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Fluorescence Analysis and Monitoring of Recirculating Aquaculture Systems

Final Report Summary - FAMORAS (Fluorescence Analysis and Monitoring of Recirculating Aquaculture Systems)

The three main research objectives of FAMoRAS were:

1) Detailed sampling studies of Recirculating Aquaculture Systems: The first objective was to establish typical fluorescence signatures for RASs during normal operation. This involved intensive grab sampling and analysis of RAS water over extended periods to capture variability and directional changes in water quality. Analytical measurements included fluorescence EEM spectroscopy, and bulk parameters including TOC, pH, dissolved oxygen (DO), turbidity, ammonia, nitrates, phosphates, and UV254 absorbance.

2) Statistical analysis: The use of fluorescence EEMs linked with multivariate data analysis such as Principal Components Analysis (PCA), Partial Least Squares (PLS), and Parallel Factor Analysis (PARAFAC). This was used to help identify subtle changes within these systems. This is not possible by analysis with conventional bulk parameters alone; however, coupling bulk parameters with fluorescence spectroscopy further enhance sensitivity. Consequently, conventional water quality parameters also required analysis and interpretation.

3) Design, construct, and test an online fluorescence sensor for RAS water quality monitoring: Construction and testing of an in situ fluorescence sensor was carried out, after being optimised for online, single wavelength monitoring of RASs according to results obtained from grab sampling analyses within the previous two research objectives.

Objectives 1 and 2 were successfully carried out during the previous reporting period (06/2014 – 06/2015) and preliminary results have been published in a high-impact peer-reviewed journal (see below). These results described the difference in organic matter character due to changes in feed loading, and how these small changes are likely very important in managing RAS water quality and subsequent treatment requirements.
Due to the success and timeliness of these initial sampling programs, further sampling has also been carried out to elucidate the changes in organic matter during the entire routine operational lifetime of a RAS. These trials were carried out between March 2015 and August 2015, with subsequent sample analysis and chemometrics. The results have shown the changes in organic matter character during the startup/buildup phase of a freshwater RAS, how each organic matter component comes to equilibrium with the biological treatment systems, an how each component then responds to changes in feed loading once at an equilibrium. The results from these studies are currently being prepared for publication.
Objective 3 was carried out between December and April 2016, which included the construction and bench testing of an online fluorescence spectrometer. Following successfully bench testing of the prototype system, this setup was subsequently trialed in situ, connected to a running, freshwater RAS at equilibrium. Grab sampling was also carried out at the same time, for calibration and further analysis of bacterial populations, to see the effect of “spikes” in organic matter loading on the bacterial community stability. The results for objective 3 are currently being prepared for publication.

From the results of these studies carried out within FAMoRAS, the potential of fluorescence spectroscopy has shown clear potential as a viable way to monitor organic matter with recirculating aquaculture systems. As such, there are also clear potential benefits for EU aquaculture industry, to further develop such an online sensor and optimize the management and operation of aquaculture facilities. This is an important topic, as aquaculture is essentially the future of seafood production for human consumption. The incoming researcher was able to make a number of new collaborations with EU research institutions, and is currently preparing funding proposals for further research into this topic.