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close this bookGATE - 1/84 - Wind Energy (GTZ GATE, 1984, 56 p.)
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View the documentNew apple containers for Himachal Pradesh
View the documentAquaculture-fish breeding in a closed water system with simultaneous biofiltration
View the documentSome socio-economic aspects in the utilization of bio-gas among rural farmers in Sri Lanka

New apple containers for Himachal Pradesh

by Klaus Vorhauer.

Apples have been commercially grown in Himachal Pradesh since 1918. Their cultivation was introduced by the American missionary Satyanand Stokes, who later became a convert to Hinduism, and rapidly spread as a source of profitable produce. These apples can be bought today in all large Indian towns, and their shiny, red exterior (Red Delicious) contains the exotic perfume of the Western world.

They are transported in the same way as other produce. They are packed in crates, transported by men, mules and trucks (in that order) to the large distribution market in Delhi, and dispatched to all parts of India.

Apples are now grown on over 100,000 hectares of land, and the total annual harvest is over 300,000 metric tonnes. The trend is upwards, and for the year 2000 the harvest estimate is almost half a million metric tonnes of apples.

Up to now the apples had been packed in the same way as their first ancestors: in solid wooden crates containing approximately 20 kilos. For a figure of 300,000 tonnes this means 15 million crates per year, and considering that one cubic metre of wood yields, under the production conditions prevalent in Himachal Pradesh, 30 to 50 crates, it is simple to calculate that between 300,000 and 500,000 cubic metres of wood have to be felled annually to meet these requirements. In other words the weight of the wood required is more or less identical to that of the apples dispatched.

In order to replace the annual timber consumption with poorer quality trees of narrower trunk widths would, under the most favourable conditions and given an area of 2.5 x 2.5 km, take approximately 60 years - in this case probably twice as long.

When one also realizes that the production of the crates causes an annual average wastage of 50 to 70 percent of the wood used, i.e. over 250,000 cubic metres, one's patience rapidly begins to evaporate.

The total amount of timber felled in Himachal Pradesh amounts to 600,000 cubic metres per year. It is not difficult to calculate that the wealth which apple-growing has brought to the mountainous regions of India will, in the end, turn into a catastrophe - with the last apples being packed in crates made from the wood of the apple trees themselves!

Yet another hair-raising aspect: this abuse of natural resources is given financial support by the Government of Himachal Pradesh, almost as if they wished to accelerate the end.

So far our considerations have been restricted to the sacrifice of the raw material timber. But the consequences of this "sell out" of the forests are much more serious. Without the protection of the trees, the steep mountain slopes will be subject to erosion. Valuable agricultural land will be transformed into a moonscape of rocks and scree. Without the retention capacity of the forests the water levels of the rivers will be subjected to even greater variations than at present.

Every year thousands drown in the swirling rivers, hundreds of thousands of houses and huts are destroyed and millions of hectares of fertile farming land are flooded. 300 million Indians living in the valleys of the Ganges, Brahmaputra and Indus are threatened by these catastrophes. Indiscriminate felling of the Himalayan forests is leading to a national state of emergency.

These dangers have been recognized not only by the Indian Government but by organisations all over the world. The World Bank, USAID, SIDA, CIDA and others are in the forefront of the battle to stop erosion.

Since 1980, GTZ, with an extensive programme within the Indo German Dhauladhar Project, Palampur, has been in the front line, too.

The aim of the project, which consists of over 70 sub-projects, is the long-term improvement of the living conditions of those living in the foothills of the Himalayas, the reduction of the risk of flooding and the fight against the sedimentation of water reservoirs. These targets have resulted in a comprehensive programme of reafforestation and erosion control.

Within the framework of this project I was asked to develop a new apple crate. It was to be technically appropriate, to make use of local resources and to take the ecological problems of Himachal Pradesh into account. The new crate was expected to save wood and thus make a contribution towards saving the forests.

Too valuable to turn into crates

The forests are state property. The state forestry administration supplies the wood for making the crates and pays the government Rs 50 per cubic metre, compared to Rs 300 in the case of wood for other purposes.

