4: Environmental Microbiology Flashcards
We can think of soil as a “_______”
biological fire
a gaseous product of microbes that gives soil its musty odor
geosmin
microbial pathogen in soil, which can cause botulism, tetanus, and gas gangrene
clostridium
gram positive bacillus or “box cars” found in soil that forms endospores and hates oxygen. causes gas gangrene (amputation is only treatment)
clostridium perfringens
microbes are essential for the recycling of certain chemical elements so that they can be reused
biogeochemcial cycle
What “fixes” CO2 into organic compounds?
green plants, algae, and bacteria
Why is nitrogen needed by all organisms?
for the synthesis of proteins, nucleic acids, and other nitrogen-containing compounds
Free nitrogen gas makes up _____ of the atmosphere
80%
What do microbes fix atmospheric nitrogen and nitrogen in organic matter into?
ammonia (NH3) gas
Ammonia is further processed by microbes into _____ which are directly used by plants for _____.
nitrates (NO3-), protein synthesis
formed a symbiotic relationship with roots of leguminous plants. the bacteria causes roots for form nodules where the bacteria thrive. What does the bacteria do in return for the plant?
Rhizobium fixates nitrogen into ammonia, to be converted to nitrates for use by the plant
The fixation of nitrogen gas by microbes is accomplished by what microbial enzyme?
nitrogenase
combination of fungus and an alga, or a cyanobacterium in a mutualistic relationship
lichens
most dangerous form of water pollution
fecal contamination
responsible for over 2 million deaths (globally) each year, mostly among children under 5 yrs.
waterborne diseases
most important criterion is that it is consistently in human feces in substantial numbers so that its detection is a good indication that human wastes are entering the water
indicator organism
usual indicator organisms for water purity tests
coliform bacteria
predominant fecal coliform
escherichia coli
direct method of determining the presence and numbers of coliforms and is probably the most widely used method in North America and Europe (water purity test)
membrane filtration method
5 Steps of Water Treatment
standing in reservoir, flocculation, surface absorption, chlorination, and storage reservoirs
During water treatment, what is the purpose of water standing for a period of time in a reservoir?
allows large particulate matter to settle out
During water treatment, flocculation treatment includes what substance? What effect does this substance have?
alum, causes small particles to stick together and settle. many bacteria and viruses are removed by this step
During water treatment, what is used for surface absorption?
sand or crushed anthracite coal filtration
During water treatment, what is the surface absorption step effective at removing?
giardia lamblia and cryptosporidium cysts. almost all viruses and bacteria remaining are removed by this step.
have pore openings as small as 0.2 micrometers and are more reliable for removal of giardia and cryptosporidium
low pressure membrane filtration systems
During water treatment, what is chlorination not very effective at killing?
viruses and protozoan cysts
Name two alternatives to chlorination for water treatment
UV light irradiation, treatment with ozone
process by which algal blooms use up all the dissolved O2, killing life below surface of water
eutrophication
a measurement used to determine how much organic matter remains after each step in sewage treatment. The amount of biologically degradable organic matter in the water is estimated by measuring the the amount of _____ required by bacteria to metabolize it.
Biochemical Oxygen Demand (BOD), oxygen
The BOD will _____ as organic material is removed at each step in sewage treatment.
decrease
_______ is the first step of sewage treatment and it relies mostly upon ________.
Primary Treatment, physical processes
what step of sewage treatment uses sedimentation tanks? what is another name for these tanks?
Primary Treatment, clarification tanks
settled solids in clarification tanks
primary sludge
liquid flowing out of clarification tanks
primary effluent
Secondary Treatment (Sewage) is mainly a _______ and is designed to further reduce organic matter in sewage. This is done by _____ the sewage to encourage the growth of ________ which can oxidize the wastes to CO2 and water.
biological process, aerating, aerobic bacteria
Name the three basic methods of secondary sewage treatment
Activated Sludge System, Trickling Filter, and Rotating Biological Contactro
secondary sewage treatment which relies on blowing air through the sewage to promote bacterial decomposition
activated sludge system
secondary sewage treatment in which sewage is sprayed over zoogleal slime covered rocks or plastic. The aerobic microbes in the slime digest the organic matter
trickling filter
secondary sewage treatment which is a series of disks several feet in diameter, mounted on a shaft, which rotate slowly with their lower 40% submerged in the wastewater
rotating biological contactor
what is the purpose of rotation in the rotating biological contactor system?
provides aeration and contact between the biofilm on the disks and the wastewater. also causes accumulated biofilm to slough off when it becomes too thick
What two end products do all secondary sewage treatment methods make?
liquid effluent (goes on to tertiary treatment) and secondary sludge (processed by anaerobic sludge digestion)
sludge from primary and secondary treatment is processed by __________
anaerobic sludge digesters
What is the methane produced by the anaerobic sludge digesters used for?
fuel to heat the digester and to run other equipment at the plant
remaining undigested sludge that is dumped
recalcitrant sludge, or biosolids
_____ is often the final step (unless tertiary treatment is used) and it uses _____ to treat the effluent from secondary treatment prior to release.
Disinfection, chemical processes
What chemical processes are used in Disinfection to kill any remaining microbes
chlorine or UV light
must have a very large leeching field in order for wast to be broken down
septic tanks
have fountains (aerators) to aerate the water so solid waste is broken down to CO2 gas and water
oxidation ponds, sewage lagoons, stabilization ponds
What is the purpose of the wetland at the sewage treatment plant? What plants are used in the wetland to aid in this process?
removes residual ammonia and phosphorus, cattails and bullrushes
is designed to remove all remaining BOD, nitrogen, and phosphorus
tertiary sewage treatment
In tertiary sewage treatment, what is used to remove the phosphorus?
chemical precipitation
In tertiary sewage treatment, what is used to remove small particulate matter and dissolved chemicals?
filters of fine sands and activated charcoal
In tertiary sewage treatment, what is converted to ammonia and released into the air?
nitrogen
In tertiary sewage treatment, what do they do to the purified water?
it is chlorinated
