Solvents waste resulting from

Nuclear Waste. NRC defines high level radioactive waste to include (/) irradiated (spent) reactor fuel (2) Hquid waste resulting from the operation of the first cycle solvent extraction system, and the concentrated wastes from subsequent extraction cycles, in a faciHty for reprocessing irradiated reactor fuel and (3) soHds into which such Hquid wastes have been converted. Approximately 23,000 metric tons of spent nuclear fuel has been stored at commercial nuclear reactors as of 1991. This amount is expected to double by the year 2001. 

High-level waste is the aqueous wastes resulting from operation of a first-cycle solvent extraction system, or equivalent, and concentrated wastes from subsequent extraction cycles, or equivalent, in a facility for fuel reprocessing. 

However, the significance of results from such analyses depends on the quality of the input data. For example, laboratory recipes often do not meticulously document solvent and auxiliary input masses. In many cases, water inputs and waste management are not determined before the pilot stage is reached. Estimates similar to those applied in LCA may be used in order to complete a preliminary mass balance. While such estimations cause considerable uncertainty, it seems more appropriate to evaluate alternatives based on preliminary information, that is, experience-based assumptions concerning the production of substrate or catalyst, than to simply ignore potentially important contributions to the mass balance. 

Household Hazardous Waste (HHW) is defined by the U.S. EPA as solid wastes, discarded from homes or similar sources, that are either hazardous wastes or wastes that exhibit any of the following characteristics ignitabiUty, corrosivity, reactivity, or toxicity. A significant fraction of HHW is generated by home mechanics who use such products as motor oil, cleaners and solvents, refrigerants, and batteries. The results indicate that most of the survey respondents perceive automotive products to pose significant health and environmental risks, and they tend to dispose of these wastes in an environmentally conscious manner. There is qnite often a discrepancy between human perception and scientific reality (see table 8.2) (Shorten et al., 1995). 

Crude TNT contains isomers and nitrated phenolic compounds resulting from side reactions. The usual method of purification is to treat crude TNT with 4% sodium sulfite solution at pH 8-9, which converts the unsymmetrical trinitro compounds to sulfonic acid derivatives. These by-products are then removed by washing with an alkaline solution. Pure TNT is then washed with hot water, flaked and packed. It is important to remove the waste acid and unsymmetrical trinitrotoluenes together with any by-products of nitration as they will degrade the TNT, reduce its shelf life, increase its sensitivity and reduce its compatibility with metals and other materials. Trace amounts of unsymmetrical trinitrotoluenes and by-products will also lower the melting point of TNT. TNT can be further recrystallized from organic solvents or 62% nitric acid. 

Significantly endothermic AHf (1) 147 kJ/mole 2.8 kJ/g. The monomer is sensitive to light, and even when inhibited (with aqueous ammonia) it will polymerise exother-mally at above 200°C [1]. It must never be stored uninhibited, or adjacent to acids or bases [2]. Polymerisation of the monomer in a sealed tube in an oil bath at 110°C led to a violent explosion. It was calculated that the critical condition for runaway thermal explosion was exceeded by a factor of 15 [3]. Runaway polymerisation in a distillation column led to an explosion and fire [4]. Another loss of containment and fire resulted from acrylonitrile polymerisation in a waste solvent tank also containing toluene and peroxides (peroxides are polymerisation initiators) [5]. Use of the nitrile as a reagent in synthesis can lead to condensation of its vapour in unseen parts of the equipment, such as vent-pipes and valves, which may then be obstructed or blocked by polymer [6]. 

Like supercritical carbon dioxide, supercritical water is a very interesting substance that has strikingly different properties from those of liquid water. For example, recent experiments have shown that supercritical (superfluid) water can behave simultaneously as both a polar and a nonpolar solvent. While the reasons for this unusual behavior remain unclear, the practical value of this behavior is very clear It makes superfluid water a very useful reaction medium for a wide variety of substances. One extremely important application of this idea involves the environmentally sound destruction of industrial wastes. Most hazardous organic (nonpolar) substances can be dissolved in supercritical water and oxidized by dissolved 02 in a matter of minutes. The products of these reactions are water, carbon dioxide, and possibly simple acids (which result when halogen-containing compounds are reacted). Therefore, the aqueous mixture that results from the reaction often can be disposed of with little further treatment. In contrast to the incinerators used to destroy organic waste products, a supercritical water reactor is a closed system (has no emissions). 

Cleaning Up Combine all aqueous filtrates and solutions, neutralize them, and flush the resulting solution down the drain with a large excess of water. U sed ether should be placed in the organic solvents container, and the sodium sulfate, once the solvent has evaporated from it, can be placed in the nonhazardous solid waste container. Any 4-chloroaniline should be placed in the chlorinated organic compounds container. 

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