Developments in solid-state electronics and small high-powered light sources (like the LEDs in this image) have supported rapid progress with optical sensor technology during the last decade.
Advances in technology, including miniature sensors and robotic fish, are leading a rapid advance in online smart monitoring of the quality of water in both municipal and industrial systems across the world, according to a new report.
A new Insight Report from BlueTech® Research* states that water quality issues and monitoring technologies in developing markets are likely to drive double digit global growth in the coming years. The Asia-Pacific region is expected to emerge as the fastest growing market.
The water analysis industry has seen dramatic growth in recent years due to rapid rises in population and increasing concerns over water contamination. The call for safe, clean water has led to tighter, more stringent water quality regulations.
Equipment in a water system can fail, leading to a change in water quality. The use of smart water networks is one way in which utilities are seeking holistic approaches to water management, within which they aim to identify health and operational risks, either before an incident develops or within the shortest possible response time.
New developments in sensor technologies currently focus on two types of technologies:
1. Biosensors for the detection of bacteria and other microorganisms
2. Optical sensors.
Figure 1 shows an overview of the developmental stages of new technologies, the results expected from each stage and some examples of companies currently at each stage of commercial development.
Figure 1: Developmental stages of monitoring technologies
Until recently, the development of online monitoring equipment focused on the detection and analysis of physico/chemical compounds. Now, there is a shift towards sensors that can rapidly and reliably detect harmful microorganisms such as Legionella, Cryptosporidium, Giardia and E. coli.
The rapid and accurate detection of micro-organisms is of particular value in the drinking water sector. Currently, analysis still relies on slow culturing methods or polymerase chain reaction (PCR) methods, both of which can only be performed in a laboratory.
The arrival of solid-state electronics and small high-powered light sources (LEDs, laser diodes, small Xenon lamps) has triggered a rapid development of optical sensor technology during the last decade. The most interesting aspect of the current generation of optical sensors is that they operate without the need for chemicals and use components that are less prone to fouling.
When replacing wet-chemical analysers, the elimination of the use of chemicals also eliminates the production of waste products during the analysis. This is a major advantage optical sensors have over wet-chemical analysers.
New developments in the field of optical sensors focus on the following approaches:
• Development of luminescence-based technologies based on the success of the Luminescent Dissolved Oxygen (LDO) probes, to measure other important parameters such as pH
• Use of optical imaging techniques, for example, in the detection and classification of particles and micro-organisms
• Use of unconventional physical properties as water quality indicators (for example, refractive index)
• Contact-free measurement (remote sensing)
Recent developments in water quality sensor networks include:
• Miniaturised sensors for monitoring colour, sum organics (COD, TOC, DOC) and turbidity in a drinking water distribution network (s::can, AT; Vitens Water Company, NL; funded by the European Commission)
• Non-mobile wireless sensors located in ponds and streams to measure various parameters such as turbidity, salinity, pH and nitrate (University of Minnesota, USA)
• Robotic fish equipped with tiny chemical sensors to locate sources of potentially hazardous pollutants in the water, such as leaking underwater pipelines (University of Essex, UK; funded by the European Commission)
Maintenance requirements and battery life are currently two important barriers to the successful large-scale implementation of smart water quality sensor networks.
For further details on the state of existing and emerging online water and wastewater monitoring technologies, the drivers and barriers for these technologies, and the market profile, see Online Water and Wastewater Sensors and Analysers published by BlueTech Research in September 2014.