Water Pollution

Economics Aspects and Research Needs

Allen V. Kneese

• Verlag: Routledge
• Jahr: 2015
• ISBN:
  9781317387558
• Auflage: 1
• Thema: Economics
• Thema: Environmental Economics

Public agencies and industry will probably spend tens of billions of dollars on new water pollution abatement facilities in the next few decades. Added billions will be spent for the operation of new and existing facilities. How can physical science research reduce the cost of achieving objectives? And how can social science research make sure that the right objectives are being efficiently pursued? This title, first published in 1962, is directed to the orientation of the research effort, and the tool used for this purpose is an economic framework. This book will be of interest to students of economics and environmental studies.

Part I As ECONOMIC FRAMEWORK

IIntroduction

Some early projections of national water requirements failed to consider that water use ordinarily is not completely consumptive and that residuals are available for further use. In several more recent studies this oversight was corrected, or perhaps even over-corrected. Consumption of water came to be regarded as a physical phenomenon resulting almost entirely from evaporation and transpiration. From the point of view of economics such a definition is inadequate. While evaporation and transpiration are indeed consumptive in that they preclude further uses, other changes resulting from water use may have an analogous effect. It is exclusion or increased cost of alternative uses that constitutes loss or consumption, or better yet, the real cost of water use. Emphasis on losses or costs viewed as foregone opportunities helps to clarify the problem of water resources use and development and helps to tie the analysis into the general framework of an economic allocation theory. It is evident, of course, that changes in water quality resulting from various uses may either foreclose completely or raise the cost of subsequent uses of water, and thus be as clearly consumptive as if an actual transformation from the liquid to the vapor state had occurred.

Most recent, general studies of water resources have given at least a nod to quality problems. However, the first comprehensive projection of water requirements that formally and specifically includes requirements for pollution abatement was recently undertaken by Resources for the Future, with the co-operation of the Senate Select Committee on Water Resources. The study was directed by Dr. Nathaniel Wollman and a report of preliminary findings was published as a print of the Senate Select Committee.¹

¹ Water Resources Activities in the United States—Water Supply and Demand, Select Committee on National Water Resources, United States Senate, Committee Print No. 32 (Washington: U.S. Government Printing Office, August 1960). See also Committee Print No. 29 (July 1960), Water Requirements for Pollution Abatement by George W. Reid, from which the estimates of dilution water requirements used in Print 32 were obtained.

The report concludes that in most regions—especially in the East—a far larger share of future water supplies must be devoted to providing dilution for industrial and domestic organic wastes than will be consumed by evaporation and transpiration. This result emerged even when high levels of waste treatment were assumed. The conclusions were based upon the assumption that current relationships of wastes produced to population and economic activity would continue, that a rate of 4 ppm of dissolved oxygen was to be maintained in all streams, and that standard biological treatment and augmentation of low stream flows for waste dilution would be the only devices used to deal with pollution loadings. Given these assumptions, the report further concluded that a minimum cost combination of flow augmentation and treatment would require an additional abatement investment of perhaps $100 billion (1954 prices) by the year 2000.

This is indeed a huge sum. By contrast, the cost of completing the Bureau of Reclamation program of multipurpose development is estimated at a mere $4 billion after 1954, and the aggregate of federal appropriations for water resource development from 1824 to 1954 was reported to have been only $14 billion.²

² Task Force on Water Resources and Power for the Commission on Organization of the Executive Branch of the Government, Report on Water Resources and Power (Washington: U.S. Government Printing Office, 1957), p. 6. Since the appropriations for the period 1924–1954 were made at current prices throughout the period, valuation in terms of present prices would raise the amount considerably.

Preliminary results of the RFF-Senate Select Committee study cannot be viewed as much more than a broad indicator of the potential magnitude of various aspects of water supply problems. However, they do suggest that future water quality control investment could be larger than any other public investment in natural resources development. Thus it will certainly be highly deserving of the attention of those interested in efficient investment and operating decisions in the resources field. A variety of complexities, a number of which will emerge in the discussion of the following sections, makes efficient and socially meaningful planning for pollution control unusually difficult. The physical sciences, engineering, economics, political science, and public administration must all play a role in dealing with a wide range of complex problems.

