HACH TU 5 SERIES TURBIDIMETERS SOP: COMPARISON LAB AND PROCESS. The next standard in the evolution of turbidity

Transcription

1 HACH TU 5 SERIES TURBIDIMETERS SOP: COMPARISON LAB AND PROCESS The next standard in the evolution of turbidity

2 COMPARE TU5 LAB AND PROCESS GUIDE & TROUBLESHOOT To guarantee that lab and process readings show best match the thorough & clean sample taking and handling is key. Specially in ranges <1NTU every pollution matters, like residuals in vessels, salt crystals on the glass ware, lint from tissues, air bubbles. The TU5200 sees more of your sample than any other instrument, but also any contamination and interference like air bubbles. Non matching results? The following procedures applies for samples <1NTU. 2

3 TABLE OF CONTENTS Preparation Containers & Vials Sampling Sample Reading Trouble Shoot general Trouble Shoot air bubbles Trouble Shoot condensation 1-pager demo guide Order information 3

4 SAMPLE COLLECTION - CONTAINERS Use glass containers that can be sealed for sampling. ( volume 100 ml ) Don t collect samples right away in the sample cell. The likelihood to trap air bubbles is high. A sample treatment in the sample cell to remove air bubbles is difficult. 4

5 SAMPLE COLLECTION PREPARATION OF CONTAINERS AND VIALS Items to collect: Hydrochloric acid (concentration 10%) Laboratory cleaning detergent for glass (concentration 0.1%) Distilled or deonized water Dilution water Vial wiper (optional) No-lint cloth Procedure: Put the exterior and interior surfaces of the sample vial and container and the caps in 10% hydrochloric acid for 15 minutes. Clean the exterior and interior surfaces of the sample vial and container and the cap with laboratory cleaning detergent for glass (concentration 0.1%). Fully rinse the sample vial and container three times with distilled or deionized water. 5

6 SAMPLE COLLECTION PREPARATION OF CONTAINERS AND VIALS Note: If the sample vial is used to measure low range turbidity samples or dilution water, rinse with sample or dilution water itself (not distilled or deionized water). For the best results, clean the sample vial with the optional vial wiper. Then fully rinse the sample vial again. Refer to Figure 7. Dry the external surfaces of the sample cell with a soft, no-lint cloth. Do not let the sample vial air dry. 6

7 SAMPLE COLLECTION PREPARATION OF CONTAINERS AND VIAL For storage, fill the sample vial with distilled or demineralized water. Immediately put the cap on the sample vial to keep the interior of the sample vial wet. Store sample containers only with closed with cap. 7

8 SAMPLE COLLECTION 8 When collecting a sample from a water tap in a distribution system or treatment plant, turn the water on for at least five minutes, then collect the sample. Do not adjust the flow because this can add particles. Rinse the container a minimum of 3-times with the sample. Take the sample from the outlet of the TU 5300/5400 When collecting a sample from a body of water (e.g., a stream or storage tank), collect at least one liter (1 quart) and fully mix before taking an aliquot for measurement. If the quality of the ample source is not constant, collect samples at many locations at different depths as necessary. Then, mix the samples together to prepare one sample for measurement.

9 9 SAMPLE COLLECTION Fill the container. Let the container overflow with the sample and then immediately put the cap on the sample container so that there is no headspace (air) above the sample. Write the sample information on the container. Start analysis as soon as possible to prevent temperature changes, bacteria growth and settling. Each Source and drinking water has a individual equilibrium of ph, temperature, carbon, oxygen, iron, manganese etc. Sample collecting at a water pressure line can unbalance the solubility of gases in liquids and can have an impact of the dissolved substances like carbonate or hydrogencarbonate. This is reasonable why a fast verification of a grab sample can be a key factor.

