YSI Environmental Monitoring Systems. Water Quality Training Seminar

Transcription

1 YSI Environmental Monitoring Systems Water Quality Training Seminar

2 6-Series Products 600QS 6820/ R 6820V2/6920V2 600LS 6600/6600EDS 600OMS 6600V2 600XL/600XLM

3 600 QS (Quick Sample)

4 600 QS, 600R

5 600LS

6 600XL, 600XLM, 600 OMS

7 6820V2-1, 6920V2-1

8 6820 V2-2, 6920 V2-2

9 6600V2-2

10 6600EDSV2-2

11 6600 V2-4

12 6600 V2-4 w/ PAR Photosynthetically Active Radiation (PAR)

13 Telemetry Platforms

14 Telemetry Platforms

15 Autonomous Underwater Vehicles

16 Autonomous Underwater Vehicles

17 ProPlus

18 ProODO

19 556 & 85

20 EcoSense

21 Sensor Technology

22 Sensor Technology Chlorophyll Temperature Rhodamine Conductivity Blue-Green Algae Dissolved Oxygen Chloride ph/orp Ammonia Water Depth/Level Nitrate Turbidity

23 Temperature High precision thermistor 2252 ohms at 25C (+/- 1%) Resistance changes with temperature - uses thermistor algorithm to convert to temperature Thin wall titanium sleeve Fast response Resists corrosion

24 Conductivity AC voltage applied to nickel electrodes Conductivity electrodes placed in sample to be measured Electrical current flows through the electrodes and the sample Electrical current level has direct relationship with conductivity of the solution 4 pure nickel electrodes Cell constant = 5.00 Temperature probe Fresh, brackish and sea water capability

25 Conductivity Conductivity will vary with temperature changes Specific Conductance is commonly expressed in reference to a specific temperature Specific Conductance = Conductivity corrected to 25 C.

26 Differences between ROX and Rapid Pulse Sensors ROX No electrolyte Self-cleaning sensor Not affected by H 2 S Zero-cal option Rapid Pulse Electrolyte required Not self-cleaning (EDS sonde required for membrane cleaning) Affected by H 2 S No zero-cal option

27 Dissolved Oxygen Two main types of Polarographic Oxygen Sensors Steady State Pulsed

28 Dissolved Oxygen Oxygen diffuses through Teflon membrane Oxygen reduced at gold cathode Electrons flow = electrical signal Oxygen concentration proportional to signal level e - O 2 O 2 e - Gold Cathode H 2 O e - H 2 O e - O 2 Silver Anode O 2 KCl O 2 H 2 O H2 O O 2 O 2 O 2 H 2 O H 2 O H 2 O H 2 O H 2 O H 2 O O 2 O 2 O 2 Teflon membrane H 2 O H 2 O H 2 O

29 Rapid Pulse Dissolved Oxygen On Rapid-Pulse refined the technology Pulses on / off during measurement sequence Incorporates new electrode design which utilizes a separate silver reference electrode and anode instead of combining the two. This configuration is required to polarize / de-polarize the electrode consistently for a very short period of time (40mS) Utilizes digital electronics Eliminates need for stirring 40ms Off 3960ms 4 sec

30 Rapid Pulse Dissolved Oxygen Long Term Stability Less susceptible to fouling accurate long term data Accurate results in low flow conditions no stirring device required, <2% stirring dependence Ultra low power requirements long battery life Reliable long term deployments Diagnostics Serviceable

31 Rapid Pulse Dissolved Oxygen Removed Stirring 100 Percent Saturation Rapid Pulse Response Steady State Response

32 Optical DO Step 1: The sensor emits blue light, which causes the sensing element to luminesce red light. In the presence of oxygen, the sensor measures a change in phase-shift of luminescent emissions as a function of oxygen concentration. The luminescence signal from the blue excitation is compared to that of the red excitation (next slide) and a stable DO concentration is calculated.

