Design and Operation of a Remote Phosphorus Analyzer
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Transcript of Design and Operation of a Remote Phosphorus Analyzer
Design and Operation of a Remote Phosphorus Analyzer
David M. Struve
Supervising Chemist
Water Quality Analysis Division
South Florida Water Management District
“On mechanical slavery, on the slaver of the machine, the future of the world depends.”
Oscar Wilde
Considerations for Remote Analysis
• Reliability
• Accuracy and Precision
• Communication and Control
• Flexibility and Speed
• Maintenance
• Waste and the Environment
Benefits of Remote Analysis
• Data generated 24/7, rain or shine
• Ability to observe short term trends
• No travel time
• No sample handling
• No lab costs
• Higher Frequency of Analysis
• Event Driven
Design Parameters for Phosphorous Determinations• Use a standard chemistry• Results comparable to lab analyses• Control analyzer temperature• Determine total and reactive portions• Easy access to all data• Fault detection• Low maintenance• Calibration standards “on board”
Project Overview
• System developed by Greenspan Technology, Australia
• Deployed February 2002
• System uses standard molybdate chemistry (SM4500PF)
• 3 point calibration and color correction
• 3 month maintenance cycle
• CPDP Modem Technology
• Deployed at STA1W - Site G310
D2
Wash
ThermalDigest
UVDigest
D1
Wash
AIR
AIR
STD 1
STD 2
STD 3
SAMPLE
AIR
AIR
Wash
Color 1
Color 2
Surfactant
Color 3
P0 - 8 Channel60:1 1/8” ID05-40 rpm
02
05
20
23
25
32
31
3022
04
01
00
03
06
21
24
26
V10NONC
Air
V14
NC
NO
V12
NC
NO
SwitchV17
Chamber 1
Waste 2
V11NCNO
Waste 2
WaterTrap
Chamber 2
Detector
V16NC
NO
V 13
NC
Waste 2
Waste 3
V 27
NC
NO
Air
Waste 1
P130:1 1/8” ID10-65 rpm
NO
Analytical Conditions
• Sampling frequency• Sample intake• 3 point calibration (0 – 124 ppb P)• Determination of reactive phosphorous• Sample digestion• Determination of total phosphorous• Monitoring of digester temperature, cabinet
temperature, leak detectors, reagent volumes
8000
9000
10000
11000
12000
13000
14000
15000
0 20 40 60 80 100 120 140
P Conc. (ug/L)
ST
D R
esp
on
se
SR = (9229(41.9±1.9)Pc
R2 = 0.9996±0.0016n = 642
Detection Limit Study(3 hour sample cycle)
10
20
30
40
50
60
70
80
0 1 2 3 4 5 6 7 8 9
Measurement
P (
ug
/L)
TRP
TP
Reactive PhosphorusMean = 36.0 ug/LSTDDEV = 0.534 ug/LMDL = 1.6 ug/L
Total PhosphorusMean = 53.5 ug/LSTDDEV = 1.07 ug/LMDL = 3.2 ug/L
Remote Analyzer Data - G310Total Phosphorous and Total Reactive Phosphorous
0
20
40
60
80
100
120
140
20-Aug 9-Sep 29-Sep 19-Oct 8-Nov 28-NovDate/Time
[P],
ug
/L
Grab TPO4 (ppb) TPO4 (ppb) TRP (ppb)Grab OPO4 (ppb) 8 per. Mov. Avg. (TPO4 (ppb)) 8 per. Mov. Avg. (TRP (ppb))2 per. Mov. Avg. (Grab TPO4 (ppb)) 2 per. Mov. Avg. (Grab OPO4 (ppb))
0
500
1000
1500
2000
2500
3000
10/27 0:00 10/27 12:00 10/28 0:00 10/28 12:00 10/29 0:00 10/29 12:00 10/30 0:00 10/30 12:00 10/31 0:00
Time
Flo
w (
ft3 /S
)
0
10
20
30
40
50
60
70
80
90
100
110
TP
( g
/L)
flow TP
Overall Observations
• Comparative results excellent
• Good detection limits (~4ppb)
• Communications flawless
• Control and error detection good
• Interesting data
The Project Team
• Greenspan Technology• Robert Briggs• Chris Gibson• Tom Baber• Bill Harrington• Dr. Meifang Zhou• Kim Hanes• AirLink Communications• SFWMD
Questions?