In view of this high subsidy, steps have to be taken to ensure that this wood is not used for other purposes. The trunks are thus sawn "in situ" into billets no longer than 120 cm. Anyone with any feeling for wood feels his stomach turn at the sight of this marvellously straight-grained wood from centuries-old trees being mutilated in this way. This sawing into small pieces naturally increases the amount of waste - a direct consequence of subsidization.

This wood is of such high quality that it is used in the construction of gliders, combining as it does extreme strength with relatively low weight.

If its forestry economy were properly run, Himachal Pradesh could, at some future date, become a wealthy state. Reafforestation measures, however, are inadequate and are frustrated to a great extent by the ravages of stray cattle.

There are over 3000 sawmills in Himachal Pradesh. Each is equipped with a bandsaw on which, without the help of an adjustable stop-piece and dependent on the skill of the machine-man", the boards for the crates are sawn from the billets. The huge amounts of waste consisting of bits of wood and sawdust are simply tipped into the valley behind the sawmill shed. Women glean the larger pieces for firewood, but most of the wood in the heap is left to rot - in a country where over four hours a day per family are spent in search of firewood!

The Forest Research Institute and College in Dekra Dun have been working for years on packaging suggestions that would save wood, and a large number of models have been produced.

Stimulated by the various technical possibilities - the production of corrugated cardboard and barked wood, the processing of hardboards and pressing them into laminates - I made some experiments of my own and constructed further models. During my fieldwork studies I tried out possible mass-production methods and adapted the models to the given conditions.

In various stages the new models are intended to save wood. The step-by-step approach is necessary in order to get the crates accepted by the fruit farmers and the sawmills more readily.

Traditional Simla Box.

Non-returnable crates

The main components of this model are two frames, similar to picture frames and mitred at the corners. All six sides of the crate can be fixed (nailed, tacked or glued) to these two frames. The sides can consist of wooden boards, hardboards, barked wood or cardboard.

At the start I would suggest using wooden boards. The external appearance of this crate would then

The main point, however, would be the introduction and practice of mitring as a construction method for the frames. Covering the two ends the "pictures" in the frames described above - with hardboard would be the next step.

This is where pine-needle boards could most usefully be used - for providing rigidity. A pilot factory for the production of pine-needle hardboard is under construction as part of the Indo German Dhauladhar Project.

The use of barked wood for the sides of the crates would be the next effective step towards saving timber. It should be noted that this method would enable up to 400 crates to be manufactured from one cubic metre of timber.

The combination of wooden frames, hardboard stiffening and barked wood boards provides, in my opinion, an optimal solution for non-returnable crates.

Multiple-use crates
Wooden-frame crates

For repeated use I would also suggest a reinforced version of the mitred-frame construction, using the same materials as the non-returnable crate described above. These crates, however, would not be nailed together but held together by means of bands or wire. When the crates reach their destination the bands can be unfastened and the six individual sections of the crate returned to sender.

Steel-frame crates

This container consists of a rigid frame of circular iron rods shaped in such a way that the empty containers can be stacked like conical glasses. When filled they can be stacked crossways, also linking into each other horizontally to form a kind of brickwork bond.

The container sides should be of woven split bamboo. This method of weaving would tie in with traditional techniques and also create a large number of workplaces, particularly as the sides would have to be replaced from time to time.

Crate for multiple use between fruit orchards and packing shed (shuttle box)

For this purpose I produced two versions of a wooden box based on the well-tried Lake Constance crate.

Two sawmills cut the individual parts for 600 crates with mitred frames and wooden sides, 100 of which were provided with pine-needle hardboard to make the ends rigid. In addition, fifty of each of the two shuttle box versions were produced. In order to ensure that these crates could be built more quickly and to the prescribed measurements, I started by making patterns, the usefulness of which was quickly appreciated.

The wooden crates have meanwhile reached Delhi's wholesale fruit market, where they have stood up well to the strains imposed on them.

Supplementary measures

In India the only products made from apples are apple juice and apple jam. Some ten other products are, however, feasible. I am thinking in particular of dried fruit, the production of which recommends itself particularly in the case of orchards far from the beaten track in view of the transport savings involved. At these elevations, simple solar drying installations would work marvellously.

