Waste multiphase

Waste reduction is a multimedia (multiphase) problem. The solution to a wastewater problem may lie in the gas phase. 

Before leaving ionic liquids it is worth mentioning their potential value in separation processes. Organic solvents are frequently used in multiphase extraction processes and pose the same problems in terms of VOC containment and recovery as they do in syntheses, hence ionic liquids could offer a more benign alternative. Interesting applications along this line which have been studied include separation of spent nuclear fuel from other nuclear waste and extraction of the antibiotic erythromycin-A. 

Other multiphase ceramics. Numerous multiphase ceramic formulations for conditioning of various wastes have been designed (Harker 1988). These so-called tailored ceramics were developed for immobilization of complex defence wastes at the Savannah River Plant and Rockwell Hanford Operation (Harker 1988). Tailored ceramics include ACT and REE hosts (fluorite-structure solid solutions, zirconolite. 

To test the effectiveness of the CHEMFIX process as a treatment option, the solidified samples were subjected to the TCLP test and a comparison made with the TCLP results on a raw sample. This test was designed to determine the mobility of contaminants present in liquid, solid and multiphasic wastes. If the TCLP extract from a representative sample contained any of the listed contaminants above the regulatory levels it would be considered a hazardous waste and should adhere to the strict disposal requirements. )... 

There are vastly different levels of knowledge requirement in the study of multiphase chemical reactions, depending on the objective of the study. Development of a chemical process rarely requires an in-depth understanding of the kinetics and mechanism, and industrial chemists work on a strict need to know basis, since the acquisition of non-essential information is regarded as a waste of money. A key and difficult judgement is that of deciding what constitutes a minimum information requirement. For the industrial chemist, it will... 

Stratified random sampling, which is a variation of simple random sampling, is used for media that are stratified with respect to their chemical and physical properties. Each stratum is identified and randomly sampled. The number of grab samples and the sampling point selection depend on the nature of contaminant distribution within each stratum. Stratified random sampling is used for the characterization of multiphase liquid wastes or process waste batches that undergo stratification over time and/or space. 

Current multimedia models are inadequate in many respects. Description of intermedia transport across the soil-air and unsaturated soil-saturated soil zones suffers from the absence of a suitable theory for multiphase transport through the multiphase soil matrix. These phenomena are crucial in describing pollutant migration associated with hazardous chemical waste sites. Existing unsaturated-zone soil transport models fail to include mass transfer limitations associated with adsorption and desorption and with absorption and volatilization processes. Rather, most models assume equilibrium among the soil-air, soil-solid, solid-water, and soil-contaminant phases. 

These systems are common in liquid extraction and also in a multiphase reactor with an organic and an aqueous phase. Common sources of pollution are incomplete separation and contamination due to trace organics in the aqueous phase. An example is in alkylation reactions (e.g., n-butane reaction with olefins to form isooctanes). Strong acids, such as sulfuric and hydrofluoric acids, are used as catalysts, and the recovery and the recycle of acid need to be optimized in order to reduce the waste generation. 

Mixtures of water (main component), organic substances and gases such as O2 or CO2 are multiphase systems under normal conditions. Pressures above 221 bar and temperatures higher than 374 °C generally provide single-phase behaviour and facilitate very fast oxidation reactions. These advantages led to the attempt to turn SCWO into a commercially available industrial process for sewage disposal especially in the case of hazardous waste. 

During the past ten years, there has been considerable research devoted to the development of crystalline waste forms for actinide immobilization [7,8,24,27, 28,39,40,67,68,41-43,69]. Many of the phases are based on studies of minerals that contain Th and U, such as pyrochlore [16-18], zirconolite [70,71], zircon [1,72], monazite [73], britholite [74]. Based on their degrees of alteration, most of the minerals are considered to have an acceptable chemical durability. In addition, closely related mineral structures, such as murataite and garnet, which do not contain U or Th have been synthesized with actinides [29,75,76]. Multiphase ceramics. Ceramic matrices were initially designed for the immobilization of non-partitioned HLW from SNF reprocessing and considered... 

L. K. Wang, M. H. S. Wang, S. Yaksich, and M. L. Granstrom, Water treatment with multiphase flow reactor and cationic surfactants, J. Am. Water Works Assc. 70, 522-528 (1978). V. Kondratazicius, Removal of synthetic surface-active agents from waste waters of tanneries, Kozk. Obur. Prom. (USSR) 11, 18-18 (1969). 

The distinction in previous sections of electroanalysis, inorganic electrochemistry (particularly metal systems), and electroorganic synthesis leaves out a number of other electrochemical systems. Ultrasound has been applied to many of these, to interesting effect, and this section concerns a number of such systems. There is, of course, overlap in any attempt at compartmentalization, and here some studies on batteries, electrochemiluminescence, and micellar systems could be considered as contributing to electroanalysis, while other multiphase electrolyses might be considered as electrosynthesis. In addition, most multiphase electrolysis is directed to the destruction of haloorganics and is aimed at waste treatment. There are also one-off applications of ultrasound in electrochemistry, which are collected at the end of this section. 

To what extent must a polymer be purified for re-use Almost any mixture of polyn rs will be multiphased since few polymers are mutually compatible even when Aey have chemically similar structures. Optical transparency is invariably lost in a mixture and strength usually suffers. A separation step is invariably a benefit for the re-use of a waste stream. The more homogeneous the product, the broader its field of applications. 

The waste streams from production can be large, complex and multiphase. A study was undertaken to investigate the possibilities to reduce the volume of solvent required and to recover and reuse the waste solvents from one process. This approach is in accordance with the hierarchy of preferred options for handling waste (see Figure 2) and in line with the European Union s Fifth Action Programme. 

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