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1/23/2019
1
NUTRIENTS AND NUTRIENT ANALYSIS IN
WASTEWATER TREATMENT
BNR Lab Testing Parameters
Nitrogen
TNT 826 Total NEffluent Monitoring 826
TNT 880 Simplified TKN 880.pdfEffluent Monitoring
Customer approval required per region
DRB200
BNR LAB TESTING PARAMETERS
NitrogenTNT831 Ammonia 831.pdf
Influent, Effluent, and Process verificationTNT835 Nitrate 835
Effluent limits, anoxic and aerobic zones
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LAB TESTING FOR PHOSPHORUS
TNT843 for both Total P and OrthophosphateAnoxic , Aerobic, Effluent, and Process verificationLR 0.05─1.50 mg/L PO₄─P
0.15─4.50 mg/L PO₄ 843
TNT 843 can be used for ULR P
USEPA PhosVer3 PP method 8048 for the determination of Orthophosphate
VOLATILE FATTY ACIDS
For maximum Phosphorus release in an anaerobic zone an abundant supply of VFA should be available. 872
50─2500 mg/L as Acetic Acid
OUTLINE
(-3)
(-)
(-)
H
HH
N
N
O
O
O
N
OO
P
O O
O
O
• What are Nutrients?• Nitrogen• Phosphorous• Why Nutrients Matter• Nutrient Removal in Wastewater Treatment • Nutrient Analysis
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WHAT ARE NUTRIENTS?
• The term “nutrients” in the context of wastewater treatment describes a group of organic and inorganic nitrogen- and phosphorous-containing compounds
– Nitrogen• Inorganic - nitrate, nitrite, ammonia
• Organic - Urea, amino acids, proteins
– Phosphorous• Inorganic - orthophosphates, pyrophosphate, calcium phosphate
• Organic – nucleic acids, phospholipids, phosphoproteins, polyphosphates
NITROGEN• Present in fertilizers• Major contributor to nutrient pollution • Nitrogen gas (N2) makes up about 80% of our atmosphere• Can take on different forms in WW process
FORMS OF NITROGEN
• Main Forms of Nitrogen in a WWTP
N
OO
(-)
(-)
N
O
O
O
H
HH
N
NN
Ammonia (NH3)
Nitrite (NO2-)
Nitrate (NO3-)
Nitrogen gas (N2)
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PHOSPHOROUS• Present in fertilizers and detergents• Major contributor to nutrient pollution • Orthophosphate (PO4
-3) = Reactive Phosphorous • Can be present in different forms in WW process
FORMS OF PHOSPHOROUS• Polyphosphates/ Pyrophosphates • Orthophosphate ion (PO4
-3) • Orthophosphate may take the form of H2PO4
- and HPO4-2 ,
depending on pH• Can occur in different forms in WW process
Pyrophosphate
Adenosine Triphosphate
(ATP)
Phosphoric acidSodium Hexametaphosphate
WHY NUTRIENTS MATTER • Why nutrients matter
– Nutrients in wastewater effluent can accumulate at the outfall of a wastewater treatment facility and create conditions that are detrimental to both humans and the environment.
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WHY NUTRIENTS MATTER
• Environmental Effects– Eutrophication - A process where
increased nutrient levels promote excessive growth of algae and certain types of bacteria.
– Hypoxia – A result of eutrophication. When large colonies of algae die, and accumulate at the bottom of a river or lake, their subsequent decomposition and decay causes the aquatic environment to become oxygen-depleted. Hypoxia can be fatal to fish, crustaceans, and any other aquatic organisms that require oxygen to survive.
