An integrated water quality sensing system : a review and analysis of critical parameters and an evaluation of contact and non-contact sensors : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University Albany, New Zealand

Figure 7 is re-used under a Creative Commons Attribution-ShareAlike 3.0 Unported (CC BY-SA 3.0) license. Figure 8 is re-used under a Creative Commons Attribution 4.0 International (CC BY 4.0) license. Figure 9 is re-used with the publisher's permission. Permission has been granted for the re-use of Figures copyrighted to IEEE (© IEEE).Several methodologies and standards exist for the measurement of water quality. The use of established water quality indices is embedded in these methodologies/standards and the measurement approach of these indices involves several different techniques and sensor technologies. Recent development in the field of water quality measurement has moved towards wireless sensor network systems to enable the monitoring of multiple bodies of water in any given geographical region, with most of the research focussing on the use of the Internet of Things (IoT) for the associated water quality sensing systems. There exists a small amount of research into combined sensor technologies that enable measurement simultaneously of multiple parameters. There is currently, however, no analysis available on the feasibility of developing a fully integrated system to measure all desirable water quality parameters simultaneously. Sensor solutions and analysis techniques for such a fully integrated system are therefore lacking. This research analyses common water quality measurement methods, comparing them particularly to non-contact alternatives to determine the viability of a cost effective and fully integrated water quality sensing system. In parallel it seeks to determine which types of sensors are best for effective analysis of water quality in distributed bodies of water. Literature analysis determined that a cost-effective, fully integrated water quality sensing system was feasible if the water quality parameters being measured were limited. As a result, an analysis of contact and non-contact sensors for the selected parameters was conducted. The results of this analysis were varied, and it was concluded that the types of sensor that should be used in an integrated water quality sensing system are dependent on the design of the critical parameter set being measured

Turbidity and RI Dependency of a Polymer Optical Fiber-Based Chromatic Sensor

An in-line and real time chromatic sensor for liquids based on plastic optical fiber was developed. It uses an air gap, fiber to fiber, transmission principle. Its dependency to turbidity and refractive index is studied and characterized. This information will provide the necessary knowledge for future implementation of more complex auto-compensations routines. Due to the predictable behavior of the sensor to variations of turbidity and refractive index, it is shown that a posterior compensation could be applied for the discrimination of color. The real-time color sensor can be used in different turbid liquids and contain different refractive indices