Download Microbiology of Water & sewage - Belle Vernon Area School District

Microbiology of Water & sewage
I. Why is it important to know?
1. Disease prevention A.
- Vibro cholerae
Severe diarrhea (white rice)
Loss of 20 L/day
Vomiting, muscle cramps
5 pandemic since the early 1800's
1832-1836 200,000 Americans dies
1961 - Indonesia
1989 - Africa
1991 – Peru
B.
- Salmonella typhi
Salmonella infections
Enteric fever
Headache
Intestine rupture
Bleeding
C.
- inflammation of the brain or meninges
D.
- intestinal inflammation
Waterborne Disease
E.
- skin inflammation
1. 1993 - 94 30 outbreaks in 17 states (22 from
microorganisms, 8 chemical - lead, copper, floride).
a. Drinking water, pools, rivers, ponds, lakes
2. 403, 000 crytosporidisses - Milwuawkee ( 5 outbreaks)
a. Mostly Gastroenteritis & Dermatitis
3. 100 chemical contamination
a. Lead, copper
4. Remainder from known organisms. ( 33% parasites.
23% bacteria, 26% chemicals, 16% unknown)
2. Prevent pollution - drinking
water, pools, whirlpools,
hot tubs, ponds, lakes,
rivers .
Why ? Water is needed for
everyday living.
II. Sewer Systems
A. Since roman times.
B. 1840 - Chadwick - sewer
system & use sludge for
fertilizer.
1.
to increase water
pressure.
2. Did not accomplish
Sludge
C. 1848 - England ,
because of the threat of
chorea.
D. 1866 - NY city, because
of the threat of chorea.
E. By 19th century, most of
the major cities have some
type of sewer system.
Review

What disease is the main reason for the
sewage system?
III. Water testing & treatment
A. Why? Detecting & removing contamination (pathogenic
microorganisms).
Avg. American
150 gal of water/day
4 lbs of food
19 lbs of fossil fuels
Per Day
120 gal of sewage
5 lbs of trash
2 lbs of pollutants
B. Three types of water
1.
City with 1 million people
120 million gal of raw sewage
- fit for drinking.
2.
- Poisonous chemicals or pathogenic
organisms (clear & sparkling).
3.
- may or may not be contaminated but
has an undesirable appearance or taste.
B. Typical treatment
1. Water stands to let solid
mater
.
2. Water is removed &
mixed with flocculent to
bind with bacteria &
viruses (
- Chemical) - clumping.
3. Clumping settles out.
4. Filter through
gravel or
earth.
5. Disinfect with
.
,
C. Types of Treatment
Organic to inorganic Mineralization or Stabilization
1.
- removal of large objects (
Screening & Sedimentation).
2.
- chemical is added to convert
remaining material in sewage into an odorless
inorganic substance.
3.
- Removal of phosphates &
nitrogen - may cause eutrophication.
D. Microorganisms Degrade the components of Sewage to
inorganic Compounds.
1.
- microbial oxidation = Carbon Dioxide &
inorganic nitrogen containing nutrients for plants.
2.
- Carbon dioxide & methane
E.
(BOD) - Oxygen consuming property
is equal to the proportional to the amount of degradable
organic material.
1. Incubate a sample for 5 days @ 20C.
2. Measure oxygen consumed growing in the sample (eat
organic matter).
3. Aerobic microorganisms- CO2, Anaerobic
microorganisms.
4. High
= High
= High
IV. Role of bacteria in Purification of stream & rivers
Beginning
Dump wastes in river & there was no harm to the
ecosystem.
- microorganism (aerobes (more efficient)&
anaerobes(less efficient)) were able to break down the
organic wastes to inorganic to be recycled back into the
system.
Now - Overload.
consume oxygen (air) quickly for the river.
in micro floral and not all aerobic bacteria
get oxygen, therefore they die.
Anaerobic bacteria can not keep up with the break
down of wastes.
Large organisms (plant & animals) start to die off &
add to the waste build up.
V. Methods for Wastes treatment
A. Primary Treatment
1. Remove material that will settle out (sticks, rags, &
trash).
2. Removed by a series of screens then stand for 90
minutes to 2 hours.
3. Sometime flooculate is added alum to settle out
quicker.
4. Remaining material is then sent to secondary
treatment.
5. Sediment material is sent to a digester or is
incinerated.
B. Secondary Treatment - used municipals.
1. Designed to stabilize most organic material & reduce
BOD of sewage.
2. Activated Sludge Treatment - sewage is a nutrient
for aerobic organisms.
3. Oxygen is applied by mixing sewage in an aerator.
4. Most degradable organic material is then converted
into a gas.
5. Bacteria is then food for protozoans.
6. Small increase in organisms & a large decrease in
BOD.
7. Microorganisms are then removed by a digester & a
portion is left behind to inoculum a new load of wastes.
C. Tertiary Treatment
1. Designed to reduce eutrophication.
2. Discard effluent into rivers & lakes (contains large
amounts of phospahtes or nitrates).
3. May increase growth of microorganisms & gradually
deplete oxygen supply & threaten aquatic life.