About 60 percent of the annual investments made by fruit farmers for their plantations are spent on pesticides. Tested combinations of plants could considerably reduce this expenditure.

At relatively low investment cost the bandsaws could be equipped with additional equipment which would enable work to be done more accurately and thus reduce the amounts of timber wasted. The availability of simple tools and the training involved would also have a salutary effect on tasks other than the manufacture of wooden crates.

A use for the sawdust must be found. It could, for example, be mixed with the clay used in brick-making to make the bricks porous. This would considerably enhance their insulating qualities.

Gravity lifts could be built for inclined hoists lifting wood uphill. A water tank as counterweight could be filled with water at the top and emptied at the bottom.

Refrigeration depots should not be built on specially cleared sites in the valleys, where it is warm, but situated higher up, where the roads cross passes and where it is colder. An even better suggestion: they should be built into the mountains themselves, where they could even be run on natural ice gathered in the winter.

The wheel arches of the trucks protrude into the payload space. These should be squared to the packing pattern of the crates with a few strips of wood. This would avoid packing the crates on the slant and save a lot of breakages.

I would like to conclude with this suggestion of how to improve load distribution over the wheel arches, a ridiculously petty matter in view of the overall problems. - A saving of only one gram of wood per crate would mean an overall saving, for all crates, of 12 metric tonnes of wood per year.

Hightec and softtec, used responsibly and with a lot of imagination, are necessary if we wish to continue to live a reasonably tolerable life on this planet. But the train will only run if it is coupled to a locomotive that is prepared to pull us towards a future worth living in.

Aquaculture-fish breeding in a closed water system with simultaneous biofiltration

by Adam Onken

Only a few years ago, the development of aquaculture seemed to be the best method so far devised of rapidly eliminating the international problem of malnutrition. But meanwhile the euphoria has dissipated, and has been replaced by a more sober assessment of the potential amounts of protein obtainable by breeding water organisms under controlled conditions.

As far as the developing countries are concerned, it can be stated that in those regions which had already an existing aquaculture tradition e.g., Indonesia, The Philippines or Birma, its value has been recognized reinvigorated and in some cases even substantially promoted over the last few years. On the other hand, hardly any progress can be observed in those countries which do not have such an aquaculture tradition.

In industrialized countries, and in particular in the Federal Republic of Germany the new term aquaculture gained some recognition as a new scientific discipline and was able to attract considerable funds. These, however, were channelled primarily to those projects aiming at highly intensive, mostly semi-industrial fish breeding.

However, the results were modest, due mostly to hygienic problems, and failed to come up to expectations by far. Furthermore production was primarily concentrated on species which must be regarded as luxury foods and can only be produced at a very low level of conversion efficiency like trout, eels, shrimps, etc.

During the last few years, very effective biological methods of sewage water treatment have been developed, which with appropriate modifications and a more ecological approach might also be applicable for fish waste water treatment. Aquaculture in a closed water cycle, though difficult and ambitious, is worth further efforts since one of its most attractive feature is that it renders fish breeding independent of an abundant water supply.

It is this aspect of decentralization which is a very attractive and rewarding feature of the closed aquaculture system since fish can be produced more closely to consumer demand and even smaller and much less intensive units may guarantee a sufficient supply.

Aquacultural/Agricultural Methods

Both in the USA and in the Federal Republic there has been no shortage of attempts to design fish breeding units with water recycling on ecological lines. These efforts were based on the many different forms of integrated agricultural/aquacultural systems in Asia, which represent a symbiosis of plant and animal production. The end-products of metabolism secreted by fish and other animals serve as nutrients for plants and are thus removed productively from the water.

Aquaculture systems which are based on this universal principle generally use vegetable green as the plant component of the unit. Usually they are cultivated in gravel or other non-earth materials as "hydroponics". The assimilation capacity of the plants, i.e., the removal of the nutrients contained in the water and their fixation in vegetable biomass, is vital to the function of the system.

However, with this concept of water purification through plant biomass increment some important facts seem to have been neglected.

