Scottish Water, the publicly owned water supplier for Scotland, have recently invested in new chlorine analysers for sodium hypochlorite monitoring- the HypoSense from Process Instruments (Pi).

The HypoSense from Pi uses an optical sensor with a range of 0-16% and is specifically designed to withstand the harsh chemical environment of industrial bleach (sodium hypochlorite).

Key benefits of the HypoSense include:

• Robust – can withstand harsh chemical environments
• Optical sensors – solid state with no moving parts
• Inbuilt temperature sensor – automatically temperature compensated
• No chemical reagents needed – reduced cost of ownership
• Stable and reliable – excellent process control
• Zero maintenance – reduced cost of ownership
• Up to 15 years life – reduced whole life cost

One issue with chlorine in bleach is the formation of chlorates as the hypochlorite degrades over time. When hypochlorite is used to disinfect drinking water, it can introduce chlorates with a potential detriment to consumer’s health.  The WHO  proposes a maximum of 0.7mg/L, with the DWI considering a 0.25mg/L limit, although currently there are no legal maximums in the UK. Chlorates are formed when the hypochlorite ion oxidises forming sodium chlorate and sodium chloride. As the reaction increases with increasing temperature it can be challenging to monitor and control.                  In order to manage the degradation of sodium hypochlorite held on a drinking water site, Scottish Water are able to use the HypoSense to track the chlorine levels to ensure that the chlorate levels stay within acceptable limits.

The HypoSense was the best option for batch strength and temperature control analysis across three different Scottish Water sites. The addition of the HypoSense chlorine analyser means that current processes in place can be controlled more effectively, therefore minimising the risks associated with chlorate formation.

For more information about the HypoSense, please click here, or contact our sales team by clicking here.