ColiMinder (CMI-02) online E. coli and transmittance dataset in reclaimed water - Roquetas de Mar WWTP

This dataset contains the data collected by the ColiMinder (CMI-02) device, specifically enzymatic activity measurements of Echerichia Coli (E.Coli) in mMFU/100 mL and the water transmittance in percentage (%). This data was used to evaluate ColiMinder (CMI-02) viability as an online early-warning system for E. coli detection in reclaimed water at Roquetas de Mar wastewater treatment plant (WWTP), with the aim of supporting compliance with RD 1085/2024 for A.A type quality water. The study aim to compare ColiMinder E. Coli measurements against the reference method IDEXX Colilert-18, used daily at the WWTP, to identify a potential correlation between both methods. The data set also includes Coliminder installation, commissioning, laboratory testing, plant trials, and two pre-validation processes. Additionally WWTP measurements related to water quality such as residual chlorine, UV transmittance, UV dose, turbidity, pH, and conductivity are also included. The initial laboratory-scale setup of the ColiMinder demonstrated the potential applicability of the equipment for monitoring microbiological activity, with measured values ranging between approximately 500 and 1,200 mMFU/100 mL. This preliminary assessment was consistent with the intended use of ColiMinder as a rapid enzymatic activity-based monitoring system for microbiological water quality, including E. coli-related activity. However, during the pre-validation of a limit test aimed at defining an alert threshold associated with values above 7 E. coli/100 mL, the relationship between ColiMinder and the Colilert-18 reference method remained weak, with an R² value of 0.153. Consequently, the limit-test approach could not establish a reliable ColiMinder value range associated with Colilert-18 results above 7 E. coli/100 mL. This is particularly relevant because on-site validation should be based on parallel measurements between ColiMinder and the laboratory reference method under representative conditions. In the second prevalidation campaign, the reference method detected 0 MPN/100 mL, while ColiMinder continued to report activity in the range of approximately 169 to 234 mMFU/100 mL. These results indicate that, under the current operating conditions and matrix evaluated in the reclaimed water tank, ColiMinder activity could not be reliably associated with E. coli presence as determined by Colilert-18. Therefore, the study concluded that the device is not recommended as an early-warning system for E. coli in the reclaimed water tank under the current operating conditions.