Since the nitrogen in cultivated plants such as lettuce or cabbage accounts for no more than 0.5 to 1% of the dry mass even with intensive plant growth, only limited amounts of nitrogen can be absorbed. On the other hand, to achieve a satisfactory fish biomass increment, which certainly is the aim of every aquaculture activities, at least 2 9 of nitrogen per kg of fish have to be added as protein feed every day. Of this about 50% is absorbed by fish while the remaining is released into the water. To remove it effectively, a prerequisite for all closed aquaculture operations, at least 100 to 200 times more green biomass has to be produced. This, however, also means a tremendous increase in evapotranspiration and thus water losses, which can amount for 60 mm per day. In addition thermal losses would increase considerably, especially with the more productive warmwater fish-farming.

Water treatment with simultaneous biochemical reactions

In order to avoid the difficulties described above, which result from hydroponics in combination with aquaculture, a different approach to water treatment with plants has been adopted. Continuing investigations into the use of emergent aquatic plants for domestic sewage treatment, the common reed (Phragmites) was studied with regard to its suitability as a plant component in a closed water cycle for fish-breeding. Like other aquatic plants, reed has a wide-meshed air-retaining tissue in the interior of its stalks, and this tissue extends down to the tips of the roots. As a result of active oxygen transport in this tissue, an oxidation reduction potential develops directly at the roots even under anaerobic soil conditions, and this makes high rates of conversion of matter possible

The special functions fulfilled by emergent aquatic plants in a filtering unit may be summarized as follows:
1. The plants grow through the filtering unit with a dense root meshwork to a depth of up to 2 m, keeping the filter open mechanically even when there is considerable contamination by organic matter. The effective cleaning volume is large in relation to the surface area.
2. The oxygen from the air, transported through the roots, leads to nitrification of the ammonium nitrogen (NH4-NO2-No3) from the fish culture in areas near the roots.
3. In anaerobic areas of the filter further away from the roots, the nitrate-nitrogen formed by nitrification is denitrified (NO3-N2) and escapes as gas.
4. The fecal sludge settles on the surface of the filter between the stalks of the reed. Secondary roots emerging from the nodes of the stalks cause the sludge to dehydrate within a short time. Finally it is mineralized.

Thus, when used for this application, the plants contribute primarily to an intensification and acceleration of microbial processes. The proximity of the nitrification and denitrification processes promises a very high degree of purification.

The Kassel Aquaculture

A system with a capacity of 4 m³ was set up on these principles in Kassel. It has been in operation for several years now, and thanks to its modular construction can be enlarged to any desired size. The basic components are two cylindrical tanks which can be made at very low cost on a do-it-yourself basis from 1 mm thick translucent fibre-reinforced polyester strips. The tanks are stabilized as cylindrical forms by the pressure of the water in them. The first tank is for fish growth, the second of approximately the same size is used exclusively for water treatment and has a filling of granular porous earthenware-like material with a large sorption-active surface, which plays an important part in the degradation of larger organic molecules.

The filter tank is planted with reed, about 4 to 6 rhizomes per m². After about two vegetation cycles the filter material is mostly penetrated by a dense network of roots. Water from the fish tank containing fecal sludge is driven continuously into the biofilter by air lift pumping. While the sludge settles on the surface of the filter between the stalks and is allowed to dry out, the water flows vertically downward through the filter. After passing through the filter, hydrostatic pressure causes it to flow back into the fish tank via a rising tube.

During the growing season this system can be operated as warm water aquaculture even under temperate middle-European climatic conditions requiring no auxiliary equipment.

Once the installation has reached maximum working capacity it can handle a load of approx. 10 9 of fish per 1 litre of water. Even under these semi-intensive conditions of production, nitrogen concentrations remain for the most part below detectable levels. By analyzing the nitrogen dynamics it has been found that 1 m³ of biofilter volume removes about 6 9 of nitrogen from the water cycle per day. However, only 2 percent of this quantity is assimilated by the plants, the remainder is degased by denitrification. Therefore, simultaneous aerobic and anaerobic degradations within the filter are vital processes. In this combination they are extremely effective in preventing any accumulation of nutrients in the recycled water.

