Algae in Water Supplies: An Illustrated Manual on the Identification, Significance, and Control of Algae in Water Supplies. Page: 64
viii, 88 p. : ill. (some color) ; 31 cm.View a full description of this book.
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CHAPTER XI
ADDITIONAL USES FOR
ALGAE FOUND IN WATER SUPPLIESREFERENCE has already been made (ch. VI) to the utilization
of algae as indicators of domestic sewage pollution and
of natural purification in streams. They are also considered
useful as indicators of tlhe sources of a particular water
supply, the pollution of ground water supplies with surface
water, the progress of sewage change in oxidation ponds, the
pollution of marine and estuarine waters, the pH and temperature
ranges of a stream or lake, the toxicity of industrial
wastes, and the relative abundance il water of chemicals
such as sodium chloride, iron, and calcium phosphate.
INDUSTRIAL USES
Algae also constitute the raw materials used commercially
in the manufacture of sodium alginate, agar, iodine, diatomaceous
earth, and various food products. The food products
known under various names such as amanori, kombu,
kan-ten, carrageen, dulse, and limu are an important part
of the diet in Hawaii, Japan, China, the Philippines, Ireland,
and several other areas. These products are derived principally
from marine algae.
The utilization of fresh-water algae in large amounts
awaits the development of practical methods for their mass
culture and harvesting (1). Their potential value as producers
of concentrated proteiii, carbohydrate, and fat is very
great, for there is no waste in the form of fibrous orI woody
portions that are always present in land plants. The cheapest
source of nutrients for their mass culturing is undoubtedly
sewage and organic industrial wastes. Investigations
are now under way to develop )racticable methods for the
utilization of sewage in the production of algae that would be
suitable for animal feeds, fertilizers, and other products (2).
Algae may serve in the near future as commercial sources
for vitamins. hormones, and antibiotics (3). It has been
estimated that, each year, about 5 million tons of algal nutrients
are wasted in the l-nited States alone by present methods
of sewage disposal (4). Where algae are grown in a
closed system for treatment of sewage, there need be no waste
of the nutrients.
ALGAE AS WATER SOURCE INDICATORS
It is often possible to determine the probable source of a
sample of surface water through a determination of the number
and kinds of algae and related organisms present. This
is possible because tlle number and kinds of microorganisms
which develop are related to the hydrographic features ofbodies of water. Six chief types of lakes, for instance, are:
(a) the hard water lake with an outlet; (b) hard water
landlocked lake; (c) soft water lake witl an outlet; (d) soft
water landlocked lake; (e) acid bog lake; and (f) alkaline
bog lake.
The hard water lake with an outlet tends to have an algal
flora tlat is predominantly the blue-green-diatom type.
Typical comIlonents of this hard water landlocked lake inclhde
an equal abundance of greens and blue-greens plus
sonie of tile euglenoids and yellow-greens (Chrysophyta).
In thle soft water lake with an outlet, the algal flora is predominantly
comnlosed of green algae and the total number is
low. The soft water landlocked lake has a scant algal flora
and the filamentous forms are practically nonexistent. This
type of lake may tend to produce blooms of blue-green algae,
but tlhe number of species involved would still be small. In
an acid bog lake, a great variety of desmids will be present.
Certain particular species of blue-greens can be expected.
Plankton forms are not abundant but filamentous ones will
be well developed and common. The alkaline bog lake has
an algal flora which is poor both in numbers and kinds.
Hard water organisms such as Chara and Spirogyra cracsa
alld Spi'ogyrat deei ienta are often abundant (6). A knowledge
of tle typical algal floras of various lakes which represent
the sources of a water supply will help, therefore, in
determinilng the breeding grounds of the particular algae
tliat interfere witll the treatment or use of the water.
ALGAE IN WASTE TREATMENT SYSTEMS
Reference has been made in cllapter VI to tile use of algae
for production of oxygen in sewage stabilization ponds. Research
carried out in (California (7) has illdicated that the
determination of the number and kinds of thle more abtundant
algae in these ponds can be used as a reliable index of
the progress in oxidation of the sewaNge. If tle effluent
contains principally (Chlorella. the pond is assumed to be
working at or over its capacity. If it contains a mixed flora
the pond can handle a heavier load. Ch7amydomona- . is one
of the coilmmon forms in tihe mixed flora w licll develops when
most of the organic matter is gone an(l mineral nutrients
hIave been precipitated because of a high pH. (hlaminydoomonax^.
in turn. appears to excrete an organic compound which
again makes the minerals available for algal growth.
Examination of tile pond effluent for its algal flora may,
therefore, be a useful tool for operators of sewage plants496792 0-59-6
55
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Palmer, Charles Mervin, 1900-. Algae in Water Supplies: An Illustrated Manual on the Identification, Significance, and Control of Algae in Water Supplies., book, 1959; Cincinnati, Ohio. (https://digital.library.unt.edu/ark:/67531/metadc9129/m1/64/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.