The principal objective of this project was to develop a new on-line measurement system based on infrared attenuated total reflection (ATR) using a polymer-coated sapphire rod for direct quantification of the total hydrocarbon index in water employing the C-H stretching vibration. The sensor was evaluated via laboratory and industrial trials and was developed to a pre-competitive technical prototype stage.
An on-line hydrocarbons in water measurement prototype system was developed. The LOD at present for the laboratory prototype, is 5ppb for Undecane with a PDMS sensing layer. The detection limit for the smaller hydrocarbons is in the region of 10ppm. The prototype system has achieved similar sensitivities. This is sufficient for an alarm level indicator for river water intake.
The ability to measure a wide range of hydrocarbons was shown for the range of aliphatic hydrocarbons from C5 to C20. A prototype system was developed and tested on site at a water treatment works by an industrial partner. The performance to date has shown good reliability with no erroneous readings and compares favourably with existing commercial monitors.
Hydrocarbons can enter surface water by anthropogenic means from industrial discharges and by spillages. In the case of heavier accidents hydrocarbons may even enter groundwater and as a result pose a threat to human health. In recent years the standard procedure for the determination of hydrocarbons in water included extraction using perhalogenated solvents and subsequent IR spectrometry. However, these solvents have been shown to be hazardous to the environment and must be removed from future use due to EU legislation. Also laboratory analysis by its nature is time consuming, expensive and the inherent time delay means that environmental damage is not being properly monitored.
To achieve the project goals the following work packages were undertaken: (1) Instrument Definition: including a review of relevant component technology, identification of analytes to be detected, instrument design and definition of a comprehensive measurement methodology. (2) Sensor Head Optimisation: identification and evaluation of appropriate polymers, functionality testing of the polymer coated sapphire rods and optimisation of the sensor head. (3) System Integration: fabrication and testing of the technical prototype and software development. (4) System Calibration and Optimisation. (5) Industrial Evaluation by End Users: incorporating field trials at end user sites.
Funding SchemeCSC - Cost-sharing contracts
B76 9BL Sutton Coldfield
B26 3PU Birmingham