Interdisciplinary approaches for innovations in the textile

Interdisciplinary approaches for innovations in the textile sector

At a time when the German textile industry is increasingly faced with competition from low-wage countries, innovations in the production, composition and application of new textiles may be able to create more stability in this sector. A growing proportion of new technologies in textile production and processing serve as a driving force behind innovation in high-tech textile products. New processes will lead to new products and hence to an expansion of the traditional textile industries, both in terms of supply and production.

Biotechnology is one of the technologies that could make a contribution to innovation. Biotechnology deals with research into cells, cell components, molecular and biological interactions as well as the exploitation of the findings gained. Biotechnology already has an enormous influence in many areas of our lives, even if this is not always directly apparent from the products we consume.

Textile: New processes will lead to new products. (Photo: BIOPRO)

In addition to this, at the interface between textile and biotechnology industries are synergies and products already jointly being developed for future markets. In the field of tissue engineering, for example, textile carrier materials are being optimised for their application in wound treatment. In the field of transplants, synthetic vessels can be coated with autologous vascular cells, thereby preventing rejection or a second vascular obliteration.

Information exchange leads to new applications

The majority of people are unaware of the ways in which biotechnological products can be used, in particular enzymes, which are heavily involved in textile production and finishing. For example, certain enzymes are used to soften cotton fibres. Nevertheless, it is possible to increase the awareness of end-users for the further applications of biotechnology. In order to identify potential synergies between the textile and biotechnology industries, further investigation in both areas needs to be done. It is only by identifying the demands and learning about the technologies used by the respective partners that future fields of application will be opened up.

As a starting point, both sectors need to be interested in potential applications. Then any relevant information must be provided before the final goal of putting business development deals in place can be achieved. This is the specific aim of BIOPRO Baden-Württemberg GmH - to use the enormous potential in the textile and biotechnology industry for boosting joint profit.

Bionics – biology as a model for technology

It fastens jackets, shoes and bags. It is practical, maybe even indispensable, and it is in fact the first bionic product to become world famous. We are talking about Velcro®. In the mid 1950s, Belgium scientists developed Velcro® from the seeds of the avens plant. Despite the popularity of the Velcro® fastener and although bionics is currently a hot topic, only insiders really seem to understand what “bionics” is all about. This scientific discipline takes findings and observations from biological research and transfers them to technical applications.

“Bionics” is a neologism, derived from the words “biology” and “mechanics”, although the more commonly recognised term is biomimetics, which is derived from the English words “biology” and “mimesis” (imitation). Within the next three years, the German Federal Ministry for Education and Research (BMBF) will provide funding of €60 million to bionics projects. The state of Baden-Württemberg has just decided to extend the funding period of the biomimetics competence network for another two years. Landesstiftung Baden-Württemberg is founding projects either.

The process of bionic development is a continuous procedure, without specifically defined areas where the biologist’s work ends and the engineer’s work begins. Using the giant reed (above) and the winter horsetail (below) as models, bionically inspired products such as the technical blade of grass were developed. (Figure: Plant Biomechanics Group Freiburg)

Bionics does not usually involve the direct transfer of an observation in nature to the development of a product, but rather it involves the creative implementation of biological concepts into technological products. Thomas Speck, Professor of Functional Morphology and Head of the Botanical Gardens at Freiburg University, likes to describe this process as “a ‘re-invention’ inspired by nature, usually going through several steps of abstraction and modification“. Bionics is considered to be an unusually strong interdisciplinary field of research, in which biologists, chemists, physicists, and engineers in particular join forces to conduct experiments and research. Experience shows that it is of great importance for biologists and engineers to work closely together throughout the entire process of development from the biological model to the bionically inspired market-ready product. “This is the only way we can guarantee the efficient transfer of research results to technical products along the entire value-added chain“, said the scientist from Freiburg (see also Freiburg BioRegion’s interview with Prof. Speck about the potential, innovative strength and the limits of bionics).

