b'Kiosk Instrument Summary. NitrataxAnalytes being measured continuously at-Total oxidised nitrogen, every 10 minutes (approx.) 10min intervals are: (Range 0.150 mg N L- 1 ).-Total Phosphorus in mg L- 1 The Nitratax unit uses spectrophotometry to -Ortho-Phosphate P in mg L- 1 measure the total oxidized nitrogen (nitrate plus -Total Oxidised Nitrogen in mg L- 1 nitrite, where nitrite concentrations are usually very -Turbidity in NTU low or zero). Total oxidized nitrogen absorbs light -Electrical Conductivity in micro at 210nm wavelength, so a beam of UV light at this -Siemens/cm wavelength is passed through the sample and the -Total Organic Carbon in mgL - 1 amount of light absorbed is measured. A second -Temperature in degrees Celsius. beam of light is passed at 350nm to correct for Instruments and measurement principles are: turbidity and organic matter. A calibration equation -All instruments are manufactured by Hach is use to convert Ultraviolet absorbance into total -Our instruments and sample delivery systems oxidized nitrogen concentration.were supplied and commissioned by anIrish company, UISCE Technology. Currently weSolitaxhave a service contract with an independent-Turbidity (NTU), every 10mins. Range 02000HachtNTU.-Lange trained technician The Solitax unit also uses spectrophotometry -Water is delivered continuously to a header tank to measure the turbidity of the water. A beam ofin each kiosk via a submersible pump infrared light is passed through the water sample which is anchored to the river bed. All sensors areand two receptors detect the amount of light that is housed in, or sampled from, the header tank scattered at an angle by the particles in the water.-All kiosks are supplied with (necessary) mains 230V AC power. UVAS plus sc Sensor (Total Organic Carbon)-Total Organic Carbon, every 10 minutes.Sigmatax sample preparation and PhosphaxThe UVAS unit uses spectrophotometry to measure Sigma the total organic carbon of the surface water. Total -Total Phosphorus (TP) organic carbon absorbs light at 254nm wavelength. -Ortho-Phosphate P (OP). The amount of light absorbed at this wavelength is The Sigmatax sample preparation unit takes ameasured. A calibration equation is used to convert sample in, mixes it using ultrasonic vibration thenUV absorbance into total organic carbon measured the sample is fed to the Phosphax. The equipmentin mg L- 1 .analyses unfiltered river water samples for total digested P (TP) and total molybdate-reactive PTemperature and Conductivity sensor 3400 (TRP) concentrations from 0.01 mg L-1 to 5.00 mgseriesL-1.The method alternates the digestion (using high temperature and the electrical conductivity oftemperature and acid in the central cuvette) stepthe water are measured every 10 minutes.to give up to 3 TP and up to 3 TRP data-points in each hour. An automated single point calibrationFlow measurementand cleaning cycle occurs daily. The equipment isWater level (m) is recorded via OTT Orpheus Mini routinely maintained and serviced and the and OTT ecoLog 500 vented-pressure instruments analytical method and quality control of theseand discharge (m3 s- 1 ) calculated via rating curves types of instrument suites are described by developed on non-standard Corbett flat-v weirs Jordan et al., 2007, and Cassidy and Jordan, 2011.using the velocity-area method with OTT Acoustic Doppler Current-meters.Real-time and historical data for the ecoLog 500 instruments is accessible via OTT HydrometCloud.84'