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.

Bacteriological challenges to asbestos cement water distribution pipelines.

Asbestos cement (AC) pipes were commonly installed in the drinking water distribution systems from the mid 1920s to the late 1980s. In recent years, an increase in the number of water main breaks has occurred in the AC portions of some pipe networks, which can be partially attributed to the corrosion of the aged pipes. This study evaluated the potential role that microorganisms may have played in the degeneration and failure of AC pipes. In this study, a fresh AC pipe section was collected from the distribution network of the City of Regina, Canada and examined for microbiological activities and growth on inside surfaces of pipe sample. Black slime bacterial growths were found to be attached to inner pipe surfaces and a distinctively fibrous internal coating (patina) with iron oxides was formed over the time. The microbial populations inside the patina and the black slime were tested with BART testers. Heterotrophic aerobic bacteria (HAB) and slime forming bacteria (SLYM) dominated in both the black growths and inside the patina. Iron related bacteria, denitrification bacteria and sulfate reducing bacteria were also commonly present. Microbial challenge assays were conducted by submerging the cut segments of the AC pipe into selected bacterial cultures for a period of 10 days under both aerobic and anaerobic environments. Weight changes were determined and the surface morphology was examined for each of the assayed pipe segments. Results indicated that acid producing bacteria, SLYM and HAB could facilitate the pipe weight loss under anaerobicenvironments.

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.

RMS Titanic and the emergence of new concepts on consortial nature of microbial events.

The RMS Titanic sank in 1912 and created a historical event that still ripples through time. Stories were told and lessons learned but the science has only just begun. Today the fading remains of the ship resemble the hanging gardens of Babylon except that it is not plants that drape the walls but complex microbial growths called rusticles. These organisms have been found to be not a species, like plants and animals, but to be structures created by complex communities of bacterial species. Like the discovery of tube worms in the mid-oceanic vents, the nature of these rusticles presents another biological discovery of a fundamental nature. Essentially these microbial consortia on the RMS Titanic have generated structures of a mass that would rival whales and elephants while gradually extracting the iron from the steel. Rusticle-like consortia appear to play many roles within the environment, and it is perhaps the RMS Titanic that is showing that there is a new way to understand the form, function, and nature of microorganisms. This understanding would develop by considering the bacteria not as individual species functioning independently but as consortia of species functioning in community structures within a common habitat. This concept, if adopted, would change dramatically the manner in which a microbial ecologist and any scientist or engineer would view the occurrence of a slime, encrustation, biocolloid, rust flake, iron pan, salt deposit, and perhaps even some of the diseases that remain unexplained as a disease of unknown cause.