Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Civil Engineering


Nature of the Project The City of Brookings, South Dakota, is a university town with a total estimated population of 13,000, including a campus enrollment of 6,000. On March 3; 1970, Brookings' voters passed a bond issue to expand the present water treatment facilities by increasing both production and storage. The new treatment plant will have a maximum daily production capacity of 4 million gallons, storage for 3 million gallons and will supplement the supply being treated by the existing plant. The new plant will consist of aeration to remove iron and manganese, lime and alum treatment to partially soften the water and to assist in the precipitation of the iron and manganese, an upflow basin for sludge sedimentation, a rapid sand filtration unit, chlorination and fluoridation. The lime and sludge will be pumped to a lagoon for dewatering prior to final disposal. The cost of the plant including construction costs for additional water storage has been estimated at $631,000. Brookings, located in a hard water area, has an average raw water hardness of 643 mg/1 and a finished water hardness of 485 mg/1. The primary objective of this project was to assess the economic feasibility of incorporating additional water hardness reduction capabilities into the new municipal plant. Brookings' residents ·presently obtain soft water by using the ion-exchange process, either by subscribing to home-serviced softening provided by companies or by operating home-owned softening units. It was desired to determine whether softened water could be obtained in the most economical manner by a combination of improved municipal hardness reduction in conjunction with home softening. The specific objectives of the study were: 1. to determine the percentage of the water used in Brookings that was softened and the cost to the residents per unit volume of soft water, 2. to determine the extent to which the water could be economically softened, 3. to determine the combination of softening practices that would be most economical to the water user, and 4. to evaluate the economic feasibility of installing additional softening capabilities in the new municipal water treatment plant. If the reduction of the water hardness by municipal treatment would prove economical then it would appear desirable to incorporate additional softening into the new plant. In this manner, the users would be provided with a softened water supply at a cost that would be less than they have paid to soften only a portion of their water supply.

Library of Congress Subject Headings

Water -- softening

Water-supply -- South Dakota -- Brookings

South Dakota State University Theses



Number of Pages



South Dakota State University