egyptian particleboard standard 906/1991 [5]. This opens the way of development of a particleboard industry, complementary to Arabesque or blockboard industries, to satisfy the objective of integrated use of the palm midrib.

5.1.4 A lumber-like product from palm midrib.

As a response to the acute shortage and high prices of wood in Egypt, a research has been conducted to investigate the possibility of manufacture of a local substitute of solid wood, made from palm midribs. The research results indicate that palm midrib blocks enjoy values of modulus of rupture (MOR) and other mechanical properties similar to those of red pine and spruce. This opens a great potentiality for use of palm midribs to manufacture products that would partially substitute imported solid wood in Egypt and the whole Arab region. This research [16], has been awarded the Euromate-97 conference prize for the best poster, 21-23 April 1997, Maastricht.

5.1.5 A super strong material from the palm midrib.

The anatomical structure of the palm midrib [13], has shown that the outer layer differs from the inner part of the midrib by a higher density and smaller diameter of the fibro-vascular bundles. This suggests that this outer layer may have better mechanical properties, as compared with the average properties of the midrib. Besides, this layer constitutes an unused residue of the palm midrib blockboard industry. Thus, research was conducted to determine the tensile strength of the outer 1.5 mm layer of the midrib. The research results [S] (See Table 2) clearly indicate that the outer layer of the midrib enjoys a tensile strength (^ 25 kg/mm2) comparable with that of commercial steel. This indicates that the palm midrib outer layer is a super strong material that could find wide applications in industrial composites.

5.2 Use of Cotton Stalks for the Manufacture of Particleboards,
5.2.1 Objectives

Cotton is one of the main crops being cultivated in about 420000 ha in Egypt. Therefore, an annual amount of about 1.6 million tons of cotton stalks are being burned at present after cotton collection to get rid of the cotton boll pink worm residing in the unopened bolls. Besides, 300 million L.E. are spent for the purchase of pesticides every year to combat these insects. In addition, solar is added to the irrigation water to kill this worm. Nevertheless, Egypt loses in average about 20% of its cotton fiber crop due to the destructive effect of this insect [6]. All the aforementioned practices are very environment-unfriendly and uneconomic. It is suggested that the industrial use of cotton stalks is both an environment-friendly and economically rational alternative for the combat with the pink worm, especially because Egypt suffers an acute shortage in the lignocellulosic material supply.

The particleboard industry in most of the industrialized countries relies on the residues of the sawmills and wood-working industry as a source of supply of raw material. Tn Egypt the alternative raw material supply is the agricultural residues, such as cotton stalks. One of the large particleboard companies in Egypt used the casuarinas trunks as a raw material for particleboard. This proved to be unsustainable, because the rate of renewable of casuarina is very slow. As a result the quantities of casuarinas stems became less available and their prices went high. Therefore, it was decided to run a research project on the substitution of casuarina by the more cheap and available cotton stalks.

The first phase of the research project was conducted in laboratory conditions. This phase proved the possibility of the manufacture of one-layer and three-layer particleboard from cotton stalks satisfying the requirements of the Egyptian Standard No. 906/1991 for particleboards [6]. Besides, it was possible during this phase to determine the optimum process parameters of the manufacture of one-layer and three- layer particleboard from cotton stalks.

5.2.2 Methodology and Procedure

For the conduction of the pilot phase of the research project, a methodology was worked out to guarantee:

• The shift of as many steps of preparation of the raw material as possible near the location of cotton plantations to realize more justice in distributing the benefits of industry between rural and urban areas and to make use of the good economics of the rural areas (lower rental rates of land for storage and drying of cotton stalks, cheaper wages, etc.)

• The use to the maximum, and with least modifications, of available equipment in the Egyptian village and preferably during the dead season of their operation, which has social and economic advantages.

• The maximum participation of members of the local community in the processes of preparation of the cotton stalks, either in the brain storming meetings of the project, in operation of the equipment or as subcontractors for the supervision of the whole process of preparation of cotton stalks.

^te ^ gives 9Q idea OB the procedure used for the preparation of cotton stalks in the field in El-Dakahliah govemorate [7]. The cotton stalks were transported to a collection site not far from cotton plantations. The cotton stalks were stacked up to 3 meters height leaving corridors for transportation. Air-drying was very successful taking about 30 days to decrease the moisture content from 140% to 20% [7]. Threshing was very successfully conducted using the traditional old wheat threshers. Thus, cotton stalks were converted into bales with standard dimensions and bulk density ^ 0.2 ton/m3 to be transported to the factory.

