Fiachra Collins

CMAS: fully integrated portable centrifugal microfluidic analysis system for on-site colorimetric analysis

A portable, wireless system capable of in situ reagent-based colorimetric analysis is demonstrated. The system is based on a reconfigurable low cost optical detection method employing a paired emitter detector diode device, which allows a wide range of centrifugal microfluidic layouts to be implemented. Due to the wireless communication, acquisition parameters can be controlled remotely and results can be downloaded in distant locations and displayed in real time. The stand-alone capabilities of the system, combined with the portability and wireless communication, provide the flexibility crucial for on-site water monitoring. The centrifugal microfluidic disc presented here is designed for nitrite detection in water samples, as a proof of principle. A limit of detection of 9.31 ppb, along with similar coefficients of correlation and precision, were obtained from the Centrifugal Microfluidic Analysis System compared with the same parameters measured using a UV-Vis spectrophotometer.

Remote Real-Time Monitoring of Subsurface Landfill Gas Migration

The cost of monitoring greenhouse gas emissions from landfill sites is of major concern for regulatory authorities. The current monitoring procedure is recognised as labour intensive, requiring agency inspectors to physically travel to perimeter borehole wells in rough terrain and manually measure gas concentration levels with expensive hand-held instrumentation. In this article we present a cost-effective and efficient system for remotely monitoring landfill subsurface migration of methane and carbon dioxide concentration levels. Based purely on an autonomous sensing architecture, the proposed sensing platform was capable of performing complex analytical measurements in situ and successfully communicating the data remotely to a cloud database. A web tool was developed to present the sensed data to relevant stakeholders. We report our experiences in deploying such an approach in the field over a period of approximately 16 months.

Web-based monitoring of year-length deployments of autonomous gas sensing platforms on landfill sites

This paper describes multiple field deployments of autonomous gas monitoring platforms spanning durations in excess of 12 months. These trials form part of an on-going collaboration with the Environmental Protection Agency (EPA) in monitoring landfill migration of greenhouse gases, i.e. methane (CH4) and carbon dioxide (CO2). Target gas concentrations were automatically recorded via infrared (IR) gas sensors calibrated for the respective gases, with this data being logged remotely every six hours to a central base-station. The autonomous platform with its web-based portal interface provides a flexible alternative to the existing labor-intensive, manual monitoring routines. The duration of the data herein represents one of the longest continuous field deployments of an environmental monitoring device. The real-time monitoring of the gas levels achieved by the bespoke platforms has proven to contribute significantly towards the improved management of landfill sites.

Distributed Environmental Monitoring

With the increasingly ubiquitous use of web-based technologies in modern society, autonomous sensor networks represent the future in large-scale information acquisition for applications ranging from environmental monitoring to in-vivo sensing. This chapter presents a range of on-going projects with an emphasis on environmental sensing; relevant literature pertaining to sensor networks is reviewed, validated sensing applications are described and the contribution of high-resolution temporal data to better decision-making is discussed.