TEST 3 CE 326

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point source
- discharge from treatment plants
- NPDES
non-point source pollution
- 1. storm water runoff
- 2. run off from parking lots
- stormwater NPDES
- (usually tied to population)
- 3. farm run off
combined sewer
- 1. has BOTH
- a. stormwater
- b. wastewater (from residence, toilet , sink, washing machine)
- 2. CON: combined sewer overflow , untreated sewage going into stream
separate sewer

dedicated sewer for wastewater
Biochemical oxygen demand
- 1. measure the dissolved oxygen at time 0
- 2. D.O. at 5 days
- 3. oxygen consumed by sample
- 4. oxygen consumed by blank
- 5. = BOD5
- 6. BODt = Lo - Lt
- 7. Lt = Loe^-kt
- 8. k = rate constant , d-1
- 9. Lo = BOD ult
- 10. k = .35-.7 d-1 , raw wastewater, has more organic material
- 11. .12-.35 d-1 , treated wastewater
BOD life graph
Four levels of treatment
- 1. preliminary treatment: screens, grit removal
- bar rack/screen : 2"- to remove debris, wood, large rocks, dead animals, etc.
- fine screen: 1/4 - 1/2"
- a. grit removal: remove inorganic settleble solids (sand)
- b. rotate flow in degridder tank, settlement sticks to outside of tank then falls down through the end.
- 2. Preliminary Treatment: remove settleable solids
- 3. Secondary Treatmnt: biological treatment
- a. converting pollutants into bacteria (biomass) secondary sludge
- 4. Tertiary Treatment: nutrient removal - biological and or physical/chemical step
comminutor (sp?)

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CWA
- only upholds primary treatment as mandate
- 3. atlantic side has shallow life bed in ocean, can hold nutrients way better for life
- 4. CWA lost battle against LA and must do secondary
medium strength wastewater
- 200 mg/L BODs
- 200 mg/L TSS = total suspended solids
- 10,000 mg/L = 1% solids
- 1000 mg/L = .1
- 100 mg/L = .01
goal of WWT

concentrate and remove pollutants
deeper air tank in activated sludge,

higher oxygen transfer
activated sludge
- air, is MAIN COST
- in before primary, 200 mg/L
- after primary, 100 mg/L TSS
Vertical loop reactor

?
wastewater generation
- airport , passenger: 11
- cabin, resort: 150
- cafeteria, cust.: 8
- cafeteria, employee: 38
- campground: 115
- cocktail lounge: ?
collection systems
- 1. combined systems (older): stormwater + sanitary
- 2. ?
slide i missed!
3 goals of wastewater treatment
- 1. remove soluble and insoluble organic matter
- 2. remove nutrients ( namely N,P)
- 3. remove pathogens
- a. ames just began removing pathogens with UV light., significant removal, motivated by the high civilian use of the river that wastewater is funneled to
wastewater treatment steps
- 1. preliminary treatment
- 2. primary sedimentation
- 3. biological kldjfljfd?
4 Levels of wastewater TREATMENT
- 1. preliminary: screens, grit
- 2. primary: sedimentation
- 3. secondary: biological (followed by sedimentation)
- 4. tertiary: ( N & P removal)
- a. fldsfjkdf?
Premlinary
- 1. screens and grids
- a. bar screens ( 2")
- b. other screen, 1/4 "
- 2. "teacup" spin, and things fall. (like washer)
Secondary Treatment
- heterotroph vs. autotroph
- 1. BOD + O₂-(biomass)-> CO2 + H2O
- a. heterotrophs: use organic carbon & energy source
- 2. BOD: oxygen consuming organic matter
- a. NH4 + O2 -biomass-> NO3-
- b. autotroph: inorganic energy source carbon from CO2
2.
Terminal electron acceptor
- 1. aerobic: O2 = t.e.a
- a. form energy in form of ATP
- 2. anoxic: nitrate (NO3-): t.e.a
- 3. anaerobic : CO2 serve as t.e.a
Terminal Electron Acceptor ex/ *** will show on test
- carbonaceous BOD removal
- nitrification --> NH4 -> NO3^-
- BOTH aerobic!
- denitrification
- BOD + NO₃- -> CO₂ + H₂O + N₂ (gas)
- anaerobic digestion
- organic matter -> CH₄ + CO₂(biogas)
- (4 just listed)
Classification by T
- 1. psychrophilos: optimum temp below 25 C
- 2. mesophiles: " " 25-45 C
- 3. thermophiles: " " 55-65 C
- 4. Class A solids: 55 C for a certain amount of hrs
classification by growth environment
- aerobic
- anoxic
- dflskfj
10 growth requirements ** test question
- 1. carbon source
- 2. energy source
- 3. terminal electron acceptor
- 4. macronutrients (N, P, K)
- 5. micronutrients (Fe, Co, Ni, Mb)
- a. involved in electron transfer/transport
- 6. appropriate T
- 7. " pH
- 8. absence of inhibition
- 9. moisture (like compost)
- 10. mixing/contact
vertical loop reactor
- 3-5 ft deep, tank is beneath that floor,
- something catches air bubbles, so that there is an air pocket at the top of the plate
a lip , the fan creates a velocity /firce strong enough to push sludge up, but then it will hit a small extended wall while clean water goes up
AMes