However, the capacity of the biofilter is primarily limited by its conductivity more than by its biochemical reactivity. After two years of growth the vertical flow-velocity attained in the filter tub becomes constant, permitting a hydraulic load of about 1 litre per second per m². Since the surface area is small in relation to the effective filter volume, losses due to evaporation are relatively low. On average the weekly water losses do not exceed two percent of the total water quantity contained in the system. They even can be reduced by using

Not only suitable for fish breeding

Fish breeding in a closed water recycling system is feasible and can be managed with rather simple technology, making use of ecologically sound principales. With reed in a special filter bed and simultaneous aerobic and anaerobic degradation of noxious compounds water qualities are attainable that permit aquaculture with high productivity. Only limited amounts of extra energy for ventilation and water circulation are required which come to not more than 10 kWh per kg of fish biomass gained. Most of these energy requirements could also be met by alternative sources of energy.

A system like this undoubtedly can be employed for a wide range of applications. It could be a great help for breeding fish fry and sensitive water organisms as well as all sorts of food organisms.

In horticulture it could be a very interesting and rational expansion of existing activities even in smaller gardens in town and could contribute to an ecologically more stable food production and to local self-sufficiency.

Average Efficiency of a Simultan Biofilter

Data of Filter

Data of Water quality

Filter volume (H 135 cm, 0cm)










Hydraulic Load

m³/m² d





Flow [Kf]






Suldge Load [DM]






Organic Load(BOD5)












Some socio-economic aspects in the utilization of bio-gas among rural farmers in Sri Lanka

by M. Edward Perera

A few decades back the idea of producing big-gas from bio mass was almost nothing more than a fantasy for many people. In the context of Sri Lanka, fit is an entirely new concept which has come into being since a few enthusiastic scientists engaged in the search for alternative means of energy production in order to minimize the pressure associated with the growing prices of traditional energy sources.

At present, several groups have extended their activities among rural peasents in Sri Lanka with the intention of introducing the technology of producing big-gas by using number of different substances which are freely available locally.

The pioneers of big-gas plants in Sri Lanka have obtained their expertise abroad. Some of these Research Scientists have gained some relevant experience in Western Academies, a few others in China and in India. The attempts to develop an appropriate method have been very successful in that the ordinary farmers can afford such simple methods of producing energy in a very economical and practical way; Nearly 55 percent of the existing big-gas units in Sri Lanka are constructed basically on Chinese principales. The dissemination of big-gas units is still confined to a few localities where sufficient know-how is available and geographical conditions are favourable.

It is quite interesting to notice that the personality factor too has some significant impact in disseminating the concept of big-gas consumption among rural farmers in Sri Lanka.

An agriculturist who has gained a considerable knowledge about the technology of big-gas production in China and India, is totally devoted to promoting this simple method of energy production among rural peasants in Sri Lanka.

While rendering his services as the Principal of two leading Agricultural Schools simultaneously, one at Gannoruwa, Kandy District and the other one at Angunakolapalessa in Hambantota District, in the south-east of Sri Lanka, he has proved his ability to convince unsophisticated rural farmers to develop some confidence in this technology.

He has succeeded in many ways in bringing this very idea of adopting appropriate technology as an alternative source of energy production, to the rural people as well as to the urban folk.

In this particular study, we could identify one of his effective strategies in his methods of instructing uneducated rural farmers, i.e. the exploitation of sentiments of tradition-bound people in Sri Lanka for a progressive purpose. Teachers are always regarded as the pioneers and the builders of the nation. As an efficient teacher in the formal education sector and with a high regard for his profession, he has been more successful than his many counterparts in this field especially in the introduction of this system to the broad masses.

At the Agricultural School of Angunakolapalessa, farmers from the suburbs are given practical training together with students who are undergoing formal education in agriculture. This method of educating adults to improve their living conditions has become very effective due to a number of reasons, namely:
1. the disparity between academics and peasants would be reduced to a certain extent by providing a common basis in the learning,
2. the degree of confidence among peasants will be increased in the process of acknowledging new methods,
3. the convenience of consulting staff members or students at the school in the case of maintenance problems,
4. regular control and further instruction from the school staff,
5. opportunity for students to understand the nature of attitudes and expectations of the peasants in respective areas.

