" "
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Roundtable Highlights Need for Improved Maintenance of DO Sensors

Published: Tuesday, February 12, 2013
Last Updated: Monday, February 11, 2013
Bookmark and Share
Improved maintenance of dissolved oxygen sensors for increased efficiency and accuracy for water treatment plants.

A roundtable discussion with water industry and regulatory experts has agreed that there is a need for improved maintenance of dissolved oxygen sensors to increase the accuracy of dissolved oxygen measurements.

The roundtable, which was hosted by the specialist electrochemical-sensor manufacturer, Analytical Technology (ATI), was made up of leading industry and regulatory experts.

The panel was chaired by Michael Strahand, General Manager of ATI Europe and included Alan Henson from Yorkshire Water, Andy Morse, Richard Bragg and Khaled Gajam from United Utilities, Jorgen Jonsson from The Water Research Centre and Robin Lennox from South West Water.

The panel was invited together to share their views concerning dissolved oxygen sensors for reliable dissolved oxygen measurement.

Optical D.O. sensors developed in the last few years use a technique that essentially measures the rate at which oxygen absorbs an optical signal generated within a membrane impregnated with a fluorescent dye.

Galvanic oxygen sensors measure the current produced in an electrochemical reaction cell. A membrane serves as a barrier to allow molecular oxygen to diffuse into the reaction cell where it is reduced at the working electrode.

This reaction produces a small current which is proportional to oxygen concentration.

There are some fundamental differences between the technologies. Galvanic dissolved oxygen sensors are inherently more precise when measuring low levels of dissolved oxygen. At zero oxygen concentration there is no current.

At low concentrations there is little quenching of the fluorescence, the processor has to reliably measure the small difference between two large numbers.

Galvanic sensors consume oxygen and need a flowing or moving sample. Optical sensors work in stagnant water. One important thing that both types of sensor have in common is that both have a membrane.

The membrane on a galvanic sensor controls the rate of diffusion into the electrochemical reaction cell; on an optical sensor its primary role is to prevent ambient light affecting the measurement.

The cleanliness of the membrane is vital to both types of sensor.

Although most water companies use optical sensors due to the guidance of their frameworks, there is a highlighted concern from the industry as to which type of sensor, if any, is more accurate and efficient.

The panel started proceedings discussing why many water treatment plants are running their treatment plants at dissolved oxygen levels higher than strictly necessary to optimize the process.

The main factors that emerged were a historic lack of confidence in the ability of monitors to reliably measure low dissolved oxygen levels and also the need to comply with regulations mapped out by the Environment Agency.

This over aeration was blamed in the discussion as a reason for large energy costs built up by water treatment plants. Producing high dissolved oxygen concentrations requires large amounts of energy, a waste if dissolved oxygen levels become too high.

Feedback from the Analytical Technology’s roundtable was that water companies prefer to remain on the safe side by over-aerating sewage in order to over-treat it and thus incur large electricity bills rather than incur penalties for breaching consents with the Environmental agency.

There was a consensus among the panel that the most pressing problem with dissolved oxygen sensors is the difficulty cleaning both optical and galvanic sensors, resulting in the build up of sludge which affects the accuracy of both instrument types.

Problems with cleaning dissolved oxygen sensors also unearthed an issue of damaged trust between manufacturers of sensors and water companies, as previously some manufacturers had sold sensors as “maintenance free”.

Those present at the meeting claimed large amounts of time and resources were being spent each year on cleaning sensors. Panel members asked suppliers of dissolved oxygen sensors present, for more information and guidance on the cleaning of these instruments.

The overarching conclusion of the discussion was that instrument maintenance is more important to users than the technology; the instrument must be properly maintained and regularly cleaned in order to measure dissolved oxygen accurately.

It was accepted that electrochemical and optical sensor are both capable of delivering the accuracy and reliability required by water companies if they are kept clean and well maintained.

It was suggested that manufacturers include a maintenance warranty and a technological demand was raised for the auto-cleaning functions of dissolved oxygen sensors to include a sensor to detect when it needs cleaning and to sound an alarm.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,900+ scientific posters on ePosters
  • More Than 4,200+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Roundtable Meeting Highlights Move towards Self-Monitoring of Trade Effluents
Confidence in continuous monitoring equipment grows.
Thursday, August 09, 2012
Analytical Technology Expands Team
Company is expanding its team to increase capacity as prestigious contract wins are secured.
Tuesday, January 17, 2012
Manchester-based Analytical Technology Achieves Record Turnover as Water Industry Thrives
Achievement demonstrates the buoyancy of the current market for water monitoring instrumentation, despite the present economic recession.
Wednesday, August 03, 2011
Scientific News
Breaking Cell Barriers with Retractable Protein Nanoneedles
Adapting a bacterial structure, institute researchers have developed protein actuators that can mechanically puncture cells.
Gene Signature could Lead to a New Way of Diagnosing Lyme Disease
Lyme disease patients had distinctive gene signatures that persisted for at least three weeks, even after they had taken the antibiotics.
Retractable Protein Nanoneedles
The ability to control the transfer of molecules through cellular membranes is an important function in synthetic biology; a new study from researchers at Harvard’s Wyss Institute for Biologically Inspired Engineering and Harvard Medical School (HMS) introduces a novel mechanical method for controlling release of molecules inside cells.
Leukemia’s Surroundings Key to its Growth
Researchers at The University of Texas at Austin have discovered that a type of cancer found primarily in children can grow only when signaled to do so by other nearby cells that are noncancerous.
Common Cell Transformed into Master Heart Cell
By genetically reprogramming the most common type of cell in mammalian connective tissue, researchers at the University of Wisconsin—Madison have generated master heart cells — primitive progenitors that form the developing heart.
‘Smelling’ Prostate Cancer
A research team from the University of Liverpool and the University of the West of England (UWE Bristol) has reached an important milestone towards creating a urine diagnostic test for prostate cancer that could mean that invasive diagnostic procedures that men currently undergo eventually become a thing of the past.
Genetic Mutation that Prevents Diabetes Complications
The most significant complications of diabetes include diabetic retinal disease, or retinopathy, and diabetic kidney disease, or nephropathy. Both involve damaged capillaries.
A Crystal Clear View of Biomolecules
Fundamental discovery triggers paradigm shift in crystallography.
Could the Food we Eat Affect Our Genes?
Almost all of our genes may be influenced by the food we eat, according to new research.
NIH Seeks Research Applications to Study Zika in Pregnancy, Developing Fetus
Institute has announced that the new effort seeks to understand virus effect on reproduction and child development.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,200+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!