33 Optical DO Step 2: The sensor emits red light, which is reflected by the sensing element. The reflected red light is measured by the sensor and serves as a reference for the lifetime luminescence calculations

34 ph Glass sensing bulb is filled with solution of stable ph (ph 7) so inside of glass surface experiences constant binding of H+ ions Outside of bulb is exposed to sample where H+ varies Differential of H+ creates a potential which is read versus the stable potential of the reference electrode AgCl-coated Ag wire H + H + H + H + H + H + E membrane KCl Gel Reference Junction

35 ph Plot - Nernst Equation mv ph -200 ph slope ph /- 50mV ph slope

36 Sensor - Glass imbedded platinum ring - Solution potential read versus ph reference electrode Oxidation reduction potential (ORP) of the sample is determined by measuring the potential of a chemically-inert (platinum) electrode which is immersed in the solution The sensing electrode potential is read relative to the reference electrode of the ph probe and the value is presented in millivolts Value represents the overall oxidizing (positive values) and reducing (negative values) ability of the sample ORP

37 ISE Works exactly like ph except the sensor is a PVC membrane selective for the analyte rather than a glass bulb selective for H+ ions Sensor module contains a static concentration of the analyte which binds to the inner membrane Potential is related to the analyte concentration using the Nernst Equation

38 ISE ph Reference Electrode + - ISE Module AgCl-coated Ag wire NH 4+ solution PVC membrane with ionpore NH 4 + NH + NH NH + 4 NH 4 + NH 4 + E membrane

39 Optical Sensor Design Integrated Improved Replaceable Non-corroding Easy to wiper replace, o-ring optical wiper with titanium seals durable fiber shaft new seal switch wiper membrane for shaft controlled longer for with long-life a sensor usable parking life Hsystem 2 of S and one low year oxygen environments

40 Optical Probes Wiper Motor Wiper Sponge Wiper

41 Turbidity Techniques Nephelometric Angle of Reflection 90º ISO Recommended method

42 Turbidity Method Probe contains an LED with a wavelength of 860 NM (Emitter) Probe contains a photodiode (detector) Optical fibers connected to emitter and detector intersect probe face at opposing 45 degree angles - net angle is 90 degrees Light from emitter enters sample and scatters off the particles - light scattered at 90 degrees enter detector fiber and is measured by the photodiode Circuit board in the sonde quantifies sample signal relative to standards and generates a value in NTU Based on ISO 7027 Method

43 Turbidity Light Source (infrared) Photodetector Fiber optic cables molded at a 45 degree angle 90º Intersect

44 Chlorophyll Chlorophyll fluoresces when irradiated with light of a particular wavelength ( nm), emits light of a higher wavelength ( nm.) The ability of chlorophyll to fluoresce is the basis of commercial in-situ fluorometers. These fluorometers induce chlorophyll to fluoresce by shining a beam of light of the proper wavelength into the water and then measuring the higher wavelength light which is emitted. Measurement is made in the field without disrupting cells.

45 Chlorophyll

46 YSI 6025 Chlorophyll Probe Light Source 470 nm Photodetector Optical Filter Optical Fiber

47 YSI 6025 Chlorophyll Probe

48 Blue-Green Algae (Cyanobacteria) Theory of detection same as Chlorophyll sensors (in vivo fluorescence of pigments in living cells) Chlorophyll a not available for fluorescence detection in cyanobacteria We look for accessory pigments Phycocyanin: Freshwater Species Phycoerythrin: Saltwater Species Recommended to use chlorophyll and BGA sensors in concert If a significant BGA population is present, relying solely on the chlorophyll sensor will underestimate total algal biomass

49 Blue-Green Algae (Cyanobacteria)

50 Blue-Green Algae (Cyanobacteria) Early Warning Indicator

51 Rhodamine Probe contains an LED with a wavelength of 540 nm (Emitter) Probe contains a photodiode (detector) Optical fibers connected to emitter and detector Light from emitter enters sample and the Rhodamine WT dye in the sample fluoresces. Probe picks up the high wavelength emission, and uses filter to restrict other source of emission.

52 Rhodamine Light Source Photodetector Optical Filter Fiber optic cables

53 Depth Sensor Sensor: Stainless Steel Strain Gauge in four different sensitivities shallow vented, shallow, medium and deep. Shallow Vented 0-3m ± 0.003/3-9.1m ± 0.02m Shallow 0-9.1m ± 0.02m Medium m ± 0.12m Deep 0-200m ± 0.3m (YSI 6600 only) Voltage from Strain Gauge is proportional to hydrostatic pressure.

