Researchers at the UK’s Centre for Ecology & Hydrology (CEH) have conducted trials on the river Thames to evaluate a new remote phosphate monitoring technology (Cycle-P)as part of a high-frequency (hourly resolution) monitoring programme that is studying river nutrient concentrations and how they are affected by algal abundance. The monitoring system ran continuously over the summer of 2014,measuring total reactive phosphate levels in the river, day and night, seven days a week. These results have now been compared with manually collected samples that were analysed in a laboratory with the traditional Murphy and Riley spectrophotometric method on unfiltered samples, and Dr Mike Bowes, senior nutrient hydrochemist at CEH, says: “The Cycle-P is working really well; the system operated independently for long periods and produced results that tracked our lab samples closely.”
Most water quality parameters are relatively simple to measure with low-power accurate sensors. However, the measurement of phosphate necessitates colorimetric analysis and this presents a significant challenge in remote locations with difficult access or where mains power is not available. The Cycle PO4 from OTT Hydrometry (known as the Cycle-P) is therefore gathering considerable interest because it is battery powered and able to operate unattended in the field,running over 1,000 tests before a field service is necessary to change the reagents.