Incineration disadvantages

The principal disadvantage of absorption bleaching is the problem of disposal of spent bleaching clay. Oil absorbed on the clay is exposed to air and is generally too oxidized to recover. Furthermore, spontaneous combustion of the oil-laden clay is a possibiUty in a landfill. Incineration of the spent clay along with sohd municipal waste to recover otherwise wasted energy is an attractive possibiUty. 

List the advantages and disadvantages of a municipal sanitary landfill and a municipal incinerator. 

The advantages of thermal incineration are that it is simple in concept, has a wide application, and results in almost complete destruction of pollutants with no liquid or solid residue. Thermal incineration provides an opportunity for heat recovery and has low maintenance requirements and low capital cost. Thermal incineration units for small or moderate exhaust streams are generally compact and light. Such units can be installed on a roof when the plant area is limited. = The main disadvantage is the auxiliary fuel cost, which is partly offset with an efficient heat-recovery system. The formation of nitric oxides during the combustion processes must be reduced by control of excess air temperature, fuel supply, and combustion air distribution at the burner inlet, The formation of thermal NO increases dramatically above 980 Table 13.10)... 

About 10% of the ethylene produced in the U.S. is used to make vinyl chloride, which in the chemical trade is usually referred to as vinyl chloride monomer or VCM. The largest use of VCM is for polymerization to poly(vinyl chloride) (PVC), a thermoplastic, which in terms of volume is second only to polyethylene. PVC is used in such diverse areas as containers, floor coverings (linoleum), plastic pipes, raincoats, and many, many others. PVC has an evironmental disadvantage over non-chlorine containing plastics in that when it is disposed of by incineration it produces hydrogen chloride, which dissolves in atmospheric water to give hydrochloric acid. Polyethylene does not have this undesirable feature. 

Critics of waste incineration argue that these plants often create more environmental problems than they solve. They point out, for example, that incinerators are a major source of dioxin, mercury, and halogenated hydrocarbon release into the atmosphere. In addition, incinerators are very expensive to build and to maintain, and they provide fewer jobs to members of the surrounding community than other methods of solid waste disposal. Also, companies have a dismal record of siting incinerators in disadvantaged communities, where residents suffer the worst consequences of incinerator use. Finally, waste-to-energy incinerators are of little value in tropical and subtropical countries, where the cost of plants and the availability of additional energy sources make them impractical. 

High-temperature treatment systems involve destruction of contaminant(s) through complete oxidation, whereas low-temperature systems increase the rate of phase transfer (e.g., liquid phase to gaseous phase), and thus encourage contaminant partitioning from soil. Some of the disadvantages of heat treatment include its high cost and its ineffectiveness with some contaminants (e.g., low volatilization potential or incineration actually produces more toxic substances). 

The advantages of fluidized bed incinerators include simple compact design, low cost, high combustion efficiency, low gas temperatures, and large surface area for reaction. The disadvantages are the ash removal and carbon that build up in the bed. They are mainly used in petroleum and paper industries, wood chips, and sewage sludge disposal. 

Nanofiltration or reverse osmosis treated water is needed in the most demanding places of the null such as for the high-pressure showers in a paper machine. Surface water used in the mill as intake freshwater may also need NF or RO treatment. Permeation of monovalent ions, in particular chloride ions, is both an advantage and a disadvantage of NF compared to RO. Monovalent salts cause significant osmotic pressure when retained in RO. In NF their permeation keeps the osmotic pressure lower and thus the transmembrane pressure needed to overcome the osmotic pressure is lower. The permeation of chloride ions in NF may restrict the reuse of the permeate because of concerns regarding corrosion caused by chloride. On the other hand, the concentrate then contains less chloride and its reuse or incineration is safer. 

Ashes from incinerated paper industries sludges were studied for their potential use in cement concrete interlocking block. Addition of ashes induced an increase of the water/cement ratios and moisture absorption and a decrease of the flexural strength of cement mortar or concrete. However, such disadvantages could be overcome by adding polymer latex and the interlocking blocks containing ashes met the Korean Standard. 

Chemical treatment involves the waste to be treated undergoing a chemical reaction to convert it to a less hazardous substance. Examples of chemical treatment are oxidation, incineration, and neutralization. An advantage of chemical treatment is that the waste may be converted into a substance that can be released into the environment as is. Also, chemical treatment may produce a usable end product. Disadvantages include possible need for an energy source, as well as reactants. Some reactions may also require extensive process control to be effective. 

Incineration is an obvious way to dispose of wastes. A big advantage is the reduction in the volume of solids that must be stored somewhere. Another advantage is the destruction of organic life that might be a health hazard. A big disadvantage is the atmospheric pollution resulting from the burning process. In essence, incineration merely trades one form of pollution for another. 

ProductiOTi and use of polymer products is environmentally disadvantageous wherever other materials perform the same function with less impacton the environment. Which types of materials these may be again depends on the specific function. Depending on the polymer type between 25 and several 100s Ml of non-renewable energy resources are consumed for the production of 1 kg of polymer. In the polymer s end-of-life tuily a fraction of 15-50 MJ, which is embodied in the polymer can be recovered for example as electricity and steam from waste incineration plants. Furthermore, new incineration plants are able to recover quality hydrochloric acid from the chlorine content of the polymers (and of course other non-polymer chlorine inputs). The remainder is lost. Production of synthetic polymers indeed consumes a high amount of energy, of which only a share can be recovered. While polymers are not per se environmentally bad, but in contrast often the better material alternative, they nevertheless must not be wasted, of course. 

ADVANTAGES AND DISADVANTAGES OF POSSIBLE ALTERATIONS TO BASELINE INCINERATION (continued)... 

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