WHY NUTRIENTS MATTER• The USEPA has identified nutrient pollution
as a significant problem
• The National Pollutant Discharge Elimination System (NPDES) grants permits to wastewater treatment plants (WWTPs) that discharge their treated water back into the environment
• Any WWTPs that discharges to the environment have maximum nitrogen and/or phosphorous levels on their effluent permits
• If maximum levels are exceeded, the treatment facility can incur fines until the problem is corrected
WHY NUTRIENTS MATTER• In addition to the environmental impacts
that nutrients pose, wastewater plants are also interested in quantifying various nutrient levels to make their treatment processes more efficient, which can ultimately save them time and money
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SAMPLE NPDES PERMIT
WHERE ARE NUTRIENTS MEASURED?• Some measurement points in a WWTP
– Primary Clarifier – plant nutrient loading and overall removal
– Aeration Basin – A-basin nutrient loading and organics : nutrients ratio
– Nutrient Removal Basin Zones (aerobic, anoxic, anaerobic) – monitoring optimal nutrient removal conditions, and removal performance
– Secondary Clarifier – monitoring chemicalnutrient removal performance and chemical dosing
– Final Effluent – monitoring discharge permit compliance; overall nutrient removal performance
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NUTRIENT REMOVALPROCESS
MONITORING & CONTROL
• Nitrogen Removal –– Nitrification – Convert ammonia (NH3) to nitrate (NO3
-)
– Denitrification – Convert nitrate (NO3-) to nitrogen gas (N2)
• Phosphorous Removal (Biological) –– Phosphate release under anaerobic conditions
– Phosphate luxury uptake under aerobic conditions
– Phosphate removed by sludge wasting (WAS)
• Phosphorous Removal (Chemical) –– Dose chemical and settle out particulates containing phosphorous
NUTRIENT REMOVAL OVERVIEW
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NITROGEN REMOVAL
NITROGEN • Nitrogen Removal
– Nitrification - A 2-step process
• Bacteria (Nitrosomonas) convert ammonia to nitrite in the presence of oxygen
• Bacteria (Nitrobacter) convert nitrite to nitrate in the presence of oxygen
AMMONIA(NH3 )
NITRITE(NO2
-)→+ OXYGEN
(O2)
→+ OXYGEN
(O2)NITRITE
(NO2-)
NITRATE(NO3
-)
(Nitrosomonas)
(Nitrobacter)Step 2.
Step 1.
NITROGEN • Nitrogen Removal
– Denitrification – Under anoxic conditions nitrate is converted to nitrite, and ultimately to nitrogen gas.
NITRITE(NO2-)
NITROGEN GAS (N2 )
→NITRATE(NO3-)
→
NITRICOXIDE(NO)
NITROUSOXIDE(N2O)
→ →
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NITROGEN • Nitrification Monitoring and Control
BIOLOGICAL NITROGEN REMOVAL
O2 O2O2O2
Aerobic Zone
Anoxic Zone
NH3
Q (Flow)
Recycle to anoxic zone
O2
To 2o Clarifier
NITRIFICATIONDENITRIFICATION
N2 N2N2
|
|
|
NH3
NITROGEN • Nitrification – Controlling The Process
– Parameters
• Ammonia
• Nitrate
• DO
• ORP
• pH
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AMMONIA
•Where•Plant Influent
•Why•Monitor the ammonia loading before it gets to the nitrification basin (aeration basin).
•What
•AMTAXsc with Filter Probe sc• A-ISEsc, ANISEsc Ammonium probe
AMMONIA
AMTAX SC ANALYTICAL SECTION
(1) GSE: Gas Sensitive Electrode as detector
(2) Air pump to move liquids
(3) Dosing pump for reagent
(4) Electrolyte storage
(5) Cleaning solution
(6) 2 standard solutions
(7) Reagent
(8) Membrane storage
Range: 0.05 to 1000mg/L
1
2
5
4
6 6 7
3
8
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AMTAX SC GAS SENSITIVE ELECTRODE (GSE)
(1) Electrode
(2) Removable membrane cap
(3) Gas Sensitive Membrane
Filtrax Sample Filtration System
SAMPLE FILTRATION - BEST
Filtrax Sample Filtration System•Operating Principle
•The Filtrax prepares the sample through two ultra-filtration membranes (0.15 µ) that are immersed in the process tank
AMMONIA
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•Where•Nitrification Basin (Aeration Basin)
•Why•Monitor the efficiency of the nitrification system
•Control the amount of oxygen added (cost savings)
•What
•AMTAXsc with Filter Probe sc•A-ISEsc, ANISEsc Ammonium probe
AMMONIA
Real Time Nitrogen Control of Blowers.Lower Blower Costs
•Where•Plant Effluent
•Why•Monitor for upsets in the plant, or hidden processes
•Compliance with regulations
•What
•AMTAXsc
AMMONIA
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NITRATE
•Where•Between Denitrification and Nitrification basins
•Why•Control the amount of recirculated nitrates
•Optimize nitrogen removal system
•What
•NITRATAXsc UV Nitrate Analyzer
•N-ISEsc, ANISEsc
NITRATE
• Nitratax plus
• Nitratax eco
• Nitratax clear
• Self Cleaning
• Measurement Interval
– 1 to 30 minutes (user-selectable)
NITRATAX SC
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•The probe emits two wavelengths of ultraviolet light (210nm & 350nm)
•One photodetctor detects the absorbance of the 210nm light (mainly due to nitrates and nitrites)
•The other detector measures the absorbance of the 350nm light (organics, solids, and turbidity) flash
lamp
measuring gap
lmeß
lref
receiver
NITROGEN
NITRATAX PLUS SC
•Application Note
Nitratax Data
•Application Note
Nitratax Data
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•Where•Post Nitrification Basin (Aeration Basin)
•Why•Monitor the nitrification process
•Optimize nitrogen removal system
•What
•NITRATAXsc UV Nitrate Analyzer
•N-ISEsc, ANISEsc
NITRATE
•Where•Plant Effluent
•Why•Monitor for upsets in the plant, or hidden processes
•Compliance with regulations
•What
•NITRATAXsc UV Nitrate Analyzer
•N-ISEsc, ANISEsc
NITRATE
NITROGEN • Ammonia and Nitrate
– ANISE sc, N-ISE SC
• Ion selective electrode
• Automatic Chloride and Potassium compensation to eliminate interferences
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Sensor cartridge
(only wearing part)Sensor body
NITROGEN
• Ammonia and Nitrate
CARTRICAL Sensor Cartridge - One piece rugged
construction...
