Waste minimization cycle

To the process designer, life-cycle analysis is useful because focusing exclusively on waste minimization at some point in the life cycle sometimes creates problems elsewhere in the cycle. The designer can often obtain useful insights by changing the boundaries of the system under consideration so that they are wider than those of the process being designed. 

As air pollution management moves forward, economics has a major role in reducing pollution. Multimedia considerations are forcing a blend of traditional emission reduction approaches and innovative methods for waste minimization. These efforts are directed toward full cost accounting of the life cycle of products and residuals from the manufacturing, use, and ultimate disposal of materials. 

Waste Minimization VIP The waste minimization VIP involves a formal process stream-by-stream analysis to identify ways to eliminate or reduce the generation of wastes or nonuseful streams within the chemical process itself For those streams not eliminated or converted to salable by-products, it provides the method for managing the resulting wastes. This VIP incorporates environmental requirements into the facility design and combines life cycle environmental... 

Handbook of Green Chemistry and Technology, J. H. Clark and D. J. Macquarrie, Eds., Blackwell Publishing 2002, 540 pp., ISBN 0-632-05715-7. This collection of 22 review essays covers all the important areas of green chemistry, including environmental impact and life-cycle analysis, waste minimization, catalysts and their industrial applications, new synthesis methods, dean energy, and novel solvent systems. The chapters are well referenced and contain pertinent examples and case studies. 

Durucan, S. and A. Korre. 2000. Life cycle assessment of mining projects for waste minimization and long term control of rehabilitated sites. Proceedings of the 3rd Annual Workshop EUROTHEN, p. 257. 

Figure 1 Typical waste minimization and cleaner production cycle.

Topics covered include life cycle analysis, identifying and prioritizing pollutants for industrial sites, selecting environmentally compatible materials, design of unit operations for waste minimization, and pollution prevention economics. 

A key theme of this chapter is the reutilization of chemicals via available disposition routes. Any surplus chemicals still remaining at the end of the disposition cycle may re-enter it or be subject to final disposal as solid waste. Exceptions include chemicals that qualify for recycling and recovery (e.g., precious metals, ethylene glycol, anti-ffeeze solutions) or can be classified as Universal waste (see def.) under applicable environmental regulations. These pollution prevention and waste-minimization activities are covered in Chapter 7 ( Pollution Prevention and Waste Minimization ). However, requirements related to waste operations, such as the identification, storage, handling, transportation, treatment and disposal of waste fall outside the scope of the present chapter on chemical disposition. 

In other cases, waste minimization technologies can result in enhanced product quality. A continuous process data analysis system is one example. Rather than operator experience and intuition guiding when to cycle a process bath, computer analysis can be instituted to monitor key indicators of the process solution and automatically adjust the bath conditions. The result can be longer bath life, a more consistent product, and greater product engineer confidence (Dickinson 1995). 

The decisive criterion in the case of wood substitution is the life expectancy ratio (LER) of the compared products made of mixed plastics or wood, respectively. Only above a certain limit value (in the examined case LER = >3.3) — that is, a clearly longer life cycle of the plastic product as compared with the wooden product—is the level of resource reduction in feedstock recycling/energy recovery reached. The situation is similar as far as acidification and eutrophication are concerned. Advantages are found only with regard to waste minimization. 

Achieving goals of safety, cost innovation, resource sustainability, and long-lived waste minimization has involved various potential design choices both during early development and recent MSR proposals. Early MSR development was mandated as a breeder program and the focus was upon breeding ratio and fuel cycle costs at perhaps the expense of capital cost reduction. 

The once-through fuel cycle could be entirely appropriate for initiating market penetration of small reactors without on-site refuelling. On the other hand, successful market penetration may lead to a requirement to close the fuel cycle as the way to achieve efficient waste minimization and fuel utilization. 

In a more distant future, it will be necessary to change to an entirely closed nuclear fuel cycle. The time period for this change would be defined by the industrial development of economically effective spent fuel reprocessing technologies that should also be acceptable from the standpoint of non-proliferation and radioactive waste minimization. 

The gas velocity in the lower chamber is influenced by several factors. The gas which evolves from the chamber is a result of the interaction of the air, the auxiUary fuel, and the oxidation and volatilization prodncts from the waste. The quantity of gas from the waste can vary substantially depending on chamber conditions of the waste and could therefore alter the gas velocity in the lower chamber significantly. The airflow controls of the npper and lower chambers are integrated in order to minimize cycling and provide a uniform flow of gases. This is important for controlling pollution performance and especially so for an efficient energy-recovery system. 

Ray, Chittaranjan, Ravi K. Jain, Bernard A. Donahue, and E. Dean Smith, Hazardous Waste Minimization Through Life Cycle Cost Analysis at Federal Faeilities, Journal of the Air and Waste Management Association, 49, 17-27 (1999). 

Reduced Life Cycle Impact of structures on the environment, especially by Choices of Materials (e.g., depending on local availability and forest management practices wood can be a versatile, sustainable alternative) and Construction Methods that Minimize the Production of GHGs —Construction Waste Management including Recycling and Reuse. 

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". 

Nuclear fuel recycling allows more efficient nuclear fuel usage and less buildup of nuclear waste. Nuclear power reactors are designed to minimize plutonium build up and much of the plutonium that is produced inside the reactor is used during an ordinary fuel cycle. 

From an environmental point of view, it is desirable to minimize the amount of waste for each organic transformation. We chose the reaction between benzal-dehyde, aniline, and (1-phenylvinyloxy) trimethylsilane to study the effect of recycling the catalyst solution for subsequent runs. As the corresponding (S-aminoketone was insoluble in acetonitrile, it could be easily recovered by simple filtration. The catalyst solution was recycled for subsequent cycles. Up to four runs could be achieved without noticeable decrease in yield (Scheme 14). 

---