In many cases, it is not a single plant or a certain animal that inspires the bionics people in their work, but rather several models influence the development of a bionic product. For example, the winter horsetail Equisetum hyemale as well as the giant reed Arundo donax played key roles in the development of the “technical blade of grass“, a cooperation between the Plant Biomechanics Group Freiburg and the Institute of Textile Technology and Process Engineering Denkendorf (ITV) Denkendorf. But the engineers from the ITV Denkendorf are not only collaborating with the scientists from Freiburg; they are also working on developing textiles in collaboration with the “Functional Morphology and Biomimetics“ group at Tübingen University headed by Dr. Anita Roth-Nebelsick. These textiles will function like plant stomata, automatically adapting their wicking ability to the environmental micro-climate (see STERN BioRegion’s article).

The giant reed was one of the models for the mechanical blade of grass . (Photo: T. Speck)

All three of the aforementioned research groups and institutions are partners in the biomimetics competence network, which for the last three years has been financed and supported by the Ministry of Science, Research, and the Arts of the state of Baden-Württemberg. New members of the competence network are Prof. Claus Mattheck and his research group at the Research Centre in Karlsruhe and Dr. Stanislaw Gorb, head of the “Evolutionary Biomaterials Group“ group at the Max Planck Institute for Metals Research in Stuttgart. Mattheck uses the growth of trees as his model to minimize any notch stress when constructing technical devices. He uses bones to get ideas for constructing optimised shapes using as little material as possible (see the Rhine-Neckar Triangle BioRegion’s article).

Gorb, a biologist, is studying why flies, spiders and geckos are able to walk up glass without falling off. The pads of these animals are covered with the finest hairs which possess extremely high adhesive forces. Guided by this model, the scientists in Stuttgart are developing technical surfaces that have the same adhesive properties (see STERN BioRegion’s article).

The “Smart Materials Using Nature as a Model” research project has been part of the Baden-Württemberg competence network right from the beginning. This project aims to develop and produce self-repairing and self-adapting materials. Collaboration partners are the Plant Biomechanics Group Freiburg and the Swiss company, prospective concepts ag. In Summer 2005, the partners submitted a patent for a self-repairing membrane coating, based on the tear-repair mechanism of the pipevine. They were able to file the patent application after only three years of research (see Freiburg BioRegion’s article).

Such short periods of development are not really that common in the field of bionics. The aforementioned bionics researchers succeeded in gaining their results in such a short time as a result of concentrating all their efforts on a specific industry requirement. If the researchers focused on developing a technical product from a biological model this would generally take five to ten years.

Not only is much patience required for research and construction work, but some scientists also have to invest a great deal of time trying to convince their own colleagues of the usefulness of bionic principles – as was the case with the lotus effect. Wilhelm Barthlott, a botanist who discovered the self-cleansing ability of many plants, is a perfect example. He had to combat the scepticism of his colleagues for two years before he was finally able to publish his findings in a scientific journal. Many people found it difficult to believe that a rough surface cleanses itself more easily than a smooth surface. But nowadays the physical-chemical basis of the lotus effect is well known. Since the mid-90s, dirt-repelling, self-cleansing varnishes, paints and other surface materials are being produced in collaboration with different industrial partners.

kb – 13th Dec. 2005
© BIOPRO Baden-Württemberg GmbH

Biotechnology and mechanical engineering

Biotechnology and mechanical engineering: two different worlds

From:BioPro

Modern biotechnology has become an interdisciplinary technology that not only integrates food technology, pharmacy and medical engineering, but also now biotechnology. Biotechnology has entered classical fields of industry such as chemistry and mechanical engineering. The question is how can mechanical engineering benefit biotechnology and vice versa.

At first sight, mechanical engineering and biotechnology seem to be worlds apart. However, this is not the case at all. In fact, it is worth mentioning that, at many German universities, biotechnology courses usually come under the faculty of mechanical engineering. Classical biotechnology can trace its roots back to the field of engineering sciences. Biotechnology creates new products and methods that are made possible with new mechanical or systems engineering methods. The variety of biotechnological processes has led to a similarly high number of different systems and plants that would not have been possible without classical mechanical engineering.