54 Non-Vented Depth Measurement Pressure Due to Atmosphere Pressure Due to Water Column P Total = P Water + P Atmosphere

55 Vented Depth Measurement Pressure Due to Atmosphere Pressure Due to Water Column

56 Care & Maintenance

57 Probe Installation Remove the port plug. Lightly grease the o-rings of the probe use only enough grease to make the o-ring shiny. More grease is not better it may actually hinder the seal. Align the probe in its corresponding port. Once the probe key falls into place, press the probe firmly in the bulkhead to completely seat the probe. Hold the probe with one hand to prevent twisting it while finger threading the slip nut.

58 Probe Installation If you meet resistance while threading, DO NOT continue threading. Back the slip nut out and realign the threads. Finger tighten the probe, then use the provided tool to snug the probe by turning the nut an additional ¼ turn. DO NOT over tighten. For optical probes, finger tighten, then use the provided tool to tighten the probe completely. Be sure to point the probes towards the floor while pulling from the port to minimize port contamination.

59 Temperature No maintenance required.

60 Conductivity Be sure the conductivity conduits are free from contamination/blockage. Use the small test tube brushes and a mild soap solution to periodically clean the conduits.

61 Dissolved Oxygen Membrane changes should be done as necessary (according to application) between 2-6 weeks. If the electrodes look tarnished, recondition electrode with 2400 grit sand paper (provided in 6035 kit) How do I know when it s time to recondition?

62 Dissolved Oxygen

63 Reconditioning DO Probe Remove membrane, rinse probe in clean water and dry off probe surface Use the YSI 6035 kit to service electrodes (note that the sanding disc must be struck parallel with the electrodes). Rinse probe surface area with clean water. Re-membrane probe and check DO Charge (after 5 minutes of probe burn-in). If reconditioning DO Probe does not reduce / increase charge repeat conditioning. If repeat conditioning fails, replace probe.

64 Membrane Replacement Large KCl meniscus

65 Membrane Replacement Hold the membrane with both hands and come straight down on the DO probe. Be sure not to stretch the membrane laterally, just hold it taut, and stretch it as you pull it down over the probe.

66 Be sure to adequately stretch the membrane over the probe. Membrane Replacement

67 Membrane Replacement Hold the membrane taut while placing the o-ring on to reduce bubbles and wrinkling. Be careful not to leave fingerprints on the membrane while installing the o-ring.

68 Trim the membrane about 2 to 3 mm below the o-ring. Membrane Replacement

69 The final inspection of the membrane should reveal no bubbles and no wrinkles. Membrane Replacement

70 Membranes Membranes have specific response coefficients. Membrane response coefficients are stored in the sensor and in the.glp file. Replacement membranes require new coefficients to be entered in sonde software. Membranes must remain hydrated.

71 Membrane Replacement Remove the new sensor membrane assembly from its hydrated container and dry the underside completely. Ensure both sides of the membrane cavity are dry. Topside Underside

72 Membrane Replacement 1. After installing the ROX sensor in the sonde bulkhead and replacing the membrane, connect the sonde to your computer or 650 MDS logger. 2. Locate the alphanumeric string on the sticker which contains the coded calibration information for this particular sensor membrane. 3. Access the Main Menu and select Calibrate, then Optical Dissolved Oxy. 4. Select option 3-Enter cal sheet and enter the corresponding calibration coefficients.

73 ph Clean ph Probe Dirty ph/orp Probe

74 ph Remove ph probe (if applicable) Soak in mild soap solution for 15 minutes. Rinse, then soak in tap water for 5 minutes. Soak in 1 M HCl for minutes. Rinse, then soak in tap water for 10 minutes. Soak in a 1:1 solution of bleach and water for 45 minutes. Rinse, then soak in tap water for 15 minutes.

75 Same basic care & maintenance as ph probe. ORP

76 Optical Probes Replace wiper on a regular schedule maintenance, e.g. every 30 days / before each long term deployment Wiper calibration is automatic in sondes with version 2.17 or higher. For earlier software versions, remove all power from the sonde, or if on a PC, ESC to # and type RESET <enter> Wiper calibration should be observed to confirm wiper operation Ensure wiper is not covering emitter and detector. Do not force the wiper as this will damage the motor beyond repair

77 Clean Optical Wiper

78 Dirty Optical Wiper

79 Optical Wiper

80 Depth Use the syringe provided with your maintenance kit to flush out the depth set. Do not stick anything in the holes on the depth set--you will damage the pressure transducer.

