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MICROBES.TXT
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1988-12-24
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Some Quick Facts About Microbes Likely to be Seen on Microslides
I. Bacteria
These are the most abundant life form on this planet.
Some biologists believe bacteria was the first life form.
Bacteria defy classification as animal or plant and are usually
considered as part of the the kingdom Protista(stemming from
the protozoans). Bacertia vary greatly in relative size but have
only three basic shapes...spherical(coccus), rod
shaped(bacillus), and corkscrewed or spiraled(spirilum).
The largest bacteria ranges only 2 microns (unobservable on
normal lab microscopes found in wastewater plants). Bacteria
is the major food source in a process. Protozoa are the
indicative groups that depict stages of bacterial growth. One
reference suggests a statistical mean of about 100,000 bacteria
is found per milliliter of "fresh aerated" raw sewage. In stale
sewage, the reference suggests an exponential increase...a million
or more. A further defined grouping of bacteria classifies them as
being part of a group called Monera (along with blue green
algae)...or functionally as lacking a nuclear membrane.
II. Protozoans
Originally classifed under the animal kingdom, they are now
generally recognized as in a kingdom of their own called
Protists. These are one celled organisms that use specialized
organelles(internal cell structures)for life functions. The
following is a listing of the common groups and types seen under
the wastewater microslide. The groups themselves are highly
recognizable while the various species requires some taxonomic
identification. If time permits, seek a taxonomic identification
guide for individual identifications (see end for recommended
texts):
1. amoeba (Class Sardonia)
a. two types...shelled and naked
1.) arcella vulgaris(shelled)
2.) difflugia (shelled)
3.) dimastigamoeba (naked, classic)
4.) nuclearia (naked)
2. Flagellated Protozoa (Class Mastigophora)
a. (zoomastigina)as the biocycle develops in the log growth
bacterial stages, many low order flagellated types will
develop that may require high power for observation. It
may be best to observe these as an overall activity.
b. a more advanced stage in that log growth will show higher
and larger forms of flagellates. Some of these forms
will be very recognizable.
1.) euglena
2.) peranema
3.) pleuromonas
3. Creeper Ciliates
a. "Creeper" is a convenient descriptive term that describes
the next order of protozoa to develop on the biocycle.
Creepers are more accurately part of the "Swimming
Ciliate" groups...but do not show the high motility of the
later developing kinds. These "creepers" in fact are some
of the larger and more definable protozoa to be seen under
the microslide.
1.) Aspidisca
2.) telotrochs
4. Free Swimming Ciliates
a. There is an abundant number of free swimming ciliates.
This grouping has a wide range when it appears on the
biocycle, from moderate log growth stages to early
endogenous stages. These will be some of the largest
protozoa and as well the most active and motile. Their
appearances and shapes are readily recognizable.
1.) Paramecium (appears in log growth stages)
2.) litonontus
3.) Trachelophyllum
4.) Colipidium
5.) plagiiopyla
6.) chilodonella
7.) dileptus
8.) trachelius
9.) amphileptus
10.) hemiophrys
11.) poteriodendron
5. Stalked Ciliates
a. The most definable characteristic of stalked ciliates is
their classic bell shapes. Nearly all stalked ciliates
will be seen as more or less stationary. There some
intermediate stages of some species of stalked ciliates
that are very mobile and do not show the classic
structure. A useful observation will be the appearance
of the stalks themselves...thier apparent relative
thickness and length and as well if there are only single
bells or several or many bunched together.
1.) vorticella
2.) carchesium
3.) epistylis
4.) campanella
5.) opercularia (many branches, bunches)
6.) vaginicola
III. Rotifers (phyllum Rotifera)
Rotifers of course will be one of the most advance types to be
found under the wastewater microslide. These are one of the
first forms of life that have organ functions and are
Multicellular. These are also very recognizable and will be one
of the larger organisms found in the microslide.
The following is a listing of common Rotifers as they are found in
ascending order of common occurence:
1. keratella cochlearis
2. polyarthra vulgaris
3. synchaeta pectinata
4. brachionus quadridentata
5. trichocerca iongiseta
6. rotaria sp.
7. filinia longiseta
8. kellicottia longispina
9. pompholys sp.
IV. Other types
a. The commonly seen type a lot of operators call "water bear" is
a multicellular animal, Aelosoma. very large.
b. Perhaps the largest animal seen will be roundworms. One of
the most common is Chironomus and grow to stretch across
a slide and be visible with the naked eye. These will be
segmented
c. Nematodes will be smaller worms, pointy posterior and anterior
usually unsegmented.
d. Suctoria is a commonly seen microorganism that shows rigid
tenacles and a rigid stalk. Shows on a wide range from early
log growth to endogenous stages.
e. typical fungii shapes will appear like tree twigs with branches
and segmenting.
f. water mites; very large;
g. crustaceans (not typically in mixed liquors but might be
observed in clarifier debri;)
V. Some interesting facts about Pathogens
Thoughout history, water has been the prime mode of transimssion
of desease. One of the first extensive attempts to control this
mode was the building of the famous aqueducts by the ancient
Romans. It was perhaps one of the corner stones of modern
civilization to be able to control wastewater to prevent vast
outbreaks of sickness. The most common deseases that were once
killers (and still remain to be so again if not controlled) are
typhoid fever, dysentary, and diptheria. The common bacteria
pathogens that caused these deseases are Salmonella Typhosa, Shigella
Dysenteriae, and Vibrio Comma. It is a tribute to what our field
accomplishes to realize that these deseases are virutally non-
existent in our society...and need only to look as far as
underdeveloped countries and see the high incidence of these
deseases where wastewater is not controlled well. It was not
until recently that wastewater control has directed its
attentions not only toward health and desease prevention, but
also to the effects it has on our environment.
Viruses however still remain a concern even in developed
countries due to their small size that makes them hard to
detect. There still remains extremely low occurances of any
outbreak of desease even due to viruses.
Instead of performing analysis on wastewater for specific
kinds of pathogens, a group of non-pathogens is used as a very
accurate indicator of the likelihood of pathogen presence...or
non-presence. These are of course the coliforms...and include
the genera Escherichia and Aerobacter. These are generally
accepted as originating in the intestines of warm blooded
animals (some occur naturally in soil however). Escherichia Coli
is considered as originating solely from fecal matter. This
establishes some of the reasoning as to why total coliform groups
are tested for in water quality while Escherichia Coli is tested
for specifically for pollution influence on a water...and thusly
we see the highly specific test for "Fecal Coliform" (which
relates mostly to E. Coli) at exact temperature and nutrient
inducement and the more general testing for "Total Coliform"
(some of which may originate from soil and would not be Fecal) in
water quality testing.
───────────────────────────────────────────────────────────────
This is not meant as an indepth study of wastewater
taxoconomy but is simply a short overview of types that can be
seen under the typical wastewater microslide. In depth studies
are of course only beneficial. But toward the end of process
control, the objective again is to discern the relative trends a
plant's process is moving. For this objective, such microslide
observations should be functional first and foremost and the study
made of relative groups and their general robustness rather than
specific types and their actual numbers. Differentiation of
different species can add insight however and narrow the relative
conditions for which a certain flora is thriving.
The following manual is reccomended to have on hand for
reference. The formal microbiologist's attack is of course an
ideal the operator should know as much about as possible (as found
in this manual)
"MICROSCOPIC ANALYSIS OF ACTIVATE SLUDGE-TRAINING MANUAL".
EPA-430/1-80-007. NATIONAL TRAINING AND OPERATIONAL TECHNOLOGY
CENTER, CINCINNATI, OH 45268.