10 LAB SAMPLE READING Rinse and invert vial 3 times with sample. 10

11 LAB SAMPLE READING Dry surface and bottom, keep vial at cap only. Evaluate vial immediately after filling. For reference watch this video: TU5 Series Turbidimeters - Lab and Online Measurement Comparison Using RFID 11

12 LAB SAMPLE READING INSTRUMENT SETTINGS Enable bubble rejection and minimum mode (Measuring Screen >Option>Reading Setup). Minimum Mode: In the minimum mode continuous readings are taken for the given time (e.g. 60s). The smallest reading within the 60 seconds is logged. This ensures that the representative matrix is measured and results are not influenced by air bubbles and contamination particles that would be recorded in the average mode. Attention: don t use the minimum mode for samples > 1NTU. This has the opposite effect if significant turbidity is present. 12

13 TROUBLE SHOOT RESULTS DON T MATCH Make sure TU5300 and TU5200 are both EPA versions or both ISO versions. Check instrument label. Verify a standard on both the lab and process instruments. If the standards do not match, Check expiration date Make sure vials were inverted prior to calibration as directed on screen Recalibrate or switch back to factory calibration. If the standards match, follow the procedures included above. Dry surface and bottom thoroughly, verify that there are no lint particles or visible bubbles in the sample. 13

14 TROUBLE SHOOT RESULTS DON T MATCH MITIGATION OF AIR BUBBLES 14 If sample still isn t matching, air bubbles in the lab vial are most probably the issue. If TU5300 is connected properly to the by pass or water tap the vortex in the inlet and back pressure by the valve let air bubbles evaporate. If you take a grab sample right away from the tap it has 6 bar and 50% O 2 saturation, air bubbles influence the reading and matching of results. In customer demo, take sample from the TU5300 Outlet=0.2 bar. Before sample collecting flush away at least ml To mitigate air bubbles stir sample.

15 TROUBLE SHOOT RESULTS DON T MATCH SAMPLE STIRRING Stir slowly for 5 minutes with magnetic stirrer. (Adjust to 20% of the stirrer power.) Samples with temperatures > 15 C can be processed after 5 minutes w/o any condensation effects if the criteria in the table below are met. Monitor if any condensation is visible on the outer surface of the sample vial. Room temperature C Rel. Humidity % If samples are colder than room temperature, extend temperature equilibration time 15

16 TROUBLE SHOOT RESULTS DON T MATCH Other options to remove air bubbles: Use an ultrasonic bath Do not use the sample degassing kit , as the likelihood to contaminate the sample with the syringe and the rubber cap is high. 16

17 TROUBLE SHOOT RESULTS DON T MATCH MITIGATION OF CONDENSATION Let sample and sample vial adjust to ambient lab temperature. Dry condensed glass thoroughly. If you are not sure if condensation is happening repeat reading up to 4 times: Measurement Turbidity Turbidity Δ Turbidity Laboratory Process Diff. Lab-Process [ N ] [NTU] [NTU] [Δ NTU] Average

18 1- PAGE DEMO GUIDE HAND OUT Have 2 pre-cleaned and capped glass sample containers, approx. 100 ml, wide mouth. Have 2 clean and capped sample vials filled with distilled water. Kim wipe tissues to dry vial Micro fiber tissues to polish vial Cleaned stirrer bar Let flow/tap flush for 5 minutes. Take sample. Apply 5 minutes stirring at 20% stirrer power. Rinse sample vials 3 times with sample. Fill sample vial to the fill mark. Remove any adhering water drops with the Kim wipe and clean the vial walls and bottom at least with a micro fiber tissue. Enable bubble rejection and minimum mode ( 60s ). After 30 sec. take reading. Repeat reading up to 4 times if necessary. 18

19 1- PAGE DEMO GUIDE ORDER INFORMATION TU5200 Sample Vials incl. caps (2x) - LZY946 Vial wiper LZY946 RFID label LZQ071 Beaker (150 ml) to be used as sample container HBG011 Alternative to beaker take a glass DURAN bottle with cap Magnetic stirrer LYW854 Magnetic stirrer bar LYW064 Detergent Dionized water Kim Wipes EZZ073 Micro fiber tissue LZC945 Timer clock LZC