(Photo: MTU)

No biotechnology without mechanical engineering

The complete process chain of biotechnology can be mapped out using mechanical engineering: Highly parallel robotic systems are used for the identification of new drugs and for the screening of microorganisms. Cell cultivation involves different reactor types and a complex infrastructure of tubing, pumps, valves, sensors and process control elements. The products thus generated are further processed using different separation and purification methods. And finally, the resultant pure substances are bottled and packaged using automated systems. There are examples of many other fields in which biotechnology is applied, for example, environmental protection and food production. However, there is no biotechnology without mechanical engineering – and the whole field still has huge, undiscovered potential.

Biotechnological evolution in mechanical engineering

In the course of evolution, a highly diverse and flexible world of microorganisms developed from the first primordial cells. Many organisms live under extreme environmental conditions and are equipped to tackle any kind of problem. It is worthwhile further exploiting the enormous potential these natural helpers have for industrial societies. Biotechnology has been known for thousands of years; the fermentation processes originally used in the production of food have since been further developed to produce highly effective recombinant pharmaceuticals. But it is difficult to see how it is possible for biotechnology to be used to remove rust from metals? What else may be possible?

Potential of biotechnology

Biotechnological processes involve the composition, modification and decomposition of material using living organised systems. Mechanical engineering also deals with these topics. For example, bionics is a bridge between natural construction principles and mechanical engineering. Examples of bionic development are the production of light but stable working parts and better hydro- and aerodynamics. Mechanical engineering also concerns the modification and protection of surfaces. Microorganisms grow on surfaces and modify the structure of such surfaces. What are the advantages and disadvantages of this nanoscale interaction and how can new materials be generated? Is it possible to convert cellular production processes into mechanical engineering processes? Can biological systems be used as examples for micro- and nanomachines? Biotechnology is already used in mechanical engineering. Biolubricants, produced from renewable resources, can not only be degraded biologically, but also have better qualities than traditional lubricants. More than 450 different biolubricants and hydraulic oils are already on the market.

BIOPRO Baden-Württemberg: furthering potential development

In the field of interdisciplinary applications, BIOPRO Baden-Württemberg aims to advance the dialogue between the different fields by putting experts from industry, research and education in active contact with each other. The innovative potential of biotechnology for the classical industries is far from being exhausted and represents an interesting field for diversification and growth.

GM buys into cellulosic ethanol

By STAFF REPORT

The news that the world’s largest car maker, General Motors, has invested in biology-based renewable energy company Coskata came as no great surprise to those who’ve been following GM’s courtship with the biofuels industry.

After working alongside ethanol producers to develop fuel formulations aimed at providing optimum performance in vehicle engines, GM began promoting ethanol more than 20 years ago. It was the first manufacturer to enable its entire U.S. fleet to operate on E10.

Globally, GM has about 3.5 million flex-fuel vehicles on the road in the U.S., Canada, Europe and Brazil. About 2.5 million of them are capable of running on any percentage of petrol and ethanol – up to 85 percent of the biofuel.

GM has long held the belief that ethanol used as a fuel – not just as a petrol additive – is the best near-term alternative to the surging global demand for oil. The company has a stated aim to reinvent the car through a range of clean transport technologies that reduce CO2 emissions and petroleum use.

The decision to buy a stake in Coskata comes as GM sets out to ensure a steady supply for the flex-fuel, ethanol-capable vehicles it is producing.

Coskata, founded in 2006 by leading renewable energy investors and entrepreneurs, has developed a commercially viable process to bring cellulosic ethanol to the market in 2011.

It has the means to produce the “next generation” ethanol from virtually any carbon-containing feedstock – including woodchips, municipal garbage and plant waste – for less than $US1 a gallon – about half the cost of producing petrol.

Coskata’s three-step process starts with carbon-based materials being converted into synthesis gas (syngas) by using well-established gasification technologies. After the chemical bonds are broken using gasification, micro-organisms convert the resulting syngas into ethanol by consuming carbon monoxide and hydrogen in the gas stream. Once the gas-to-liquid conversion process has occurred, the resulting ethanol is recovered from the solution using vapour permeation technology.

