Wastewater 2017 Flashcards
How quickly does wastewater travel from home to sewer plant?
At least 2ft/sec
At most, 2 days to reach plant
How far apart are manholes?
300-500ft
When is the heaviest flow of sewage through a wastewater treatment plant?
Between 3-9 pm
Define domestic waste water
sanitary waste out of home, general business, and institution from toilet, showers, sick, etc
Define industrial waste water
waste water discharged from manufacturing plant, restaurants, hospitals, meat processors, refineries, etc
How does ground water affect waste water?
can infiltrate sewer system by cracks in sewer pipe
How does storm drain runoff affect waste water?
certain amount of water infiltration from leaky pipes
high water table can be introduced into system by open drain
What is the National Pollution Discharge Elimination System?
SPDES
prohibits draining of any type of wastewater onto public streets
What is leachate?
liquid waste coming out of the ground at refuse landfills
can be from rainfall seeping into landfill or liquid waste intentionally dumped
What are the physical characteristics of waste water?
fresh - 99.8% water
0.2% solid concentration
aka Gray Water
What are the three temperature types of bacteria involved in waste water?
Thermophillic zone - 113-158F
Mesophillic zone - 59-112F
Psychrophillic zone - 35-50F
What is surface disposal?
surface disposal pipes drain liquid onto land
What is tile fields disposal?
shallow underground collection of pipes, tiles segmented loosely to allow water to percolate
What is subsurface disposal?
leach lines laid 2-5’ undergrounds with perforated pipes 4” thick
What is dilution disposal?
no longer accepted
dispose of waste water into large water body, river, stream, etc
What is effluent?
Waste water being treated, going out of a waste water system and into a treatment plant
What is absorption?
something that is taken into material
What is adsorption
something that adheres to material
What is the standard weight of one gallon of water?
8.34 lbs
One cubic feet of water is how many gallons?
7.48
What is preliminary treatment of waste water?
bar screening - removed large objects
grit removal - sand/gravel
pre-aeration - introduces oxygen, helps remove oil/scum
flow meter - measures rate of flow
chlorine - optional
What is primary treatment of waste water?
sedimentation - clarification tanks, removes solids that can settle and floating debris
What is secondary treatment of waste water?
collects raw sludge and relocates for sludge digestion
bio/chem/physical treatment - further removal of solids and dissolved solids of the waste water
What is tertiary treatment of waste water?
filtration - filters to remove particles, color, odor
disinfection - destroys pathogenic bacteria
used mainly for reclaimed water
What is the aerobic treatment process?
activated sludge, trickling filter, oxidation ponds, composting, subsurface disposal field
What are examples of anaerobic treatment process?
sludge digestion, methane production, septic tanks, composting
What are examples of the anaerobic treatment process?
sludge digestion, methane production, septic tanks, composting
What is a stabilization pont?
Lagoonization
holds volume of water for period of time at shallow depths (3-5’) to promote aerobic activity and purify water
remains for 45-60 days before use
Define sludge in general
solid portion of waste water
Define raw sludge
most biologically active, high potential to turn septic
Define activated sludge
contains biological agents that gidest sludge into inorganic materials, aka “Mixed Liquor”
Define digested sludge
product of total anaerobic digestion
most stable
What is a pit privy?
simple hole dug
only used in the past, now only used in emergencies
What is a cesspool?
wastewater designed to seep into ground from cesspool vault
What is a septic tank
used when there is an inability to connect to sewer
waste water retained in multi-compartment tank for ~24hrs where 60-70% of sludge settles
What does a purple pipe indicate?
reclaimed water
What does a yellow pipe indicate?
steam, gas, oil
What does a green pipe indicate?
sewer
What does a blue pipe indicate?
potable water
What does a red pipe indicate?
electrical
What does a while pipe indicate?
leach line
