Woody construction wastes on account of various adhesives; paint etc. may have some limitations because of fungicidal properties. The technology has great promise in South East Asia and other areas where agricultural woody wastes are generated in large quantities.

Lignin is given off as waste. Lignin is a complex mixture of polymers. The molecular unit is partially aromatic with phenolic hydroxyl, methoxyl and carboxyl groups attached. It has found little use. A recent promising use is in the manufacture of Dimethyl Sulphide and Dimethyl Sulfoxide which is used as a spinning solvent in polyester yarn making. Other end uses for Lignin include as road binders for asphalt emulsions, adhesives for floor coverings, core binders in foundry practice and in the preparation of Levulinic acid. Activated Carbon can also be manufactured from the Lignins. Lignins can be removed from solutions by acidulation with either Carbon Dioxide or Sulphuric Acid.

The Coskata Process promoted by General Motors uses a wide variety of  different feedstocks to produce Ethanol. Agricultural wastes, purposefully grown crops and other waste materials like old tires and even municipal waste streams can be used with very little or Zero land fill waste. Anaerobic bacteria in a reactor are fed Carbon Monoxide and hydrogen produced by the gasification of the feed stock. The reactor is a sealed plastic tube with millions of filaments on which the bacteria live. Bacteria feed on the Carbon monoxide and hydrogen and produce ethanol. This process does not use genetically modified organisms and the microbes that are being used are not pathogenic. Being anaerobic they are poisoned as soon as they come into contact with air. The process is also less taxing on water. While other current methods of ethanol production take three to four times of water per unit of alcohol produced, the Coskata process needs less than a unit of water per unit of ethanol produced.

Coors Brewing Company, Aurora, Colorado Brewery is producing Alcohol from Beer waste. Ethanol is stripped from the waste Beer stream. They are also building a second unit to process waste biomass to ethanol. The brewing operations result in almost 87000 tonnes of brewers grains on a dry matter basis plus nine other byproducts that contain fermentable starches or some ethanol. The Biomass conversion plant will produce in excess of 4 million gallons of ethanol per year through enzymatic conversion of starches to fermentable sugars, yeast fermentation, stripping, distillation and dehydration of Ethanol. The residual wet distillers grains and solubles are utilized as cattle feed and in Dairy operations.

Star Techs Plasma Converter system contains a plasma field that reaches temperatures up to 30000 degrees Celsius. The plasma breaks down feedstock materials such as waste coal, used tires, wood wastes, raw sewage, municipal solid wastes, biomass, discarded roof shingles, coal waste, discarded corn stalks, and other agricultural by products to their core elements. The Synthesis gas thus produced can be used as feed stock for anaerobic bacteria to produce ethanol or heat, pressure and a catalyst can be used to convert the gas to alcohol.

Some researchers have pointed out that Ethanol and Bio diesel from agriproducts do not provide as much energy as it takes to create them.

Animal manures are truly renewable feedstocks for Ethanol production. The quantity of Swine manure produced in the U.S. estimated at 5 billion  tones dry matter per year is sufficient to contribute substantially to Ethanol production. With a conversion efficiency of 40% there is a theoretical yield of 500 million gallons a year.

Industries that are likely to be benefited from the waste to Ethanol services include food and beverages, breweries and wineries, biotechnology, pharmaceutical, chemical and consumer goods and agriproducts.

Tokyo Gas has built a plant to produce both Ethanol and methane from organic waste in the ward of Koto, Tokyo. Organic waste from school lunches is mashed and then taken to saccharisation tanks. Enzymes are added to the tank to breakdown starch into sugars. The suspension is then separated into the soluble and insoluble portions. The soluble part is rich in glucose which is fermented and distilled to give Ethanol. The solids are mixed with the distillation wastes and used for the generation of methane.

Sources

www.nedo3r.com/techsheet

www.tsk-g.co.jp

www.ecogeek.org/content

www.greencarcongress.com/2005

www.greencarcongress.com/2006

www.consumeraffairs.com/news04

www.glinden.blogspot.com/2004

www.terradaily.com

www.mark.asci.ncsu.edu/SWINEREPORTS/2001

www.ars.usda.gov

www.vincentcorp.com

www.sciencelinks.lipi.go.id

Agriculture scientists would like the farmers to realise that reduction of chemical based fertilizers and pesticides can benefit both man and earth over the long run, and in particular for farmers, as a major portion of whose money is spent on buying these chemicals.

