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8/4/2019 Lagoons_deepak c Devender
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A
Presentationon
Oxidation Ponds & Lagoons
By
DEEPAK CHHIMPA
DAVINDER SINGH
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Oxidation Ponds
What are Oxidation Ponds ?
Oxidation Ponds are large earthen basins in which waste water
is treated by natural processes involving bacteria and in many
instances algae.
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Types Of Oxidation ponds
Aerobic Ponds
Anaerobic Ponds
Facultative Ponds
Maturation or Tertiary Ponds
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New
Algae
Algae
O2
Bacteria
CO2, NH3, PO4, H2O
NewBacteria
OrganicBacteria
Solar
Energy
Symbiosis
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Aerobic Ponds
The aerobic pond is shallow pond in which light
penetrates to the bottom there by maintaining active
algal photosynthesis through out the entire system.
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ALGAE
AEROBIC BACTERIA
Light Energy from Sun
New Algal
Biomass
New
Bacterial
Biomass
Organics
from
Waste
Water
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Diurnal Variations in Aerobic Ponds
Diurnal variation in DO concentration
Diurnal variation in pH
Extreme values of these, in either direction may be
detrimental to microbial activity.
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Design Considerations
Parameter Value
Depth in mts. 0.15-.5
Retention time (day) 2-6
BODu loading( lb/acre-day) 100-200
BODu removal(%) 80-90
Algae concentration(mg/l) 100-200Re-circulation ratio 0.2-2.0
Effluent suspended solids
concentration(mg/l)
150-350
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Problems
Nuisance vegetation
Inhibitory temperatures
Oxygen retention
Shock loads
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Anaerobic Ponds
These ponds requires no D.O. for microbial activity
as the organisms use O2 from compounds such asNO3, SO4 as their hydrogen acceptors and give end
product such as methane, carbon dioxide etc.
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Acid producing Bacteria
Methane producing
bacteria
H2O, CO2, CH4
Organic Wastes
H2O, CO2
Bacterial
Cells
Bacterial Cells
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Facultative Ponds
These are neither fully aerobic nor fully anaerobic. They are
often about 1 to 2 m in depth and favor algal growth along
with the growth of aerobic, anaerobic and facultativemicroorganisms. Such ponds are predominantly aerobic
during day light as well as for some hours of the light. In the
few remaining hours the pond bottom may turn anaerobic.
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Wind
CO2
Anaerobi
cZone
A
erobic
Anaerobi
cZone
Facultative
Zone
O2
alga
e
(CO2, NO2, PO4, SO4)
Aerobic
Bacteria
Biomass
Biomass
Anaerobic
Bacteria
Sludge Blanket
Organic acids &
Compounds of C, N, P, S
Im ermeable linin
Sunligh
t
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Maturation / Tertiary Ponds
These are similar to aerobic ponds but are very
lightly loaded with organic wastes. Generally
used for upgrading effluents from conventionalsecondary treatment processes. The principal
purpose is to achieve reduction in fecal colliform
count.
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Applications
Type of Ponds Applications
Aerobic Nutrient removal, treatment of soluble
organic waste & effluents from waste water
treatment plants.Anaerobic Treatment of domestic and industrial wastes.
Facultative Treatment of untreated screened waste waterand industrial wastes.
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Outlet of pond
Oxidation pond
Hamirpur REC Campus
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Reasons For Poor Performance of
Oxidation Pond
DO level in the pond during night & early morning hours was
almost zero.
BOD removal efficiency was only 50-58%
BOD loading rate was 91.20 kg/day as compared to the design
BOD of 81kg/day.
Black effluent was found exerting very high BOD values of
80-110mg/l.
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LAGOONS
Lagoons are deep waste stabilization ponds -like
bodies of water or basins designed to receive, hold,
and treat wastewater for a predetermined period of
time by artificial means of aeration. In the lagoon, wastewater is treated through a
combination of physical, biological, and chemical
processes.
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TYPES OF LAGOONS
According to the microbial activity in the aerated
lagoons-
Aerobic aerated lagoons.
Facultative aerated lagoons.
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AEROBIC AERATED LAGOONS
Dissolved oxygen is present throughout much of the
depth of aerobic lagoons.
They tend to be much shallower than other lagoons.
They are better suited for warm, sunny climates,where they are less likely to freeze.
HRT = 2 to 3 days.
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FACULTATIVE AERATED
LAGOONS
Three types of zones are present
Aerobic Zone.
Anaerobic Zone.Facultative Zone.
HRT is higher than aerobic lagoons because
time requires for the solids to settle and formany pathogens viruses to either die off or
settle out.
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Two, Three, or Four Lagoons Are
Better Than One
Each lagoon cell has a different function to perform,
and a different kind of lagoon design may be used for
each cell.
In SeriesWhen lagoons operate in
series, more of the solid
material in the wastewater,
such as algae, has an
opportunity to settle out
before the effluent is
disposed of.
In ParallelThis system design is
particularly useful in
cold climates or where
lagoons are covered
with ice for parts of the
year
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Factors to consider for transfer of
the oxygen
Alpha factor.
Beta factor.
Theta factor. Atmospheric pressure.
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Misleading Parameters
The first myth is that effluent BOD5measures the
biodegradable carbonaceous material in the effluent
The second myth is that the effluent BOD5, or
CBOD5, is the residual of the BOD5 in the influent to
the lagoon.
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Operation And Maintenance
For Aerobic Lagoons
Any earthen structures used as impoundments must be periodically
inspected. If left unchecked, rodent damage can cause severe
weakening of lagoon embankments.
In submerged diffused aeration, the routine application of HCl gas
in the system is used to dissolve accumulated material on the
diffuser units
The use of submerged perforated tubing for diffused aeration
requires maintenance and cleaning on a routine basis to maintain
design aeration rates
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Operation And Maintenance
For Facultative Lagoons
Most facultative lagoons are designed to operate by gravity flow.
The system is not maintenance intensive and power costs are
minimal because pumps and other electrically operated devicesmay not be required.
Earthen structures used as impoundments must be inspected
for rodent damage.
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Applicability
Type of Lagoon Application
Aerobic Lagoon Municipal and industrial wastewaters of
low to medium strength.
Facultative Lagoon Treated raw, screened, or primary settled
municipal wastewater and biodegradable
industrial wastewaters.
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LimitationsFor Aerated Lagoons
Aerated lagoons may experience ice formation on the water
surface during cold weather periods
Reduced rates of biological activity also occur during cold
weatherFormation of ice on Floating Aerators.
For facultative Lagoons
The inability of the process to meet a 30 mg/L limit for TSS
due to the presence of algae in the effluent.
Odors may be a problem in the spring and fall during periods of
excessive algal blooms and unfavorable weather conditions
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Thanks