nwlpp

The sampling team is responsible for taking a range of representative samples related to every water production asset supplying our customers. That is 600 samples per week from: –30 Treatment Works –208 Service Reservoirs –125 Customer House Taps (via cold calling) In an area stretching from the south of Scotland to North Yorkshire, and from Kielder reservoir to the coast (including Hartlepool Water). With a team of 16 samplers on 12 designated programmed rounds

nwlpp What is sampled, the analysis required and how often is determined by the DWI and pre-planned in a sampling schedule Each individual sampling event consists of taking between 1 and 25 different bottles of varying type depending on the analysis required On-site tests such as chlorine, temperature, taste and odour are also taken To do this each member of the team is trained in 5 methods: –L1 – Chemical and Micro Sampling –L7 – Determination of the Temperature of a Liquid –L16 – Qualitative Taste and Odour –L13 – Total and Free Chlorine –L17 – Cryptosporidium Sampling Once a year everyone is audited internally onsite to check they are complying with each method. Everyone is also subject to random spot check audits.

nwlpp L1 – Chemical and Micro Sampling

nwlpp Split into 2 parts 1.Chemical Sampling 2.Microbiological Sampling

nwlpp Is lead sample required? If so take sample. Is lead sample required? If so take sample. Is a tap swab required? If so swab tap. Is a tap swab required? If so swab tap. Carry out any on-site tests Take any chemical samples Is the tap constantly running? YES NO Flush tap for a minimum of 2 mins or as indicated at the sample point. Chemical Sampling

nwlpp Take pre- sterilisation samples Sterilise sample point Chemical sterilisation Flame sterilisation Check background chlorine (L13) Take Sample Take post sterilisation swab if required. Microbiological Sampling

nwlpp L13 – Total and Free Chlorine

nwlpp Equipment: ‾Pocket Colorimeter ‾4 x 10ml glass cells ‾Set of 3 DPD reagents (A,B & C) RINSE the Free Chlorine Cell BLANKREAD Add 3 Drops of DPD Reagent A Add 3 Drops of DPD Reagent B Fill to the 10ml Line RINSE the Total Chlorine Cell BLANKREAD Add 1 Drops of DPD Reagent C Add contents of Free Chlorine Cell Wait 2 Minutes Free Chlorine Total Chlorine

nwlpp Every part of the process is noted down on the samplers run sheet including: –Date & time of sample –Location if different from target (including reasons why) –Equipment and methods used as part of the sampling process This ensures we have complete traceability over each sample for audit purposes. Each sample is also labelled with a pre-printed bar coded label so it can be clearly identified through the administration and analysis process

nwlpp It can take several hours between samples being taken and arriving back at the laboratory. To ensure the most accurate representation of the water’s quality, samples need to be stored at a constant temperature between 2°C and 8°C Each sampler has a refrigerated van set to these parameters. Van temperature is monitored daily throughout each samplers shift with a calibrated fridge thermometer.

nwlpp To ensure any results we produce for on-site tests are accurate, a strict calibration process is employed. The following are examples of everyday equipment requiring calibration that every sampler carries: –Colorimeters: used to measure Free and Total Chlorine levels, these are calibrated annually. However they are also subject to a daily gel standard check and are used as part of the internal & external PT schemes on a monthly and quarterly basis. –Stick Thermometers: Used to determine the temperature of the water we sample. Calibrated quarterly at three different temperatures. –Van Thermometers: Used to ensure sampler van fridges are running at the appropriate temperature. Calibrated annually