Value of waste
The focus, they believe must shift to educating farmers on the value of waste matter being generated in both their fields and homes and the technology to convert these waste into wealth. Their farm economics will definitely improve if they realise and adopt this.

It is precisely on these lines that scientists at the Myrada Krishi Vigyan Kendra at Gobichettipalayam, in Erode, Tamil Nadu have been working for the past several years in implementing a project called IFD (Integrated farm development model). Also called as LESA (Low External Input Sustainable Agriculture) the project is at present operational in about 32 villages in Erode district of Tamil Nadu.
Innovative model

According to P. Alagesan, Programme Coordinator, IFD is an innovative model especially designed for small scale farmers in improving farm productivity in a sustainable manner through integrating farm resources by recycling farm and home wastes. “The main concept of IFD is to integrate the animal and human wastes into useful and productive components such as for the manufacture of vermicompost, pest repellants and biogas thereby reducing input cost for farmers,” he said.
Bio pest repellants

For example, in villages, the urine and dung from cattle is usually washed into a drain or the dung is collected, dried and used as cooking fuel.

“But our IFD farmers collect the urine and dung in a collection tank and use it for generating biogas and manufacturing biogrowth promoters such as Panchagavya and Amirtha karaisal, to make bio pest-repellants,” explained Mr. Alagesan.

The spent slurry from the bio gas plant is used to make high quality manure by adding other farm wastes to it, and can also be used to breed earth worms.

“To ensure food and fodder security our research team has been conducting several programmes to emphasize the importance of kitchen gardens. The size of the kitchen garden depends upon the family size and income (usually 2-5 cents). A limited supply of water channelled through a low cost micro irrigation system ensures a good harvest,” he said.

High yielding green fodder varieties are also grown in these gardens to provide fodder to the animals. By growing these fodder varieties, the cost of buying feed has come down to nearly 12 per cent, explained Mr. Alagesan.

Farmer friendly
Technology must be farmer friendly and IFD farmers have been trained on scientific storage of harvested produce. The farmers store their harvested grains in special grain structures called ‘pucca koti’ (Hindi word) and metal bins.

These storage structures have been able to minimize grain loss to nearly 20 per cent and also protect the harvested produce from pest and pathogenic infestations. Finally, the waste generated from the farmer’s family is also not wasted. A eco-san toilet has been designed to collect the faeces and urine separately.
Rich nutrient

The faeces is covered with wood ash after every use and it falls into a soil pit and decomposes into a rich nutrient which can be safely used as manure for the field.

The urine is separately channelled to the kitchen garden where it seeps through the earth to nourish the plants.

Studies conducted in these villages have shown that about 35 per cent of external input cost has been reduced by effective utilization of farm and home wastes.
Forest regeneration

Use of biogas (2 cubic metre capacity has the potential to save about 210 kg of fuel wood per month) brought down firewood consumption. In a village called M.P. Doddi about nine tonnes of fuel wood in a month has been saved which has a direct impact on regeneration of forest area around the region.

Respiratory problems commonly encountered by the rural women in smokey kitchens have largely been minimized.

UNICEF has identified this as an innovative model and has planned to replicate it in other parts of the nation.

At a small coastal Industrial zone Kalundborg near Copenhagan an exemplary material exchange is being practiced. The exchange involves a 1500M.W. Power plant,(Asuaes Power Station),a 3.2 million metric tones capacity oil refinery,(Stat Oil),a 14 million square meters of Gypsum Board manufacturing unit,(Gyproc),an Intermational Biotechnology company with a sales in excess of $2 Billion and the city of Kalundborg which supplies residential heat and hot water to the residents.
The Power plant supplies waste steam to the refinery and in turn gets refinery gas which substitutes some of the coal. Excess steam is also supplied to the Biotechnology Company, (Novo Nosdisk) and the city of Kalundborg for heating. This replaces almost 3500 individual furnaces which otherwise are a source of high air pollution. Desulphurization at the Power plant also produces Gypsum which meets1/3rd of the need of Gypsum in the Board manufacturing unit. Sludge from the Biotechnology Company is used as fertilizer on nearby farms and surplus yeast from its Insulin plant is sold to farmers as pig food.

From:
Damle Anand- Use of Fly Ash in Burnt Clay manufacturing, Cleaner Technology, Impacts/12/2003-2004, MOEF-CPCB, Govt. of India, 2003 pages11-21