Development of a Low-Cost Portable Water Quality Sensor Array for Real-Time Monitoring of Drinking Water Contaminants Using Microfluidic Integration

Project Abstract

This study presents the design, fabrication, and validation of a low-cost, portable water quality sensor array capable of real-time monitoring of drinking water contaminants through microfluidic integration. The system combines a multiplexed sensor array with microfluidic channels to enable simultaneous detection of multiple parameter classes, including inorganic ions (e.g., lead, nitrate, chloride), organic contaminants (e.g., total organic carbon, pesticide residues), biological indicators (e.g., E. coli-derived surrogate assays), and physical properties (pH, turbidity, temperature). The core sensing modalities include electrochemical amperometry/voltammetry, impedance spectroscopy, colorimetric microdroplet assays, and integrated on-chip plasmonic or fluorometric readouts, chosen for compatibility with low-cost printed circuit board (PCB) electronics and mass-manufacturable microfluidic substrates such as cyclic olefin copolymer (COC) or paper-based microfluidics. A modular approach enables plug-and-play sensor cartridges, enabling adaptability to evolving regulatory standards and target contaminants. The microfluidic network is designed to minimize sample volume (<100 µL per assay) and ensure rapid mixing, controlled incubation, and waste containment, while preserving portability through battery-powered operation and low-power circuitry. Data acquisition is conducted with a compact microcontroller unit (MCU) and a Bluetooth Low Energy (BLE) communication module, enabling edge computing for preliminary data processing, calibration correction, and anomaly detection. A lightweight firmware stack supports onboard timestamping, data logging, and cloud synchronization for longitudinal monitoring of municipal supply lines or field deployments in rural communities. The study emphasizes low-cost materials and scalable manufacturing strategies, including screen-printed electrodes, inexpensive nanomaterials, off-the-shelf microfluidic manifolds, and open-source software frameworks, to reduce the overall system cost to a target under $150 per unit without compromising analytical performance. Analytical performance is validated through laboratory calibration against standard reference methods, followed by field trials in diverse water matrices, including tap water, groundwater, and surface water from multiple geographic regions. Performance metrics assessed include limit of detection, linear dynamic range, selectivity against common interferents, response time, reproducibility, environmental stability, and robustness to mechanical perturbations. The integration framework addresses cross-talk mitigation, sensor drift, and calibration transfer between devices, leveraging machine learning-based correction models trained on multi-parameter datasets. The results demonstrate reliable real-time monitoring of key water quality indicators under continuous operation, with rapid alert generation when contaminant levels exceed safety thresholds. The developed platform provides a scalable, affordable solution for continuous water quality surveillance in resource-limited settings, enabling proactive public health interventions and empowering end-users with actionable water safety information. Ethical considerations regarding data privacy, user consent, and community engagement are incorporated into deployment strategies, ensuring responsible access to water quality insights. The study also discusses potential environmental and safety implications of disposable sensor components and outlines pathways for sustainable end-of-life management. Overall, the work contributes a practical blueprint for democratizing access to comprehensive drinking water analytics through an integrated microfluidic-sensor platform designed for portability, affordability, and resilience in challenging field environments.

Project Overview

What This Project Is About

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A straightforward study of a compact system that can test drinking water for common contaminants in real time. It combines low-cost sensors with microfluidic channels to move small water samples through measurement zones, giving quick readings without sending samples to a lab.

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The Problem It Addresses

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Many communities lack easy access to fast, affordable water quality testing. Traditional lab tests are slow and expensive, delaying detection of pollutants. This project aims to create a portable, inexpensive device that can monitor water on-site and alert users to potential issues.

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Objectives of the Project

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1. Design a compact sensor array capable of detecting multiple water contaminants.
2. Integrate microfluidic channels to handle tiny water samples efficiently.
3. Keep production costs low while maintaining reliable measurements.
4. Test the device with common contaminants (e.g., pH, turbidity, chlorine).
5. Develop simple data display and interpretation for non-experts.

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What You Will Do Step by Step

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1. Survey existing sensors and microfluidic components to choose suitable parts.
2. Prototype a small, handheld device housing sensors and microfluidic paths.
3. Calibrate sensors using standard water samples and known contaminant levels.
4. Build a basic readout system (visual/numeric display) and data logging capability.
5. Run field tests with real water samples and compare results to lab tests.
6. Analyze data for accuracy, precision, and response time.
7. Document design choices and assess manufacturability and cost.
8. Prepare a user guide and safety considerations for operation.

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Expected Outcome

The project should yield a functioning low-cost portable sensor array capable of real-time water quality readings, with validated accuracy for selected indicators and a simple user interface. It will demonstrate feasibility for on-site monitoring and potential deployment in communities lacking laboratory access.