Biodegradable wastes

Biodegradable waste Sewage Food waste Organic chemicals... 

Forestry imports > Biodegradable waste Forestry residues Forestry products Agricultural residues a Agricultural products... 

The waste products of a home include paper, containers, tin cans, aluminum cans, and food scraps, as well as sewage. The waste products of industry and commerce include paper, wood, and metal scraps, as well as agricultural waste products. Biodegradable wastes, such as paper fines and industrial biosludge, into mixed alcohol fuels (e g., isopropanol, isobutanol, isopentanol). The wastes are first treated with lime to enhance reactivity. Then, they are converted to volatile fatly acids (VFAs) such as acetic acid, propionic acid, and butyric acid, using a mixed culture of microorganisms derived from cattle rumen or anaerobic waste treatment facihties. 

For anaerobic systems, methane gas is an important product. Depending on the type and nature of the biological components, different yields can be obtained for different biodegradable wastes. For pure cellulose, for example, the biogas product is 50% methane and 50% carbon dioxide. Mixed waste feedstocks yield biogas with methane concentrations of 40-60% (by volume). Fats and oils can yield biogas with 70% methane content. 

This traditional system is still the disposal method most widely used in the EU. In landfills, biodegradable waste decomposes to produce landfill gas and leachate. The landfill gas consists mainly of methane and, if not captured, contributes considerably to the greenhouse effect. For this reason, the move away from landfill is an important part of the European Waste Framework Directive. 

An additional 7 percent of biodegradable wastes were recycled in 2005 for composting. That number increased from 0 percent in 1960, 1970, and 1980, and from 2 percent in 1990, the first year in which measurable amounts of biodegradable materials were recycled in the country. 

Cutting-oil is a hazardous and poorly biodegradable waste, composed of two immiscible phases, an aqueous phase that represents 3A of the total volume, and an oily phase. The waste was diluted with a solution of iso-propanol in water, in order to give a more homogenous feed, and to fix the enthalpy of the waste in the range 4 103 KJ/Kg. 

EC (2000c). Working document. Biological treatment of biodegradable waste on sludge, first draft. European Commission, Bruxelles. 

Sonesson, U., Bjorklund, A., Carlsson, M., and Dalemo, M. (2000). Environmental and economic analysis of management systems for biodegradable waste. Resour. Conserv. Recyd. 28(1—2), 29—53. 

LATS is a market-based mechanism that introduces progressively tighter restrictions on the amount of paper, food and garden waste that authorities can landfill. Local authorities are allocated an annual landfill allowance for municipal biodegradable waste. They are under a duty not to exceed this allowance and face punitive fines for every tonne landfilled above the total amount of allowances they hold. EU fines imposed on the UK for failure to meet the targets will be split between local authorities in direct proportion to their contribution in breaching the targets. 

A notable development for BioBag was the selection of BioBag by the city of San Francisco for their residential food waste collection programme. The city is distributing 100,000 rolls of BioBags to residents within the county so that they can divert food and other biodegradable waste from landfill. San Francisco residents can now purchase additional supplies at over 100 outlets in the bay area. 

In the field of waste management, natura supplies biodegradable waste bags in many different shapes and sizes, from 8 to 240 litres. The bags are used for kitchen and garden waste bins and compost easily after use. 

Chemistry is also used to transform complex, although biodegradable, wastes into simpler products that can be easily incorporated in the biogeo-chemical cycle of the elements. It is often used to mimic natural chemical or biochemical processes under human-controlled circumstances. In optimal conditions these processes are kinetically favored, achieve high efficiencies, and completion of the reactions in shorter times as compared to the corresponding natural rates of change. This ideally leads... 

Arvanitoyannis and Varzakas (2008) summarized in their recent review the main advantages of the biodegradation waste management as follows ... 

Landfill Directive (99/31/EC) Introduced new technical and operational requirements for landfills across Europe and targets for the reduction in landfill of biodegradable wastes.The Decision (2003/ 33/EC), which comes into force in July 2004, is crucial for the implementation of the 1999 Landfill Directive. It outlines criteria for the waste that can be accepted at each of the defined types of site and for underground storage, sets out strict EU-wide leaching limit values and defines testing methods. The criteria are to be applied by Member States by July 2005. 

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