The company’s Vice President of Business Development, Wes Bolsen said the process addressed many of the constraints lodged against current renewable energy options including environmental, transportation and land-use concerns.

“The Coskata process has the potential to yield more than 100 gallons (378.5 litres) of ethanol per dry ton of carbonaceous feedstock – reducing costs to less than $1 per gallon,” he said.

The process is based on research and technology developed by Oklahoma State University’s Biofuels Team and licensed exclusively to Coskata.

GM Chairman and CEO Rick Wagoner announced the company’s investment in Coskata at January’s North American International Auto Show in Detroit.

“General Motors is very excited about what this breakthrough will mean to the viability of biofuels and, more importantly, to the company’s ability to reduce dependence on petroleum,” he told a news conference.

“This could lead to joint efforts in markets such as China, where growing energy demand and a new energy research centre could jumpstart a significant effort into ethanol made from biomass. There is no question in my mind that making ethanol more widely available is absolutely the most effective and environmentally sound solution – and it’s one that can be acted on immediately.”

Two hours after GM announced the partnership to produce ethanol from non-food sources, arch rival Toyota declared it was also involved in research to derive ethanol from wood.

10 Steps in Compost Production

To achieve self-sufficiency in rice, production must be pursued within a sustainable framework, one that meets the country’s current food demand and yet protects the environment. The use of organic fertilizers, such as compost, either alone or in combination with inorganic fertilizers, is one of the measures incorporated in the Agrikulturang MakaMASA program to promote sustainable crop production.

Past efforts to promote compost-making have been constrained, to a large extent, by the relatively low cost of chemical fertilizers. But even with the increased cost of fertilizers in recent years, few farmers adopted this technology because of the following reasons:

• It takes a long time to produce
• It takes large quantities of raw materials.
• It is laborious.
• Beneficial effects on the soil are not easily seen or felt.

But now, composting technology has considerably improved so that compost can be made in just 3-4 weeks!

What is a Compost?

Compost is a mixture of decayed organic materials decomposed by microorganisms in a warm, moist, and aerobic environment, releasing nutrients into readily available forms for plant use.

Why Use Compost?

• There is a need for sustainable production through integrated nutrient management.
• Compost produces less methane than uncomposted rice straw when incorporated in the soil.
• It solves the problem of declining yield.
• It corrects micronutrient problems such as zinc deficiency.

Benefits of Using Compost

• Big savings, increase farmers self reliance.
• Increases yields.
• Improves soil tilt and structure.
• Increases water-holding capacity of the soil.
• Improves aeration.
• Provides humus or organic matter, vitamins, hormones, and plant enzymes which are not supplied by chemical fertilizers.
• Acts as buffer to changes in soil pH.
• Kills pathogenic organisms, weeds and other unwanted seeds when temperatures of over 60 C is reached.
• Mature compost quickly comes into equilibrium with the soil.
• Different materials can be blended or mixed which can increase the nutrient content of the compost fertilizer.

Recommended Fertilizer Rate

The Agrikulturang MakaMASA program recommends basal application of 6-8 bags inorganic fertilizer and 8 bags organic fertilizer per hectare. By composting all the rice straw after harvest, this requirement is adequately met, and one does not need to buy commercial organic fertilizer.
- 5 tons rice straw (0.58% N) and;
- 2 tons compost (1.5%-3%N)
Enriched with animal manure, nitrogen-rich farm residues such as legumes, and acted upon by microorganims like fungus Trichoderma sp. and nitrogen fixing bacteria, Azotobacter sp.

3 ways of making compost

Traditional Method

This is slow process, requiring 3-4 months before warm wastes are fully decomposed and ready for use as compost fertilizer. This means that the fertilizer can only be used after one planting season. This also requires a bigger composting area. However, this method involves only eight steps, and it is inexpensive to produce, requiring no extensive inputs except labor.

