The Cost of Waste

The Triple Bottom Line (TBL) is a term coined by management consultant John Elkington in 1997. It refers to the three interlinked strands of social, environmental and financial accountability. 

TBL is directly tied to the concept of sustainable development if analysed properly it will provide information to enable others to assess how sustainable an organization s operations are. The premise is that to be sustainable in the long term the organization must be financially secure, it must minimize (or ideally eliminate) its negative environmental impacts and it must act to conform to societal expectations. These three aspects are highly related. 

To find a common currency for reporting all three aspects of the TBL is not simple. Currently it is widely recognized that different indicators will often need to be assessed in different ways, sometimes quantitative, sometimes qualitative. 

Many governments, including the UK, are now actively encouraging TBL indicators to be covered in annual reports and are naming companies that fall below expectations. Green investment companies are also using TBL indicators as one criterion on which their investments are made. 

The direct effect of the cost of waste on production costs varies widely from product to product, and industry sector to industry sector. The fact that a sector or particular process has a high E-factor does not necessarily mean that waste is a significant proportion of production costs. For example many pharmaceutical processes use expensive chiral reagents, and the products are made in small batches, entailing expensive labour 

It is the formation of this material which makes the reaction have a low atom economy and, owing to the cost of disposal (usually by conversion to calcium phosphate and disposal as hazardous waste), has limited its commercial usefulness to high value products. Several methods have been developed to recycle (Ph)3PO into (Ph)3P but these have proved more complex than might be expected. Typically the oxide is converted to the chloride which is reduced by heating with aluminium. Overall this recovery is expensive and also produces significant amounts of waste. 

A hazard can be defined as a situation which may lead to harm, whilst risk is the probability that harm will occur. From the point of view of harm being caused by exposure to a chemical. Equation 1.3 is applicable. 

Many methods have now been developed for measuring the potential harmful effects chemicals can have. Common tests include those for irritancy, mutagenic effects, reproductive effects and acute toxicity. 

Although there is much controversy over using animals in tests such as these, the information is an essential part of the legal testing required when new chemicals are introduced onto the market in significant quantities. These and other toxicity test results are used to help develop Material Safety Data Sheets, establish Occupational Exposure Limits and guidelines for use of appropriate safety equipment. 

Whilst it is obvious that the lower the LD50 or LC50 is the more toxic the chemical, it is difficult to obtain a feel for how toxic the chemical may be to humans. Several scales have been developed to help compare toxicity data, a commonly used one developed by Hodge and Sterner is shown in Table 1.2. 

---

Copper etchants do not directly influence the electroless plating process, but are used merely to remove unwanted copper, and should not affect the deposit properties. The costs of waste treatment and disposal have led to disuse of throw-away systems such as chromic—sulfuric acid, ferric chloride, and ammonium persulfate. Newer types of regenerable etchants include cupric chloride, stabilized peroxide, and proprietary ammoniacal etchant baths. 

Over the years the trend has been toward an increasing use of the more expensive elastomers. Concern has been expressed about the cost of waste compound when using a multicavity mold and injection molding, primarily due to the amount of elastomeric compound in the runner system. There are three approaches to overcome the problem ... 

Water is historically thought to be free, and is still so cheap that its wastage is not felt to raise a serious cost. This commonly leads to pointless waste. It is unusual for a works to meter the water usage of different operations on one site, and so the cost of waste is not made clear to those who are immediately responsible for it. Occasional spot estimates of water usage (which may be possible... 

In the U.S. about 8% of the energy is provided by biomass and almost 90% of this comes from the combustion of wood and wood residues. The use of biomass increased from an installed capacity of 200 megawatts in 1980 to over 7,700 megawatts in 1990. The search for cleaner fuels and landfill restraints are the main reasons for increased biomass utilization. The cost of waste disposal has soared and landfill sites are closing faster than new ones are opening up. The Environmental Protection Agency (EPA) estimated that between 1978 and 1988, 70% of the nation s landfills, about 14,000 sites closed. 

That is, compared to conventional (small molecnle) drng prodnct mannfactnre, biopharmacentical mannfac-turing necessitates an even higher state of PAT for robnst process nnderstanding and control. Not only are the processes more complex but the cost of waste is often mnch higher. 

The first and second major drivers for pollution prevention, as described above, are regulations and laws and the cost of waste treatment. Extrapolation of the two curves in Fig. 6 would imply that future laws and regulations will be even more stringent and, if solved by end-of-pipe treatment, even more costly. 

