The Treatment of Textile Wastes
L. C. LEATHERLAND, Engineer
State Water Control Board
Richmond, Virginia
INTRODUCTION
It is useful to realize that much of the information on waste waters of the textile
industry is applicable to waste waters from other industries. For example, a knowledge
of a particular industry gives a designer a strong basis for resolving a wastewater
problem in that industry. Any designer faced with a lack of this knowledge certainly
should study at least that portion of the industry related directly to his waste water
problem.
The collection of samples of a waste water should be planned with an understanding of the processes and operations which produce this waste water. A textile
finishing plant operating continuous processes will produce a more uniform waste
water than will one which processes its product on a batch basis. Also, certain operations may be conducted irregularly throughout a week or a day. If grab samples are
collected manually a number of composites should be collected over different periods
of time and at various time intervals. The presence of a known pollutant in a waste
water could fail to be detected if the duration and frequency of its discharge miss the
times when grab samples are taken. In such a case it is necessary to take grab samples
at random time intervals for a number of hours.
In some situations it is practical to use continuous samplers which operate in
relation to the flow rates of the stream of waste water. Some of these collect a series
of small grab samples. A sampler which collects one ounce grabs to provide a gallon
composite in 24 hr will pick up a sample on an average of each 11.25 min. A sampler
which collects a continuous sample at varying flow rates will collect a gallon in 24 hr
at the average rate of 2.6 ml/min. In either case the concentration of suspended solids
in the composite sample may not be representative of the waste stream. A designer
must be satisfied that the samples to be analyzed will provide adequate information
for design purposes.
At the present time the analytical procedures given in "Standard Methods for
the Examination of Water and Wastewater" must be used, since they are the most
acceptable ones. However some of them are far from being satisfactory in many
cases. For example, the method of analyzing for small quantities of petroleum
solvents is cumbersome and inaccurate. These methods need revisions as rapidly as
possible. Also, greater use should be made of analytical techniques such as chromo-
tography and spectroscopy.
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