15 April 2024

Prototyping of a portable sensor for pathogen monitoring for domestic wastewater treatment processes

Author/Compiled by
Santiago Gómez Cuervo (AIMEN)
Miguel Placer Lorenzo, (AIMEN)

Executive Summary

What was the purpose of this prototype project?

This prototype project was about developing and field-testing a portable pathogen sensor based on Tryptophan-like fluorescence (TLF). Initially, this sensor was supposed to be designed for pathogen detection for an UV disinfection system in a pilot plant on the premises of AMU in Aligarh. In the course of the project, the application context for the sensor was adapted to pathogen detection in groundwater at PAVITR’s wastewater-fertigated Short Rotation Plantation pilot site.


Project Milestones & Key-learnings

Factsheet Block Body

Below we describe some of the main steps we took during the implementation of this prototype project. Also, we share some of the practical challenges we ran into along the way and how we overcame them.

  • Design & compilation: initially, the sensor was designed to be applied for measuring pathogens in primary effluent of an UV disinfection system. Eventually, it turned out that the unit envisaged for this field-application was no longer operated. For this reason, we instead projected to field-test the sensor for pathogen monitoring in groundwater at PAVITR’s wfSRP site in Aligarh.
  • Calibration: to assure the accuracy of the sensor, it was first calibrated in AIMEN’s lab facilities in Spain, using E. coli laboratory cultured samples, tap water and groundwater from local sampling points. This approach was chosen due to the logistical challenge of sending samples from India to Europe to carry out calibration. Due to the change in the field-testing site (see above), a second calibration campaign was performed in order to adapt the sensor to the new application context. Lack of certified laboratories to perform coliforms testing nearby the site as well as administrative challenges made these campaigns really complicated.
  • Validation: to assure and document the sensor consistently provides acceptable results, validation was carried out for local water conditions (turbidity, chemical composition, biological contamination of groundwaters, etc.) as part of the wfSRP piloting activities in Aligarh, India.
  • Setting up the sensor operation: anticipating potential staff rotations and lack of specifically trained and assigned operation personal to use the sensor– the following measures were taken to prepare the operational phase: first of all, the sensor was designed as “easy-to-use” model allowing staff that only received basic training to use it. Also, the O&M training held by AIMEN was organised on two occasions and also recorded so the content could also be made available for new operation staff.

Collection and management of testing results: initially, it was planned to connect the sensor to a gateway that would allow automatic data analysis, results display and data upload to a cloud. However, due to several reasons, it was impossible for AIMEN to stablish a functional data communication system. So, a work-around was organised where the results data are downloaded from the sensor via USB by the operator himself.


Operational experience and performance

Factsheet Block Body

Three additional testing campaigns have been undertaken by AMU research staff during September 2023, sampling wfSRP groundwater at different areas and measuring it on the portable pathogen sensor. This testing campaigns were very efficient, because the measurement only takes seconds (the water sampling needs to be done anyway for the wfSRP operation), the volume needed is only 5 ml and the data is easy to store. The pathogen sensor has proven to be a robust option, with high sensitivity, good correlation with lab analysis results, easy to use and relatively low-cost.


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