Development of an analytical microbial consortia method for enhancing performance monitoring at aerobic wastewater treatment plants.

An analytical method to produce profiles of bacterial biomass fatty acid methyl esters (FAME) was developed employing rapid agitation followed by static incubation (RASI) using selective media of wastewater microbial communities. The results were compiled to produce a unique library for comparison and performance analysis at a Wastewater Treatment Plant (WWTP). A total of 146 samples from the aerated WWTP, comprising 73 samples of each secondary and tertiary effluent, were included analyzed. For comparison purposes, all samples were evaluated via a similarity index (SI) with secondary effluents producing an SI of 0.88 with 2.7% variation and tertiary samples producing an SI 0.86 with 5.0% variation. The results also highlighted significant differences between the fatty acid profiles of the tertiary and secondary effluents indicating considerable shifts in the bacterial community profile between these treatment phases. The WWTP performance results using this method were highly replicable and reproducible indicating that the protocol has potential as a performance-monitoring tool for aerated WWTPs. The results quickly and accurately reflect shifts in dominant bacterial communities that result when processes operations and performance change.

Quantitative bacteriological assessment of aerobic wastewater treatment quality and plant performance.

The application of a novel method for measuring changes in defined bacterial populations during aerobic wastewater treatment was investigated. Changes in bacterial communities and total active cells can be used as surrogates for identifying potential WWTP treatment train efficiency and operational performance malfunctions. In this study, the quantities of active heterotrophic aerobic bacteria (HAB) in weekly wastewater samples collected from twelve locations across a WWTP were determined colorimetrically using biological activity reaction tests (BART). Samples were collected for 2 months from primary, secondary and tertiary unit processes. The results show a mean HAB population decrease of 99.8% from primary influent to tertiary effluent, with the largest reductions occurring in the secondary aerobic lagoons. The results were reproducible and robust supporting the applied BART analytical method as an indicator not only of overall efficacy of the WWTP processes but also of potential WWTP process malfunctions.

A rapid methodology using fatty acid methyl esters to profile bacterial community structures in microbial fuel cells.

A new methodology is presented here as an effective, preliminary technique for the identification of indigenous aerobic and facultatively anaerobic bacterial communities found within microbial fuel cells (MFCs). The dual-phased method, named Rapid Agitation Static Incubation-Microbial Identification, or RASI-MIDI, is comprised of rapidly agitating the sample within a SLYM-BART tester followed by stationary incubation which produces a biomass that is subjected to extraction of methyl ester fatty acids. These distinctive fatty acid profiles represent a bacterial community fingerprint unique to the MFC, and are stored in a library for analysis. A total of 84 samples were analyzed for bacterial community structures from seven different groups of MFCs, with each MFC group comprised of a different bacterial community. Results showed that comparisons of replicate MFCs comprising the same bacterial communities generated high similarity index (SI) numbers (SI values ranging from 0.77 to 0.97), indicating highly correlated fatty acid profiles. In contrast, comparisons of MFCs having known dissimilar community structures did not consistently generate SI values in the analysis considered to be a significant match. It was found that this protocol described herein uniquely and accurately produced MFC fatty acid profiles contained in bacterial communities and thus provides a potential method for routinely studying MFC bacterial community fingerprints.