Using the Turner Designs Model 10AU Fluorometer to Perform Flow
Contents
1. should remain at the default of 48 Remove the Distilled Water Blank Set the concentration range to HIGH From screen 2 4 press lt 2 gt to bring up screen 2 42 change concentration range and press lt ENT gt to toggle Go to the HOME screen or screen 3 2 Insert a cuvette containing your Recovery Standard Record the reading from the HOME screen or screen 3 2 This reading is not an actual concentration Since you have not calibrated with a standard of known concentration what you are reading is relative concentration You only need to know relative concentration for this method Insert a cuvette containing your Sewage Standard Record the reading from the HOME screen or screen 3 2 Insert the cuvette containing your Sewage Blank Record the reading from the HOME screen or screen 3 2 For better resolution read on the MED range TURNER D DESIGNS Reliable Instruments for an Unreliable World www turnerdesigns com 998 5001 Page 4 of 6 10 AU Field Fluorometer 10 Subtract reading 9 from reading 8 This net reading is the reading due to the dye present in the sewage 11 Divide the net reading from step 10 by the reading from step 7 to get the Recovery Ratio To see what the ratio means refer to Recovery Ratio Test in the Sanitary Sewers monograph 12 Proceed to the next section Reading Samples Remember we are looking for the ratio of the Sewage Standard to samples i e t2. recovery standard is to see whether the reading of a given concentration of dye is the same in clean water and sewage in other words whether the dye is all recovered in sewage Sewage Standard A known dilution of the dye being injected mixed with sewage collected just prior to the start of dye injection Sewage Blank Sewage collected just prior to the start of dye injection This will represent the amount of fluorescent materials occurring naturally in the system expressed as a concentration of the fluorescent material being measured To perform your recovery ratio test and run your samples you will need 1 One cuvette filled with a blank of distilled water 2 Two cuvettes filled with Recovery Standard 3 Two cuvettes filled with Sewage Standard 4 One cuvette filled with Sewage Blank If you are studying Blank variability you may have a number of cuvettes filled with Sewage Blank Refer to the Dye Injection Dye Concentration section of the Sanitary Sewers monograph 5 Your various samples each in its own cuvette MEASUREMENTS We are looking for the ratio of the Sewage Standard to samples i e the readings of samples relative to the Sewage Standard Thus we will set the Model 10 AU to subtract the Sewage Blank but will not use Application Note Using the Turner Designs Model 10 AU Fluorometer to Perform Flow Measurements in Sanitary Sewers by Dye Dilution a known concentration of the Sewa
3. The averaged reading will be displayed for 10 seconds so you can write it down 2 Auto ranging In AUTO the fluorometer will automatically select the range with the best resolution for the sample being read You will however have to wait for the instrument to change ranges as well as for the reading to TURNER D DESIGNS jeliable Instruments for an Unreliable World Re www turnerdesigns com 998 5001 Revision A Page 3 of 6 10 AU Field Fluorometer stabilize The instrument will change ranges whenever the light cap is removed To set to auto ranging access screen 2 43 and set to AUTO For these reasons we recommend that you read samples in the manual mode MAN set on screen 2 43 The best resolution is obtained by reading samples on the lowest range possible In most however even if you read all of your samples on the HIGH range you will obtain adequate results as the 10 AU has been designed with good range to range correlation Recovery Ratio Before proceeding if you have not already done so before using the instrument for the FIRST time set the basic operating level of your fluorometer as described in the previous section Recovery Ratio tests are important in predicting the precision of your flow measurements and guiding you in improving this precision 1 Turn on the fluorometer and allow it to warm up for 10 minutes From the Main Menu press lt 2 gt to access screen 2 0 Cali
