Project Reference Number
School/Institute/Research Group
SEBE_DSS_RRI_1
School of Engineering and Built Environment/Institute for Sustainable
Engineering and Technology Research/ Diagnostic Systems & Sensors
Research
Research Discipline
Wastewater treatment, optical sensors, instrumentation, fluorescence
Project Title
Optical Dissolved Oxygen Sensor Incorporating Novel Concentrator
Research Project Summary
Traditionally, dissolved oxygen (DO) has been measured through electrochemical sensors and conducted in laboratories. Unfortunately, such sensors suffer from a number of weaknesses, which include poor response at low concentrations and the need of regular re-calibration due to time-based drifts. This has motivated the development of alternative techniques based on optical sensors, which allow more sensitive, accurate and stable readings than their electrochemical counterparts. A possible application of optical DO sensors is in a wastewater treatment (WWT) plant where accurate monitoring of the DO concentration is required in the aeration process to avoid waste of energy.
A popular opto-chemical method to measure DO is based on the principle of fluorescence quenching by oxygen. Sensors based on this method typically incorporate a source of light (e.g. an LED), which illuminates a fluorescent compound immobilised in a polymer membrane with visible light at around
475nm. The re-emitted light at around 650 nm, is then detected by a photodetector. The fluorescent emission from fluorophores, when quenched by
O
2 results in a decrease in intensity and florescence lifetime. Unfortunately optical sensors suffer from photo-degradation and in a number of cases from a low sensitivity as indicated by the industrial partner.
The proposed project aims at developing a novel optical DO sensor based on optical concentration/collimation techniques capable of outperforming electrochemical and other opto-chemical DO sensors currently employed by industry. This sensor must be robust, low cost and highly sensitive. The fact that industry is increasingly requiring optical sensing techniques in order to remain competitive, as indicated by Strathkelvin Ltd. in their letter of support, demonstrates the timeliness of this project. The solutions to two specific problems are of particular value to the industrial partner: the separation of illumination and re-emitted light wavelengths and the optimum collection of light from the fluorophores.

Supervisory Team
Staff Contact
Dr. Roberto Ramirez-Iniguez (Director of studies)
Department: Computer, Communications and Interactive Systems
School of Engineering and Built Environment
Institute for Sustainable Engineering and Technology Research http://www.gcu.ac.uk/ebe/staff/rramireziniguez/
Dr. Sheila Smith (Co-supervisor)
Department: Mechanical, Electrical and Environmental Engineering
School of Engineering and Built Environment
Institute for Sustainable Engineering and Technology Research http://www.gcu.ac.uk/ebe/staff/drasheilasmith/
Note: the third supervisor will be confirmed next week
Dr. Roberto Ramirez-Iniguez
E: roberto.ramireziniguez@gcu.ac.uk
T: +44 (0)141 331 3527