4. Certain bacteria (Bacillus, Pseudomonas) are used to
removed nitrates & phosphates by denitrification.
5. Chemical are added.
6. Nitrogen is then removed.
D. Digester treatment Anaerobically Stabilizes Sewage
1. Anaerobic organisms act of the solids remaining
after aerobic treatment.
2. Removes water from the sewage so that a minimum
of solid matter remains.
3. Anaerobic organisms produces
.
Sewage
Treatment
E. Pathogens May survive During Sewage Treatment.
Pathogenic organisms are general removed fro sewage at
the secondary treatment, but viruses may survive.
1. Bacteria
a. Bacteria are in feces are usually diluted by water in
sewage.
b. These bacteria must compete with a huge mass of
bacteria in secondary treatment that have been
adapted to those conditions.
c. Most are out
.
2. Viruses
a. Animal viruses lack appropriate host cells in sewage,
although may survive a long time.
b. If large quantities are present, may survive after
secondary treatment.
c. Viruses adhere to
, which then can be
.
VI. Small Scale Treatment
A.
1. Sewage is channeled into
swallow ponds (lagoons).
2. Stays for
to months.
a. Setting occurs
b. Sewage is stabilized
by aerobic &/or
anaerobic bacteria
3. Pathogenic bacteria are
usually eliminated by
competition.
B. Tricking Filter
1. Used frequently by smaller
treatment plants.
2. Used in place of
in secondary treatment.
3. Pebbles & rocks get coated with
aerobic microorganisms &
aerobically degraded sewage.
2mm thick layer
Outer layer - fungi
Middle layer Fungi, algae,
cyanobacteria
Inner - bact.,
algae, protozoa.
C. Septic Tanks
1. Individual dwelling or small communities.
2. Sewage is collected in
.
3. Solid wastes settles out & is degraded by anaerobic
microorganisms.
4. Fluid overflow (high BOD) -
.
5. Depends on aeration & soil (Clay prevent proper
function).
D. Artificial Wetlands
VI. Micro Floral of Water
A. Habitat for many different microorganisms
Sulfur bacteria, iron bacteria, free-living spiral forms, spore
forms
B. Water has soil in it so soil habitants are also included
microorganisms bacillus.
VIII. Testing water Potability
Presence of organisms capable of causing disease.
A.
- any water contaminated with feces
contains a pathogen and is therefore considered
unpotable Acaule
B. Lab Test - by health dept. for fecal contamination
1.
test - lactose test (fermented or
not)
2.
test - Present- small sample.
Incubated & if gas is produced, contaminated.
3.
test - agar plat
4.
- describe gram negative testing
C. Membrane filter technique
Water Testing
IX. Control of water borne diseases
A. Coagulation, sedimentation, filtration, & use of
chemicals.
1.
water.
any suspended material from untreated
2. Add
(aluminum potassium sulfate).
3. Alum settles out and carries a large amount of
bacteria with it.
4.
bacteria.
the remaining particles & residue
5.
is added.
B. Swimming Pools
Respiratory tract, eye & ear, intestinal tract diseases
Athlete foot from damp area
- chlorine & bromine
C. Drinking fountain
direct contact
Respiratory area
D. Ice
Use
water
Scoops & clan machines
E. Sewage Disposal
Reduce the amount of
Oxygen Demand
- Biological
Primary Treatment
1. Remove the greater part of solids (Sludge) - flows into a
large sedimentation tank.
2. Sent or second tank for anaerobic digestion
Turns to acids, methane, and carbon dioxide.
3. Sludge is pumped into open areas for air drying or
filtered to remove most of the water.
Final can be used as fertilizer or soil conditioner
Secondary Treatment
Oxidizes all organic material - removing any BOD
Accomplished by aerobic breakdown by organisms within flora
of sewage waste.
Not enough to accomplished this in a reasonable amount of
time.
1. Activate Sludge Process
Pumps affluent from to a large tank for aeration
2. Trickle Filter
Sewage is sprayed over a gravel filter (6 mo. To setup)
Aerobic microorganisms attaches to the rocks.
3. Tertiary Treatment
Effluent from secondary has a large amount of nitrogen &
phosphorus)
Removes the reaming amount of nitrogen & phosphorus to
prevent algae growth.
Septic Tank
Only on the surface
Exposed to air through a long drain embedded in gravel.
X. Microbiology of Solid Wastes
A. US
million tons / yr from industries, homes.
B. Landfills
1 Use near town & communities, cheap.
2. Sanitary
a.
with
each day.
b.
used for recreation or site
development.
c. Disadvantages
1.
number of sites
2.
anaerobic decomposition up to
50 yrs.
3. Produces
gas which may
lead to explosion if not removed.
4. Pollutants may
– heavy
metals, pesticides.
C.
– paper,
plastics, Glass, Metals
D.
1. Natural decomposition of
organic solids.
2. Backyard
a. Garden debris,
kitchen organic wastes
(except meats).
b. Place in box with
soil & let sit in sun.
c. heat kills pathogens
leaving nutrients for
yard usage.
3. Commercial