Flammable waste products

Miners and spelunkers use a lamp fueled by water combined with calcium carbide (CaC2) to produce the flammable acetylene (C2H2) and the waste product calcium hydroxide (Ca(OH)2) ... 

For many plants handling monomers and other hazardous materials, sealless pumps are the first choice. They can practically eliminate the pump problems that can occur due to seal leaks, which can include product loss, flammability, waste disposal, and exposure of personnel to hazardous vapors. 

Entrepreneurs wasted no time in finding other commercial applications for tadium. Mixed with zinc sulphide, it produced a phosphorescent substance that was used to make luminous watch faces and aircraft instrumentation. Since radium dissipated stadc chai in surrounding air, it also reduced sparks, which made it useful in factories where flammable vapours could be ignited. Public f ination with the new wonder substance created a market for commercial applications of more dubious utility. Radium paint was used to create glow-in-the-daik slipper buttons, roulette wheels, and fish bait, and farmers were sold radioactive manures that had waste products fiom radium refineries mixed into them. 

The testing of chemicals/wastes to establish the nature of their hazard capacity/threat in accordance with regulatory requirements falls into four categories (1) reactivity, (2) ignitability/flammability, (3) corrosivity, and (4) EP toxicity. Commercial chemical products, specific wastes, and wastes from specific processes may be listed as hazardous wastes because they are known to present toxic hazards in the manner of the tests above and/or are known to present serious toxic hazards to mammals/humans. In the discussion to follow, various chemical groups will be examined primarily in the context of reactivity, ignitability, and corrosivity. 

A survey is made of methods for the recycling of PVC and mixed waste containing PVC, including incineration with energy recovery, pyrolysis and chemical recycling. Consideration is also given to the flammability of PVC and the toxicity of its combustion products. 82 refs. 

MITI is currently undergoing research to develop technology for the recycling of non-flammable plastics such as those used in business machines and computers. Their National Institute for Resources and Environment plans to decompose, without the production of harmful substances, non-flammable polymers by means of liquid phase hydrocracking, and to recover from them light oils such as benzene, toluene and xylene. The key to the technology, it is claimed, lies in the development of a catalyst which will be able to combine hazardous substances such as bromine and chlorine contained in the waste plastics. 

Production processes used in the pharmaceutical/fine chemical, cosmetic, textile, rubber, and other industries result in wastewaters containing significant levels of aliphatic solvents. It has been reported that of the 1000 tons per year of EC-defined toxic wastes generated in Ireland, organic solvents contribute 66% of the waste [27]. A survey of the constituents of pharmaceutical wastewater in Ireland has reported that aliphatic solvents contribute a significant proportion of the BOD/COD content of pharmaceutical effluents. Organic solvents are flammable, malodorous, and potentially toxic to aquatic organisms and thus require complete elimination by wastewater treatment systems. 

Manufacturing of the products from the raw materials and intermediates is done in industrial plants, where flammability, explosion, and toxic hazards exist for the workers and their neighbors. Plant discharges into the air and of liquid and solid wastes on to the land and into the water pose another set of potential hazards. 

Plant workers are exposed to the raw materials, intermediates, products, byproducts, and waste discharge. Regulations for the protection of plant workers are under the jurisdiction of the OSHA, and supported by the research arm of National Institute of Occupational Safety and Health (NIOSH). They issue a number of enforceable guidelines for safety, and they also issue advisories that are suggested but not required. We concentrate here on hazards that are specific to chemicals flammability, and toxicity through breathing the air and by skin exposure. 

Listed" waste is any waste that contains a substance that is "listed" by the USEPA as hazardous. This type of waste has been listed based on the waste s "toxicity, persistence, and degradability in nature, potential for accumulation in tissue, and other related factors such as flammability, corrosiveness, and other hazard characteristic." Rules have been developed by the USEPA to ensure proper disposal of these types of hazardous waste. The mixture rule states that any substance mixed with a "listed" hazardous waste becomes a hazardous waste. If it is not a "listed" waste, but instead a characteristic waste, and the mixture does not exhibit any of the characteristics, the mixture is not considered hazardous. The "derived from" rule states that any waste derived from the treatment of a "listed" hazardous waste remains a hazardous waste. Similar to the mixture rule, if the by-product of a characteristic waste does not exhibit any of the hazardous characteristics, it is not considered hazardous. 

In the event of a major plant accident, large quantities of nitrogen oxides could be released into the atmosphere and product nitric acid may well be released to the drains. There is little that can be done to provide for such a situation. The emphasis would be on dilution of any liquid wastes expelled. It would be left to the prevailing winds to disperse the nitrogen oxide cloud. Fortunately this gas cloud is not flammable, but it is highly toxic. Nitrogen oxide fumes either from nitric acid or from process gases may have a deceptive delayed action. The victim may feel no pain or discomfort at the time of the low-level inhalation, or for up to 48 hours thereafter, but then serious respiratory and cardiac problems can occur. 

Etliylene production involves liigli temperatures (1500°F) in tlie pyrolysis section and cryogenic temperatures in tlie purification section. Tlie feedstocks, products, and by-products of pyrolysis are flammable and pose severe fire liazards. Benzene, wliich is p-oduced in small amounts as a byproduct, is a known carcinogen. Table 21.7.1 summarizes some of tlie properties of etliane (feedstock) and tlie product gases. Figure 21.7.1 sliows a simplified schematic diagram of the pyrolysis and waste lieat recovery section on an etliylene plant. 

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