Rapid Method

With the aid of fungus activator Trichoderma harzianum, decomposition of farm wastes is accelerated to just 3-4weeks! This means that the compost can be used in the next planting season. This involves ten steps.

Bio-Enriched Method

Employing both a fungus activator and a nitrogen-fixing bacteria, farm wastes are first decomposed by Trychoderma sp. for 2-3 weeks, after which the resulting compost is inculated with live N-fixing bacteria Azobacter sp. inocubation for one week produces a nitrogen-enriched compost that can supply a rice crop’s total N requirement. Depending on the material used, soil condition, and planting season, this involves 10 steps.

NOTE: For the Rapid and Bio-Enriched methods of composting, procedures in preparing these microorganism activators are available at the Institute of Biological Sciences (IBS) and the National Institute of Molecular Biology and Biotechnology (BIOTECH) of the University of the Philippines in Los Banos (UPLB), College, Laguna; and at the Department of Science and Technology (DOST).

Simplified guide to compost production

Most of the steps are common to the three methods of composting. Step 4 or the addition of fungus activator, however, does not apply to the traditional method. Step 8 or the addition of bacteria inocula, on the other hand, applies only to the Bio-Enriched method of composting.

Step 1. Gather Materials

Gather rice straw, weeds, sugarcane bagasse, corn stalks and stovers, leguminous materials such as ipil-ipil, azolla sesbania, mungbean, cowpea, soybean crop residues, and animal manure. Soak rice straw for 6-12 hours before piling. Chop materials for easier decomposition.

Ideal proportion of composting materials is 3 parts rice straw and 1 part mixture of animal manure (75%) and leguminous plant residues (25%). Less than this proportion prolongs the decomposition process.

Step 2. Prepare compost area

Choose a shaded and well-drained area.

To compost 5 tons of rice straw, we need a volume of 90 m3. A plot size of 2m x 6m 1.5 m can accommodate 1 ton of rice straw. Make 5 plots. If you want smaller plot size of 2m x 3m x 1.5m can accommodate 500 kg of rice straw materials. Make 10 small plots to be able to compost 5 tons rice straw.

Step 3. Pile materials

Traditional Method

Make six layers of compost materials, each layer about 25 cm thick. A layer of compost material consists of three parts rice straw, one part manure, soil, and ash or lime spread on top of each other. Stack the layers until the compost heap reaches 1.5m high. Insert several perforated bamboo poles into compost bed to serve as breathers.

Rapid Method (Trichoderma)

To provide aeration at the bottom, construct a platform or use available materials such as coconut leaf midribs, kakawate, banana trunk, and bamboo.

Make six layers of compost materials, each layer about 25 cm thick. A layer of compost material consists of three parts rice straw, one part mixture of animal manure and leguminous materials, and a thin layer of fungus activator known as compost Fungal Activator (CFA). There is no need to put ash/lime or bamboo breathers.

Bio-Enriched Method (Trichoderma and Azotobacter)

Mix all the rice straw, animal manure, and leguminous materials into 3:1 proportion. Apply 2.5 kg of the fungus activator, know as BIO-QUICK to every tone of composting material. Spread evenly on top of the first layer. Place 2-3 perforated bamboo poles horizontally across the first layer before adding the next layer. Make three layers.

Step 4. Spread fungus activator

Spread evenly 5-10 kg of Trichoderma fungus activator to every ton of composting material.

Step 5. Water compost heap

Water each layer compost heap until it is sufficiently moist.

Step 6. Cover compost heap

Cover with plastic sheet, used sacks, banana and coconut leaves to increase temperature and prevent too much water into the compost heap which could leach the nutrients.

Step 7. Turn compost heap

Traditional Method

Turn up side down or rotate, or mix compost heap after 3 weeks, then again after 5 weeks.

Rapid Method (Trichoderma)

Turn compost heap from top to bottom after 2 weeks. This step, however, is optional.

Bio-Enriched Method (Trichoderma and Azobacter )

Remove cover after 2-3 weeks or when the compost heap has decomposed. Separate undecomposed materials for further composting.

