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188 to be balanced. It lends itself to elaboration at any level of detail. It also lends itself to refinement by integrating evaluations of short- and long-term environ- mental impacts into a single predictive statistic and by integrating institutional and environmental factors. This matrix is similar to one that was developed to compare the environmental impacts of ocean disposal with those related to alternative disposal practices and submitted in conjunction with an Ocean Dumping Permit Application to the Environmental Protection Agency (Energy Resources Co., Inc., 1981). The case study of the Acid Waste Dumpsite presented later in this chapter evaluates ocean disposal of acid-iron wastes and an alternative method under which the wastes would be neutralized and then placed in a landfill. This is a simplified case that demonstrates how the assessment system can be used; it is derived from numerous actual studies and experience. The third step in a multimedia assessment is decision making. This is the point at which the results of the impact assessment, the capital and operating costs, and the policy and strategy considerations of the owner of the waste confront the regulatory and political processes. The matrix approach helps to ensure that all possible media and processes are considered in deter- mining how to manage a particular waste. The proposed approach is sometimes subjective and sometimes objective. It approximates natural decision- making processes but is more structured to facilitate decision making. The analysis may be simple or detailed, depending on the complexity of the problem, the wishes of decision makers, and the availability of data. 6 . 2 CONSIDERATION OF ALTERNATIVES Decisions on how to deal with wastes first require identification of the available options. In addition to various disposal techniques, those options may include changes in processes, recycling of wastes, changes in raw materials, the separation or relocation of manufacturing steps, and others (see Table 6.1). The use of alter- natives is likely to result in wastes of differing quan- tity with different physical, chemical, and biological characteristics. These wastes may be gaseous, liquid, or solid in varying proportions
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189 TABLE 6.1 Examples of Waste-Management Alternatives Revise process to reduce waste volumes or change waste character Change raw materials Sell, use, or recycle wastes Pretreat wastes or intermediate streams Apply wastes to land for treatment Send wastes to landfill Dispose of in ocean Incincerate . . Inject into a deep well Store Develop other land-based alternatives Shut down generating process 6.2.1 Screening of Alternatives Once all the alternatives are identified, some type of screening process is necessary. The alternatives are normally screened to determine: Technical feasibility Economic reasonableness Environmental acceptability An evaluation of technical feasibility involves determining whether a particular alternative can be accomplished. Deep-well disposal of a waste, for example, might be quickly eliminated as an option if no geologic formations that could accept wastes in the quantities anticipated were known to existe An examination of economic reasonableness might show that certain options would be prohibitively expensive because of the effects of utilizing such options on the price of a product. An example would be incineration of a waste. Although incineration might be technically feasible, a preliminary evaluation might show that the additional cost of the fuel needed for incineration would make a particular product uncompetitive in the marketplace. Some options might be shown, with relatively little study, to be environmentally unacceptable. An example would be incineration that caused an unacceptable level
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191 management, operating, and service personnel. The sources and costs of required raw materials, utility services, and transportation should be specified. The salability of by-products will need to be identified, or, if such by-products must be disposed of, the costs of such disposal must be specified. Various secondary problems should be addressed as well, such as a need for increased production of raw materials. An instance of this would be the need to produce more lime to neutralize acidic wastewater. This might entail additional mining operations and consumption of larger amounts of the fuel used in calcining the limestone. 6.2.4 Final Listing of Alternatives The final alternatives, typically two to five, will include those that are considered technically and economically feasible and environmentally acceptable. Of critical importance, too, is whether each alternative can be implemented within a required time. The time con- straints will be determined by marketing strategies, by statute, or by management or political edict. If the final alternatives are found to be equally desirable or satisfactory, an environmental impact assess- ment can expedite the process of deciding which one to adopt. Table 6.2 lists the types of information required for environmental and institutional assessments. 6.3 IMPACT ASSESSMENT In this section, the panel proposes a matrix for com- paring final disposal alternatives with respect to their impacts on air, water, land, ocean, institutional, and community variables. The system is illustrated by an example from the Acid Waste Dumpsite. Waste-management alternatives that still appear feasible after the initial evaluation can be compared by using a matrix approach. By using a matrix it is possible to make a comparison on the basis of composite point totals that indicate short- and long-term impacts. The higher the point total, the greater the impact of the alternative. Table 6.3 shows the matrix that was developed. There are five environmental media to be considered (air, surface water, groundwater, land, and
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192 TABLE 6.2 Information Needed for Environmental and Institutional Assessments of a Waste-Management Alternative . Description of the waste-management alternative Process flow sheets Material balances Detailed design Equipment lists Materials of construction Capital costs Operating costs Manpower requirements Transportation needs Waste streams--character, quantity Time needed to install Energy requirements Definition of major secondary factors (energy, raw material, waste, or new product) Market information if sale of a by product or new product is involved Key economic ratios (e.g., return on assets and discounted cash flow) Technical feasibility--what are the odds that the alternative will work? Location of generating process Waste disposal locations Character of waste disposal location (e.g., geology, hydrology, climatology, topography) ocean), and there is also a set of institutional con- siderations (the effect of each disposal option on com- munity attitudes, services, economy, and safety). Each environmental medium has four areas of concern--human health, human welfare, biota, property--with each area of concern rated on a scale of 1 to 3, with 3 signifying greatest relative importance. Since human health is the most important environmental consideration, it is assigned a 3. Human welfare, a category that includes such factors as aesthetics and recreational value, and biota are generally assigned an intermediate rating of 2. Property (land, buildings, roads, for example) is assigned a relative importance of 1.
