Minimization of waste

Minimization of Waste from the Separation and Recycle System... 

Understanding the chemistry of the process also provides the greatest opportunity in applying the principles of inherent safety at the chemical synthesis stage. Process chemistry greatly determines the potential impact of the processing facility on people and the environment. It also determines such important safety variables as inventory, ancillary unit operations, by-product disposal, etc. Creative design and selection of process chemistry can result in the use of inherently safer chemicals, a reduction in the inventories of hazardous chemicals and/or a minimization of waste treatment requirements. 

Die Natur der Chemie, FUTURE (Hoechst Magazin), August 1996 Vision of large-scale production in shoebox-sized plants nature and plant ceUs as model for micro reactors sustainable development central role of catalysis general advantages of micro flow use of clean raw materials minimization of waste the next step in the sequence acetylene-to-efhylene chemistry ethane chemistry renewable resources combinatorial chemistry intelligent and creative solutions [229]. 

Intensification of hazardous material results in a safer process. The minimization of waste will most often bring environmental benefits. 

Within the broad framework of sustainable development, we should strive to maximize resource efficiency through activities such as energy and nonrenewable resource conservation, risk minimization, pollution prevention, minimization of waste at all stages of a product life-cycle, and the development of products that are durable and can be re-used and recycled. Sustainable chemistry strives to accomplish these ends through the design, manufacture and use of efficient and effective, more environmentally benign chemical products and processes". 

Avoidance or minimization of wastes. Even with high yield methods, for one ton of finished dye, one ton of by-product may arise in addition to auxiliaries such as solvents, catalysts. 

As a model metathesis reaction, diethyl diallyhnalonate was cychzed in the presence of 5 mol% (41) within forty minutes in methylene chloride at 40 °C the product was isolated as a colorless oil after filtration and removal of volatiles. An analogous reaction with the soluble catalyst (29) was complete in less than five minutes, suggesting that metathesis reactions catalyzed by (41) are diffusion-controlled. Nonetheless, a reaction time of forty minutes is reasonable, and the validation for this chemistry lies in the simplified purification procedure and minimization of waste streams. 

Pavel, S.K., Elvin, FJ., Extraction and Processing for the Treatment and Minimization of Wastes, Minerals, Metals, and Materials Society, Warrendale, PA (1994)... 

Optimization is the maximizing or minimizing a response by changing one or more input variables. In this chapter optimization is synonymous with maximization, as any minimization can be turned into a maximization by a straightforward transformation Minimization of cost can be seen as maximization of profit minimization of waste turns into maximization of production minimization of/(x) is maximization of l//(x) or Before describing methods of effecting such an optimization, the term optimization must be carefully defined, and what is being optimized must be clearly understood. 

The last two decades have seen an increased interest in the use of supercritical fluids in separation science. Supercritical C02 has often been employed as a naturally occurring medium for the separation, purification, and determination of organic substances in environmental samples. However, there are only limited reports on the use of supercritical fluid as solvent in the separation of metal ions from solutions as well as various solid matrices. The supercritical fluid extraction (SFE) technology offers several advantages over conventional solvent-based methods, including the ability to extract radionuclides directly from solids, easy separation of solutes from C02, and minimization of waste generation. It can easily be removed from the extracted substances by degasification under atmospheric pressure and temperature. 

The minimization of waste is an important issue. Recycling is a good option but should only be considered if reuse is not possible. For a sustainable future, it is necessary to recycle as much as possible. The amount of waste varies from country to country, with the United States leading the list with 0.88 ton per person per year, followed by Australia (0.74 ton per person per year), and Canada (0.5 ton per person per year) [35,36]. Only 27% of the municipal solid waste generated in the United States in 1995 was recycled. Materials typically recycled included paper, plastic, wood, steel, aluminum, and glass. 

In spite of these efforts, it is unlikely that public perception about incinerators will shift toward a more assenting view, and thus the difficulties to be met in situating incinerators prefigure a problematical future for them. U.S. EPA strategies in this regard emphasize less reliance on this technique and greater confidence in the minimization of waste generation. This last subject is discussed in Chapter 12. 

Van t Hul, J.P., Racz, I.G., andReith, T., The appUcation of membrane technology for reuse of process water and minimization of waste water in a texHle washing range, J. Soc. Dyers Colour, 113, 287, 1997. 

Y. L. Huang and T. F. Edgar, Knowledge-based Design Approach for the Simultaneous Minimization of Waste Generation and Energy Consumption in a Petroleum Refinery, ... 

C. C. Nesbitt and T. E. Davis, Removal of Heavy Metals from Metallurgical Effluents by the Simultaneous Precipitation and Flotation of Metal Sulfides Using Column Cells, in Extraction and Processing for the Treatment and Minimization of Wastes, J. Hager, B. Hansen, W. Imrie, J. Pusateri, and V. Ramachandran (eds.), TMS, Warrendale, PA, 1994, pp. 331-342. 

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