Step 8. Add bacteria inoculum

For every ton of compost material, spread evenly on top of each compost layer 2.5 kg of bacteria inocula, known as BIO-FIX and incubate for 1 week. Cover the compost heap but do not allow to dry.

Step 9. Harvest compost

Traditional Method

Harvest 4 weeks after the second rotation of the compost heap. The N content of the compost is now 1.5%. Use 2 tons of compost per hectare.

Rapid Method (Trichoderma)

Harvest 1-2 weeks after rotating the compost heap. The N content of the ripe compost varies from 1.0% - 3.0% depending on the amount of manure and nitrogenous plant materials used as substrates. Use all the compost produced in the field which could be about 2.0 tons per hectare. If commercial organic fertilizer produced through the rapid composting method is used, mix 8-10 bags per hectare.

Bio-Enriched Method (Trichoderma and Azobacter)

After 1 week of incubation of the bacteria inocula, the compost is ready for use. N content of the compost ranges from ranges from 1.5% to 3%. You need only apply 250-500 kg or 5-10 bags compost per hectare. Presence of live N-fixing bacteria in the compost will boost total N in the soil.

There are currently 36 Mass Production Centers (MPC) for fungal activators and 17 Compost Production Centers (CPC) accredited by the Department of Science and Technology (DOST) to make these activators available to farmers. These centers include government, nongovernment organizations, and cooperatives. There are 15 similar agencies producing both fungal activators and ready-to-use compost.

BIOTECH and IBS also provide training for cooperatives and entrepreneurs who wish to go into commercial organic fertilizer and mass production of these microorganisms.

Step 10. Apply compost

Broadcast compost as basal fertilizer before final harrowing during land preparation.

Health precautions

1. The decomposing compost heap can generate heat up to 60°C. Exercise care in handling the compost while rotating it. Wear protective gloves or foot gear so as not to scald your hands and feet.

2. Composting materials and microorganisms may cause allergies, although they are nonpathogenic. To avoid inconvenience from itching, cover nose and mouth with mask, use longsleeved clothes, and wash body and hand after working on the compost.

قابل توجه جناب آقای مهندس مجتبی خوارزمی

سرور عزیزم ،آقای مهندس مجتبی خوارزمی امر کردند تا مطالبی رو درخصوص بازیابی منابع و اختصاصا درمورد کمپست توی وبلاگ بذارم .حسب فرمایش ایشان این ۶-۷ مطلب اخیر را گذاشتم.امیدوارم از نظرات خودشون بنده را محروم نکنند.

درضمن تحقیق بسیار مفیدی را از خانم شکوفه سلیمانی نیا که تحت نظر دکتر مهرزاد مستشاری محصص انجام شده پیدا کردم که به محض دریافت نظر وبمستر ماخذ تحقیقشون( آقای سیاوش) و اخذ اجازه خانم سلیمانی توی وبلاگ میذارمش

Biotechnology in waste management

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Sewage farms - a public service we all need but prefer not to think about - are a classic example of traditional biotechnology. So are the compost heaps in many suburban gardens. The voracious appetites of bacteria are used to break down the huge quantities of human wastes discharged into the world's sewers each day. They and other microbes also help turn leaves, twigs and vegetable scraps into fertile humus to improve garden soil.

However, modern biotechnology can do more. Recent developments in biotechnology are providing new ways to clean up industrial wastes and yielding efficient new production methods that are less polluting than traditional processes. Biotechnology can even help convert industrial and other wastes into useful products.

What is biotechnology doing for industrial wastes?

Treating Waste Water

Biotechnology has always played a key role in removing organic solids like human waste from the millions of litres of waste water generated every day in Australia. Other contaminants, though, like phosphorus and nitrogen, have often been discharged into rivers and other waterbodies where they can disrupt the delicate ecological balance.

Being nutrients, phosphorus and nitrogen can cause excessive plant and algal growth. Overgrowth of aquatic plants can choke rivers and dams, and algae can produce toxins that poison fish and livestock. To remove nutrients from waste water, sewage farms have been using costly chemicals. Biotechnology, however, offers a cheaper and cleaner alternative. An extra anaerobic stage (one without oxygen) is added to the beginning of the sewage treatment process to help break down the organic materials. In the next aerobic phase, where oxygen is available, bacteria responsible for phosphorus removal can proliferate and consume the readily available organic food source.