Nitrate ISE
Chloride electrode for
automatic compensation
from chloride interferences
pHD Reference for drift stable reference
...Factory calibrated -
A matrix correction is necessary only
Temperature Sensor for
temperature compensation
Ammonium ISE
Potassium electrode for
automatic compensation from
potassium interferences
NITROGEN
NITRIFICATION CONTROL PARAMETERS Parameter Laboratory Instrument Process Instrument
Ammonia • ISE + HQd• Colorimeter/Spectrophotometer
- DR6000- DR3900- DR900- PCII
• RTC-N, RTC-DN• Amtax sc• ANISE sc
Nitrate • ISE + HQd• Colorimeter/Spectrophotometer
- DR6000- DR3900- DR900- PCII
• ANISE sc• Nitratax sc
DissolvedOxygen
• LDO + HQd• Colorimeter/Spectrophotometer
- DR6000- DR3900- DR900- PCII
• LDO Model 2• Galvanic DO Sensor
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BENCHTOP PORTABLE DR6000 DR3900 DR900 Pocket
Colorimeter
• UV and white light source
• Over 250 pre-programmed methods
• 200 programmable custommethods
• White light source only• 240 pre-programmed
methods• 100 programmable
custom methods
• LED light source(4 fixed LEDs)
• 90 pre-programmed methods
• LED light source(1 fixed LED)
• Single parameter• 34 models
NITROGEN ANALYSIS
Nitrogen TestingTotal Nitrogen (TN)
Total Kjeldahl Nitrogen (TKN)
[Organic Nitrogen + Ammonia (inorganic )]
Nitrate (NO3-)
Nitrite (NO2-)
Inorganic Nitrogen
or[Total Nitrogen – (Nitrate + Nitrite)]
NITROGEN • Nitrification – Controlling The Process
– Other Parameters
• ORP
• pH
• Alkalinity
• TSS
• Organics
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PHOSPHOROUS REMOVAL
PHOSPHOROUS • Biological Phosphorous Removal
– Also a 2-step process
• Under anaerobic conditions, phosphate accumulating organisms (PAOs) consume organics (volatile fatty acids, VFAs) and release phosphate
• Under aerobic conditions, phosphate accumulating organisms take up all phosphate released during anaerobic phase, as well as any other phosphate in solution
ORGANIC(VFA )
→+
PAO
→+
PAO
OXYGEN(O2)
PHOSPHATELUXURY UPTAKE
Step 2.
