(1) microbiology of water Flashcards
In aquatic systems, on what does the biological activity depends on?
The PRIMARY PRODUCERS (phototrophs) -> phytoplankton -> serve as food for (chemoheterotrophs) -> bacteria, protozoan, fish, …
Define the photic zone
Zone receiving light where primary producers live
How can aquatic systems can be categorized as? (2)
Eutrophic: a lot of nutrient
Oligotrophic: low concentration of essential nutrients (N, P, Fe)
How can marine environment can be classified as (2)?
Costal water (eutrophic) Open ocean (oligotrophic)
How can freshwater environment differ? (2)
Oligotrophic (Oxygen is saturated; clear water)
Eutrophic (low oxygen concentration, anaerobic zones (H2S production) -> may cause cyanobacteria & algae bloom)
What happens with lakes in temperate climates (4)
Process called SUMMER STRATIFICATION:
- Epilimnion (hot, less dense => aerobic)
- Thermocline (zone of rapid temp. change)
- Hypolimnion (cold, denser => anaerobic)
What is defined as BOD?
Biochemical oxygen demand: the higher it is, the more organic matter is consumed => high chances polluted water
What are the two indicators of water quality?
Coliforms: facultative aerobic, lactose fermenters w/ gas formation (not necessarily of intestinal origin)
Fecal coliforms: derived from warm-blooded animals’ intestines
What is the conclusion when fecal coliforms are found in water?
Indicates fecal contamination
What is the conclusion when no fecal coliforms are found in water?
No conclusion (does not mean it is safe)
What are the 4 steps in water treatment
Sedimentation (large particule settle)
Flocculation (flocculating chemical added to coagulate)
Filtration (though sand -> removes G. lamblia cysts.)
Disinfection (chlorination -> does not kill G. lamblia & C. parvum cysts; Ozone -> more effective (no more G. lamblia nor C. parvum cysts, but shorter half-life)
What are the 4 steps in water treatment
Sedimentation (large particule settle)
Flocculation (flocculating chemical added to coagulate)
Filtration (though sand -> removes G. lamblia cysts.)
Disinfection (chlorination -> does not kill G. lamblia & C. parvum cysts; Ozone -> more effective (no more G. lamblia nor C. parvum cysts, but shorter half-life)
What is the reference amount for Montreal’s quality control?
per 100 mL: <10 coliforms & <1 fecal coliform
What are the wastewater/sewage treatments?
Primary treatment: Sedimentation (may use flocculants) -> results in liquid + primary sludge
Secondary treatment: use microorgs. to reduce BOD & bacterial load of separated liquid
a) Trickling filter: micoorganism on a medium use nutriens found in liquid (oxidation)
b) Activated sludge: air blown into liquid -> bacteria clump together (& settle) to form activated sludge -> sent to a digester
Tertiary treatment: further flocculate, filtrate, disinfect to make water drinking water
What happens to the sludge produced in the primary and secondary treatment of wastewater treatment?
Sent to anaerobic digester tank -> CH4 produced that can power part of treatment plant.