5.2.3 Evaluation of the Project Results.

▲ Top

Technical Appraisal.

The particleboard factory was operated by 326 tons (air-dry weight) of cotton stalks for the production of three-layer particleboards, laminated by melamine- impregnated paper. Table 3 illustrates the results of evaluation of main mechanical and physical properties of the factory product using different blends of casuarina and cotton stalks. It is clear from the table that the 100% cotton stalks boards satisfy the requirements of the Egyptian standard No. 906/1991 for particleboard [7].

Economic Appraisal.

In order to evaluate the economic feasibility of use of cotton stalks as a substitute for casuarina in particleboard production the criterion of cost of one ton of particles oven dry with resign on [II], was used. This criterion, excluding all common economic details of calculation, could measure the economic significance of introducing a new material in manufacture. Therefore, it was found that the net economic gain per ton, realized by the substitution of casuarina by cotton stalks, is equal to 63 L.E. [7]. In addition, the energy cost needed for drying of cotton stalks is much less, leading to the saving of about 8 tons/day of heavy oil (one ton of heavy oil costs about 800 L.E.) In addition, the preparation of cotton stalks needs much cheaper equipment, less costly in operation in terms of tools and energy, than casuarina.

5.3 Use of Products of Pruning and Renewal of Fruit Trees as a Substitute for Imported Wood.

5.3.1 Objectives

Egypt (and the Arab region) is famous for the growing of fruit trees of all kinds, such as: mulberry, guava, mango, olive, apricot, etc. These trees should be regularly pruned according to the horicultural rules followed with each of them. There are several practices of pruning associated with fruit trees. The products of pruning are usually treated as waste and are bumed directly in the field. After the end of the useful or productive life of a tree: either due to low productivity, low product quality or to infestation by insects, the wooden material of these trees is usually sold to merchants of charcoal to use them in charcoal making. These are very environment-unfriendly and economically irrational practices, because Egypt (and the whole region) spends a lot of its hard currency on the importation of wood. It is suggested to investigate the possibility of use of the products of pruning and renewal of fruit trees in handicraft, woodworking and furniture industries.

5.3.2 Field research.

Field research was conducted to evaluate the quantity of products of pruning of the following fruit trees: -

• Mulberry

• Mango

• Pear

• Plum

• Guava

• Olive

• Lemon & orange

• Apricot.

Besides, whole parts of trunks of the aforementioned trees were obtained from the charcoal merchants to conduct the experimental work needed.

5.3.3 Experimentation and laboratory tests

Samples of the aforementioned trees were subject to known carpentry work, such as; saw cutting, molding, carving, sanding and painting. In several cases (mango and apricot) rotary peeling was conducted on whole pieces of the tree trunk to obtain a 2 mm veneer. Production experiments were conducted to manufacture final products from the aforementioned materials. Besides, laboratory tests were conducted to determine the modulus of rupture, modulus of elasticity, maximum compressive strength and hardness. As a datum for comparison, the same tests were conducted on samples from beech wood.

5.3.4 Results and discussion.

Fig. 5 illustrates a comparison between several mechanical properties of lemon, orange, pear, apricot, mulberry, guava and mango wood with beech wood. It is clear from this figure that as far as the modulus of rupture is concerned all the species have values very adjacent to that for beech. Lemon and orange, as well as pear are higher than beech in bending strength. As far as the modulus of elasticity is concerned, the mango has the highest value (10031.4 N/mm2) approaching that for beech (11097.4 N/mm2). The lowest in elasticity is guava (5433 N/mm3). Concerning the maximum compressive strength apricot is the highest, followed by mango, pear and lemon & orange: all higher than beech. The lowest in maximum compressive strength is guava, followed by mulberry. As far as the hardness is concerned, the apricot is the highest, 1.7 times higher than the hardness of beech, followed by lemon and orange, 1.6 times, mango, 1.4, and pear, 1.4 times. It is clear from the aforementioned that all the species tested are higher in hardness than beech.

Fig. 6 illustrates the surface texture of mango wood. It is clear from the figure that mango texture is superior, compared with imported wood species. Fig. 7 illustrates the texture of apricot, which was successfully tested in parquet. Mango gave excellent results in carving, as shown in Fig. 8. Apricot veneers gave excellent results in overlaying, as shown in Fig 9. The olive wood gave excellent texture, as shown in Fig. 10 and was successfully used in table making. Guava for table legs and lemon for table frame gave excellent results, as shown in Fig. 11, whereas apricot gave excellent results in door. Fig. 12, and furniture manufacture. Fig. 13. Lemon wood gave outstanding results in making of partitions. Fig. 14, as well as handicrafts products,
Fig 15.

