Introduction to Chlorosense

Transcription

1 Introduction to Chlorosense Presented by: Environmental lpublic Health lthservices First Nations and Inuit Health, Health Canada Alberta Region Purpose of Today s Session This session is intended to introduce you to Chlorosense, a new instrument for measuring chlorine residuals in your community s water systems. This will be delivered through a powerpoint presentation, a short instructional video and a question and answer period at the end of the session. Objectives After the session, participants should: 1. Understand the importance of reporting accurate measurements of chlorine residuals to their Environmental Health Officer. 2 Identifykey advantagesand benefits ofswitching to 2. Identify key advantages and benefits of switching to Chlorosense. 3. Become familiar with the key components of the Chlorosense instrument and how to properly conduct a test for chlorine residuals. 1

2 Presentation Outline Part I Disinfection of Drinking Water Supplies Why do we disinfect our drinking water? Importance of Chlorination to Public Health Current Practices Hach Pocket Colorimeter Potential Issues with Hach Pocket Colorimeter Presentation Outline Part II Using a Chlorosense Test Kit Overview of Chlorosense Using Chlorosense Instructional Video Major Advantages of Chlorosense Benefits of Chlorosense Questions Why do we disinfect our drinking water? Throughout history waterborne diseases have been a major cause of human disease. However, the widespread use of chlorine and other disinfectantshas practically eliminatedwaterborne disease in developed countries. 2

3 Why do we disinfect our drinking water? However, tragic outbreaks of illness such as the E. coli 0157:H7 outbreak in Walkerton highlights the importance of adequate disinfection. Ensuring safe drinking water requires ongoing monitoring and vigilance by all those involved. Picture: Site of the now defunct well 5, the original source of water contamination in Walkerton, ON. In May 2000, tainted water sickened 2500 and killed 7. Why do we disinfect our drinking water? Drinking water must be disinfected to destroy pathogenic microbes that can cause disease outbreaks. The most common disinfectant used to treat drinking water is Chlorine. Primary Disinfection: using chlorine to disinfect water before entry into the distribution system. Secondary disinfection: maintaining a chlorine residual inside the distribution system. Chlorine Residuals In a chlorinated community water system, the chlorine residual will exist in 3 forms: Free Chlorine is chlorine the amount of chlorine available once chlorine demand is met; it is readily available to react with pathogens or organics that might be present. Combined Chlorine is chlorine that has already reacted with organics in the water. It is not as powerful as free chlorine. Total Chlorine is obtained by adding free and combined chlorine. As the CBWM you measure both free and total chlorine; combined chlorine is the difference of the two. 3

4 Chlorine Residuals Chlorine levels must be properly maintained at the water plant and throughout the distribution system. Minimum Concentration Maximum Concentration Leaving Water Treatment Plant 0.20 mg/l (measured as free or combined) 4.0 mg/l (Measured as free) Or 3.0 mg/l (measured as combined) In Distribution System 0.10 mg/l (Measured as free, combined or total) 4.0 mg/l (Measured as free) Or 3.0 mg/l (measured as combined) Chlorine Residuals If you re encountering chlorine residuals that are too low or too high, you must contact the EHO immediately. These situations may represent a potentially serious and immediate public health issue that must be investigated to ensure that appropriate action is taken. Importance of Chlorination to Public Health Adequate chlorine readings indicate that the water has been properly disinfected and that a residual is available for secondary disinfection. Additionally, chlorine readings reported by the CBWM to their EHOare critical because they areused by EPHSin our approach to safe drinking water. 4

5 Importance to Public Health Environmental Public Health Services must have confidence in the data that is reported as they may be used in decisions and actions which impact public health such as: Issuing Boil Water Advisories or Do Not Drink Advisories. Directing water treatment plant operators, public works directors and circuit rider trainers. Correspondence requiring action on behalf of community leaders and INAC. Compiling data for use in community reports. Current Practices Up until recently, the majority of CBWMs measure chlorine residuals during their routine weekly sampling using the Hach Colorimeter II. Potential Issues with the Hach Pocket Colorimeter Despite being widely used and accepted by many jurisdictions, there can be issues that affect results obtained by the Hach Colorimeter II. Inorderforaccurateandprecise readings fromthe Hach In order for accurate and precise readings from the Hach Colorimeter II, the procedure must be done properly each and every time it is carried out. There may be difficulties in getting consistent results as there are multiple steps and time sensitivities involved. 5

