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29 Cards in this Set

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specific microorganisms that, if present in a water supply, indicate that the water source might be contaminated with pathogens
indicator organisms
usually associated with the intestinal tract; their presence indicates fecal contamination of the water source
indicator organisms
the most widely used indicator organism
coliforms
all aerobic and facultative aerobic, gram-negative, nonspore-forming, lactose-fermenting bacteria
coliforms
presence of coliform organisms in a water sample indicates
fecal contamination of that water, making that water unsafe
the two most commonly used tests for coliforms in water samples
most-probable-number (MPN) and membrane filter (MF) procedures
coliform test that employs liquid culture medium in test tubes, in which samples of drinking water are added to the media.
MPN. most probable number
coliform test in which a minimum of 100ml water sample flows through a sterile membrane filter which removes the bacteria. the filter is then placed on the surface of a plate of EMB culture medium, which is selective for coliforms.
MF. membrane filter
procedures used to reduce microbial load in water supplies
filtration and chlorination
liquid effluent derived from domestic sewage or industrial sources that cannot be discarded in untreated form into lakes or stream due to public health, economic, and aesthetic considerations
wastewater
liquid effluent contaminated with human or animal fecal materials
sewage
the amount of dissolved oxygen consumed by microorganisms for complete oxidation of organic and inorganic material in a water sample
biochemical oxygen demand, (BOD)
the efficiency of wastewater treatment can be expressed in terms of a reduction in the
BOD, biochemical oxygen demand
primary wastewater treatment consists of ___; the process involves running wastewater through a series of grates and screens that remove large objects, and then sit in a pool for until sediment drops to the bottom
physical separation only
involves a series of digestive and fermentative reactions carried out by a number of bacterial species
anoxic secondary wastewater treatment
the trickling filter and activated sludge methods are the two most common methods of
aerobic secondary treatment
expensive wastewater treatment method that is a physicochemical process employing precipitation, filtration, and chlorination procedures similar to those employed for drinking water purification
tertiary treatment
water treated by secondary methods are generally not ___, or safe for human consumption
potable
a measure of suspended particles
turbidity
untreated water
raw water
a large holding tank in drinking water purification where coagulation takes place
coagulation basin/clarifier
water purification process by which small particles aggregate into large masses;
flocculation
in the water purification process, after coagulation and flocculation, ____ takes place
filtration
pure, drinkable water is known as
finished water
disinfection step of water purification is accomplished with
chlorination
because chlorine gas is volatile, ____ is introduced, resulting in the stable chlorine-containing compound chloramine
ammonia gas
the formation of large insoluble particles from much smaller, colloidal particles by the addition of aluminum sulfate and anionic polymers
coagulation
the water treatment process after coagulation that uses gentle stirring to cause suspended particles to form larger aggregated masses
flocculation, the aggregated masses are called flocs.
water pipes, storage reservoirs, tanks, and other means used to deliver drinking water to consumers or store it before delivery
distribution system