28 Water / Wastewater
Economic Monitoring of Uranium in Drinking and Mineral Water
Determining trace levels of uranium in drinking and mineral water by inductively coupled plasma mass spectroscopy (ICP-MS) requires expensive analytical instrumentation. In contrast, adsorptive cathodic stripping voltammetry (AdCSV) using Metrohm’s (Switzerland) 797 VA Computrace is a straightforward, much less expensive alternative allowing measurements with superior sensitivity. Uranium is radioactive, toxic and a suspected teratogen. While different national health authorities prescribe limits in drinking water ranging from 0 up to 10 µg/L, the World Health Organization (WHO) recommends a concentration limit of 15 µg/L. The AdCSV method for the voltammetric determination of the uranium content is based on complexing U(VI) with chloranilic acid (CAA) at a pH between 1.8 and 2.5. After preconcentration of the uranium-chloranilic acid complex at the working electrode, the uranium content can be determined down to the ng/L range by using the differential pulse measuring technique (DP). The determination of uranium(VI) is specific and selective, as the positive deposition potential means that other metal-CAA complexes or organic matrix components of natural waters are either not adsorbed on the working electrode or hardly adsorbed at all. The German standard DIN 38406-17 is currently being drawn up based on this AdCSV method. This means that in future the voltammetric determination of uranium can be used as a generally recognised method for monitoring drinking and mineral water in daily practice.
Reader Reply Card no 98 Water Quality Assessment
ecoAlert (UK) is delighted to announce that it has successfully completed the field trials of its water quality assessment equipment, and third-party validation by a laboratory conforming to GLP (Good Laboratory Practice) standards. Field trials were conducted on a variety of water bodies, including fresh river water, raw sewage and treated wastewater. The ecoAlert assay provides an indication of the health of water bodies by measuring the health of key natural bacteria. Bacterial response indicates whether a broad range of pollutants are present, providing a fast, sensitive and robust result. The assay is also available in an in-situ version (a passive monitor) whereby contained bacteria are suspended within the water body (river, lake) to monitor cumulative effects of pollutants over time. The test provides early warnings for those charged with assessing water quality and can be used on spot samples to obtain results within 4 hours. Through the innovative use of naturally occurring bacteria, the ecoAlert assay provides a fast, cost-effective, solution. Legislation such as the new European Water Framework Directive (WFD) has led to a step-change in the assessment of water bodies across Europe by imposing a requirement to achieve “Good Ecological Status”. Moreover, Environmental health is strongly reflected in the United Nations’ Millennium Development Goals which are driving significant initiatives worldwide. The global market size for products such as the ecoAlert assay is estimated at US$1.45bn. Jenny Rohde, CEO of ecoALert, commented: “We are delighted with this important seal of approval for the ecoAlert Assay. This means that there is now a validated, easy and inexpensive way of monitoring water quality that can be used around the world to help to protect our aquatic environment.”
Reader Reply Card no 99 Analyser for Hydrocarbons for (VOC’s) in Water
The ability to analytically quantify volatile organic compounds (VOC’s) in cooling towers, heat exchangers, holding ponds, run-off water and waste water is greatly enhanced with the Model 204/174. The exclusive & patented Sample Transfer Stripper provides a ultra clean sample for the readout of choice. The standard tin oxide solid state sensor and/or other readout offered by Analytical Systems International/KECO R & D offers a cost effective & accurate analysis. The analyser system utilises many patented and exclusive features only available from ASI KECO (USA).
The principal of operation requires a consistent free flowing liquid sample into a Sample Transfer Stripper unit that separates the liquids from the VOC’s. A hydrocarbon free carrier then sweeps the VOC’s in a gaseous form into the tin oxide solid state sensor or other readout for quantitative analysis in ppb w, ppm w or up to saturation levels. Lower detectable limit is less than 1 ppb w. An optional liquid validation/calibration by Perm Tube TM is available. This unattended on-line analyzer is economically superior to others. Shell Global had designated the model 204 as “preferred vendor” & TCEQ as “Best Available Control Technology” and “Equivalency” for continuous monitoring of cooling tower & waste water applications.
Reader Reply Card no 100
As lime is a product derived from the Earth, it is fitting that many of its uses also benefit the Earth. In fact, the second leading use of lime is in environmental applications, including drinking water and wastewater. Optiflex is widely used to indicate lime levels in storage silos. It usually replaces non-reliable ultrasonic or electromechanical systems that are expensive to maintain. Lime powder is used to treat industrial and mining wastewater by adjusting the pH of acidic waste, removing phosphorus and nitrogen, and promoting clarification. Operating under the so-called TDR (Time Domain Reflectometry) measuring principle, the instrument is immune to dust and harsh environments. Optiflex is the third generation of TDR level meters
from KROHNE (Germany), available in compact or remote design, high-performance and field-proven. Up to 5 sensor options are available for various applications and requirements: level measurement of liquids or solids. The OPTIFLEX true four-button keypad offers quick and easy access to all instrument functions. Once the user has performed a quick , simple and intuitive setup operation, the instrument will directly display the actual silo level, which increases user confidence. The local display is extremely easy to read, allowing users to view level, distance and volume indications in various units. In addition to the displayed variables, an oscilloscope view is also available, ensuring complete application diagnostics.
For remote diagnostics and parameterization, the instrument comes with the famous PACTware software and DTM (Device Type Manager) instruments free of charge. All parameters and analysis data are then accessible using the HART protocol signal through a 2- wire current loop. For use in specific locations such as hazardous areas, OPTIFLEX can be certified as intrinsically safe or explosion proof according to ATEX, FM, CSA, IEC, NEPSI etc. In terms of applications, Optiflex measures lime levels in silos directly at supplier quarries as well as in the drinking water of final users at water treatment stations.
Reader Reply Card no 101
Measurement of Lime Levels in Drinking Water & Wastewater
New Monitor for Water Leak Detection
The new noise logger as an innovative extension to the SePem® range of products. The new generation of SEWERIN (Germany) noise loggers is small and compact. The combination of SePem® 01 and communication appliance SePem® 01-Master is one backed up with convincing arguments. The SePem® 01 noise logger is designed for fixed deployment for water leak detection purposes. The heart of each and every logger is a newly developed, highly sensitive microphone for recording leak noises. Its specifications are such as to permit large distances – even in the case of non-metallic piping - between the measurement points. Thanks to its novel housing geometry, the logger can be installed either horizontally or vertically. Whether underground fire hydrant or gate valves at varying installation depths - SePem® 01 fits in everywhere! A digital high- performance wireless link with automatic error correction exchanges data between logger SePem® 01 and communicator SePem® 01- Master. The control vehicle crosses the measurement point and receives all the data without any being lost. State-of-the-art technology is inside the lightweight and handy casing of the SePem® 01 - Master communicator. The user soon learns to appreciate the perfected menu control. Even though no separate software is needed, numerous functions are on hand for programming the loggers and presenting the readings. Thanks to the easy, intuitive operation of the SePem® 01 - Master, users with only a smattering of PC knowledge very quickly obtain precision findings. Summarising: the logger and communicator combination features precise measurements thanks to the highly-sensitive microphone together with powerful radio data transmission and evaluation of readings directly on the spot.
Reader Reply Card no 102
October/November 2008
AET
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