chemscan. com © 2006 asa, inc. on-line nutrient monitoring strategies in eastern us and canada 2009...

ChemScan.com © 2006 ASA, Inc.

On-line Nutrient Monitoring Strategiesin Eastern US and Canada

2009 Wuhan International Conference on the Environment

Wuhan, Hubei Province, China

October 17, 2009

Wei ZhangRegional Manger – Eastern US & Canada

ASA Analytics, Inc.


Outlines

• Historical biological nutrient removal (BNR) overview in the region

• Current municipal discharge regulations

• Monitoring technologies

• Application/Case Studies

• Question & Answers


Historical Perspective

• 1800’s wastewater treatment concept• 1900-1930: development of biological treatment• 1960: milestone – 50% of population covered. • 1972: Clean Water Act

• Point source. NPDES discharge permitting program • Non-point source

• Mid 1990 – current: nutrients focus• Great Lakes (treaty obligations)• Chesapeake Bay• Delaware River Basin


Great Lakes Region


Chesapeake Bay

.


Delaware River Basin


Where in the Map

ChemScan.com © 2006 ASA, Inc.AppliedSpectrometry

Associates, Inc.


Why On-line Nutrient Today?

• Technology is more mature/proven

• Tighter TN/TP discharge limits

• Verify process performance

• Operation cost saving: Chemical, Energy

• If You Want to Control Process Chemistry, you need to Measure Process Chemistry


On-line Analyzer Category• In-Situ Type

– Galvanic, polaorgraphic, luminescent type of “sensor” or “probe” immersed in the treatment process.

– Most have single parameter

• Central Type– Sample extracted from multiple process locations

and analysis in a centralized flow through device in a analyzer

– Allow multiple sample lines– Allow multiple parameters at each sample line


Comparison: Pros & Cons

• Single locations vs. multiple locations

• Single parameter vs. multiple parameters

• Calibration issues

• Cycle time issues


Polarography (pō'lərŏg'rəfē), in chemistry, method for analyzing the composition of a dilute electrolyte. Two electrodes are placed in the solution: One has a fixed potential (voltage) and is called the reference electrode, and the other has a variable potential and is called the polarizable electrode. As voltage is applied to the polarizable electrode, the resulting change in the current through the solution is monitored. By plotting the pairs of values for voltage and current, a series of current-voltage curves (polarograms) can be generated. The general name for this method is voltametry; the term polarography was formerly restricted to those cases where the polarizable electrode is a dropping mercury electrode, though now this distinction is often disregarded. Current-voltage curves, which look like a series of steps called polarographic waves, can be used to determine the reduction potentials of any reducible species present in the solution, e.g., inorganic ions or complex organic intermediates. Conversely, unknown substances can be identified by their characteristic reduction potentials. Quantitative titrations of an oxidizing agent by a reducing agent can be performed using a polarographic cell to determine the equivalence point by monitoring changes in the current.


Associates, Inc.


2. Application and Performance


Typical Application

• Denitrification/phosphorus removal bio-filter• Chemical feed control scheme using nutrient

parameter is well developed

Denitrification Filter

BOD Removal Nitrification

Methanol


A ENR Process Flow Diagram using DynaSand Continuous Backwash Filter


BNR Process Schematic• Nitrification/Denitrification. No supplemental carbon

• Similar to Modified Ludzack Ettinger (MLE) process

• Some simultaneous nitrification/denitrification (SND)

FinalClarifier Oxidation

Ditch AX Primary Eff.

WAS

RAS


Application in Advanced BNR• Advanced BNR Processes

– Discharge limits on either total N or total P or both;

– Treatment process involves more than one stand-alone BNR process

• Advantages to use centralized analyzer– Confirming process performance between

parallel treatment trains– Providing process profile for overall plant– Avoid possible calibration errors between

individual sensors


.