Step 1.(NO OXYGEN)
PHOSPHATERELEASE
• Biological Phosphorous Removal – Aeration Basin – Under anaerobic conditions, phosphate-accumulating organisms
convert small organic compounds (volatile fatty acids) to other organic compounds that ultimately result in the release of phosphate from the organism
PHOSPHOROUS
Organics - VFA(e.g., C2H4O2)
Orthophosphate(PO4
-3)
Anaerobic Conditions
O2O2 O2
PAO
PAOPAO
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• Phosphorous Removal – Aeration Basin (biological)– Under aerobic conditions, phosphate-accumulating organisms
consume all the phosphate released in the anaerobic phase, as well as any other phosphate in solution (luxury uptake). Then phosphate-loaded bacteria are removed through the sludge wasting process, resulting in phosphorous removal
PHOSPHOROUS
phosphate (PO4-3)
from anaerobic stage
Aerobic Conditions
+ more phosphate
in solution
O2
O2
O2
O2
O2
O2
PAO
PAOPAO
O2
O2
BIOLOGICAL P REMOVAL
ANAEROBICNo DO, No Nitrate
AEROBICDO > 0.5mg/L
Poly-P
PHA
Glycogen
EMP
CO2
NADH
VFA
Ac-COA
Energy
PO4
PO4 PO4
Poly-P
PHA
Glycogen
CO2 + H2O
O2
PO4
PO4
You can’t control bacteriaYou can only control their environment
COMBINED BIOLOGICAL PHOSPHOROUS & NITROGEN REMOVAL
Aerobic Zone
Anoxic Zone
Anaerobic Zone
O2O2NO3
DENITRIFICATION
NITRIFICATION
Biological
Phosphorous
Removal
O2O2 O2
O2
3 ZonesPO4-3NH3
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PHOSPHOROUS
PHOSPHOROUS ANALYSIS
Phosphorous Testing
Total Phosphorous (TP)
Organic Phosphorous Inorganic Phosphorous
•Orthophosphate
• Calcium Phosphate
• Nucleic Acids• Phosphoproteins• ATP
** Effluent Permit Limits are in Total Phosphorous (TP)
•Where•Plant Influent
•Why•Monitor phosphorous load before it gets to phosphorous removal system
•What
•PHOSPHAXsc Phosphate Analyzer with Filter Probe sc
PHOSPHOROUS
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PHOSPHAX SC ANALYTICAL SECTION
(1) 2-beam-LED-photometer with colorimetric method (yellow), two ranges
(2) Air pump to move liquids
(3) Dosing pump for reagent
(4) Cleaning solution
(5) Reagent
Range: 0.05 to 50mg/L PO4-P
1
2
54
3
•Where•Phosphorous Removal System
•Why•Monitor or control chemical addition/efficiency of removal system
•Monitor Biological Phosphorus Removal system
•What
•PHOSPHAXsc Phosphate Analyzer with Filtration
PHOSPHOROUS
Real Time Phosphorus Chemical Feed Control.Optimize Chemical Dosing
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•Where•Plant Effluent
•Why•Monitor for upsets in the plant
•Compliance with regulations
•What
•PHOSPHAXsc Phosphate Analyzer with Filtration
PHOSPHOROUS
NUTRIENT REMOVAL PARAMETERS
• pH and Alkalinity- pH can be depressed by Nitrification.
7.14 lb. of alkalinity consumed per lb. of NH₃ oxidized.
• ORP/Oxidation Reduction Potential
Dissolved Oxygen is difficult to measure accurately in both an Anoxic and Anaerobic environment.
• And of Course the all important DO measurement in an Aerobic environment for Nitrification and Luxury uptake of Phosphorus or consider Ammonia based aeration
with RTC LDO2
BIOLOGICAL NUTRIENT REMOVAL BASICS
Anaerobic ZonePAO release huge amounts of P to access VFA.
Anoxic ZoneHeterotrophic Facultative Bacteria respirate using the oxygen attached to Nitrate.
Aerobic ZoneConversion of Ammonia through nitrification.Organisms take up to ten times their body weight in Phosphorus in a processcalled “Luxury Uptake”.
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BNR TREATMENT SCHEMES
DO between 2.0 and 4.0 mg/L or RTC with Ammonia based Aeration
Three Stage Phoredox A²/O
AnaerobicP release
Anoxicdenitrification
AerobicNitrification and Luxury uptakeDO 0.0 mg/l
ORP < -150 mvDO < .5 mg/LORP between -150 and + 150 mv
BNR TREATMENT SCHEMESUNIVERSITY OF CAPETOWN AND VIRGINIA INITIATIVE PROCESSES
DO between 2.0 and 4.0
mg/L or RTC withAmmonia based Aeration
AnaerobicP release
Anoxicdenitrification
AerobicNitrification and Luxury uptakeDO 0.0 mg/l
ORP < -150 mvDO < .5 mg/LORP between -150 and + 150 mv
RAS
Denitrified MLSS
BNR TREATMENT SCHEMESFIVE-STAGE BARDENPHO PROCESS
DO between 2.0 and 4.0 mg/L or RTC withAmmonia based Aeration
Optional Carbon Source
Reaeration
AnaerobicP release
Anoxicdenitrification
AerobicNitrification and Luxury uptake
Denitrified RAS
Nitrified MLSS
DO 0.0 mg/lORP < -150 m
DO < .5 mg/LORP between -150 and + 150 mv