Regina, Canada
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Razban B.,University of Regina | Nelson K.Y.,University of Regina | McMartin D.W.,University of Regina | Cullimore D.R.,Droycon Bioconcepts Inc. | And 2 more authors.
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering | Year: 2012

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. © 2012 Copyright Taylor and Francis Group, LLC.

Wang D.,National Research Council Canada | Cullimore R.,Droycon Bioconcepts Inc. | Hu Y.,National Research Council Canada | Chowdhury R.,National Research Council Canada
International Biodeterioration and Biodegradation | Year: 2011

Various types of microorganisms have been found to inhabit the inner surfaces of asbestos cement (AC) pipe and their activities can cause significant structural damage. They cause a patina to form on the inside surface of AC pipes as a distinctively continuous coating, commonly 2-5 mm in thickness and generally pigmented as yellow, orange, brown or black depending on the metallic cations that have been incorporated into the surface of biofilm (bioaccumulation). Four sublayers can be identified in the patina, from the outer sublayer that directly interacts with the conveyed drinking water to the inner sublayer that is in proximity of the intact cement matrix. The microbes in the outer sublayer are composed mainly of inactive biomass that separates the aerobic environment of the flowing water from the anaerobic conditions inside the patina. The bacteriological community structure shifts from mixed heterotrophic bacteria (HAB), iron-related bacteria (IRB) and slime-forming bacteria (SLYM) in the outer layer, to a more diverse community with IRB, acid-producing bacteria (APB) and SLYM and HAB in the middle sublayer, and further to the SLYM dominated in the inner sublayer. By directly interacting with cementitious materials, including generating organic acids, IRB and APB play important roles in the leaching of free lime and the dissolution of calcium (Ca)-bearing hydrated components of AC pipes, creating porous structure and reducing the pipe strength. Scanning electron microscopy with an energy dispersive X-ray has revealed that bacterial activity on the internal AC pipe wall had resulted in a significant loss of hydrated cement matrix, which can cause pipe failure when stresses imposed on the pipe exceed the remaining pipe strength. © 2011.

Razban B.,Droycon Bioconcepts Inc. | Chen W.,University of Regina | Wang D.,National Research Council Canada | McMartin D.,University of Regina | Cullimore R.,Droycon Bioconcepts Inc.
NACE - International Corrosion Conference Series | Year: 2010

Asbestos reinforced concrete (ARC) pipes were commonly used for drinking water distribution networks in North American, primarily from middle1940s to early 1980s. In the City of Regina, Canada approximately 68% of all water mains are ARC pipes, to a total length of 535 km. In this preliminary research it was found that bacteriological activities within the internal surface coating (patina) as well as within the concrete could induce bio-deterioration, which eventually leads to pipe failures. Identification of the bacterial consortia was performed using the S43048 protocols for the chromatographic detection of the C5 to C20 fatty acids methyl esters (FAME). Using proprietary library software, high similarity indexes were statistically generated, confirming the ubiquitous nature of the bacterial community (consortium) within the patina (a distinctively fibrous internal coating) of various pipe samples. Bacteriological activities caused deterioration to the ARC pipes was primarily related to acid producing bacteria. These bacteria are fermentative in the reductive environments, generating sufficient fatty acids that would reduce the pH into the acidic range of 3.5 to 5.5 and could cause structural failures in the concrete. © 2010 by NACE International.

Nelson K.Y.,University of Regina | Razban B.,University of Regina | McMartin D.W.,University of Regina | Cullimore D.R.,Droycon Bioconcepts Inc. | And 2 more authors.
Bioelectrochemistry | Year: 2010

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. © 2009 Elsevier B.V. All rights reserved.

Razban B.,University of Regina | Nelson K.Y.,University of Regina | Cullimore D.R.,Droycon Bioconcepts Inc. | Cullimore J.,Droycon Bioconcepts Inc. | McMartin D.W.,University of Regina
Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering | Year: 2012

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. © 2012 Copyright Taylor and Francis Group, LLC.

Wang D.,NRC Institute for Research in Construction | Cullimore D.R.,Droycon Bioconcepts Inc.
Journal of Environmental Sciences | Year: 2010

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(tm) 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 anaerobic environments. © 2010 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences.

Cullimore D.R.,Droycon Bioconcepts Inc. | Johnston L.,Droycon Bioconcepts Inc.
Corrosion and Materials | Year: 2011

Traditionally microbiologically influenced corrosion (MIC) processes have been linked to the activities of the sulfate reducing bacteria (SRB). Here the major daughter product is hydrogen sulfide (H2S) which then triggers electrolytic corrosion. Corrosion can be initiated when H2S gas comes into contact with the surfaces of steels. Microbiological investigations of MIC have been found to involve a sequence of events including: Biomass attaching to surfaces, growth activities, impacts on the supporting matrices below the attachment surfaces, and then corrosion of the matrices commonly leading to structural collapse. From the studies primarily on mild steels, but also including concrete and wood, a pattern of microbiological activity has been observed that commonly occurs when corrosion risks are significant. These include the physical and chemical nature of the surface to which the biomass attaches and grows; the nature of the environment at the surface interface; the form of biomass growth; interactive nature of the biomass with the matrix; and the final states of stabilization or destruction of the matrix and associated biomass. Critical to the MIC corrosive process is the form and function of the associated attached active biomass interacting with the surfaces of the potentially vulnerable matrix. Three investigative stages are described to allow investigation of the role that biomass plays in the development and functioning of corrosion. First stage involves the biochemical determination of the intrinsic metabolic activity using an enhanced total adenosine triphosphate (E-tATP) as the key activity indicator. If the E-tATP analysis was found to be higher than 100picograms/g or mL then the second investigative stage would be enacted. Here the investigation proceeds to examine differential cultural activities using biological activity reaction testers for sulfate reducing (SRB-), acid producing (APB-), iron related (IRB-), slime forming (SLYM-) and general heterotrophic (HAB-) bacteria. Significant MIC can now be linked to specific reactions (e.g. SRB-, BB or BT; APB-, DY) within the testing method and predicted active cell populations generated (pac/ g or mL). Where cultural activity was indicated, then a significant MIC biomass may be considered to be both present and active. This now triggers the third investigative stage through the biochemical identification of the operational taxonomic community (OTC) involved. This is performed using a rapid agitation static incubation (RASI) technique using libraries of OTC fatty acid methyl esters extracted from the biomass. Identification of the C5 to C20 chain length fatty acids is performed using a customised gas chromatograph and compared using a similarity index based on the other OTC in the library generated using the Microbiological Identification Inc. (MIDI, Newark) system which identifies microorganisms on the basis of the composition of specific extractable C5 to C20 fatty acid methyl esters. MIC processes have been observed using the three phased investigative approach. Examples of investigations conducted are described including the corrosion of steels on the RMS Titanic associated with bioconcretions (rusticles); ochrous biofilm formation on steel coupons under laboratory and field conditions; above mudline bio-preservation of wooden hulled vessels sunk in the nineteenth century; plugging and corrosion of fire sprinkler systems; and the impact of MIC on concretes.

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