Wastewater COLLECTION and Treatment Flashcards
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absorption
The taking in or soaking up of a substance into the body (cell) by molecular or chemical action
activated sludge
sludge particles produced in clarified wastewater by the growth of organism in the aeration tank in the presence of DISSOLVED OXYGEN
activated sludge process
the secondary wastewater treatment process which utilizes activated sludge for the REMOVAL OF POLLUTANTS
adsorption
the gathering of gas, liquid, or dissolved substance on the surface of another material
aerobic
when OXYGEN is present
anoxic
a condition of oxygen DEFICIENCY or insufficient oxygen
biochemical oxygen demand
a laboratory measure of the strength of wastewater. it is the MEASURE of the rate of the USE OF OXYGEN BY MICROORGANISMS while stabilizing decomposable organic matter under aerobic conditions. (5 day)
bound water
water contained within the cell mass of sludges or strongly held on the surface of colloidal particles. one of the two causes of bulking sludges in the activated sludge process.
breakpoint chlorination
addition of chlorine to water or wastewater until the chlorine demand has been satisfied at which point further additions of chlorine result in a residual directly proportional to the amount of chlorine added beyond the breakpoint.
brinelling
a type of BEARING FAILURE. tiny indentations (dents) high on the shoulder of the bearing race or bearing.
buffer
a solution of liquid whose chemical makeup neutralizes acids or bases without a great change in pH
carbonaceous stage
generally referred to as first stage BOD. a stage of decomposition that occurs in biological treatment processes when aerobic bacteria using dissolved oxygen change carbon compounds into carbon dioxide.
cavitation
the formation and collapsed of gas bubbles on the blade of an impeller or valve causing the removal of some of the metal. it generally creates noticeable noise in the volute of pump casings.
chemical oxygen demand
another laboratory measure of the strength of wastewater. a measure of the oxygen-consuming capacity of organic matter present in wastewater. COD usually runs higher than BOD for split samples (4 hours)
chemical precipitation
precipitation induced by the addition of chemicals
chlorine contact unit
a baffled basin that provides sufficient detention time for disinfection to occur**
ciliates
a class of single-celled protozoans having short cilia (hairs) on all or part of their bodies
coagulation
the clumping together of very fine particles into larger particles (floc) caused by the use of chemical coagulants
coliform
a type of bacteria. it is used as a surrogate in testing for the potential presence of pathogenic organisms
combined available chlorine
the total chlorine, present as chloramines or other combined derivatives. combined available chlorine is still available for disinfection purposes but is not as aggressive as free chlorines
combined sewer
a sewer designed to carry both sanitary wastewater and storm water runoff
comminutor
a shredding device used to reduce the size of larger solids in wastewater streams
cross connection
any connection between a potable water supply and a supply of questionable quality
denitrification
the reduction of nitrate nitrogen to nitrogen gas under anaerobic conditions
detention time
the length of time it takes to fill a tank at a given flow rate. the theoretical time it takes for a plug of water to flow from the entrance of a tank to the exit of the tank.
digester
a unit (tank) into which sludge is placed to undergo further treatment, either under aerobic or anaerobic conditions
disinfection
the process of killing or inactivation most pathogens in wastewater
dissolved oxygen
molecular oxygen dissolved in water. normally referred to as DO.
effluent
that treated water which exists or leaves the wastewater treatment process. in one sense the product which is generated by the processes.
facultative
bacteria are those who can live and thrive under both aerobic and anaerobic conditions
facultative pond
the most common type of pond in use today. the upper layer is under aerobic conditions while the lower layers are under anaerobic conditions.
floc
clumps of bacteria and particles that have come together to form a cluster
force main
a pipeline which carries wastewater under pressure from a pump or lift station to a point at which gravity drain occurs
free available chlorine
the amount of uncombined chlorine available in water. it may take one of three forms: dissolved chlorine gas, hypochlorous acid (HOCL), or hypochlorite ion (OCL-)
hepatitis
an inflammation of the liver usually caused by an acute viral infection. yellow jaundice is one symptom.
hydraulic loading
a measure of the volumetric flow which a plant (unit) in the plant receives. important because plant (unit) performance is directly impacted by the rate of flow.
hydrologic cycle
the water cycle. the natural process of evaporation, precipitation, and water movement across through and under the surface of the earth as it returns to oceans to begin the cycle over again.
imhoff cone
a clear, one liter cone-shaped container with graduations used to measure settleable solids
free chlorine
molecular chlorine in liquid or gaseous form
infiltration
seepage of groundwater into wastewater collection systems through smalls cracks and imperfections of the collection pipeline system
inflow
water discharged into the sanitary wastewater collection system resulting from rainfall runoff