Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Electrical and Computer Engineering

First Advisor

James B. Chiomor

Second Advisor

L. Cusley

Third Advisor

A. E. Schwertz


The general purpose of this research is to determine the optimal economic wastewater treatment levels for individual users in a river basin. This dissertation presents concepts, however, which are applicable in the general area of the economics of environmental quality management. There are two specific objectives of this research: 1. to examine the relationship of the treatment and damage costs when the economic optimum is obtained, and 2. to present a prototype simulation program for analyzing water quality management policies. The specific case used in this study consists of a series of firrns located along a river, such as municipalities, wet process industries, or recreational facilities, which have the river as their only source of raw water supply, and as the ultimate discharge point of their wastewater. A given firm thus imposes damages, in the form of pollution of intake water, on those located downstream of it. The magnitude of these damages depends on how much waste this firm discharges into the stream. In this study, it is assumed that downstream damages can be measured in monetary terms. The alternatives of waste discharge available to the firm in question include waste treatment and withholding the waste from discharge into the stream. Both of these procedures impose costs, or technological diseconomies,on the user. For this study, the economically optimal wastewater treatment assignment levels are defined as the minimization of the sum of costs imposed on the individual users for wastewater treatment and of those resulting from damages caused by waste discharges of the upstream users. The first objective of this study is to examine the nature of the relationship of treatment and damage cost functions when the economic optimum is obtained. For the case in which waste discharge is not constrained by physical limitations, it is shown mathematically that the optimum occurs when, for all users, the marginal treatment cost equals the sum of the respective downstream marginal damage costs. Marginal cost is conventionally defined as the first derivative of total cost. The effect of physically constrained waste discharges on the marginal cost relationships is also considered in this study. Assignment of the optimal individual waste treatment levels provides a rational basis for the determination of some water quality management policy, such as effluent charges or standards. However, a policy so determined is applicable only as conditions such as streamflow and maxmum possible waste production by a user result in the same wastewater treatment and damage cost functions as those originally utilized. Thus, analyses of the effectiveness of a given policy in maintaining reasonable economic efficiency as various conditions change are necessary. Such analyses can be done by computer simulation programs which are designed to take the effect of these factors into account. Therefore, the second objective of this study is to present a prototype simulation program in order to consider such an approach in river basin planning activities. In addition to considering the effects of various conditions, findings of the mathematical analysis of the cost functions are compared with the results obtained from the simulation runs. This study is then concluded with a presentation of items and approaches which would make future environmental quality studies of this nature more effective.