81 Calibration

82 Temperature Factory Set - No calibration required.

83 Conductivity Calibrate using SpCond (Specific Conductivity). Place into clean conductivity standard e.g.: 1000 µs/cm (most standards are labeled in µs/cm, BUT the calibration value has to be entered as a ms/cm). Allow one minute to stabilize before accepting the calibration, or if reading has not changed for 30 Sec. Check Cell Constant in Advanced Menu. Readings should be 5.0 ± 0.45 If Cell Constant is out of range clean and recalibrate. Never accept an Out of Range

84 ph In Report / Setup Parameters, enable ph mv Place into a ph 7.0 buffer and allow to stabilize for at least one minute. Record mv Offset value 0 +/- 50. Input value of ph 4.0 buffer into Sonde, then rinse. Place into a ph 4.0 buffer, the reading should be close to 4 within a few seconds. Allow to stabilize and record mv slope. Should be 180 mv different than the value recorded for ph buffer 7, +/- 50 mv. Repeat a third time using ph 10.0 buffer. mv should have a slope of -180 mv different than the value recorded for ph buffer 7, +/- 50 mv.. If mv readings/slope are out of spec, or if there is slow response, perform cleaning procedure. If the mv is out of range, or response does not improve then soak probe for hours in 2M KCl or ph 4 Buffer.

85 ORP Allow temperature to stabilize. Use temperature compensation chart that came with ORP Standard to verify value.

86 Dissolved Oxygen The following tips are how to get the most accurate results for a SAMPLING APPLICATION: Allow probe to warm-up for 4-5 minutes before accepting calibration (RS232 auto sleep disabled) Make sure probe is in a saturated environment Enter current barometer reading (mmhg) Record DO Charge for QA/QC purposes Record DO Gain for QA/QC purposes (after calibration) Confirm DO Warm-up Pattern Never accept an Out of Range

87 Dissolved Oxygen The following tips are how to get the most accurate results for an UNATTENDED APPLICATION: Probe will self calibrate after the selected warm-up time from advanced menu. (RS232 auto sleep enabled) Make sure probe is in a saturated environment Enter current barometer reading (mmhg) Record DO Charge for QA/QC purposes Record DO Gain for QA/QC purposes (after calibration) Confirm DO Warm-up Pattern Never accept an Out of Range

88 Calibration Values for Various Atmospheric Pressures & Altitudes In Hg mmhg mbars feet meters %sat

89 Checking DO Warm-up Stop Discrete and Unattended sampling. Confirm that auto-sleep RS-232 is enabled Be sure DO% is set in the report menu. Turn off Sonde for 1-2 minutes. Power up Sonde. Start discrete sampling at 4 second intervals. DO% must display a positive number and decrease with each 4 second sample, eventually stabilizing to the calibration value in approximately seconds. Disregard the first two samples they can be affected by electronics warm-up.

90 DO Warm-up Accept/Reject Criteria The DO% must start at a positive number and decrease during the warm-up. Example: 123, 117, 114, 113, 110, 107, 104, 102, 101, 100, 100 Should the display read a negative number or start at a low number and climb up to the calibration point, the probe should be rejected and must not be deployed.

91 Turbidity Choose 1 or 2-point calibration. Zero must be the first calibration point. Be sure your zero/di water is clear--no particulates. When using the cal cup, only engage one thread. If using the 6136 probe you must have a black bottom cal cup and probe guard. Never accept an Out of Range

92 Chlorophyll Do 1 point calibration to zero the probe and use for screening and/or monitoring trends Check for drift and slightly enhance accuracy using dye solution to simulate chlorophyll (2 point cal) Use extractive analysis results from field samples to post calibrate all readings Never accept an Out of Range

93 Post-calibration of In Vivo Chl Readings

94 Rhodamine Do a 2-point calibration initially. A 1 point calibration can be used to zero the probe and check for screening and/or monitoring trends Never accept an Out of Range

95 Depth Make sure flow through holes are cleaned with syringe (proved in Maintenance Kit) Leaving the Sonde in air, zero the depth sensor Using advanced menu check the Pressure Offset readings. Readings should be ± 6.0 Never accept an Out of Range

96 Tips & Tricks

97 Biofouling Prevention

98 Biofouling Prevention

99 Biofouling Prevention

100 Biofouling Prevention

101 Questions? Barrett Gaylord Northeast Representative