benefits of online monitoring of carbon, nitrogen and phosporus · (inorganic) nitrite (no2)...
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Benefits of On-line Monitoring of Carbon, Nitrogen and Phosphorus
New Jersey Water Environment Association
Dan DavisShimadzu Scientific Instruments
Benefits of On-Line Monitoring
• Environment
• Consumers
• Treatment Facilities
Environmental Impact
Why Carbon, Nitrogen and Phosphorus?
Potomac River
• These elements are nutrients and can enrich aquatic systems
• The problem is when we over enrich: Eutrophication
Because of their environmental impact
Drinking Water: TOC
EPA established two drinking water Regulations:
• Stage 1 Disinfection Byproducts Rule (DBPR)1Protects customers from disinfectants and disinfectant byproducts (DBP)
• Enhanced Surface Water Treatment Rule (IESWTR)1Reduce microbial contamination in drinking water
Federal Register, December 16, 1998, Volume 63, Number 241, or 40 CFR Parts 9, 141, and142 http://www.epa.gov./OGWDW/mdbp/mdbp.html
Response by EPA: Nitrogen & Phosphorus
• States & EPA : issue permits to all wastewater treatment facilities that regulate pollutants such as nitrogen and phosphorus
• “Nutrient Criteria Technical Guidance Manual for ₋ Lakes & Reservoir” (EPA-822-B-00-001), released 5/2000₋ Rivers & Streams” (EPA-822-B-00-002), released 7/2000₋ Estuarines and Coastal Waters” (EPA-822-B-00-003), released 10/2001
• http://www.epa.gov/ost/criteria/nutrient/guidance/
Total Organic Carbon
Consists of:• Purgeable Organic Carbon (POC)• Non-purgeable Organic Carbon (NPOC)
i.e. TOC = POC + NPOC
Analysis: There are 2 methods, • Difference method : TOC = (TC – IC)• Direct method : TOC ≅ NPOC (if no POC)
TOC (Total Organic Carbon):
Organic carbon bonding with hydrogen or oxygen to form organic compounds
Measure the sample (dilute)
Decomposition : 680℃ with Pt catalyst
Inorganic Carbon Removal
Obtain the TOC Result
Hydrochloric Acid SolutionAgitate
Total Organic Carbon Measurement
Formation of CO2
Removal of CO2
Total Nitrogen
Organic Nitrogen (R-N)(Inorganic) Nitrate (NO3)(Inorganic) Nitrite (NO2)(Inorganic) Ammonia (NH3)
Does not include:
Nitrogen Gas (N2)Chemical unreactive and not very reactive biologically Not detected by TN Method
TN (Total Nitrogen):
Sum of Both Organic Nitrogen and Inorganic Nitrogen:
Measure the sample (dilute)
Decomposition : 720℃ with Pt catalyst
Ozone
Obtain the TN Result
O2
Electricity
Total Nitrogen Measurement
Formation of NO
Formation of NO2* , -> NO2, Photon Emission
Relaxation of NO2* to NO2 by emitting light
Total Phosphorous Measurement
Measure(dilute) the sample
Decomposition : 95℃ with UV irradiation and air
Sulfuric acid solution
Sodium hydroxide solution for pH control
Obtain the TP Result
L-ascorbic acid solutionSulfuric acid ammonium molybdate
Color the solution to blue
Measure 880nm absorbance of Phosphomolybdate blue
COD, BOD & TOC
• Permits are usually written on COD, BOD, or TOC
• TOC can be used in place of COD or BOD after conversion trends (correlation) have been made.
• Running COD or BOD and TOC in parallel
COD, BOD & TOC
All treatment plants are required to measure one of these three items as a measure of the pollution value water.
• COD or Chemical Oxygen Demand is the total measurement of all chemicals in the water that can be oxidized.
• BOD or Biological Oxygen Demand is supposed to measure the amount of food (or organic carbons) that bacteria can oxidize.
• TOC or Total Organic Carbon is the measurement of organic carbons.
What is the difference between BOD, COD or TOC? Why do I have to measure them?
COD, BOD & TOC
COD -COD is a chemically chelated/thermal oxidation reaction and can be measured in 2 hours.
False Lows and False HighsA COD test measures all organic carbon with the exception of certain aromatics (benzene, toluene, phenol, etc.) which are not completely oxidized in the reaction, other reduced substances such as sulfides, sulfites, and ferrous iron will also be oxidized and reported as COD.
NH3-N (ammonia) will NOT be oxidized as COD. • No indication for nitrogen loading
COD, BOD & TOC
BOD…
• Two Types C-BOD & BOD
BOD5 measures the oxidation of carbons and possibly nitrogenous compounds present in a water sample. CBOD only measures oxidation of carbons.
• 5-day test
• Need to do Both
Places where the nitrification of ammonia may not be complete (i.e., incomplete conversion of ammonia (NH3) to nitrate (NO3)) or where high levels of amines or ammonia are present, false BOD readings may occur. This can occur in municipal lagoons, wineries and general industry.
COD, BOD & TOC
BOD Uses and Limitations
• BOD testing has its widest application in measuring waste loadings of treatment plants, and in evaluating the efficiency of treatment processes.
• It is usually seeded with the type of bacteria found in municipal plants. The types of bacteria needed in wineries and general industry usually differ in species.
• The hard to degrade organics found in some of these systems also may take longer than five days to break down, so a BOD test will give an inaccurate measurement.
COD, BOD & TOC
What is Total Organic Carbon?
• Organic matter content is typically measured as total organic carbon and dissolved organic carbon, which components of the carbon cycle.
