With customers in industries such as municipal water and waste water plants, PAAB work closely with Pi, acting as a distributor of Pi’s products in Sweden. PAAB identified a company in Sweden that required an alternative to traditional colourimetric DPD testing. This customer found that DPD testing was not only costly but did not generate sufficient data for the lower levels of chlorine to be measured.

Traditional DPD colorimetric measurements involve adding DPD reagents to a water sample, leading to a colour change to pink in the presence of chlorine and other oxidising agents. The depth of the colour change is measured and is proportional to the amount of free chlorine and/or total chlorine present. Applications of DPD testing include but are not limited to:

• Municipal drinking water
• Secondary chlorination
• Cooling towers
• Food preparation
• Free chlorine
• Total chlorine

The use of DPD testing methods means that extremely low levels of total chlorine can be difficult to measure. Also, the DPD chemical must be restocked, and this can be costly.

Through Pi’s partnership with PAAB, this customer was offered a more suitable option; the HaloSense from Pi.

The introduction of the HaloSense provided stable and reliable measurements, reduced maintenance and reduced whole life costs. The HaloSense utilises amperometric sensors to accurately and consistently measure chlorine levels within a water without the need for costly reagents. Paired with Pi’s CRONOS®, a high quality, low cost transmitter, the client in Sweden saw immediate success and has plans to upgrade more of their existing DPD installations to HaloSense analysers.