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193 The relative impacts of each waste disposal option are then rated in terms of their short-term and long-term effects. Short-term effects are those that are evident shortly after an alternative is implemented; they are normally reversible. Long-term effects are those that persist far into the future and may be irreversible. Separate ratings are assigned for short- and long-term effects. These ratings are assigned on a -5 to +5 scale where O signifies no effect, +5 signifies a serious adverse impact, and -5 signifies a very positive benefit. These impacts can best be determined by experts who have studied cause-and-effect relationships and can properly quantify impacts. If the impact of a waste disposal option is so severe as to be environmentally unacceptable, the option probably will have been rejected during the screening phase. But it is also possible that new information indicating environmental unacceptability will only come to light during the assessment. Environmental evaluation factors (EEF) for each area are then derived by multiplying the relative importance score by the relative impact score. The EEFs are summed to derive separate scores for environmental/short-term, environmental/long-term, institutional/ short-term, and institutional/long-term impacts. The matrix approach offers flexibility in choosing among waste disposal alternatives, but balance in the matrix must be maintained. The relative emphases in the subcategories should be similar, and no medium should be weighted much more heavily than another. Indeed, an alternative that impacts substantially on more than one medium could be difficult to manage in an environmentally acceptable manner. Institutional considerations should also be weighted more or less equally. The matrix is a semiquantitative tool based on information of varying degrees of accuracy. Thus, small differences in summary scores probably will not be important. 6.3.1 Environmental Impacts The impact of a waste disposal option on the air would consist of changes in air quality affecting human health, human welfare, biota, and property. Human-health impacts would be the impacts resulting from excessive concentra- tions of sulfur dioxide or carbon monoxide. Human welfare impacts would be such things as decreased
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195 TABLE 6 . 3 (continued) Relat ive I mpor Lance Med ium and Areas of Concern Scale 1-3 Impacts (-5 to +5 ) Short Term Long Term Mag · a EEFL, Mag . EEF B. Institutional Considerations Effects on Community a . Att itudes b . Serv ices c. Economy d. Safety TOTALS 2 3 aMag.: Magnitude of impact on each environmental and institutional resource considered is estimated on a scale of -5 to +5 with negative numbers indicating benef icial impacts (-5 = greatest benef icial impact) and positive numbers denoting harmful impacts (+5 = greatest harmful impact). bEEF: Environmental evaluation factor = (relative importance of environmental var table) x (magnitude of impact) .
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196 visibility and odors. Impacts on biota would be such things as damage to fish populations from acid rain or damage to vegetation from air pollutants. Impact on property might consist of damage to buildings caused by acid rain. Similarly, a waste disposal option could have impacts on surface waters. A human welfare impact on surface water might be loss of recreational fishing in a lake because of pollution. Damage to a freshwater aquatic community because of a change in water quality would be an impact on the biota. ~ ~ ~- An impact on property would be damage to structures in the water, such as boats or docks. A human-health impact would be contamination of a surface- water source of drinking water. In the groundwater medium, the major human-health con- cern would be the protection of drinking-water supplies. An impact on human welfare would be the rendering of groundwater less usable for agricultural irrigation. Although neither biota nor structures are normally present in groundwater, biota and property are included in the matrix to take account of the impact of groundwater pollution on aquatic species in underground waters and on structures elsewhere. With respect to land, a direct impact on human health would be caused by contact with contaminated soil; an indirect impact would be human consumption of contaminated crops. Human welfare, such as aesthetic or recreational opportunities, could be impacted by the use of large areas of land for waste disposal. The impact would be short term or long term, depending on whether the land could be returned to other use after disposal was com- pleted. A waste disposal option could have an impact on land biota, such as vegetation or animals, if the waste was placed in a vegetated area. An impact on property would be the razing of buildings to make space for a power plant's waste disposal. Ocean disposal considerations are discussed in greater detail in Section 6.5. Ocean disposal might affect human health if fish contaminated at disposal sites were con- sumed as food, although the possibility of this appears to be slight. ~ ~ ~~ ~ An impact on human welfare WOU1O he per- ceived loss of recreational and aesthetic values, such as beach damage caused by ocean dumping. Damage to the biota could be short term (reversible) and long term (irreversible). The impact on property would again be confined to physical structures, such as boats and docks