186 MGD
digesters in ground
- due to smell
- temperature drop from winters
- egg shape (above ground): better mixing
Back river WWTP
- a mercury seal in rotary distributors,
- ditched trickling filters: goes to effluent channel
- for activated sludge
3 objectives in WWT
- 1. remove soluble and insoluble organic matter
- 2. remove nutrients
- 3. remove pathogens
dS/dt
- 1. = -uX/Y
- 2. S: soluble substrate
- 3. X = biomass (bacteria) concentration
dX/dt
- 1. uX- k_dx
- 2. u= specific growth rate
- 3. kd = decay coefficient
- 4. Y: yield coefficient , mass biomass formed/ (mass substrate utilized)
- 5. * sometimes u isn't a constant but a function
Monod
- u = u_max*S/(k_s + S)
- 2. substrate limiting conditions/starving conditions
- 3. first to use whole cells
- 4.
example
F: required Θ_{c to meet 30mg/L BOD5 and 30 mg/L TSS permit for the following:

Q= .15m^3

So= 84 mg/L

umax=.1 h^-1

ks= 100 mg/L

kd= .002 h^-1

Y= .5 mg VSS/mg BOD5

BOD5 of TSS= .63}
- Sdesign = 30-30(.63)
- Θc= 100 + 11.1 /[(11.1*(.1-.002)) -100*.002]
- = 5.2 days (converted from hrs)
x = biomass, MLVSS
- MLVSS = mixed liquor volatile suspended solids
- 2. higher concentration may lead to smaller reactor and lower construction $
- 3. BUT
- a. maybe larger settling tank
- b. higher aeration rate to meet increase in oxygen demand
NExt step in wastewater treatment: (after theta c found)
- find return solids in aeration tank
- put water in graduated cylinder,
- a. top: supernatant,
- b. bottom: sludge
- 3. sludge volume index: SVI
- 4. in diluted SVI test, we start with 1 g/L liquor -> then slduge level = SVI ml/g
- 5. SVI 75-125 desirable SVI range
- 6. can find Xr flow! using SVI :)
finding Xr flow
- X' 10⁶ /SVI = mg/L
- X' = MLSS (mixed liquor suspended solids)= 1.2X
8 types of pollutants from the 4 principal water sources , and why each a concern?

?
Point source
- domestic and industrial wastes ,
- b. distinguishing characteristic: generally collected by a network of pipes or channels and conveyed to a single point of discharge into receiving water.
BOD, Lab procedure
- 1.inoculate water sample with bacteria,
- 2. bac. eats organic matter while consuming dissolved oxygen (aerobic digestion)
- 3 .greater the amount of organic matter present, greater dissolved oxygen content will be
effect of nitrification during BOD test
- 1. microorganims cannot oxidize nitrogen in the organic matter it eats.
- 2. the N is released as ammonia
- 3. nitrifying bacteria turns ammonia (NH3) to nitrate (NO3-)
- 5. 8+
- 4. NBOD can be calculated
- 5.effects alkalinity consumption
- ?
BOD related to incubation

?
DO sag curve
- 1. measures the ability of a river to absorb waste by measuring Dissolved Oxygen.
- 2. dips because DO drops as oxygen demanding materials are oxidized and then rises again further downstream as oxygen is replenished from the atmosphere.
- 3.
mass and heat balance

?
oxygen deficit
- D = DO_s - DO
- DOS = saturation DO concentration
- DO = ACTUAL concentration
- D = oxygen deficit
calculate t_c
- Tc: time to travel to crit. pt. (dip in sag curve)
- 2. = 1/k_d *(1 - D_a/L_a)
Dc (crit. deficit) How to Calc?
- use critical time!
- use eqn 7-41, t and d both have subscript c now
Processes
- 1. thickening
- 2. stabilization
- 3. conditioning (Al3+, Fe3+, or polymers)
thickening
- 1. has steep bottom to funnel
- 2. dilute feed leads to better thickening (Type III)
stabilization
- 1. convert max amount of organic matter to a more stable form
- 2. volume reduction
- 3. prevent odors
- 4. pathogen reduction <- saw this in AMes, a. anaerobic digestion: biogas (CH4, CO2)
- i. smaller systems
- b. aerobic digestion
conditioning
- 1. add coagulent
- a. polymer
- b. lime
- c. ferric iron, Al3+
- 2. to separate water from solids
Dewatering
- 1. vacuum, pressure , or drying methods to remove water
- 2. 25 -35% solids
- ex/ frame press, in between plates fill void w/ sludge, squeeze plates, water goes thru fabric and drips off of plates
- a. uses a lot of lime
VOlume reduction
- drying and pelletization
- incineration
Biosolids
- term for treated sludge
- class A:
- a. highest category of sludge , no detectable level of pathogens (time/T rqmt, 24 h @ 55 C)
- b. meets metals reqmt
- c. unlimited distribution
- class B: stabilized thru digestion
- b. pathogens present may still be present
- c. may have heavy metals
- d. will need permit for land application
dissolved air flotation

? in food industry
egg shaped digester
anaerobic digester
- 1. recircling the gas
- 2. draft tube, bubble gas
dewatering: belt filter press

1. as you press water through belts, ?
obligate aerobes
- 1. microbes that must have oxygen as the terminal electron acceptor
- 2. eats away at organic matter when oxygen is present (aerobic cond's)
obligate anaerobes
- 1. microorganisms that survive in the presence of oxygen.
- 2. cannot use oxygen as term. e' a.
- 3. wastewater devoid of oxygen is anaerobic,
facultative anaerobes
- 1. able to use oxygen as term. e- a., under certain conditions, can grow in the absence of oxygen,
- 2. under anoxic conds
- 3. denitrifiers use nitrite and nitrate, anoxic denitrification
How nutrient discharge effects water quality in rivers
- 1. oxygen demanding wastes most important river pollutant, but nutrients can also contribute to deteriorating water quality by plants for causing excessive plant growth.
- 2. C, N, P, trace elements
- a. N: consumes lots of DO, toxic to fish
- b. P: vital nutrient for the growth of algae,
- c.
- 3. turbidity caused by soil particles, bacteria, other factors decrease light penetrating deep water
8 pollutants in main 4 wastewater sources
- I. nutrients (N&P "limiting reagents")
- 2.algae C5H7O2N with P = 1/5 N
- 3. P will be limiting reagent for algae growth
- 4. algae is bad, a. when dies it becomes sediment with high oxygen demand
- II. chemicals (pesticides/herbicides) : "chemicals of emerging concern"
- a. pharmaceuticals
- b. endocrine disrupting compounds
- III. organic matter (oxygen consuming )IV. sediment (suspended solids)V. pathogensVI. heavy metalsVII
oxygen demanding material
- 1. theoretical oxygen demand
- 2. glucose(C₆H₁₂O₆) + 6O₂ -> 6CO₂ + 6H₂O
- 3. 6 mol O₂/(mol glucose) * 6*32 g/mol/(180 g/mol) = 1.067 g O₂/(g
- glucose)
- a. ratio of o2: other reactant * (O2 mol.mass/glucose mol.
- mass)
- 4. BOD, biological oxygen demand
- a. (INSERT GRAPH)
- b. 5 days for BOD
- test : WHY? arbitrary, set up by England
- c. d. BODt = Lo - Lt
- Lt = Lo(e^-kt)
- Lt = Lo - Loe^-kt= Lo(1-e^-kt)
assimilative capacity

how well a body of water can stay above a DO level of 5 mg/L
preliminary treatment

screens grit removal
primary clarifier
- 2. 50-60% removal of settleable solids
- 3. remove primary sludge
Secondary treatment
- 1. biological
- 2. attached growth (high pumping costs)
- 3. suspended growth (high aeration 2° clarifier)
tertiary treatment
- 1. N&P removal (sand filter)
- 2. aeration basin
SVI
- 1. sludge volume index
- 2. measure of settling characteristics of biomass
- 3. measured in a graduated cylinder after 30 min. of settling
- 4.desirable SVI: in the range of 75-150
sludg wastage
- 1. an activated sludge operational consideration
- 2. HRT, or F/M
SRT

solids retention time, also MCRT, mean cell residence time
F/M
- 1. food to microorganism is an alternative design parameter to theta C for teh operation of an activated sludge plant
- 2. F/M low in CMAS
- 3. selector avoids this, gives floc forming microorg. advantage

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haleygreenbean

322050

Card Set

TEST 3 CE 326

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final ... get your ass in gear!

Updated

2016-08-04T04:38:43Z

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