4. 0 mgd If you wish your final answer to be in cubic feet per second then convert milliliters per second 0 631 to cubic feet per second by multiplying 0 631 by 00003532 yielding 00002287 cubic feet per second Standard Dilution Ratio D You have already selected a Standard Dilution Ratio See PREPARATION OF STANDARDS in the Sanitary Sewers monograph In the example given it was 100 000 two 100 fold and one 10 fold 100 x 100 x 10 100 000 Application Note Using the Turner Designs Model 10 AU Fluorometer to Perform Flow Measurements in Sanitary Sewers by Dye Dilution Example We wish to calculate the flow in mgd 00 0000144 mgd Injection Rate 95 4 Dye Reading 24 8 Dye Reading 100 000 Standard Dilution Ratio 0 0000144 x 95 4 x 100 000 25 8 5 32 mgd or more reasonably stated 5 3 mgd q Rst r D Q Of course if you are measuring several flows from one injection the obvious thing to do is calculate q Rst D as r is the only variable from sample to sample TURNER S DESIGNS Reliable Instruments for an Unreliable World www turnerdesigns com 998 5001 Revision A Page 6 of 6
5. 4 O AU Application Note Using the Turner Designs Model 10 AU ae Fluorometer to Perform Flow Measurements in Sanitary Field Fluorometer Sewers by Dye Dilution Instrument set up Model 10 AU Digital Fluorometer equipped with the 13 mm x 100 mm cuvette holder and a 10 056 10 056R 546 nm Excitation Filter a 10 052 10 052R gt 570 nm Emission Filter 10 053 10 053R gt 535 nm Reference Filter and 10 046 Clear Quartz Lamp installed CONTENTS SUMMARY OF THE METHOD SETTING THE BASIC OPERATING LEVEL OBTAINING STANDARDS AND BLANKS MEASUREMENTS FLOW RATE CALCULATION SUMMARY OF THE METHOD The procedure requires Flow in sanitary sewers may be measured to an accuracy of 1 using fluorescent dye dilution 1 Setting the basic operating level of your techniques fluorometer this only needs to be done once prior to running samples for the FIRST time This procedural guide includes step by step instructions for using the Turner Designs Model 10 2 Obtaining Standards amp Blank AU Digital Fluorometer for measuring flow in sanitary sewers 3 Measurements a Recovery ratio test Since there is no need to crawl a manhole the b Reading samples procedure can be done by one person Samples may be measured on the spot or if preferred may be 4 Flow rate calculation taken to the office or a lab and measured at your convenience Detailed discussion of principles equipment sample collection preparation of standards
6. Rhodamine WT This standard does not have to be very accurately prepared It will not be used to standardize the instrument during calibration Its purpose is to adjust the instrument to optimum operating level which is quite broad To prepare the 100 ppb dilution 1 Dilute 1 ml of the pure tracer 20 aqueous solution to 1000 ml 2 Then 1 ml of this initial dilution to 100 ml 3 Finally 1 ml of the second dilution to 100 ml Application Note Using the Turner Designs Model 10 AU Fluorometer to Perform Flow Measurements in Sanitary Sewers by Dye Dilution Take care not to spill any liquids inside the fluorometer s sample chamber If you do have a spill turn off the fluorometer immediately and consult the Sample System appendix of your user s manual Wipe up splashes on the instrument s exterior promptly Procedure 1 Turn on the fluorometer and allow to warm up for 10 minutes 2 Onthe keypad access screen 2 0 Calibration Press lt 6 gt once and then lt 9 gt five times to reset calibration defaults 3 From screen 2 0 press lt 4 gt then lt 2 gt to access screen 2 42 Set the concentration range to HIGH 4 Access screen 3 2 Diagnostic 5 Loosen do not remove the Sensitivity Knob Lock hex screw to the left of the keypad see Figure 1 in the user s manual with the 5 32 Allen wrench behind lower right of the keypad 6 Fill a clean 13 mm test tube with the 100 ppb dilution Dry the outs
7. and flow rate calculations can be found in the Turner Designs monograph Fluorometric Facts Flow Measurements in Sanitary Sewers by Dye Dilution referred to hereafter as Sanitary Sewers TURNER DESIGNS www turnerdesigns com 998 5001 Revision A Page 1 of 6 10 AU Field Fluorometer SETTING THE BASIC OPERATING LEVEL The basic operating level of your fluorometer is set on screen 3 2 using the Sensitivity Adjustment Knob Fluorescence readout XXXX XXX PM signal output XXXX XXX Cal std val XXX XX Blank XX XXX FS XX of XXXX XXX PPB at HIGH Span level 48 lt ENT gt to next screen 3 2 Diagnostic Screen 3 2 Your user s manual contains detailed instructions for setting the basic operating level Appendix 5B of the Model 10 AU 000 Laboratory Fluorometer User s Manual and Appendix 6B of the Model 10 AU 005 Field Fluorometer User s Manual Once the basic operating level sensitivity is set you should not have to adjust it unless you want to drastically increase or decrease sensitivity Through experience we have found the following operating level to be appropriate for flow measurements in sanitary sewers The maximum concentration you will wish to read is 500 ppb 0 5 ppm This is the upper limit of the linear range for rhodamine WT While this limit is actually dependent on the path length of the cuvette this is a safe figure for even the largest cuvette Prepare a dilution of 100 ppb of
