WSP07180

• File Number: 8043
• Description: Section D General Studies-Salinity
• State: CO
• Date: 6/1/1971
• Author: WaterPowerResources
• Title: Improving Municipal Water Supplies in Colorado by Desalting
• Water Supply Pro - Doc Type: Report/Study

Section 4
WATER QUALITY CONSIDERATIONS

Although the basic considerations for selection of six study communities
revolved around the salinity of the present water supplies, namely, the total
solids content and hardness, the performance of desalting techniques suitable
for improving the quality of the water must be considered for a wider spectrum
of water characteristics. It was decided that the water quality objectives of
the study were to reduce the total hardness of present water supplies to a max-
imum of 200 mg/l* with the added requirements that total dissolved solids not
be above 1000 mg/l and that none of the USPHS rejection limits be exceeded.
These rejection limits and other criteria are shown in Table VII.

A survey of State Health Department records indicated that information
was available on the candidate communities from about 1949 to date. Records
of all available water analyses have been gathered for use in this study. It
should be recognized, however, that these data are far from complete, in that
very often only one of several wells furnishing water to a given community has
been characterized, and no information is available as to the pumping rates of
either the well sampled or other wells at the time of sampling.

Water quality information is necessary for two reasons. The total dis-
solved solids, total hardness, and certain other constituents must be quanti-
fied to establish the reduction required to meet the objectives of this study.
The above constituents and a number of other water characteristics (such as pH,
temperature, and calcium, sodium and chloride concentrations) must be quanti-
fied to predict the performance of the various desalting systems.

An attempt has been made to generate a history of water quality for each
of the candidate communities, and this information can be found in Tables VIII
through XIII. The units of each constituent found in the tables** are defined
as follows:

*

It should be noted that for purposes of this study the units of mg/l are
essentially the same as ppm. Also, one grain of hardness is equal to 17.1
mg/l, therefore 200 mg/l is equivalent to 11.7 grains of hardness.

Constituents not shown in the tables are those for which the rejection
limits have never been exceeded as indicated by the available records for
the subject communities.

**

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