A Micro Total Analysis System (μTAS) for the In Situ, Real-Time Tracking of Produced Water Discharges through Detection of PAHs and Other Aromatic Compounds

Abstract

Here, we present a novel micro Total Analysis System (μTAS) for the measurement of poly cyclic aromatic hydrocarbon (PAH) and other aromatic hydrocarbons (AHs) in water at ng/L levels in situ and in real time (IMiRO). The μTAS is based on in-line membrane extraction followed by detection of extracted aromatic substances with fluorescence. An offshore field demonstration of the method was conducted close to produced water (PW) discharged in the North Sea. PW was monitored with the IMiRO μTAS and compared to results from a simultaneously conducted independent tracer release experiment, where fluorescein was added to the PW as a tracer. The μTAS monitoring and fluorescein tracer experiment showed similar ability to track the dispersion of the PW plume in space, depth, and time. Moreover, the method detected the sum of phenanthrenes and the sum of heavier PAHs with limits of detection down to 6 ng/L, with a response time of 6 min. The novel μTAS system opens up for in situ real-time discharge monitoring of both permitted and accidental oil or PW releases from oil platforms as well as other sources. Such monitoring can also be used to test and verify dispersion models used for environmental risk assessment.