During the sewage treatment process, bacteria also help to convert nitrogenous compounds into gaseous forms of nitrogen which are allowed to escape into the atmosphere.

Cleaning up Chemicals

Biotechnology is providing environmentally acceptable methods of modifying or destroying chemical wastes so they are no longer toxic to the environment. This usually involves finding bacteria or other microbes that can digest the target pollutants. If necessary, these organisms can be genetically engineered to provide strains with better contaminant-degrading potential than their natural counterparts. An example is the research being carried out at old military dumps where TNT (2,4,6 - trinitrotoluene) explosive is being made safe by using white rot fungi to degrade the dangerous explosives to harmless products.

Decontaminating Soil

Biotechnology has uncovered some strange coincidences that can work to our advantage. White rot in timber, for example, is caused by a harmless fungus that can digest the tough lignin component of wood. It happens that white rot fungi also enjoy eating organochlorine compounds such as DDT, dieldrin, aldrin and polychlorinated biphenyls, all of which have some structural similarities to lignin. This feature offers a relatively cheap and environmentally sound way of disposing of noxious compounds which, in the past, were valued for their stability and used extensively in refrigerants, fire retardants, paints and varnishes, solvents, herbicides and pesticides.

Normally, disposing of these chemicals involves high temperature incineration or quarantining of contaminated land. However, Australian scientists are conducting field trials using one strain of white rot fungi (of which there are six to ten thousand known species) to detoxify a PCB-contaminated site in the United States. The scientists also aim to develop a process for degrading bulk toxic wastes presently stored in drums on industrial sites throughout the world.

Removing Organic Pollutants from Industrial Effluents

White rot fungi also promise to provide a cheap and practical method of treating effluent from other industries.

For example, pulp and paper mills have a particular problem with toxic effluent from bleached paper production, with chlorine bound to the lignin component being the main pollutant. Biological treatment of the effluent using the lignin-digesting white rot fungus could offer both an economically and environmentally acceptable solution.

Treatment of waste products from other industries such as food processing, chemical manufacturing, textiles, brewing and distilling can also benefit from biotechnology, which can help devise biological effluent treatment processes suited to individual waste streams. Biotechnology is also used in more direct ways in many of these industrial processes, using, for example, fermentation and enzyme technologies.

Treating Petroleum Sludge and Oil Spills

Oil sludge, normally discharged into the sea from petroleum refineries, contains toxic compounds that are a major threat to the marine ecology. All forms of aquatic life are adversely affected, and contaminated fish, when eaten by humans, present a serious health hazard.

Biotechnology, however, has shown that particular species of bacteria and fungi, normally found in soil, can protect the marine environment by breaking down various types of hydrocarbons, the main component of petroleum. To be effective in cleaning up marine oil spills, however, micro-organisms must be able to withstand the marine environment _ for example they need to survive in high salt concentrations and to grow at low temperatures.

It may be necessary to use some of the techniques of modern biotechnology to introduce these characteristics into the appropriate oil-eating micro-organisms.

Making Fuels from Waste

Biotechnology is already benefitting developing countries by providing a cheap, clean and renewable alternative to fossil fuels, but the costs of biomass fuels such as ethane are still high relative to fossil fuel equivalents. Biomass fuels are greenhouse gas neutral (i.e., carbon dioxide is consumed by photosynthesis during the growth of the plant, and equal amounts are released when the biomass fuel is burned).

Human, animal or vegetable wastes are fed into a sealed unit, called a digester, where bacteria working without oxygen ferment the wastes to produce methane gas. Methane can be used for purposes including small-scale electricity production, cooking, lighting and heating. The slurry left at the end of the process is a useful crop fertilizer. Western nations are also looking at methane as a renewable energy source. Fruit and vegetable processing factories produce millions of tonnes of solid wastes each year. These are usually dumped, burnt or fed to animals. Pilot plants, however, have shown these wastes to be a good source of methane. Some local councils in Australia and elsewhere are also running trial programs to tap the methane produced during natural decay of rubbish at municipal garbage tips.

