Name:

 Dr. John Cleary

Contact details

Qualifications

Ph.D. (2005) University of Limerick.

Thesis title: “Characterisation of a thermoreversible hydrogel for the controlled release of pharmaceutically active compounds”.

B.Sc. (1998) University of Limerick.

Industrial Chemistry; including cooperative education placement at Ely Lilly S.A. (pharmaceutical manufacturer), Kinsale, Co. Cork.

Project Summary

Autonomous monitoring of nutrient levels in natural waters.

Nutrient pollution

Pollution of natural waters by excessive inputs of nutrients is a serious issue in Ireland and many other countries. Elevated nutrient levels lead to excessive growth of algae and other aquatic fauna, which in turn cause oxygen depletion, damaging the ecosystem and leading to fish kills in severe cases. Algal blooms can result in water becoming toxic to animals and humans, impairing the use of water resources for drinking, recreation and other purposes. Phosphate is of particular significance in relation to rivers and lakes as it is typically the limiting nutrient in these freshwater ecosystems. Phosphate inputs typically come from agriculture (fertilizers and animal wastes), municipal wastewater discharges (treated and untreated) and industrial sources.

Nutrient pollution leads to excessive plant and algal growth in rivers and lakes, as shown in this 2008 photograph of the Broadmeadow River, Co. Meath.

Autonomous Monitoring

Due to the growing awareness of the need to protect our natural water resources, and to environmental legislation such as the EU's Water Framework Directive (Directive 2000/60/EC), there is a major impetus towards increased monitoring of rivers, lakes, estuarine and coastal waters, and the ocean.

Autonomous monitoring systems have the potential to significantly improve our ability to monitor the quality of the aquatic environment by allowing continuous or high frequency measurements of water quality parameters at a higher temporal and geographic density than is achievable using current approaches (generally based on manual sampling). A key requirement of these systems is the ability to function reliably for long periods of time without the need for frequent maintenance visits.

Microfluidic analysis systems offer the ability to perform rapid analysis of samples while minimizing the amounts of sample, reagents, waste storage, and power required. In combination with low power wireless communications systems, this technology enables the development of compact, low-cost analysis systems which can provide reliable information on the state of natural waters over extended deployment periods.

Microfluidic technology, such as the chip shown here, is a key component of the phosphate analyser.

Phosphate sensor

At the Adaptive Sensors Group, a portable sensor for the analysis of phosphate in aqueous samples has been developed. The sensor incorporates microfluidic technology, colorimetric detection, and wireless communications into a compact and rugged portable device. The detection method used is the molybdenum yellow method, in which a phosphate-containing sample is mixed with a reagent containing ammonium metavanadate and ammonium molybdate in an acidic medium. A yellow-coloured compound is generated and the absorption of this compound is measured using a light emitting diode (LED) light source and a photodiode detector. The absorption is directly proportional to the phosphate concentration in the original sample.

The complete analysis system, consisting of sampling, pumping, microfluidic manifold, detector, power supply, control board, data storage, GSM modem for wireless communication, and reagent and waste storage, is contained within a robust and portable enclosure.

The prototype phosphate analyser has been extensively assessed in the laboratory and during long-term deployments at Osberstown Wastewater Treatment Plant in Co. Kildare.

 A plot showing agreement between the output of the prototype phosphate analyser (P-PO4 NCSR) and that of an industry standard online monitoring system (P Aztec P100) during a trial of the prototype system at a wastewater treatment plant in 2008.

Ongoing research is focussed on:

• Optimising the performance of the phosphate analyser to yield a commercially viable water quality monitoring product. This work is being undertaken in collaboration with Episensor Ltd., Limerick.
• Using the existing system as a platform which can be further developed and expanded to allow the detection of other environmentally important analytes. Target analytes include nitrogen-based nutrients (ammonia, nitrate/nitrite) and toxic heavy metals such as lead and cadmium.

Publications

Integration of Analytical Measurements and Wireless Communications – Current Issues and Future Strategies, Dermot Diamond, King Tong Lau, Sarah Brady and John Cleary, Talanta 75 (2008) 606-612.

An Autonomous Microfluidic Sensor for Phosphate: On-Site Analysis of Treated Wastewater, John Cleary, Conor Slater, Christine McGraw and Dermot Diamond, IEEE Sensors Journal, 8 (2008) 508-515.

Autonomous microfluidic system for phosphate detection, Christina M. McGraw, Shannon E. Stitzel, John Cleary, Conor Slater and Dermot Diamond, Talanta 71 (2007) 1180–1185.

Intelligent Environmental Sensing with a Phosphate Monitoring System and Online Resources, J. Hayes, J. Cleary, C. Slater, K.-T. Lau, and D. Diamond, Computation In Modern Science And Engineering: Proceedings of the International Conference on Computational Methods in Science and Engineering 2007 (ICCMSE 2007), Volume 2, pp 1216-1219.

CO₂ Laser Microfabrication of an Integrated Polymer Microfluidic Manifold for the Determination of Phosphorus, Michaela Bowden , Oliver Geschke , Jörg P. Kutter and Dermot Diamond, Lab on a Chip, 3 (2003) 221-223.

Analysis of River Water Samples Utilising a Prototype Industrial Sensing System for Phosphorus based on Micro-system Technology, Michaela Bowden, Margaret Sequiera, Jens Peter Krog, Peter Gravesen and Dermot Diamond, J. Environ. Monit., 4 (2002) 1–6.

Further Information

For information on the state of water quality in Ireland see:

• http://www.epa.ie/environment/water/
   

For more information on the EU Water Framework Directive see:

• http://www.wfdireland.ie/index.html
  
• http://ec.europa.eu/environment/water/water-framework/info/intro_en.htm

Funding

This research is funded by Enterprise Ireland under the Innovation Partnership and Commercialisation Fund – Technology Development schemes (2008). Grant codes IP/2008/544 and CFTD/08/111 respectively.

The Adaptive Sensors Group is supported by Science Foundation Ireland under the CLARITY CSET award (07/CE/I1147).

The prototype phosphate sensor was developed during the SmartCoast project (AT/04/01/06) which was funded by the Marine Institute and the Environmental Protection Agency.