Economics can, to a degree, act as a unifying agent and provide guidelines for research in the several fields of study that have an important bearing upon the nation’s ability to respond constructively to developing pollution problems. For example, projection of economic trends and their implications, especially when done on a regional basis, can be helpful in indicating emerging challenges to technology and management and giving them some dimension. This was a useful result of the Wollman-Senate Select Committee study. The mere fact that such projections may not accurately characterize the actual evolution of events does not mean that they are useless. On the contrary, projections may go astray precisely because the problems they delineate are subsequently dealt with. The high pollution abatement costs projected by the Wollman-Senate Select Committee study may elicit research in sciences and engineering and adjustments in management procedure that will enable society to deal more efficiently with the problem.

Moreover, economic reasoning can provide guidelines for determining both the physical area of a planning unit and the scope of administrative powers. For example, it appears that unified planning over rather extensive geographical areas is necessary for dealing efficiently with pollution in economically developed regions, since water use and waste disposal by one unit can have a direct effect on the operations of others. The notion of externalities or third party effects, which is utilized extensively in succeeding sections and which is comparatively well elaborated in economic theory, sheds considerable light upon the appropriate minimum size of planning units. Such units should be large enough to comprehend or make internal the more significant influences external to individual economic units. Furthermore, economic considerations should help specify the powers of a planning authority. For example, an efficient waste-disposal plan for an area that contains numerous interdependent decision-making units may well imply a distribution of pollution costs not conducive to appropriate allocation of resources. Under these circumstances it may be desirable for the responsible agency to have the power to collect charges and pay bounties, and to finance, construct, and operate abatement works.

The interrelationships of economics and the institutions and administrative arrangements most suitable for the implementation of pollution abatement policy are interesting and highly important. However, their detailed study can best be pursued once the economics of pollution abatement and its place in intelligent social policy are better understood.

In this study waste disposal is viewed as an aspect of economic activity in an economy where the allocation of resources to alternative uses is accomplished primarily by market processes. The special circumstances surrounding waste disposal are recognized as grounds for public intervention and for the insertion of some politically determined values into the processes of public policy formation. The primary purpose is to conceptualize the pollution problem in a way that helps to identify types of physical, economic, and social knowledge that are basic to intelligent policy in the pollution field. Part I is largely devoted to establishing this general framework.

II Water Pollution – Nature, Effects, Treatment, Alternatives to Treatment

Water pollution results from a great variety of causes, includes complex changes in receiving waters, and affects subsequent water uses in numerous rather subtle, as well as obvious, ways. A full description of the physical aspects of water pollution and the technical devices available for its abatement can easily fill an extensive volume.¹ These matters are summarized here to provide background for discussion of the economics of pollution control policy.

¹ Good examples are Gordon Maskew Fair and John Charles Geyer, Water Supply and Waste-Water Disposal (New York: John Wiley and Sons, Inc., 1956), and Louis Klein, Aspects of River Pollution (New York: Academic Press, Inc., 1957).

MAJOR POLLUTANTS AND THEIR EFFECTS ON RECEIVING WATERS

Conservative and Nonconservative Pollutants

Pollutants that enter water courses as a result of man’s domestic, industrial, and agricultural activities can be grouped in a variety of ways. One very broad division, which emphasizes occurrences within the receiving water, distinguishes between conservative and nonconservative pollutants.

Conservative pollutants are not altered by the biological processes that occur in natural waters. For the most part these are the inorganic chemicals such as chlorides which, once they enter the receiving water, are diluted but not appreciably changed in quantity. Industrial wastes contain numerous such pollutants including metallic salts and other toxic, corrosive, colored, and taste-producing materials. Domestic pollution also contains chlorides and other dissolved salts. Return flow from irrigation carries dissolved solids, predominantly chlorides.

Nonconservative pollutants are substances that are changed in form and/or reduced in quantity by the biological, chemical, and physical phenomena characteristic of natural waters. By far the most widespread source of such materials is domestic sewage. This highly unstable, putrescible, organic waste can be converted to inorganic materials (bicarbonates, nitrates, sulphates, and phosphates) by the bacteria and other organisms typical of natural water bodies.

If water is not too heavily loaded, this process of “self-purification” will proceed aerobically (i.e., by the action of bacteria utilizing free oxygen) and will not produce offensive odors. If, however, the receiving waters are loaded beyond a certain level, the process of biological degradation becomes anaerobic (i.e., proceeds by the action of bacteria not utilizing free oxygen), and noxious hydrogen sulfide gas as well as methane and other gases will be produced.