6 Factors Which May Affect Results Condition of vials Scratched or dirty vials will affect readings. Condition of cell compartment. Transfer of reagents Potential for spillage and loss of reagent resulting in inaccurate readings. Use of proper reagent. DPD Free/DPD Total Factors Which May Affect Results Ensuring adequate reaction times are met. ie. Free chlorine must be read within 1 minute; Total chlorine test must allow for 3 minutes. Chloramine interference. User training i and technique. Machine Calibration. Must be calibrated by the manufacturer adding logistical challenges. Is there a better way? 6

7 Introducing : Chlorosense Overview of Chlorosense The Chlorosense method is a fundamentally different way to analyze chlorine in water. It is simple, rapid and reagent free. A significant advantage is its ability to produce, and reproduce accurate and precise results time after time, regardless of user. Removes almost all sources of technique dependence, when compared to the Hach method. Chlorosense instrument Sample Bottle Shoulder strap Plastic sensor holder Sensor strips (x100) Contact drying strips Instruction manual What s in the Bag? 7

8 Using Chlorosense Instrument Layout Display Screen Instrument Handle Power Key/ON or OFF OK/Return Key Power Sliding Catch Using Chlorosense Instrument Layout Sensor Strip Electrode Blue lever Sample Chamber (removeable) Sensor Strips Do the Work One significant difference is Chlorosense uses special sensor strips instead of powdered reagents familiar to Hach users. These sensors are pre calibrated and disposable. After each test is performed, the sensor is to be discarded. 8

9 Sensors are highly sensitive. Sensor Strips Do the Work Handle only by edges or through foil packaging. Connecting Tracks They are single use. Sensitive Surface DO NOT TOUCH Operating Instructions New Sensor Calibration Prior to using a new box of sensors for the first time, you must calibrate the machine with a calibration chip which comes with the sensors. This only has to be done once upon opening a new box. 9

10 Calibration Chip New Sensor Calibration 1. Slide the front catch to the right and open the instrument case fully. 2. Press the blue lever, and insert the contacts of the calibration chip fully into the slot revealed. Release the blue lever. New Sensor Calibration 3. Close the instrument lid and view the display. Check the new code number displayed on screen matches the number on the sensor packaging. A test can now be performed 4. If the calibration procedure was unsuccessful, an error message will be displayed DO NOT remove the calibration chip. Just open and close the lid to repeat calibration. 10

11 Verifying Codes Performing a Test for Free and Total chlorine Start Up 1. Press and hold the power button until the title screen is displayed on the LCD 2. When the instrument passes all the internal checks, the screen displays the current batch code and prompts the user to insert a sensor. If start up fails, an error will be displayed 3. Ensure the calibration code shown on screen matches with the number on the foil of the batch of sensors in use. 11

12 Performing a Test 1. Slide the front catch to the right, and open the instrument case fully. 2. Remove the sample container. Rinse and then fill to the stepped line with water sample. Using Chlorosense Analysis Mode 3. Replace the filled sample container in the instrument. 4. Tear open the foil along the pre cut marks, in the manner shown. Holding the sensor through the foil pack, expose the connecting tracks. Sensor Handling 12

13 Using Chlorosense Analysis Mode 5. Press the blue lever to open the jaws of the sensor connector. Insert the exposed end of the sensor, connecting tracks uppermost, release the lever. The jaws will close to hold the sensor in place. Slide the foil pouch off to expose the sensor. Using Chlorosense Analysis Mode 6. Gently close the instrument lid to immerse the sensor in the sample. The test starts automatically. The display indicates progress of the test. Do not disturb the instrument during the test... Using Chlorosense Analysis Mode 7. The free chlorine result will be displayed. Press the down arrow to scroll through free chlorine, total chlorine (YES it does both at once!), temperature, date, time and sample number. All results are automatically stored to the instrument tlog. 13