BIOTECHNOLOGY CAN HELP

• treat human and domestic wastes to maintain a healthy environment
• treat industrial wastes to reduce pollution
• convert some wastes to safe fertilizer to improve crop production
• remove or detoxify harmful chemical residues and accidental spills
• turn industrial and human wastes into useful fuel.

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Compost

Interest in composting as a waste management technique has increased enormously as people turn their attention to recycling technologies. The awareness that yard waste makes up 18 percent of the waste stream and food waste adds another 8 percent makes composting a high potential area for waste reduction.

In composting, a biochemical process occurs in which complex organic matter decomposes, through the action of microorganisms, into more stable organic matter. The results of this process are dark, humus-like materials that can be used for landscaping and certain agricultural purposes.

Because most of the plants start with mixed garbage , they must overcome the hurdle that much of the garbage is inorganic and does not break down in a composting process. Therefore, mixed municipal solid waste composting plants require before and after the composting process, sorting operations to remove inappropriate materials such as glass, metal, plastics and textiles.

After sorting out the inorganic materials, the composting process can begin. To get a sense of what good large-scale composting requires, the most important factors affecting the process are:

• Temperature. The temperature must be between 132 and 160 degrees Fahrenheit for a minimum of three days for a fast ans succesfull composting process.
• Moisture. At the beginning of the composting process, digesting material should have a moisture content of 50-60 percent.
• Controlled availability of oxygen. The micro-organisms in the waste need the oxygen in air to oxidize carbon matter and thus cause decomposition.
• Appropriate sizing of the waste particles. A ton of waste divided into many small pieces has more surface area than a ton of waste divided into fewer, larger pieces. Increased surface area allows micro-organisms more decomposing surface, resulting in faster composting.
• Chemical balance. The pH of the waste, which is a measure of acidity or alkalinity, should be maintained in the 7-8 range. The ratio of carbon to nitrogen is critical to the rate of composting.

Roughly, two different processes are used in the compost recycling. The first handles only yard waste. The second handles mixed solid waste.

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Recent advances

All the composting-processes which we have been describing above are so-called aerobic processes. This means that the material is composted under influence of air. However, there have been advances in composting with anaerobic processes. In these processes, the material is being composted by bacteries without influence from air. Although these anaerobic processes are currently more expensive than the traditional aerobic processes, the anaerobic processes have some advantages. They need less energy, in fact they even produce energy. Furthermore, these processes attribute less to the greenhouse- effect

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Processing mixed solid waste

There are several production steps common to MSW composting systems:

• Preprocessing. In this step large bulky items are removed and waste is shredded.
• Digestion/Composting. For this step there are two main technologies available:
  • Windrow systems. Here the waste is laid out in large, long piles known as windrows. Air is forced through these windrows or material is mechanically turned upside down to speed up the composting process.
  • Invessel systems. These systems involve continuous aeration and mixing, tumbling or turning of waste in various types of containment structures such as silosm agitated beds or tunnel reactors. In these systems the composting process needs 5-7 days to finish.
• Curing. Curing is an important phase of the composting process. It gives the material time to stabilize after the active phase of digestion. Usually this is done by laying the material in large windrows. This process takes approximately 4 weeks.
• Postprocessing. Postprocessing is performed before or after curing to remove remaining contaminants such as glass, ceramics or plastic from the compost before it is marketed. Postprocessing also can include other steps to prepare compost for end users, such as pelletizing.

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Processing yard waste

The yard waste composting process can be done in different ways depending on the available land and capital. One can distinguish a low technology system, in which composting can take 2 to 3 years. There is a medium technology system, in which composting will take 2 years. Furthermore, there is a high technology system which takes a year. The low technology approach requires much land but doesn't doesn't need much capital or technology. The high technology approach does require a lot of capital and technology but it doesn't take many land.

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