Unless the relevant surveys are conducted among these peasants to study their response to this new method of energy production, it is quite difficult to point out the most significant factors involved in the motivation. But the unbearable price of fuel, namely kerosine, has become one of the determining factors in adopting alternative means of energy production.

Although Sri Lanka is immensely blessed with natural energy resources of solar, wind and hydraulic nature and also with wood, the people in remote areas hardly benefit from the utilization of these energy sources on a rational and economic basis. The supply of electricity has not yet been extended to many rural areas in Sri Lanka. As the Minister of Land Development once unhappily quoted: the high-tension electric cables carry the power over the villages in his constituency, which are still in darkness. Long-term projects for the supply of electricity to each and every village are planned ahead.

Under the liberal economic policy of the present government, the unlimited influx of sophisticated electrical and electronic goods from industrialized countries has made a great impact on the general consumption pattern of Sri Lankans. Not merely because of convenience but also as status symbols, many electric appliances are being used by urban folk. This consumption pattern has spread to peripheral areas as well as to remote rural areas, even though the substantial power supply has not extended to these areas. This new development is mainly due to the "New Rich" those who work in Middle-east countries as guest workers. The demand for high consumption of energy has enormously increased as the potential of purchasing these sophisticated appliances by these Sri Lankan guest workers abroad has also grown.

Nor are Sri Lankan villages free of this kind of modernization. Almost every villager is informed about the new trends in modern consumer behaviour. But only a handful can afford a TV set or similar appliance. The concept "Some possess much but many possess nothing" is still applicable to Sri Lanka as a typical feature in this country too.

There are quite a number of external factors which have an impact on the process of motivating with a view to raising living conditions. The people who are unable to co-opt with the new trend of modernization are now facing a critical point of changing their life pattern. If not by sophisticated means, at least with some sort of appropriate measures, the necessary action should be implemented to improve the living conditions of the rural masses. While the prerequisites for a sophisticated modern life remain unfulfilled, people from many categories tend to adopt appropriate methods which they can afford.

Among the big-gas consumers in Sri Lanka, one can identify three major categories:
1. The Agricultural Schools where the big-gas units are installed on an experimental basis for teaching purposes and also to meet the demand of energy consumption on the school premises.
2. Non-governmental organizations such as Rural Community Development Centres and Religious Educational Centres where large numbers of young people reside in the attached hostels.
3. Unsophisticated rural farmers in remote areas where the people hardly benefit from the supply of electricity or other kinds of energy sources.

The government authorities in the respective areas have given some aid to farmers as an incentive to adopt this simple technology of producing energy. The farmers are provided with the necessary materials such as bricks, cement etc., if they are really interested in building a biogas unit. Technical know-how is extended through experts in the subject on a voluntary basis. But some organizations also extend their expertise on a commercial basis especially in the suburbs of cities.

Generally, cowdung is used in many big-gas units as it is frequently available in many parts of Sri Lanka. Straw together with Uria is being used in some places but it is commonly accepted that, qualitatively as well as quantitatively, this method is not effective when compared to the system with cowdung. In some cases, water plants like "Salviniya" are also used as substances for biogas. Human fecal substance is used in urban areas where cowdung is not sufficiently available, but still only as an exception.

Unlike the traditional Indian use of dried cowdung as a fuel, many Sri Lankan villagers once depended on fire wood to satisfy their energy needs especially for cooking. Even now a large number of Sri Lankans depend on fire wood for cooking. Within the last ten years, the price of kerosine has increased enormously. An average family can not afford buying kerosine for continuous consumption.

Under these circumstances, the concept of big-gas has growing popularity especially in rural areas where the price of kerosine plays a determining role in fuel consumption. Many school-children are unable to do their homework in the evening as their parents can not afford to buy kerosine for lighting. The great advantage of adopting the big-gas method is that it is not only useful in cooking but also as an effective means of lighting. There are some attempts in some places to generate electricity by using big-gas as fuel for a power generator and also for water pumps which normally run on diesel oil.

There are no proper statistics on big-gas units in Sri Lanka. But according to the survey findings of the Ceylon Institute of Scientific and Industrial Research there were about 300 such units all over the island in 1981. C