Fully automated on-line analyser for monitoring coliforms and Escherichia coli in water and wastewater

A new instrument, the Easychem® coli on-line from Systea SpA, which was designed for fully automated Total Coliform (TC), Escherichia coli (EC) and Faecal Coliform (FC) measurements based on specific enzyme activity, was recently launched at the IFAT trade fair in Munich. The instrument is a robotic water analyser with integrated colorimeters and fluorometers on thermostatic incubating positions that can concurrently detect both TC and EC or FC in water and wastewater. The Easychem provides timely results during 18 hour-monitoring sessions using IDEXX’s Colilert® method, a worldwide USEPA-approved recognised standard (ISO 9308-2:2012). 

Easychem® coli on-line has two main configurations for rapid detection of faecal contamination in water. In drinking water testing, the on-line analyser can be configured for presence / absence determination of TC and EC, or FC. This model comprises 56 positions for Colilert® vessels and growth media with 4 available incubating positions to perform up to 4 simultaneous automated analysis. The kinetic monitoring of colour and fluorescence variation enables the Easychem to provide early warning signals in cases of coliform detection and to estimate the contamination level.

For the on-line monitoring of wastewater, urban and industrial effluents, and ambient waters, including surface and source water, Easychem® coli on-line contains 28 Colilert® bottles and is also equipped with an 80-position cuvette reaction plate for multiple tube fermentation analysis. Quantitative determination of the population of viable organisms is achieved via the Most Probable Number (MPN), whereas the time-to-detect functionality allows the analyser to trigger early alert signals by estimating the actual contamination using the time requested to overcome the set threshold. Given the countless potential environmental scenarios, the instrument was designed with flexibility in mind, to make it easy to adjust to different applications. Typical ranges vary from 0 – 512 MPN / 100 mL for low contaminated waters to 72 – 14848 MPN / 100 mL for wastewater effluents. The analytical frequency is normally agreed upon with the user and reaches up to 10 analysis per day. A log comparison between norm-referenced manual test Quantitray® 2000 and the automated analysis executed with Easychem® coli demonstrated a statistically significant correlation (R2 = 0.94).