Water/Wastewater 13


Main application for the new AMI Turbiwell


Raw water monitoring (surface water)


Most of the measurement points are at some distance in the countryside. Due to long travel times to the site, an instrument with as little maintenance as possible is required /called for.


The sample contains harmful substances, pathogenic contaminants and particles of different sizes as mud or sand. Optical windows in direct contact with the sample would be covered with a biofilm or other sample-related precipitations which inevitably lead to turbidimeter performance failure and finally wrong measurement values.


Figure 4: Monitor AMI Turbiwell


The non-contact optics is the perfect solution to ensure measurement reliability and stability.


A programmable, automatic chamber drain clears the measurement chamber from settled particles.


ISO 7027 [2] vs. EPA 180.1 [3] ISO 7027 specifies a nephelometer uses a “red” light


source with an emitting wavelength of 860nm. There are no limitations regarding application and measurement value.


The EPA regulates the use of a nephelometer, depending on the turbidity value in the sample. Below 40 NTU, a tungsten lamp operated at a color temperature between 2200-3000°K and a detector with a spectral peak response between 400 nm and 600 nm have to be used; white light, because of the sensitivity to smaller particles (sensitivity ~ 1/λ4).


Above 40 NTU, red or white light is accepted. Water treatment process


Reliability of the instrument - especially that of the instrument’s light source and verified measurement values is the main feature in monitoring of the clarification / filter processes. Providing safe drinking water is the main objective and a deviation in turbidity will lead to different procedures.


But how to distinguish if this deviation is caused by a thin biofilm on the optical windows, a decreased lamp intensity or a real incident with the filters?


The answer is to exclude the possibility of deviation in the instrument itself.


Biofilm is not an issue for a non-contact set-up; lamp intensity monitoring and a dark current measurement provide the most accurate and verified measurement value possible.


Conclusion:


The new non-contact turbidimeter, the AMI Turbiwell with automatic or manual chamber drain and lamp intensity monitoring offers a variety of benefits in terms of reducing maintenance work and cost of ownership, and with the enhancement of reliability and stability. Therefore, not only the initial costs of a turbidimeter have to be considered. The economical factor of a low-maintenance but sophisticated instrument must also be taken into account.


[1] Standard Methods.1995.Standard Methods for Examination of Water and Wastewater, 19th edition, America Public Health Association, AWWA, Water Environment Federation. Franson, M.H., A.D. Eaton, L.S. Clesceri and A:E: Greenberg (editors). Port City Press, Baltimore, MD


[2] International Organization for Standards (ISO). 1990. International Standard 7027 – Water Quality – Determination of Turbidity. ISO


[3] Environmental Protection Agency (EPA)


[4] Federal Register / Vol. 74, No. 216 / Rules and Regulations, ALTERNATIVE TESTING METHODS FOR CONTAMINANTS LISTED AT 40 CFR 143.4(b), Tuesday, November 10, 2009


[5] AMI Turbiwell, ‘‘Continuous Measurement of Turbidity Using a SWAN AMI Turbiwell Turbidimeter,’’ August 2009. Available at http://www.nemi.gov


Ultrameter II With all new features and functions …


The Ultrameter II still delivers the most accurate dissolved solids measurements of any instrumentation and the greatest degree of accuracy available for pH, ORP and Temperature measurements, but has been redesigned to include an LSI/Hardness Calculator, Free Chlorine Measurements and Bluetooth® with the optional bluDock™ accessory.


data transfer


The LSI calculator makes it easy to analyse the scaling nature of water in the lab or in the field. The calculator computes the saturation index of a sample based on measured and inferred values for pH, temperature, hardness and alkalinity. You can then change any of these values in user adjust mode to analyse the effect of the change on water balance. User mode also allows you to input measured values for alkalinity and hardness as determined by other


independent testing for a precise saturation index value.


Within the LSI Calculator is a Hardness calculator that allows you to select either ppm or grains of hardness units.


Free chlorine measurements are mathematically derived from Oxidation Reduction Potential measurements. The mV to ppm free chlorine conversion algorithm is based on a published conversion curve and bench testing performed at the Myron L Company. With this new feature Myron L instruments can measure a dynamic range of sanitiser concentrations that is wider than the range of a colorimetric test kit.


With the bluDock™ accessory package, the Ultrameter II can now also transfer data wirelessly using Bluetooth®


technology.


The Ultrameter II also features KCl, NaCl, 442™ and User-defined solution modes for proper solution modeling in diverse applications. Autoranging allows instrument to maintain resolution for solutions with widely varying concentrations. The pH/ORP sensor is user replaceable and can be calibrated to 1, 2 or 3 points depending on requirements. 4-wire conductivity cell construction, extremely stable circuitry and proprietary conversion algorithms deliver reliable repeatable results.


Ultrameter II is compact, portable, waterproof and buoyant, easy to calibrate and easy to use.


Call the Myron L Company today to see why customers are saying this is the instrument they've been waiting for.


Phone: +1-760-438-2021 E-Mail: info@myronl.com Website: www.myronl.com


Reader Reply Card no 34 www.myronl.com Reader Reply Card no 35 August/September 2010 AET


AUTHOR DETAILS


Markus Bernasconi Sales & Support manager Swan Analytical Instruments Markus Bernasconi,


graduated from the University of Applied Sciences in Burgdorf, Switzerland in 2000 with a bachelor degree in chemistry and in 2002 with a post graduate course in integrated micro systems. He worked at the same location for about 4 years, leading research projects in the field of thin film deposition (PVD, CVD) and wet chemical wafer processing. He then changed to Mettler- Toledo Thornton, working as a project leader in the R&D. Subsequently, he joined Swan Analytical Instruments in 2006 working first as product manager and since the beginning of 2009 as a sales & support manager.


WE’VE GOT YOU COVERED


Ultrameter II™ 6Psi


Easily and accurately measure up to 7 parameters: Conductivity, Resistivity, TDS, pH, ORP, Free Chlorine and Temperature.


bluDock Enabled


NEW! bluDock™ Wireless Data Transfer (optional)


NEW! LSI and Hardness Calculator


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