40 of 124  Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements  Section 08: Electrical Works  Calibration of the system shall be easy and not require special tools or instruments. It shall be possible to  calibrate the system from the front of the transmitter and the accuracy of the calibration shall be better than 5%.  Correction of temperature, relative humidity (RH), salt content and the atmospheric pressure shall be included.  It shall be possible to select % or ppm as the range. The level of dissolved oxygen shall be indicated on a  pointer instrument in the front of the transmitter. Adjustments shall be done from the front of the transmitter.  The device shall include automatic compensation of temperature.  ORP transmitters shall be provided for measuring of the oxidizing or reducing tendency, where  necessary. Material sensor element shall be PPS and material diaphragm shall be PTFE. Electrical sensor  connection shall be digital. Transmitter shall include robust plastic housing. It shall be possible for functionality  modular extendable at any time. Transmitter shall be IP 66/67 for the field conditions. Transmitter shall be  modular 4 wire controller. Transmitter ambient temperature shall be between -20 60 $^{0}$C. Common  communication protocols and interfaces, such as 0/4...20 mA and Ethernet or 0/4…20mA/HART shall be  integrated. It shall be possible for all non-ex applications  8.8.5 ORP measurement system  8.8.6 Ammonia & Nitrate Ion Selective Probe  Ion-sensitive sensor for continuous measurement of ammonium, nitrate and other ions (potassium and/or  chloride  A complete measuring system consists of a sensor with electrodes and a transmitter with display and operating  elements. The sensor shall be used to monitor the ammonium and nitrate content in the activated sludge basin  and in the prequalification outlet. Measuring ranges for the sensor shown below:  • Ammonium: 0.1 to 1000 mg/l (NH$_{4}$-N)  • Nitrate: 0.1 to 1000 mg/l (NO$_{3}$-N)  • Potassium: 1 to 1000 mg/l  • Chloride: 1 to 1000 mg/l  Ambient temperature shall be -20°C /+50 °C. Maximum measured error shall be ± 5 % of the measured value ±  0.2 mg/l. Response time of the ion selective sensors shall be <2 min  8.8.7 Suspended Solids & Turbidity Measurement System  Measuring principle shall be scattered light with measurement wavelength 860 Nm. Sensor shall measure both  turbidity (NTU) and suspended solids (mg/l). Sensor shall be delivered with 3 points factory calibration.  Ambient temperature; -20 °C to 60 °C (-4 to 140 °F) and Process temperature; -5 °C to 50 °C (23 to 120 °F).  Measuring range for turbidity shall be 0-4.000 NTU and for suspended solids 0-300 g/l. Sensor shall be  delivered with cleaning system with pressurized air. Process temperature conditions for sensor will be between - 5°C /+50°C. Sensor element material will be EPDM and window material shall be Sapphire.  8.8.8 pH Measurement System  The pH meter shall cover a range 0 - 14 pH with an accuracy better than pH 0.02 at any temperature. It  shall be installed so that easy access for calibration would be provided. Electrode systems will be consisted of a  8_Vol3_d4 3_Section 8 electrical works_en_GIR rev6.doc 