The following is a portion of a publication delivered at Ljubljana, Jugoslavia, on the subject of environmental quality management by Blair T. Bower, associate director of RFF's quality of the environment program.
Before a meaningful discussion of environmental quality is possible, some definitions and background are necessary. First, what is environmental quality? To the public health engineer, environmental quality involves vector control, food sanitation, swimming pool inspection, maintenance of adequate quality of drinking water. To the urban designer, it could mean the visual quality of the design and arrangement of buildings in space. To the hiker, it might be the visual quality of the forest through which he walks, as that quality is affected by logging operations and by other hikers who have discarded litter along the trails. To the social worker, it might be the quality and condition of housing for workers. In sum, environmental quality probably has as many definitions as there are individuals defining it, which is why it is universally difficult to get politicians, legislators, academics, or professionals to agree on what it is or how to measure it.
But one very important subset of environmental quality problems relates to the discard or discharge of society's leftovers—non-useful outputs or no-longer-useful outputs—into one or more of the environmental media: air, water, land. This sector is termed the residuals-environmental quality sector.
A residuals-environmental quality management system in any society includes several major elements. The first and fundamental one is final demand, i.e., the total sum of goods and services desired by society. This includes
- User goods—automobiles, transistor radios, food, clothes
- Intermediate goods—steel, chemicals, wood
- Producer goods—buildings, machinery
- Services—light, heat, hair cuts, legal documents prepared by lawyers, and memos prepared by government officials.
Note the use of the term "user goods" instead of the traditional "consumer goods." For a long time we have been misled by the use of the terms "consumer good" and "consumption." In reality, these are only goods which provide service or utility or satisfaction for a shorter or longer period of time. Sooner or later a car, suit of clothes, even a building, no longer provides the desired service, and it is discarded or "thrown away." But its mass does not disappear; the same quantity of material which went into the product is still in existence and must be disposed of in some manner. The laws of conservation of mass and energy have not been overthrown in any society. This fundamental fact indicates the magnitude of the residuals problem in society: the total weight of residuals to be handled is equal to the total weight of material inputs to production and so-called consumption activities plus the weight of air withdrawn from the atmosphere for use, minus the accumulation of materials in capital goods, such as buildings.
There are only two basic methods of disposing of residuals: (1) returning them to the environment, (2) reusing them in one or more activities. Two examples will illustrate what is involved. Figure A is a more or less artistic representation of a dairy cow, and hence of the process of producing milk. The basic raw material inputs are feed and water; the product output is milk; and the non-product output is manure.
Figure A - June 1973
Note that the term "non-product output" is used rather than "residual." This is because the non-product output may or may not be a residual, depending on its value at the particular time in a society. The value depends on the relative costs of other materials which can be used instead of the non-product output (manure in this case) as factor inputs into other production processes. These costs in turn depend on the level of technology at the time. Thus, in the current U.S. economy, manure has essentially no value; its value as a raw material input into agricultural production is less than the value of the resources required to use it. Therefore, manure is a residual. In many other societies manure has a value greater than the costs of its use, and hence is not a residual. It is important to understand the economic basis of the definition of residual.
Figure B is a simplified diagram of the process of producing paper products, such as paper napkins. Some of the non-product outputs are directly recovered and reused in the production process—for example, chemicals from the pulping process and fiber from the paper machine. Depending on relative costs of the alternative factor inputs, more or less recovery and reuse of these non-product outputs will be undertaken in the absence of environmental quality controls, that is to say, constraints of one type or another on discharges to the environmental media. The remaining non-product outputs, i.e., the quantities remaining after economical recovery has been undertaken, are residuals.
Note that there are two basic types of non-product outputs and residuals—material and energy. The former type has three major forms or occurs in the three states of matter: liquid, gaseous, and solid. The major energy residuals are heat and noise. Radioactive residuals have characteristics of both material and energy residuals.
It is important to emphasize the interrelationships among the three forms of material residuals. One form of material residual can be transformed into another, and additional material and energy residuals are often produced in modifying a particular residual. Furthermore, material residuals can be traded off for energy residuals.
These interrelationships can be simply illustrated by considering a power plant using coal as the fuel for electric energy generation. The particulates formed in combustion can be discharged to the atmosphere in the gas stream, as a gaseous residual. If, however, there are constraints on such discharge, a wet scrubber could be installed to wash the particulates out of the gas stream, thereby transforming the gaseous residual into a liquid residual (suspended solids) that could then be discharged to an adjacent river. Such discharge might adversely affect water quality, with consequent damage to fish. To prevent such an impact, a settling basin could be installed to settle out the suspended solids in the liquid residual, thereby yielding a solid residual for "ultimate" disposal.
Similar possible transformations exist with respect to energy residuals. For example, in the case of the power plant, approximately 2 kilowatt hours (kwh) equivalent of residual heat are generated for every kwh of desired energy ( the "product") output produced. This residual heat—waste heat, by traditional terminology—must be dissipated in some manner. Generally, this is to the environment, traditionally by direct discharge to water courses (once-through cooling). When there are adverse effects from such discharge, a typical response is to install a cooling tower, which results in the discharge of the thermal residual to the atmosphere instead of to the water. Such discharge may in turn have adverse effects, such as increased fog in the area, icing in winter, and increased precipitation in the immediate area.
Finally, the interrelationships between energy residuals and material residuals can be illustrated by controls imposed upon aircraft to reduce the impacts of noise residuals. One typical type of control is to prescribe modified takeoff and landing patterns. Although this may reduce the impacts of aircraft noise and perhaps even reduce the quantity of noise generated, such changes often result in an increase in gaseous residuals generated.
Having defined non-product outputs and residuals and indicated their interrelationships, it is now possible to delineate the factors which affect residuals generation. These are the factors affecting the types and quantities of residuals generated in various modes such as manufacturing, mining, agriculture, and household activities.
In the absence of controls on residuals discharge, the residuals generated in manufacturing, for example, are a function of the characteristics of the raw materials used, the technology of the production process, including age and physical layout of plant, the specifications of the desired product outputs, and the operating rate (units of raw material processed or units of output, per unit of time).
With respect to the production of paper napkins (Figure B), the residuals generated are a function of the species of wood used, the method of wood preparation, the type of pulping process, the characteristics desired in the final product (wet strength, softness, absorbency, and color), the type of paper machine, and the number of tons of paper produced per hour. The degree of whiteness desired is of particular importance because this determines the amount of bleaching required. Because bleaching is a major source of residuals generation in the production of paper products, shifting the final demand from white to unbleached paper products wherever possible (brown instead of white napkins), while holding all other desired characteristics constant, would substantially reduce residuals problems in this industry. There are many examples of changes in final demand which would have similar or much larger effects.
A version of this article appeared in print in the June 1973 issue of Resources magazine.
