Slide 1

Report
Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company,
for the United States Department of Energy’s National Nuclear Security Administration
under contract DE-AC04-94AL85000.

Activated sludge processes
• Fixed film and suspended processes


Aerobic/anoxic/anaerobic processes
modifications.
Nutrient removal
• nitrification / denitrification, phosphorous removal

Water reuse and reclamation
• membrane bioreactors


Disinfection
Satellite and On-site Wastewater Treatment
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Wastewater Contaminants
‣
Bacteriological,
Vibrio Cholerae, Campylobacter, Salmonella , Shigella,
‣
Viruses
Hepatitis A, Norovirus
‣
Protozoan
Giardia, Cryptosporidium, Entamoeba
‣
Biological oxygen demand
Organic matter causes algae to thrive and deplete dissolved
oxygen
‣
Nutrient removal to prevent eutrophication
Nitrogen and phosphorus from waste, and agriculture
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Measurement
Value
Units
Total Suspended Solids (TSS)
210
mg/L
BOD
190
mg/L
TOC
430
mg/L
COD
140
mg/L
Organic Nitrogen
15
mg/L
Free Ammonia
25
mg/L
Nitrite/Nitrate
0/0
mg/L
Phosphorous
7
mg/L
Total coliform
107-109
colonies/100mL
Fecal coliform
104-106
colonies/100mL
Cryptospiridium oocysts
0.1-10
no./100mL
Giardia Lamblia
0.1-100
no./100mL
Source: Wastewater Engineering, Metcalf and Eddy- medium strength WW
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‣
Testing for pathogens directly is
expensive and hazardous
‣
Indicators from the family
Enterobacteriacae are used (E. Coli,
Citrobacter,Enterobacter, Klebsiella)
‣
Grow bacteria on a specified medai and
count the number of colonies after
incubation
‣
Other assays are used and are approved
by the US EPA (Colilert shown)
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Fixed film process
Screens
Primary settling
Grit removal
Digester
Sludge
drying
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Biofilm
Waste
Water
Aerobic
Facultative/Anaerobic
Bed Media
~1 mm
100µm
Treated Water
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Trickling filter
Uses biofilm to treat water to remove BOD
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BOD5 removal rates for trickling filters
Filter Type
Hydraulic loading
m3/m2day
BOD5 Removal (%)
Low Rate
1-4
80 - 90
Intermediate
4-10
50 - 70
High Rate
10-40
65 - 85
Roughing
Filter
40 - 65
Source: Environmental Engineers Handbook, 1997.
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Waste
Water
Activated Sludge
Anoxic
Aerobic
Coagulation
Clarifier
sludge
Return activated
sludge
Treated
Water
Anoxic – no dissolved oxygen
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Aerobic
Conditions
Anaerobic/Aerob
ic Conditions
BOD + O2
CO2 +
increased cell
mass
P
Aerobic
Conditions
Organic N
Anoxic
Conditions
NO3
NH4
Alum
inorgani
c sludge
increased
cell mass
organic
sludge
N2
NO2
NO3
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‣
‣
Use forced air suspension of biological sludge to reduce BOD
Largest expense for this process is the electrical energy required
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Activated Sludge Process Stages
Anoxic Basin
Aerobic Basin
Sedimentation
Final Clarification
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Anaerobic sludge digestors
produce methane
(65% CH4 - 35% CO2)
On-site electricity is produced
with the methane 50% of plant
power (2.2MW)
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Sedimentation
C6H14  Biomass +
CO2
NH3+  NO2
Norg  NH3+
Mixin
g
Aeration
NO2  N2
Solids
Handling
Sedimentation
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Modified LudzackEttinger (MLE Process)
A2 O
Bardenpho
RAS = Return Activated
Sludge
WAS = Waste Activated Sludge
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Solids Handling Involves Anaerobic
Conditions
Diesel
Generators
C6H14 +
H2O
Anaerobic
Fermentation
(30 days)
CH4 + CO2
6.6 MW
Biosolids
Centrifuges
Disposal
or Reuse
(150
t/day)
Aeration
Blowers
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CO2
H2S
N2
HOCl- SO2
Sewers
H2O+C+N+S
O2
Power
Settling & Aeration
Microbes
(Biosolids)
H2O
Heat CO2
Fermentation
Composting
CO2
Humus
River
NH3+
CH4
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Conventional activated sludge plant
MBR membrane cassette
• Uses submerged hollow fiber membranes
• High Solids Retention Time membrane bioreactor
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Membrane Bioreactors Offer Small
Size, High Rate of Reaction for
Satellite WW
Screens
Anoxic
Aerobic
Submerged
Membrane
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Source: Zenon Membranes
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Raw Feed and MBR Product
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Reverse Osmosis After MBR Makes
Water Suitable for Groundwater
Recharge
RO treated water is better than most surface water sources
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10% of discharge from this plant is sent to
microfiltration plant to purify for groundwater injection
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Submerged microfiltration for treated wastewater effluent
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‣ Chlorination to kill the remaining pathogens
• Cl2 HOCl
‣ Dechlorination to remove chlorine
• SO2 + HOCl + H2O  HCl + H2SO4
• SO2 + NH2Cl + 2H2O  NH4Cl + H2SO4
‣ UV radiation reduces chemical needs and chlorinated
products
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Chlorine
Ozone
UV
BOD,COD,TOC
Chlorine demand
Ozone demand
Little effect
Oil and grease
Chlorine demand
Ozone demand
May block light
Nitrite
Forms NDMA
Oxidized
No effect
Nitrate
Forms chloramines
Reduce O3
effectiveness
No effect
Oxidized
Oxidized
May block light
Yes
Yes, but
nonchlorinated
No
Iron and Manganese
Forms disinfection
byproducts
Source: Wastewater Engineering- Metcalf & Eddy
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
Satellite facilities are mid scale sewage treatment plants that
treat waste near the point of generation
• Lagoons
• Aeration ditches
• Trickling filters
• Membrane bioreactor

On-site waste disposal is septic tank system with drain field
• Provides low cost alternative
• Can be very effective
• Need little maintenance (but maintenance is important)
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