8. bration Set the concentration range control to MAN From screen 2 0 press lt 4 gt to bring up screen 2 4 then lt 3 gt to bring up screen 2 43 set conc range control and press lt ENT gt to toggle Set the concentration range to MED From screen 2 4 press lt 2 gt to bring up screen 2 42 change concentration range and press lt ENT gt to toggle Return to screen 2 0 To run the Distilled Water Blank press lt 1 gt to access screen 2 1 Make sure 2 on screen 2 1 reads YES Then from screen 2 1 press lt 1 gt to call up screen 2 11 Application Note Using the Turner Designs Model 10 AU Fluorometer to Perform Flow Measurements in Sanitary Sewers by Dye Dilution Use UP or DOWN arrow to set Blank to less than 200 Blank TC 8 SEC Range MED Span 48 Press lt 0 gt after reading is stable 2 11 aos __ Screen 2 11 If you wish to abort the blank run and revert to the former calibration settings press lt ESC gt before pressing lt 0 gt This will retain the current settings for Span and blank Fill a clean 13 mm test tube with a blank of distilled water Put the blank into in the sample chamber and replace the light cap After the Blank reading is stable TC on screen 2 11 cycles from 1 to 8 sec and assuming the Blank is less than 200 press lt 0 gt When FINISHED appears press lt HOME gt For this procedure do not adjust the Span by pressing the UP or DOWN arrows Span
9. ge Standard only a known dilution Readings will be taken from the HOME screen or Screen 3 2 see explanation below CONC MED MAN XXX PPB Time Const 2 SEC 0 499 999 lt gt for help 4 42 05 PM 1 25 93 a ess HOME Screen If you prefer to see more digits than are shown on the HOME screen XXXX XXX you MAY record your readings from the Diagnostic screen 3 2 The reading from the top line of this screen is what is sent to the HOME screen rounded off to three digits To avoid inconsistency record readings from the HOME screen or screen 3 2 but not both The Model 10 AU has two features of special interest for this method 1 The Discrete Sample Averaging capability where the instrument averages a reading over a preset period allowing you to read samples after they have been in the instrument for the same time This minimizes errors due to temperature changes and removes the guesswork from reading the digital display Defaults for this feature on the Model 10 AU are 15 seconds pre delay for the signal to stabilize and an averaging period of 10 seconds To change these periods access screen 1 63 See the appendix on Operational Parameters screen 1 63 of your user s manual To use Discrete Sample Averaging after putting in a sample from the HOME screen press lt gt and the instrument will countdown a delay period average the reading and then display DONE in the upper right hand corner of the screen
10. he readings of samples relative to the standard It is presumed that you have just run the Recovery Ratio described above Continuing from the Recovery Ratio section 1 Insert the cuvette containing your Sewage Blank For better resolution read on the MED range access screen 2 42 to change ranges Record the reading from the HOME screen or screen 3 2 If you prefer you may run this as your actual blank in place of distilled water However it is useful to know how large the Sewage Blank is If it is small compared to the standard and samples then you are more confident of the relative accuracy of the test If a small blank varies by a few percent it is negligible If a large one varies the same percentage the error in the answer will be proportionately larger Therefore we recommend that you leave the Distilled Water Blank set to zero This way you definitely have a record of the magnitude of the Sewage Blank repeats will always have positive values and you may average 3 or more cuvettes of Sewage Blank for greater accuracy You will always work with the net reading sample or standard minus the Sewage Blank 2 Set to the HIGH range on screen 2 42 Insert the cuvette containing your Sewage Standard into the instrument Record the reading from the HOME screen or screen 3 2 As with the Sewage Blank you may want to read and average 3 or more cuvettes containing the Sewage Standard 3 One by one insert the c
