Masters Theses

Date of Award

5-1989

Degree Type

Thesis

Degree Name

Master of Science

Major

Agricultural Economics

Major Professor

William Park

Committee Members

Richard Roberts, Luther Keller

Abstract

As mankind has become more aware of the frailty of the environment on planet earth, issues dealing with the disposal of by-products created by mans' existence are demanding more attention. The disposal of one type of by-product, municipal sewage sludge, was examined in this study.

A questionnaire was mailed to 150 mechanical sewage treatment plants in Tennessee in order to document the extent and characteristics of sludge application to agricultural land by municipalities in Tennessee. The cost of sludge disposal by land application is compared to other methods of disposal. Also, factors that potentially limit land application from the perspective of municipalities are identified.

Aided by data gathered from this survey and data gathered from a Tennessee Division of Water Pollution Control Survey, it was determined that over half of the municipalities in Tennessee apply a portion of their sludge to agricultural land. Based on information from both surveys, approximately AS.7% of the sludge generated in Tennessee during the 1986-88 period was applied to land. The survey indicated that a non-linear relationship existed between plant size and land application with less land application by very small and very large plants. Average N,P,K concentrations of sludge were 3.2-1.7-.5. It appeared that land application was more prevalent in East and Middle Tennessee than in West Tennessee.

The disposal cost estimations derived from the survey varied over a wide range and future case study research should attempt to more carefully assess cost. However, results from this survey suggest, at least tentatively, that land application compares favorably with other methods of disposal, especially disposal by landfilling.

Factors identified by sewage treatment plant managers that could potentially limit land application include cost, site availability, public relations, regulatory change, management inertia, and heavy metal accumulation. The potential for each of these limiting factors to affect treatment plants in general is difficult to predict because of the unique conditions relating to specific treatment plants. Addressing these potential limitations will play an important role in the increased or decreased use of land application of sewage sludge.

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