Evaluation of real-time fluorescence sensors and benchtop fluorescence for tracking and predicting sewage contamination in the Tijuana River Estuary at the US-Mexico border.

Cross-border flow of untreated sewage from Mexico into the USA via the Tijuana River is public health issue with negative consequences for coastal communities. Here we evaluate the potential application of fluorescence-based, submersible tryptophan-like (TRP) and humic-like (CDOM) fluorescence sensors for real-time tracking of wastewater pollution in an estuarine environment. Sonde fluorescence measurements were compared with benchtop fluorescence, fecal indicator bacteria (FIB) concentrations, and real-time specific conductivity measurements in the Tijuana River Estuary during dry and wet weather conditions, and with and without cross-border flow.

Low maintenance anammox enrichment and nitrogen removal with an anaerobic baffled reactor.

The stringent growth requirements of anammox bacteria may be a challenge for employing the anammox process for nutrient removal at household or decentralized scales, where low maintenance systems are more successful. Enrichment of anammox bacteria was achieved by 100 d using a lab-scale (32 L) anaerobic baffled reactor (ABR). Even though strict anaerobic conditions were not imposed, NH-N and NO-N removals of >90% were maintained after ∼100 d, with greatest removals observed in the first two chambers of the four-chamber ABR.