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199 limestone, disposal of the resulting solid waste on land, and release of treated effluent to the river or (2) disposal in the ocean (the existing practice). 188.8.131.52 Neutralization and Land Disposal (Table 6.4) The neutralization and land disposal alternative would consist of neutralization of the acid in the waste with ground limestone, followed by separation of the produced gypsum and metal hydroxide, which would then be disposed of on land. Approximately 3,100 tons of 80 percent solids would be generated per day, 365 days per year. At an increase in cost, the neutralization process can be modified to produce high-grade gypsum that would be suitable for wallboard manufacture. A study conducted by Battelle Memorial Institute determined that the gypsum could be used in cement manufacturing, provided the material was pelletized. Despite successful pilot runs (in a Canadian plant), however, no local producer of wallboard was interested in using the synthetic gypsum. The cement industry would, at best, consume less than 10 percent of the gypsum. Because prospects for the use of the gypsum were so small, a study of the land disposal requirements was then made. Three potential land disposal sites totaling 300 acres were identified. These sites could be used for 12 years, assuming the wastes were deposited to a height of 24 feet. Thereafter, additional sites at greater dis- tances from the point of generation would be needed. The wastes would amount to approximately 145 truckloads per day; that is, a truck would be entering or leaving the plant every S minutes, 24 hours per day, 365 days per year. That would mean a significant increase in truck traffic and thus a significant increase in energy consumption, air pollution, and noise. An engineering study of the neutralization process produced a detailed estimate of capital, operating, and maintenance costs and of engineering parameters (material balances, manpower, material usage, for example). The impact ratings of the neutralization process were judged to range from O to +5 (on a scale of -5 to +S). This option was found to have a small but quantifiable effect on the ambient air as a result of the increase in truck engine exhaust gases and particulates that would occur. Therefore, a value of 1 was assigned to this alternative's impact on human health. Since no irrever
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201 TABLE 6.4 (continued) Impacts Relative (-5 to +5) Importance Medium and Areas of Concern Scale 1-3 Short Term Long Term Mag.a DEFT Mag. EEF B. Institutional Considerations Effects on Community a. Attitudes 2 4 8 2 4 b. Services 1 ~2 2 2 c. Economy 2 1 2 2 4 d. Safety 3 2 6 2 6 TOTALS 18 16 aMag.: Magnitude of impact on each environmental and institutional resource considered is estimated on a scale of -5 to +5 with negative numbers indicating beneficial impacts (-5 = greatest beneficial impact) and positive numbers denoting harmful impacts (+5 greatest harmful impact). bEEF: Environmental evaluation factor = (relative importance of environmental variable) x (magnitude of impact).
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204 TABLE 6.5 Impact Assessment Matrix for the Ocean Disposal Alternative Impacts Relative (-5 to +5 ) Impor Lance Shor t Term Long Term Med tom and Areas of Concern Scale 1-3 Mag. a EEF ~Mag. EEF A . Environmental Cons ider at ions AIR a. Human: health 3 welfare (e.g., aesthetics) 2 b. Biota 2 c. Property 1 O O O O O O O O O O O O O O O O 2. SURFACE WATER a. Human: health 3 0 0 0 0 welfare 2 0 0 0 0 b . B. iota 2 0 0 0 0 c . Proper ty 1 0 0 0 0 3. GROUNDWATER a. Human: health 3 0 0 0 0 welfare 1 0 0 0 0 b . B. iota 1 0 0 0 0 c . Proper ty 1 0 0 0 0 4. LAND a. Human: health 3 0 0 0 0 welfare 2 0 0 0 0 b . B. iota 1 0 0 0 0 c . Proper ty 1 0 0 0 0 OCEAN a. Human: health 3 0 0 0 0 welfare 2 1 2 0 0 b . B. iota ( benthos and f ish) 2 1 2 0 0 c . Proper ty 1 0 0 0 0 TOTALS 4 0
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205 TABLE 6 . 5 (continued ) Impacts Relative (-5 to +5 ) Impor tance Short Term Med ium and Areas of Concern Scale 1-3 Mag. a Long Ter m EEF ~Mag. EEF B. Institutional Considerations Ef feats on Community a . Att itudes 2 b. Services 1 c. Economy d. Safety TOTALS 2 3 4 8 4 8 O O O O O O O O 1 3 1 3 11 11 aMag.: Magnitude of impact on each environmental and institutional resource considered is estimated on a scale of -5 to +5 with negative numbers indicating benef icial impacts (-5 = greatest benef icial impact) and positive numbers denoting harmful impacts (+5 greatest harmful impact). bEEF: Environmental evaluation factor = (relative importance of environmental var. table) x (magnitude of impact) .
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Representative terms from entire chapter: