Clarifier is not removing much, most is done by biological
treatment
eg: Molsons Brewery
shredding gadget
remove sand + coffee grinds
ASME + ASTM
Need happy bacteria
medium strength, primary
secondary
usually
P + AL -> ALPO4
P + Fe -> FePO4
30-35% of total cost
CO2 + E
Volatile acids
film loses adhesion breaks off = sloughing of biofilm
Cover + Bury it to
insulate and
maintain heat
maybe
Major Disadvantage = lower efficiency, <85% BOD5 removal
R = q/Q
Eoverall = (E1 + E2)-(E1*E2)
Modified Arrhenius equation
TFSC = Trickling Filter Solids Contact system
60-65% of treatment plants use activated
sludge for municipal / light industrial
soluble BOD5, N, P
upper limit
HRT = Aeration Period
inefficient compared to
activated sludge
key to Type 3
Why is this operation so important?
Because after this step it discharges into
ocean, need it for guidelines and permits
Lions Gate - 56-58\%
Winnipeg - 54%
114-121 not on test
60,000 mg/l
250,000 - 350,000 mg/l
Find a better way to reduce amount of sludge in first place
add buffer eg NaOH
best PH 6.8-7.4
Floating cover used to be used
because: its 25-30% of the cost
of a reinforced concrete fixed
cover
Two stage system
-> disposal
corolla
Supernatant goes back
to the head of the filtration plant
(back to start)
Aerobic Digestion
-> dewatering + offsite disposal
Unheated + unmixed
camry
35 - 40 deg C -> Mesophilic
15 days or less
~80%
~20%
anaerobic
must clear scum
scum
must remove
BOD
avalon
Dewatering and disposal
bigger footprint, but more efficient
payoff in 10-15 years
lexus
Option 4
2- phase process (after mixing tank)
Phase 1: Acid Bacteria -> buffer - > Methane
Bacteria
3 tanks - high capital cost, but removes 70-80% of
sludge
Faster (more oxygen = faster digestion) but aerobic digestion does not
produce methane (energy user not energy producer)
producers love this method as it is simple
No CH4
$$
mixing usually governs aerobic requirements
needs more nutrients
anerobic does not produce nutrients
Class A biosolid (permit needed)
comes from nitrates
subject to real health
issues, especially low
immunity, make it hard to
absorb O2 in body