▲ Top

6. CONCLUSIONS.

It is valid from the given examples that the agricultural residues are sufficiently available everywhere with very economic prices. It is also clear that these residues have inherent properties, which make them suitable for a wide spectrum of industrial application: beginning with Arabesque (Mashrabiah) handicrafts, small- scale industries, such as furniture and parquet to medium and large-scale industries, such as blockboard, particleboard and MDF. Therefore, the agricultural residues, could serve as a material base for an industrial revolution, which begins from the village, the palm garden and the cotton field. What is lacking is the building of the endogenous scientific and technological capabilities beginning in the rural areas. It is not the importation of turn key projects, that will industrialize the rural communities, it is rather the tuning of science and technology inputs to the specific sociocultural and ecological context of the local community.

7. REFERENCES.

1. Behage, T. Development of durable goods, packaging and disposables with dvanced materials, based on renewable resources. Conference of challenges of sustainable Development, 1NES, Amsterdam, 22-25 August 1996.

2. Bewertung von "Date Palm Leaves' Midribs Blackboard" nach deutschen Sperrholz normen, Gutachtliche Stellungsnahme, Institute fur Holz forschung der Universitat Munchen, Munchen, Germany, 4.9.1996.

3. El-Mously, H.I. The rediscovery of local raw materials: new opportunities for developing countries. Industry and Environment Vol. 20, No. 1-2, January- June, 1997.

4. El-Mously, H.I. The date palm: the princess of a sustainable future. INES Newsletter N. 23, October, 1998.

5. El-Mously, H.I., M.A. Zamzam and N.H. Ibrahim. Mechanical properties of date palm leaves' midrib (DPLM) in relation to its utilization as a substitute for solid wood. Poster presentation, IUFRO XX World Congress, Tampere, Finland, 6-12 August 1995.

6. El-Mously, H.I., M.M. Megahed and M.M. Rakha. Investigation of the possibility of use of cotton stalks in particleboard production. Poster. The 33rd International Particleboard/Composite Materials Symposium, WSU., April 12-15, 1999.

7. El-Mously, H.I., M.M. Megahed and M.M. Rakha. Agricultural residues for particleboard production: a case study on cotton stalks. Proceedings of the 7th Cairo University International MDP Conference, Cairo, Egypt, 15-17 Feb. 2000.

8. El-Shabasy A.B. And H.I. El-Mously. Study of the variation of tensile strength across the cross-section of date palm leaves' midrib. Proceedings of the f European Conference on Advanced Materials and Processes and Applications. Vol. 4, Characterization and production/Design, Maastricht, 21- 23 April, 1997.

9. El-Shimi, S.A. Types and quantities of agricultural wastes in Egypt and the avenues for use of them: a study presented to the Arab Organization of Agricultural Development, University of Arab Countries, September, 1997.

10. Evaluation of resources and uses of wood and wooden furniture 1996/1997 - 2001/2002, (in Arabic). Ministry of planning, the fourth five-year plan and the pain of its first two years: 1997/1998.

11. Lars Bach, P.E. Structural board made of straw. Poster. The 33rd International Particleboard/Composite Materials Symposium, WSU. April 12-15, 1999.

12. Lumber prices and market economics 94 update. Journal of XILON International, No. 73, March 1994.

13. Megahed M.M. and H.I. El-Mously. Anatomical structure of date palm leaves' midrib and its variation across and along the midrib. IUFRO XX World Congress Tampere, Finland, 6-12 August 1995.

14. Peter A. Drake. The Composite panel industry: a global market assessment. Proceedings of the 31st International Particleboard/Composite Materials Symposium. WSU, 1997.

15. Study of the forest resources in the Arab world, (in Arabic) University of Arab Countries. The Arab Organization of Agricultural Development. Khartoum, June 1991.

16. Taysseer A.M., H.I. El-Mousty and M.M. Megahed. A new lumber-like products from date palm leaves' midribs. Proceedings of the 5 European Conference on Advanced Materials and Processes and Applications. Vol. 4, Characterization and production/Design, Maastricht, 21-23 April 1997.

▲ Download complete version of the paper including figures and tables. Click Here