Decomposition of Organic Waste

There are two major pathways responsible for decomposing organics (plant residue, manures, synthetic organics, sewage sludges, etc.) in the soil-water environment. One pathway involves aerobic processes, and a second involves anaerobic processes. During aerobic decomposition, carbohydrates are converted to carbon dioxide and water as follows  

ORGANIC MATTER, NITROGEN, PHOSPHORUS, SYNTHETIC ORGANICS 

1 Some General Properties of Soil Organic Matter (SOM) 

As noted in Chapter 3, organic matter is a high-complex heterogeneous substance with a number of properties beneficial to soils  

As pH increases, CEC increases and the preference for polyvalent cations also increases 

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Composting is the process of aerobic thermophilic decomposition of organic wastes to a relatively stable humus. Decomposition results from the biological activity of microorganisms which exist in the waste. 

Methane is emitted during the production and transport of coal, natural gas, and oil. Methane emissions also result from the decomposition of organic wastes in municipal solid waste landfills, and the raising of livestock. More information on methane. 

Biomass energy created by waste and residues left after food processing operations, and landfill gas mainly produced during anerobic decomposition of organic waste material seem to offer the most promising source of waste heat engines. The material is already concentrated at the processing site and it creates a disposal pollution problem. 

The factors that affect the ability of microorganisms to decompose organic material include type of organic material, temperature, pH, and redox potential (Eh). Fungi and actinomycetes are primarily responsible for the initial decomposition of organic waste. After that, bacteria are able to produce protease, a proteolytic enzyme which breaks protein down into simple compounds such as amino acids. The amino acids are absorbed by the microorganisms and ammonia is released by the following reactions ... 

Very recently, for complete decomposition of organic waste materials, a potent digestion technique was developed [69] based on the prototype of an HPA device... 

The primary gaseous carrier for transport of C from the low-level radioactive-waste disposal site (lat. 41 20 N, long. 89 47 W), near Sheffield, Bureau County, Illinois is C02 (1). Production of the gas is caused by aerobic microbial decomposition of organic waste buried in waste-disposal trenches. This results in steep gradients in P C02 in undisturbed glacial and eolian sediments adjacent to the site. To collect samples of unsaturated zone gases, nests of gas piezometers were installed along a cross section in boreholes located at distances of 12,29, and 46 m from the end wall... 

Composting is the controlled biological decomposition of organic wastes by microbial activity (Cundiff and Mankin, 2003). Compost is free of unpleasant odors, does not harbor pathogens or pests, can be stored for long periods of time, and has nutrient value usable by plants. 

These plants which use the heat content and the catalytic capabilities of molten metal for the decomposition of organic waste are specially adapted for a wide variety of special waste. Fig. 7 shows a plant which is able to gasify any kind of chlorinecontaining waste and is specially designed to wash the hydrochloric acid out of the otherwise clean gases to recover it as a feedstock for the polymerisation of new PVC. 

Biogas A mixture of methane and carbon dioxide produced by the bacterial decomposition of organic wastes and used as a fuel. 

Compared to the existing state-of-tiie-art treatment facility there has been a surplus of organic waste all over the globe. GHG emissions by decomposition of organic waste are a widespread problem (Huber-Humer et al., 2008). Alternatively these wastes can be turned into valuable fuels and biochemicals by using them as the feedstock for a biorefinery. In Table 2.1 different reports on the utilization of organic waste for the production of valuable chemicals have been summarized. From Table 2.1 it can be concluded that a large variety of wastes can be considered for potential biorefinery. Likewise, microbial, enzymatic, chemical, and thermal techniques can be used for this purpose. The simultaneous treatment of wastes and the possible reduction of GHG emissions are the two deliverables of this concept. 

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