• The Total Organic Carbon test measures all organic carbon as CO2
• TOC does not differentiate between the source of organic carbon, which can be metabolized (assimilated).
• Total organic carbon is a more accurate indication of pollutants that cause problems with BOD testing.
Sampling Scheme
Collection
Sampling
Preserving
Storage
Analysis
Physical Treatment
Chemical Treatment
BatchMeasurement
Reporting
Report Generation
Review/React
Sampling Scheme
Collection
Sampling
Preserving
Storage
Analysis
Physical Treatment
Chemical Treatment
Measurement
Reporting
Report Generation
Review/React
On-Line Sampling Considerations
When selecting a sampling device Consider:
• Particulates– Are there a lot of particulates?– Do I need to include them in my reading?
• Concentration of Analyte– Are there special precautions based on level?– Do I need to consider environmental influences?
• Number of Sampling Points– Can I monitor all necessary points?
On-Line Sampling Considerations
Particulates can add to the complexities of collecting and analyzing samples.
• Do you have particulates?– If yes will they interfere with the analysis
• Do I need to consider them in my analysis?– Do they contribute to your analysis?
On-Line Sampling Considerations
Performing low level analysis can be influenced by environmental influences such as contact with air or water used in the process.
Concentration of Analyte– Are there special precautions based on level?– Do I need to consider environmental influences?
Multi-Stream Suspended Solids Unit
• Sample flows in the top and drains out the bottom
• Actuators move the sampling arm into the stream
• Sample flows down into the sampling chamber through the strainer removing larger particles
• Mixing blades homogenizes the sample
• System back flushes then washes
Movie
Multi-Stream Sample Switching Unit
• Sample flows in the bottom and out the top
• Some sample flows in lower chamber on the outside of the sample collection cup
• Actuators move the stream to the sample collection chamber.
• Reduces Sample-Air Contact
• Eliminates need for washing
Backwash Strainer Sampling Unit
• Sample flows in the bottom and out the top
• Air pressure prevents sample from entering inner chamber until sampling
• Air is turned off and sample is filtered as it enters chamber
• Sample flow dynamics self clean the sample mechanism
Movie
Field Application: Waste Water Facility
Wastewater Treatment Facility
A X
X
Points of Monitoring
(A) Currently (X) Future
Onsite Installation
Water Treatment Utility
WATER SOURCE
MANUAL TECHNIQUE
MONITORING
TECHNIQUE
CHEMICALS COST(per Analysis)
Labor(per Analysis)
Time(per Analysis)
TREATMENT
Frequency
AUTOMATIC TECHNIQUE
•AUTOMATIC ADDITION
•REDUCE ERROR
•LAST LONGER
Hourly/Weekly/ Monthly
Biweekly
Variability
Comparable Data
0
10
20
30
40
50
11/19/04 11/29/04 12/9/04 12/19/04 12/29/04 1/8/05
Aver
age
Tota
l Nitr
ogen
(m
g/L/
day)
Date
TKN vs TN TKN
TN
TN
0
5
10
15
20
25
30
35
40
12/9/04 12/19/04 12/29/04
Date
Ave
rage
Tot
al N
itrog
en
(mg/
L/da
y)TN
Manual vs AutomaticTotal Nitrogen
Manual vs AutomaticTotal Phosphorus
Comparable Data
TPK vs TP
0
1
2
3
4
5
6
7
11/19/04 11/29/04 12/9/04 12/19/04 12/29/04 1/8/05
Date
Ave
rage
Tot
al
Phos
phor
us (m
g/L/
day)
TP ManualTP
TP
0
1
2
3
4
5
12/9/04 12/19/04 12/29/04
Date
Ave
rage
Tot
al
Phos
phor
us (m
g/L/
day)
TP
MonitoringWhy Biweekly vs. Hourly ?
Manual:• To reduce cost• To reduce labor• To reduce time
Automatic:• Reduces labor• Reduces time• Reduces cost
HOURLY/DAILY/WEEKLY/ MONTHLY
REDUCES COST OF POST TREATMENT
FASTER RESPONSE
IMPROVE WATER QUALITY
BIWEEKLY
Manual vs AutomaticTotal Phosphorus
Hourly :
• More information
• Less labor
• Better quality
Relative TPK (mg/L) per day
0
1
2
3
4
5
6
7
10/4/04 11/3/04 12/3/04 1/2/05
Date
Rel
ativ
e TP
K (m
g/L)
TOC/TN/TP Relative mg/L/day
0
30
60
90
120
150
180
7:34 18:34 5:34
Time (hrs)
Rel
ativ
e C
once
ntra
tion
(mg/
L/da
y)
TOCTNTP
Biweekly
Hourly
Hourly vs Biweekly…..AllowsFASTER RESPONSE
0
1
2
3
4
5
6
7
10/4/2004 10/24/2004 11/13/2004 12/3/2004 12/23/2004
Relat
ive T
P (mg
/L)
Date
Biweekly Monitor
Hourly Monitor
0
1
2
3
4
5
6
8:32 19:32 6:32 19:32 6:32 18:32 16:32 14:32Time (Hrs)
Rela
tive
TP (m
g/L)
Sudden Changes
BiweeklyTPK
HourlyTP
Benefits of On-Line Monitoring
Achieve Maximum Efficiency
• Faster Response• Better Treatment• Cost Reduction
Reduce
• Labor• Time• Money
Flexibility of Sampling
• Hourly• Daily• Weekly• Monthly
Automatic• Sampling• Pretreatment• Digestion• Analysis• Report
Thank You!
Special Thanks to