11. ide of the tube with a lab wipe and insert it in the opening to the sample compartment Replace the light cap 7 On screen 3 2 look at the third line from the bottom FS XX of XXX ppb at HIGH Turn the Sensitivity Knob large screw to the lower right of the keypad slowly pausing between adjustments for the reading to stabilize until the FS reads approximately FS 20 of 900 000 at HIGH Turning the Sensitivity Knob clockwise increases the FS turning it counter clockwise decreases FS 8 Whenan FS of about 20 is reached use the Allen wrench to tighten the Sensitivity Knob Lock IMPORTANT 9 Remove the 100 ppb dilution from the fluorometer and set aside 10 Proceed to the next section TURNER DESIGNS jeliable Instruments for an Unreliable World Re www turnerdesigns com 998 5001 Revision A Page 2 of 6 10 AU Field Fluorometer OBTAINING STANDARDS AND BLANK Standards are required to calibrate the fluorometer precisely in terms of the dye that you injected For detailed instructions for sample collection and preparation preparation of your Sewage Blank and preparation of your Sewage and Recovery Standards consult the Preparation of Standards section of the Sanitary Sewers monograph Definitions Recovery Standard A dilution of the dye exact same dilution as the sewage standard being injected made with deionized water distilled water The purpose of the
12. obtained on your sample D is the dilution ratio used to prepare the standard We will use equation 2 TURNER D DESIGNS Reliable Instruments for an Unreliable Worid www turnerdesigns com 998 5001 Revision A Page 5 of 6 10 AU Field Fluorometer Sample Readings r Sample readings are net readings IF sewage blank was set to zero If the distilled water blank was set to zero then subtract the sewage blank reading from all readings including the standard Rst to obtain the actual net reading Injection Rate q The Injection Rate is normally determined by finding the time it takes to fill a volumetric flask See DYE INJECTION Calibrating the Injector in the Sanitary Sewers monograph Since volumetric flasks are calibrated in milliliters and elapsed time is most easily measured in seconds we must make a conversion Two handy numbers are milliliters x 0002642 U S gallons milliliters x 00003532 cubic feet As an example let s presume that when you tested your dye injector you found that it took 158 seconds to fill a 100 ml volumetric flask This means that the flow rate was 100 divided by 158 or 0 631 milliliters per second or 37 85 milliliters per minute If you wish your final answer to be in mgd then the rate of dye introduced must also be in mgd To convert milliliters per minute to gallons per minute multiply 37 85 by 0002642 yielding 01 gallons per minute or 0 0000144
13. uvettes containing your samples and record the readings from the HOME screen or screen 3 2 Application Note Using the Turner Designs Model 10 AU Fluorometer to Perform Flow Measurements in Sanitary Sewers by Dye Dilution For better resolution read your sample on the lowest range in which you can obtain an on scale reading In the MAN mode access screen 2 42 to change ranges In AUTO the instrument will find the best range If you see OVER on the LOW or MED range access screen 2 42 and change to a higher range If any sample reads OVER on the HIGH range you must dilute the sample Refer to the High Concentration Measurements section of the Sanitary Sewers monograph 4 When all samples have been read and you are finished for the day turn off the fluorometer NOTE If you are going to be reading samples off and on over the course of a few days leave the fluorometer on it won t hurt it FLOW RATE CALCULATION The mathematical equation normally used to calculate flow is 1 Q qClc Where Q isthe flow being measured q is the dye injection rate C is the concentration of the injected dye c is the concentration of dye measured downstream of injection Since fluorescence is normally proportional to concentration a more practical form of this equation is 2 Qz qxRstD r Where Q is the flow being measured q is the dye injection rate Rst is the reading obtained on your standard r is the reading
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