Organic refuse

Manchester, U.K., has developed a method of converting organic refuse into high-quality crude oil, and in collaboration with the local authority is operating a pilot plant to demonstrate its commercial viability. 

Cheng C., Zhen L. Controllable techniques and installations for organic-refuse composting. 

A risk control technique called risk avoidance is when the risk or process that causes the risk is terminated. The organization refuses to expose its employees and assets to the risk, so the risk is completely eliminated. Termination of the risk could mean stopping the process, removing the machine, or ceasing to use a hazardous substance, chemical, or process. 

There are numerous misconceptions about the sources of various chemical elements in waste, particularly those that are potential acid formers when the waste is incinerated or mechanically converted and used as a refuse-derived fuel. For example, it is often mistakenly stated that the source of chlorine in waste, hence a potential source of HCl emissions, is poly(vinyl chloride). The relative contents of selected, potentially acid-forming elements in the organic portion of a sample of waste collected from various households in one U.S. East Coast city is given in Table 2 (17). In this city, a chief source of chlorine in the waste is NaCl, probably from food waste. 

Human-made sources cover a wide spectrum of chemical and physical activities and are the major contributors to urban air pollution. Air pollutants in the United States pour out from over 10 million vehicles, the refuse of over 250 million people, the generation of billions of kilowatts of electricity, and the production of innumerable products demanded by eveiyday living. Hundreds of millions of tons of air pollutants are generated annu ly in the United States alone. The five main classes of pollutants are particulates, sulfur dioxide, nitrogen oxides, volatile organic compounds, and carbon monoxide. Total emissions in the United States are summarized by source categoiy for the year 1993 in Table 25-10. 

At the Taylor Road landfill (originally intended for the disposal of municipal refuse only), unknown quantities of hazardous wastes from industrial and residential sources were deposited. During the period when the landfill was active, soil and groundwater samples collected at the site were found to contain concentrations of volatile organic compounds and metals above acceptable safe drinking water standards. Analysis of samples collected from private drinking water wells indicated that contamination... 

Refuse tips invariably result in the production of methane from the decay of organic matter. Measures are necessary to avoid trapping the methane in or beneath the building. This can be achieved by a system of methane vent pipes in the fill together with an impermeable membrane at sub-ground-floor level. Alternatively, a vented cavity can be constmcted sub-ground floor. 

The largest releases of polycyclic aromatic hydrocarbons (PAHs) are due to the incomplete combustion of organic compounds during the course of industrial processes and other human activities. Important sources include the combustion of coal, crude oil, and natural gas for both industrial and domestic purposes, the use of such materials in industrial processes (e.g., the smelting of iron ore), the operation of the internal combustion engine, and the combustion of refuse (see Environmental Health Criteria 202, 1998). The release of crude oil into the sea by the offshore oil industry and the wreckage of oil tankers are important sources of PAH in certain areas. Forest hres, which may or may not be the consequence of human activity, are a signihcant... 

Chemical compatibility tests using U.S. EPA Method 909040 should always be performed for hazardous waste sites, but some municipal waste sites also contain hazardous, nondegradable materials. U.S. EPA conducted a 5-year study of the impact of municipal refuse on commercially available liner materials and found no evidence of deterioration within that period. However, in a current study of leachate quality in municipal landfills, the Agency has discovered some organic chemical constituents normally found in hazardous waste landfill facilities. Apparently, small quantities of household hazardous waste enter municipal sites or are disposed of as small quantity generator wastes. As a result of these findings, U.S. EPA developed a position on the need for chemical compatibility tests for thousands of municipal waste disposal sites. 

The presence of excess salt, particularly of bivalent inorganics can reduce the electrostatic repulsion between the anionic polymer and the kaolinite particles and enhance flocculation (24,25). The optimum flocculation of fine coal and coal refuse (which contained 13 to 65% clays) obtained by Lewellyn and Wang(24) with hydrolyzed polyacrylamide containing 70% acrylate in fact might have resulted from the use of recycled water which contained 55 ppm Ca and 30 ppm Mg. Other works in literature have reported maximum flocculation of kaolinite to occur with 30% hydrolyzed polyacrylamide (5,6,10,26,27). Such differences in reported results could easily result from variations in water chemistry, originating either with the water used or with dissolved organics released by the mineral itself. 

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