Techneau JANUARY UV-Vis monitoring station for calculating integrated parameters

Transcription

1 Techneau JANUARY 2007 UV-Vis monitoring station for calculating integrated parameters

2 Techneau JANUARY 2007 UV-Vis monitoring station for calculating integrated parameters 2006 is an Integrated Project Funded by the European Commission under the Sixth Framework Programme, Sustainable Development, Global Change and Ecosystems Thematic Priority Area (contractnumber ). All rights reserved. No part of this book may be reproduced, stored in a database or retrieval system, or published, in any form or in any way, electronically, mechanically, by print, photoprint, microfilm or any other means without prior written permission from the publisher

3 Colofon Title UV-Vis monitoring station for calculating integrated parameters Author(s) dr. Joep van den Broeke Quality Assurance By Bart van der Burg Deliverable number D This report is: PU = Public

4 Summary Enhancement of source water monitoring capabilities of the well established UV/Vis spectrometer probe (spectro::lyser ) is the central issue of activities in work-package WP In the first 12 months the following developments were made; Online and real-time access to monitoring stations at remote location was realised. The data, transferred to and stored on a central server in real time, can now be accessed over web application. This type of set-up can be realised with any suitable third party equipment with the new standardised communication protocols were developed for both the spectrometer probe as well as the computer terminal. These protocols allow easy and direct communication between the instruments as well as with third party systems. In this way the flexibility of the monitoring station was greatly enhanced. This type of set-up facilitates on-line access to data from remote measuring stations with the need for expensive infrastructure. Additionally, one monitoring station (spectrometer probe + computer terminal) was installed at a location of Vienna Waterworks to gather data on source water quality and fluctuations therein as well as to gather performance data on the measuring station. Algorithms for detecting changes in the UV/Vis spectrum, so called alarm parameters, were tuned for detection of changes in source water quality. scan Messtechnik January 2, 2007

5 Contents Summary 1 Contents 2 1 Development of a new early warning system for drinking water sources based on integrated UV/Vis spectrometry Introduction The monitoring station State of the art december Progress towards objectives 4 scan Messtechnik January 2, 2007

6 1 Development of a new early warning system for drinking water sources based on integrated UV/Vis spectrometry 1.1 Introduction Performance and reliability of UV/Vis spectroscopy already contributed to several early warning systems for drinking water protection. The method of "integrated on-line UV/Vis spectrometry" has opened a new perspective for detecting changes in water composition and the aim of WP3.2.2 is the exploitation of this ability of on-line UV/Vis spectrometry for drinking water source monitoring and protection; Not only can changes in parameters derived from the spectrum be monitored, UV/Vis spectrometry also offers the possibility to perform qualitative interpretation of spectral deviations from the normal source water quality, and recognition of patterns using both spectral and additional sensor signals. A system that makes possible this type of monitoring and data interpretation will be developed. Primary targets in WP3.2.2 are: - build a monitoring station for calculating "integrated parameters" based on spectral and additional sensors, for actuating early-warning tasks and for providing automated data transfer to one central station - develop a central station for centralised data storage, handling and access and for providing remote access to several monitoring stations. - research for "integrated parameters" exploiting spectral and additional sensors signals and providing distinct information needed for early warning systems of drinking water sources This report describes the first deliverable of this work package (D3.2.1): a UV/Vis monitoring station for calculating "integrated parameters". 1.2 The monitoring station All developments for with respect to on-line UV/Vis spectrometry build upon the spectrometer probes (spectro::lyser ) and terminals developed by before the start of the project. These products are commercially available and already in use with hundreds of customers worldwide. The report will only detail the system selected for the monitoring purposes of WP3.2 and the additional developments performed under WP3.2. scan Messtechnik January 2, 2007

7 State of the art december 2005 For source water monitoring the spectro::lyser instrument, which is a fully submersible UV/Vis spectrophotometer, in combination with a con::stat industrial computer for operation, control and visualisation of results, was operated. This system was capable of recording a full UV/Vis spectrum every 30 seconds, as well as reading and displaying signals from additional sensors. This system was capable of calculating the parameters turbidity, TOC, DOC and nitrate concentrations from the UV/Vis spectrum as well as triggering relays or calling out over a modem in case of transgression of alarm levels set on these parameters. Also in use was a generic alarm software that evaluated changes in the spectrum. This was available before the start of the project and forms the baseline of the monitoring station developed in WP Progress towards objectives WP3.2 focuses on monitoring of sources for drinking water, which often means monitoring of water courses / springs located in remote locations. Furthermore, many drinking water utilities rely on multiple sources, and collection of data from all sensors in a central database is important for generating an integrated overview of the water quality of the sources. Development of the envisioned system was approached along two lines: 1) installation of a monitoring system at an end-user to demonstrate capabilities and identify areas for further development 2) develop remote access capabilities and link to central station for data collection 1) Installation of monitoring system and results In April 2006 one complete monitoring system (sensor, terminal, mounting) was installed at a source of Vienna Waterworks. This monitoring station was built to the specifications for this application site, and has been running at this location until November During this time it collected data that will be used for the development of parameters for source water monitoring in task e. The system installed was of the following configuration: scan Messtechnik January 2, 2007