The aerobic and anaerobic processes, which naturally occur in streams, are utilized in sewage treatment plants and, indeed, are the major elements in ordinary sewage treatment. In essence, treatment plants systematize, control, and accelerate the processes that would have occurred in any case and by so doing can limit the self-purification burden put upon a water body.

Domestic sewage is the most widespread source of degradable organic wastes, but industry contributes about an equal amount. The food and pulp and paper industries are the greatest generators of such wastes, and in some instances individual plants emit massive loads. For example, a single sugar beet processing plant, during its seasonal period of operation, may produce organic wastes equivalent to the sewage flow of a city of half a million people.

BOD, the Oxygen Sag, and Algae

Predicting the concentration of given amounts of conservative pollutants presents no particular difficulty since dilution is essentially the only process involved. However, predicting the level of unassimilated degradable organic wastes, the rate of waste degradation, and important associated variables presents more imposing technical problems.

A measure of organic pollution load is Biochemical Oxygen Demand (BOD), which indicates the rate at which dissolved oxygen is drawn upon in a stream. The rate at which a given quantity and type of organic waste exerts oxygen demand is a function of a variety of factors; among the most important are temperature and chemical characteristics of the receiving water. Toxins, for example, may appreciably reduce the rate of BOD by inhibiting bacterial action. In extreme instances of toxic pollution a body of water may become bacteriologically “dead.” Thus a link is established between conservative and nonconservative pollutants. On the other hand, at higher temperatures bacterial action is accelerated, wastes are degraded more rapidly, and dissolved oxygen in the water is drawn upon more heavily. Furthermore, the oxygen saturation level of warm water is lower than that of cooler water. Thus increased temperatures tend to squeeze dissolved oxygen levels in waste receiving waters, conceivably to the point of producing septic (anaerobic) conditions. Warmer water—as well as typically low stream flows—tends to make summer the critical period for organic pollution. Moreover, it is in part because of its effect on the oxygen balance that heated water can be considered a pollutant.²

² It, of course, also lessens the efficiency of the receiving water as a cooling medium.

The rate of BOD combined with the rate at which oxygen is restored determines the level of dissolved oxygen. In flowing water the combined effect of BOD and reaeration results first in a fall and then in a rise in dissolved oxygen as the wastes are carried downstream. This phenomenon is described by a characteristic curve known as the oxygen sag. The low, or critical, point on the oxygen sag is the focus of attention when sewage treatment plants are designed. Other things being equal, factors that reduce the rate at which BOD is exerted lengthen and flatten the oxygen sag, while accelerated BOD has the reverse effect. The shape of the oxygen sag is also affected by other factors such as the velocity of stream flow and the rate of reaeration, which depends largely on turbulence, the area of the air-water interface relative to volume, and photosynthetic oxygen production.

Actually BOD proceeds in two distinct stages. If an untreated waste is put in a clean stream, a first and major draft upon dissolved oxygen occurs as the putrescible wastes are degraded by bacterial action. Thereafter the dissolved oxygen level tends to recover. Farther downstream, roughly five to seven days travel time, a “second stage” BOD occurs as the nitrogen embodied in organic sewage is converted to nitrite and to nitrate by aerobic “nitrifying” bacteria. The “second stage” BOD tends to be more diffuse and does not tend to carry dissolved oxygen to as low a level as does the first stage BOD.

Both the degradation of putrescible wastes and the process of nitrification can be carried on in a treatment plant rather than in the receiving water. However, orthodox treatment measures do not fully complete either process and so the water’s self-purification capacity is always called upon to a degree.

The residual products of organic waste degradation are plant nutrients (nitrogen, phosphorus, carbon), which may give rise to algae growth in the receiving water. Since algae produce organic matter by means of photosynthesis, they periodically release oxygen and affect the oxygen balance of the receiving water. If algae occur in great quantities they affect the appearance, taste, and odor of water.

Persistent Organics and Radiological Pollution

A very large number of organic compounds have been synthesized by the chemical industry. Most of these—while not strictly conservative pollutants—are to some degree resistant to attack by stream biota. Consequently they are often called the “persistent” organics. Since biota found in streams are also the ones typically utilized in waste treatment, the synthetic organics have proved resistant to treatment. Some of the organic chemicals found in streams at least intermittently are comparatively common, for example, DDT, 2,4-D, chlordane, cyanides and synthetic detergents; many others are complex industrial, agricultural, and pharmaceutical ch...