Waste Disposal by Incineration

So far we have covered the source reduction and recycling of wastes. In the next section, we are going to discuss their ultimate disposal including incineration and landfilling. 

Incineration is a well-known process that involves the conversion of toxic and hazardous waste into a less or nontoxic waste by heating at a very high temperature to convert them into gaseous and particulate matter. Incineration is considered an attractive option after source reduction, and recycling. This method is sometimes preferred over the other treatment methods because it destroys permanently the hazardous components in the waste material. 

It is also preferable to completely destroy or reduce any hazardous waste instead of keeping them in long-term land-based disposal containment. 

Normally all kinds of organic waste or combustible materials are potential candidates for incineration. Even contaminated water and soils are currently disposed by incineration. 

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Coupled with these facilities and analytical procedures are programs for routine weekly decontamination waste disposal by incineration and burial personnel protection and safety training. 

Used oil disposal trends include waste minimisation such as by reclaiming used fluid on site, as well as recycling of mineral oil lubricants instead of disposing by incineration. The recycling effort involves a system where spent mineral oils are collected then shipped to specialty refineries where the materials are distilled, hydrofinished, and re-refined into fresh base stocks. These re-refined materials are virtually identical to virgin feedstocks. 

Responsible disposal of chemicals, samples and consumables is likewise an important aspect of good operating procedures in the laboratory. Regulations are fairly strict in terms of what may be disposed of into the drainage system. It may be permissible to dispose of some chemicals directly down the drain, flushed down with copious volumes of water. For other chemicals, specific disposal instructions, where available, must be followed. These will include collection of specific types of chemical waste in containers for disposal by incineration, landfill, etc. 

Dioxins are produced naturally when wood burns, for example. They are a group of chemicals, about seventy-five in number, known chemically as dibenzodioxins. Only a few of these are regarded as particularly toxic, with TCDD (tetrachlorodibenzodioxin) being the most potent (see box, p. 122). A variety of human activities can produce dioxins, ranging from chemical synthesis to disposal by incineration of plastics such as PVC and the industrial bleaching of paper with chlorine. Burning waste of any description probably produces dioxins, as do car engines. The major sources of dioxins are ... 

All residuals from empty containers and cleaning of reactors must be stored, well labeled, and disposed of by specialized waste disposal companies. Incineration is normally suggested as the best method of disposal. The amount of waste must be controlled and kept to a minimum. 

A novel process for toxic waste handling is suggested in U.S. 4,764,282 (to Uniroyal Goodrich Tire Company). A waste liquid is soaked up into ground tire rubber to form a stable solid that can be transported with reduced risk of spillage. The resulting product can then be incinerated in a fluidized bed combustor, similar to the fluidized bed combustors used in coal-fired power stations. Estimate the cost of waste disposal via this route, allowing for a credit for the electricity produced. How does this compare to the cost of toxic waste disposal by conventional incineration ... 

Potentially infectious waste, such as material from tissue cultures, should be autoclaved and prepared for disposal by incineration. 

The disposal of municipal and industrial wastes has become an important problem because the traditional means of disposal, landfill, has become environmentally much less acceptable than previously. In addition, special incinerator systems are required to meet environmental standards for disposal by incineration. Disposal of wastes by landfill or incineration also includes a potential loss of energy sources and, in some cases, valuable mineral resources. New, much stricter regulation of these disposal methods will make the economics of waste processing for resource recovery much more favorable. 

Emissions to land the CER identifies the quantities and disposal routes for both hazardous and non-hazardous waste in 1997 and 1998. The figures include disposal by incineration. There is also a group target to reduce total waste to less than 255000 tonnes by 2000. 

Emissions to land figures are presented for production and other waste , and the volumes sent to each destination (on- and off-site disposal by incineration or landfill) are identified. During 1998 approximately 700000 tonnes of wastes were disposed of by landfill (34%) or energy recovery/ incineration (66%). 

Finding 2-12a. The Army s plan to destroy highly organic neutralent waste streams by incineration is appropriate. Plasma arc systems are also adaptable to destruction of highly organic neutralents when incineration is not available or acceptable. Use of such high-temperature processes to destroy aqueous secondary wastes would be inefficient, although it may be expedient in some cases. If such aqueous liquids cannot be disposed via publicly or federally owned treatment works (POTW or EOTW), chemical oxidation or wet air oxidation may be attractive alternatives for this purpose. 

In the former West Germany, energy recovery from incineration reduces the cost of waste disposal by 20% - 40%, in Sweden all municipal waste incinerators recover energy (ISWA, 1991), and in 1991, 137 incinerators in the USA (where approximately one sixth of municipal waste is incinerated) recovered energy. 

The removal and replacement of contaminated HEPA filters should be performed by trained professional personnel who take precautions against any exposure to themselves and to avoid contaminating the facihty. This will require planning ahead of time to provide sufficient access to the filters. For filters anticipated to be contaminated with human pathogens (or animal, where animal eiqiosures are a matter of concern), provision for isolating bag-out procedures should be made in advance. In general, HEPA filters should be disposed of as contaminated biological waste, preferably by incineration. 

As no hazardous waste arises in the production of secondary raw materials or products made of virgin materials, the scenarios for mechanical recycling substituting plastics show no effect at all (Fig. 13.30). The increased quantities of hazardous waste in the case of processes that substitute wood or concrete result largely from the final disposal by incineration (filter dust). 

Disposing of such huge quantities of higher hydrocarbon waste gases by incineration impacts on the environment as it releases carbon dioxide, nitric oxide, nitrogen dioxide and sulfur oxide emissions into the atmosphere. 

The need to meet environmental regulations can affect processing costs. Undesirable air emissions may have to be eliminated and Hquid effluents and soHd residues treated and disposed of by incineration or/and landfilling. It is possible for biomass conversion processes that utilize waste feedstocks to combine waste disposal and treatment with energy and/or biofuel production so that credits can be taken for negative feedstock costs and tipping or receiving fees. 

When disposed of, all the nitroparaffins are considered to be hazardous waste. AH have the characteristic of ignitabHity however, 2-nitropropane also is a Hsted hazardous waste (U171) because of its toxicity. The preferred method of disposal is by incineration. GeneraHy, the nitroparaffins must be... 

Due to environmental considerations, many phenol plants are equipped with a special water treatment faciUty where acetone and phenol are recovered from the wastewater stream. Also, recovered heavy residue is considered a K-022 waste material by the U.S. EPA and must be properly disposed of by incineration or other means (12). 

Emissions During Disposal and Incineration. The increasing use of modem incinerators to dispose of domestic waste results in complete combustion of plasticizers to carbon dioxide and water. The preponderance of plasticizer going into landfiUs is as plasticized PVC. Once a landfiU has been capped anaerobic conditions prevail and it is biologically relatively inactive. Under these conditions the main route by which organic components are removed from the landfiU contents is by ingress of water, extraction, and subsequent loss of water from the site to the environment. 

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