14 Use down arrow to scroll through results Using Chlorosense Analysis Mode 8. After completion, open the instrument and press the blue lever to remove the used sensor. Empty and rinse the sample container. Do not leave water within the instrument on completion of the test. 9. Press the key to carry out a new test or calibration. If no key is pressed for 5 minutes, instrument automatically switches off to save power. 10. To recall the last reading to the screen, press the key from the insert sensor screen. Chlorosense Instructional Video 14

15 Reporting Results No changes to the way chlorine readings are currently being reported. Though you may encounter: Below Detection In the event chlorine levels are below the instrument s detection limits of mg/L FAC and mg/L TAC, the display will by <0.02 mg/l and <0.05 mg/l respectively. Over Range In the event chlorine levels are above the instrument s detection range of 75 ppm for both FAC & TAC, a range will be reported; anything above 100 mg/l will display >100 mg/l. Always report what is displayed on the instrument. Reporting Results CBWM are required to submit chlorine results from routine sampling to EPHS on a weekly basis. Following your weekly routine sampling you are required to fax your results into EPHS (780) Reporting Results ROUTINE WATER QUALITY SUMMARY REPORT For Feature ID information contact Amy Fax: Water Quality Testing for: Fort McKay Submitted by: Date: Facility or Collection House Number/ Site Occupant s Name Feature Code Date(M/D/Y) & Time of Sample CHLORINE RESULTS Prov Lab Sample Drop Off Date and Time Water System -- Public Water -- Semi Public Observation -- Bulk Water Hauler -- Private Cistern/Well Free Total mg/l mg/l Multiplex Kitchen Sink Day: Nicole Mcdonald Kitchen Sink Day: Julie Huppie Kitchen Sink Day: Patricia Kitchen Grandejambe Sink Day: Emma Faichnay Kitchen Sink Day: Fort Mckay Daycare Kithen Sink Day: Day: Day: Day: Day: Reviewed by EHO (initial) Health Canada, November 2010 First Nations & Inuit Health 15

16 Tips for Getting the Best Results Handle the sensors with care. Place the instrument on a flat surface free from vibration. Do not disturb the instrument or sample during the test. Theprecision of sensor response is enhanced atlow temperatures. Operation at sample temperatures above 25 o Cis not recommended. Store the sensors at a temperature of less than 30 o C. Commonly Encountered Errors* Error Message Displayed Unable to read: Check Sensor and Contacts Unable to read: Sensor already used. Recommended Action 1. Remove sensor, dry with contact drying sticks. 2. Remove calibration chip Remove and discard wet sensor. Dry the contacts. Unable to read: Sensor missing Press key then insert sensor and restart. *These can also be found in instruction manual. Commonly Encountered Errors* Error Message Displayed Unable to read: Faulty Sensor Lid opened during test Sample not level during test Recommended Action -Remove & discard sensor. -Dry contacts -Press and start with fresh sensor. -Remove the sensor -Press and start with fresh sensor. -Remove the sensor -Press and start with fresh sensor. *These can also be found in instruction manual. 16

17 Power Supply Chlorosense is designed to operate on 4 x AA alkaline cells. If batteries require replacement a Low Battery warning will be display upon startup. The battery compartment can be found at the base of the instrument. Remove the 4 screws to access battery compartment. Re Ordering Supplies To re order supplies such as sensors, drying sticks or sample vessels, please contact: Darlene Lewis, Administrative i ti Coordinator e mail: darlene.lewis@hc sc.gc.ca phone: (780) Summary Major Advantages Chlorosense: Reduces the risk of user error when conducting the test. Reducesvariability between results fortypicalusers users. Prevents systematic errors arising from calibration. 17

18 Summary Benefits Simple process. Fast results (less than one minute). Reagent free analysis (it uses disposable electrochemical sensors). Measures both FAC and TAC chlorine simultaneously. Light weight for use in the field (<1 kg). Summary Benefits Only have to worry about one testing range (0 10 mg/l). Additional information such as temperature, date & time is provided. Equipped with a PC through USB interface for storage log of 500 tests. Approved by USEPA Summary As with any new technology that s implemented, there is potential for some technical and logistical issues in the field. Please contact your EHO if you are experiencing any problems and we will do our best to assist you. 18

19 Questions 19