8 Figure 1: Configuration of system installed for testing at Vienna Waterworks. spectro::lyser (ser. no ) with 100mm measuring path length (for highest sensitivity), UV/Vis detector, aluminium housing, no automatic cleaning con::stat III equipped with GSM modem The probe was suspended from a long PVC pipe, and the con::stat was positioned on a stone ledge. No problems were encountered with this very simple setup, despite high humidity and low temperatures on site. This demonstrated the robustness of the system and easy of operation. Figure 2: Pictures of the instruments during the test. Left the spectro::lyser and right the con::stat. scan Messtechnik January 2, 2007

9 During the test period, following data was collected: - fingerprints - turbidity - TOC concentrations - DOC concentrations - nitrate concentrations (NO3-N) - temperature - alarm parameters reporting changes in the fingerprint Figure 3: Time series depicting data recorded during test (units of measurement deleted because of data confidentiality reasons). Precision for the measured parameters was the following: turbidity: 0,05 FTU TOC: 0,005 mg/l DOC: 0,007 mg/l NO3-N: 0,003 mg/l temperature: +/- 0.1 o C The measured data clearly showed a number of events in water quality. The system was trained to recognise these events. Furthermore, the alarm parameters were revised to achieve better monitoring capabilities for this type of water source. Performance of the new alarm parameters was verified by a mathematical exercise: the spectrum of toluene was added to the spectra recorded for the water. This cumulative spectrum was passed through the alarm filter and the response was checked. Toluene could be detected in this scan Messtechnik January 2, 2007

10 way down to 0.8 mg/l. With the old alarm parameters sensitivity was limited to 2 mg/l. Areas for further development were also identified: - integration of additional sensors - this is currently possible with the con::stat terminal but not evaluated under WP3.2. This will be part of the work in WP3.5 and WA7 - GSM modem was installed for use of remote access to the monitoring station. The modem connection over GSM is, however, not suited for continuous reading out of measurement data (too slow and too costly to transfer large data volumes or to keep open continuous connection). It is only suited for checking of functionality of the system and changing of measurement settings. Alternative communication interface was part of development under WP3.2.2, see next paragraph. Figure 4: Spectral response to addition of 2 mg/l toluene to the water 2) Develop remote access capabilities and link to central station for data collection To achieve the highest flexibility, the first focus was on the development of standardised communication protocols between equipment and third party equipment. Before the start of, all equipment used a proprietary language, which was not compatible with third party equipment. The use of a standard protocol allows connection of equipment to other modules, such as a GPRS modem, and allows easy scan Messtechnik January 2, 2007

11 integration in other systems, networks etc. The standard language selected for this type of communication with third party devices, as well as for communication in between devices, is the MODBUS RTU protocol. Both the con::stat and the spectro::lyser now can communicate measurement results via this MODBUS protocol. This allows the following new system configurations: 1) connection of con::stat to central server over GPRS modem, for transfer of all parameter data in real-time and availability of all control options at the measuring site 2) direct connection of spectro::lyser to central station, limiting power consumption and allowing battery operation. No control of spectro::lyser is possible in this configuration but measurement result are available in real-time. Figure 5: New configurations available with new MODBUS protocol. Left configuration 1, and right configuration 2. Using this standard language a commercially available modem could be used to set-up a continuous connection with the monitoring station using a GPRS connection, which is more affordable, more reliable and much faster than the previously existing GSM connection possibility. This allowed a real on-line access to remote stations without a fixed infrastructure. This capability was demonstrated by connection this measurement system to a modem from the company Xeo4 and transferring measurement results, online, to the central server of Xeo4. The data could then be requested and displayed on-line over the Rilheva web-based application of Xeo4 (see figure 6). This allows selection of the measuring location over a geographical map and display of the measurement results as values or as graphs. scan Messtechnik -8- January 2, 2007

12 The website is available under and can be accessed using: company: user: public password: techneau Note: this website was not developed under but is a commercial third party product. It is not optimised for the specific application envisioned in WP3.2.2, but only used to demonstrate remote access capabilities. An improve website / concept will be developed in subsequent activities not covered in this report. Figure 6: Selection of monitoring stations from geographical map. scan Messtechnik January 2, 2007

13 Figure 7: Display of status of the monitorign station and measurement results. Areas for further development: - currently only the parameter values calculated from the spectra can be transferred in real-time. Transfer of the spectra themselves is not possible with the standard MODBUS protocol. The transfer of spectral data and development of a (web based) application to evaluate this information will be part of the further activities under WP3.2. scan Messtechnik January 2, 2007