BNR Process Schematic

• Step-feed BNR with supplemental carbon

RAS

WAS

FinalClarifier

PrimaryEffluent

Methanol Feed

AX Aerobic Aerobic Aerobic Aerobic AX AX AX


BNR Process Schematic

• Bardenpho Process with post denitrification filter• Two on-line nutrient analyzers

AX Aerobic AX

Anaerobic

PrimarySludge

FinalClarifier

Methanol

RAS

WAS

Denitrification Filter


Back River WWTPCity of Baltimore, Maryland

• Existing 180 mgd plant

• MLE Process

• Expect new discharge requirements

• Evaluation of treatment alternatives

• Modeling/Pilot testing


Associates, Inc.


Associates, Inc.

Case Study: Bonnybrook WWTP Calgary, Alberta

-0.5

0

0.5

1

1.5

2

2.5

11/18/96 - 12/2/96

mg/

l PO

4-P

18 19 20 21 22 23 24 25 26 27 28 29 30 1 2

UV-6100 LabPHOSPHATE

0

1

2

3

Sample Date

mg/l

PO

4-P

11/05 11/12 11/18 11/25 11/29 12/05 12/12 01/06 01/10 01/16 02/04 02/12 02/24 02/28

LAB

ChemScan

OrthophosphorousNov - Dec 1996 and Jan - Feb 1997

0 0.5 1 1.5 20

0.5

1

1.5

2

Lab mg/l PO4-P

Chem

Scan m

g/l

PO

4-P

ChemScan

+/- 5 % ErrorOrthophosphorous

Nov - Dec 1996 and Jan - Feb 1997

0

5

10

15

20

Sample Date

mg/l

NH

3-N

11/05 11/13 11/20 11/28 12/05 12/16 01/07 01/14 01/22 02/10 02/21 02/28

LAB

ChemScan

AmmoniaNov - Dec 1996 and Jan - Feb 1997

0 5 10 150

5

10

15

Lab mg/l NH3-N

Chem

Scan m

g/l

NH

3-N

ChemScan

+/- 5 % ErrorAmmonia


0

2

4

6

8

10

11/18/96 - 12/2/96

mg/

l NH

3-N

18 19 20 21 22 23 24 25 26 27 28 29 30 1 2

UV-6100 LabAMMONIA

Orthophosphate 4 Month Average Error 3.0 % Ammonia 4 Month Average Error 3.0 %


Associates, Inc.

Case Study: Bonnybrook WWTP Calgary, Alberta

0

2

4

6

8

10

11/18/96 - 12/2/96

mg/l N

O3-N

18 19 20 21 22 23 24 25 26 27 28 29 30 1 2

UV-6100 LabNITRATE

Nitrate 4 Month Average Error 1.7 % TSS 4 Month Average Error 3.3 %

0

5

10

15

20

Sample Date

mg/

l NO

3-N

11/05 11/13 11/20 11/28 12/05 12/16 01/07 01/14 01/22 02/10 02/21 02/28

LAB

ChemScan

NitrateNov - Dec 1996 and Jan - Feb 1997

0 2 4 6 8 10

0

2

4

6

8

10

Lab mg/l NO3-N

Che

mS

can

mg/

l NO

3-N

ChemScan

+/- 5 % ErrorNitrate


0

10

20

30

40

Sample Date

TS

S (

mg/l)

11/05 11/14 11/21 11/29 12/06 12/17 01/08 01/16 01/27 02/04 02/12 02/25

Lab

ChemScan

Total Suspended SolidsNov - Dec 1996 and Jan - Feb 1997

0 5 10 15 20 25

0

5

10

15

20

25

Lab TSS (mg/l)

Chem

Scan T

SS

(m

g/l)

ChemScan +/- 5 % ErrorTotal Suspended Solids

0 20 40 60 80 100 120

0

20

40

60

80

100

120

mg/l TSS

mg/l

TS

S

ChemScanTSS CALIBRTION


Summary

• If you want to control process chemistry, measure process chemistry

• Proven technology using nutrient parameter for process control/optimization

• Advantages of multi-parameter multi-sample line analyzer system

• Pay attention to Cost of Ownership

• Pay attention to Maintenance Requirement


Questions

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