One of the most powerful ways to drive home all of these points is by keeping track of waste. This can be done by several methods. Doxsee and Hutchison (2004) suggest performing an economic analysis of the entire process. For an economic analysis, students calculate all of the costs of reagents and solvents per gram of product obtained. This figure can be determined with or without the cost of waste disposal. Students are amazed to find that factoring in waste can often double the cost of production. 

Estimate the cost of waste disposal, as well as the treatment of volatile organic components (VOCs), polychlorinated biphenyls (PCBs), and any other materials forbidden by the environmental regulations. 

Onsite recycling It is the reuse of waste materials at the site of generation. It may be used in the same or another process (like the reuse of cleaning washes and of solvents in the production process). This type of recycling reduces the cost of raw materials as well as the cost of waste disposal. 

The book also explores the application of various acidic catalysts, such as silica-alumina, zeolites (HY, HZSM-5, mordenite) or alkaline compounds such as zinc oxide. However, the main problem with catalytic cracking is that in the course of the cracking process all catalysts deactivate very quickly. Expensive zeolite catalysts increase the cost of waste plastics cracking process to the point where it becomes economically unacceptable since the catalyst becomes contained in coke residue and therefore cannot be recovered and regenerated. 

In this expression, Fb, Fcd represent the production rates of B and CD, respectively, and Fao is the amount of fresh feed. The first term corresponds to the product value, while the second term corresponds to the cost of waste treatment for undesired products C and D. The third term corresponds to the reactor capital cost, while the fourth and the fifth terms correspond to the recycling costs. The costs incurred for maintaining a desired separation profile, C ep, is given in (PI4). 

Dilute aqueous streams are sent to waste-water treatment unless the contaminants are toxic to the bacteria in the waste-water plant. Acidic or basic wastes are neutralized prior to treatment. Neutralization is usually carried out using a base or acid that will form a solid salt that can be precipitated from the water so that the total dissolved solids (TDS) load on the waste-water plant is not excessive. The cost of waste-water treatment is typically about 6 per 1,000 gal ( 1.5 per metric ton), but there may also be local charges for spent water discharge. 

A novel process for toxic waste handling is suggested in U.S. 4,764,282 (to Uniroyal Goodrich Tire Company). A waste liquid is soaked up into ground tire rubber to form a stable solid that can be transported with reduced risk of spillage. The resulting product can then be incinerated in a fluidized bed combustor, similar to the fluidized bed combustors used in coal-fired power stations. Estimate the cost of waste disposal via this route, allowing for a credit for the electricity produced. How does this compare to the cost of toxic waste disposal by conventional incineration ... 

Considerable financial gain can be realized by minimizing the volumes of solvent used and by selecting less expensive solvents and grades of solvents, as appropriate. Minimizing the volume of solvent used also helps contain the cost of waste disposal. 

Disposal of waste plastics is expensive. Plastics deteriorate but never decompose completely and they involve a high percentage ( 42% by weight) of waste. Fortunately, in recent years recycling of plastics has become an important technology. Some plastics can be blended with unused virgin plastics to reduce the cost of waste disposal. 

The gasification system must be tailored to suit each application, in particular with regard to consumption of the energy products and availability of feed. Cost of the final energy is very sensitive to the cost of waste or biomass. The price of 14/od ton used in these analyses is felt to represent the value of wood residues as an energy source once the market for these products has been established. Of course, in many instances these residues represent a disposal problem and an energy conversion facility would have to be built for them to realize this energy value. 

The cost of waste disposal has soared and landfill sites are closing faster than new ones are opening up. The Environmental Protection Agency (EPA) estimated that between 1978 and 1988, 70% of the nation s landfills, about 14,000 sites closed. 

The cost of a process is the sum of six components. These are the raw materials cost, the overall yield of the process, the cost of waste disposal, the cost of the energy used to carry out the process, handling costs (including labour) and the capital cost of the necessary process plant. 

The design of a water-treatment plant and the selection of chemicals is a complex operation. They depend on the levels and variabilities of the impurities in the raw water, the cost effectiveness of alternative treatment chemicals, the cost of waste disposal and the required quality of the treated water. Consideration also needs to be given to the interactions between the various treatment processes [28.1,28.2]. 

The costs of waste to a chemical manufacturing company are high and diverse (Fig. 1.1-1) and, for the foreseeable future, they will get worse. 

---