Grantee Research Project Results
2014 Progress Report: Rapid Detection of Sewer Pipeline Problems Using Bacterial DNA Markers and Q-PCR Technology
EPA Grant Number: R834871Title: Rapid Detection of Sewer Pipeline Problems Using Bacterial DNA Markers and Q-PCR Technology
Investigators: Yan, Tao
Institution: University of Hawaii at Manoa
EPA Project Officer: Page, Angela
Project Period: February 1, 2011 through January 31, 2016
Project Period Covered by this Report: February 1, 2014 through January 31,2015
Project Amount: $299,956
RFA: Advancing Public Health Protection through Water Infrastructure Sustainability (2009) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
Objective:
Sewer pipeline deterioration is the primary cause of sewer accidents that threaten the public health safety. This enormous water infrastructure problem requires a technical solution that can rapidly identify deterioration in a large number of pipelines with ease. The overall goal of this project is to develop a pipeline inspection technology that is based on Q-
Progress Summary:
In the year 2014-2015, the project focused on FOG deposits in sewer systems, including the biodegradation of FOG deposits and the source of long chain fatty acids (LCFAs), which react with calcium ion to form FOG deposits in sewer environments. First, we completed the study on the biodegradation of FOG in sewer environments, and published a journal article on the topic. Laboratory microcosm experiments were conducted to determine FOG biodegradability under various redox conditions that are common in sewer environments. Microbial communities in these microcosms were analyzed by Illumina sequencing of the 16S rRNA gene amplicons. The results showed that overall biodegradation of FOG deposits was very slow and showed different levels of biodegradation under different redox conditions. Considerable biodegradation occurred under the aerobic condition and the anaerobic nitrate-reducing condition, while very limited biodegradation occurred under anaerobic sulfate-reducing condition and methanogenic condition. Microbial community analysis by Illumina sequencing of 16S rRNA gene amplicons identified corresponding microbial communities in the microcosms.
Since FOG deposits in sewer systems are formed LCFAs and calcium ion, we investigated the possibility of grease interceptors (GIs) being a source of LCFAs to sewer pipelines. Bench-scale GIs were established in the laboratory to determine the production of LCFAs with and without microbial activities as well as production of LCFAs under different hydraulic retention times (HRTs). The results showed that although LCFAs could be produced from abiotic, chemical hydrolysis of FOGs in GIs, microbial activities contributed to the majority of LCFAs in GI effluent, which was five times higher than that under only chemical hydrolysis conditions. Similar LCFA profile was found between GI effluent under the impact of microbial activities and FOG deposits. Longer HRT resulted in higher concentration of LCFAs in GI effluent as well as higher percentage of unsaturated LCFAs in total LCFA production within 60 days. However, the largest discharge amount of LCFAs was obtained under short HRT (HRT = 0.5d) while higher portion of produced LCFAs was retained in GIs under HRT = 1d and 2d, suggesting that GIs under short HRT would be a bigger concern for downstream FOG deposit formation. The results are currently being prepared in a research manuscript to be submitted for publication in the near future.
Future Activities:
We now have gained considerable understanding of the microbial processes involved sewer crown corrosion and FOG formation in sewer pipes. Future activities will focus on designing specific qPCR primers to detect these microbial processes in sewer systems. Particular focus will be placed on sewer crown corrosion, as this process appears to be only present in the sewer system and enables specific detection. We also will attempt to develop DNA markers the biodegradation of FOG deposits, which however is more complex due to the upstream processes (such as in grease interceptors) that also might contain such DNA markers.
Journal Articles on this Report : 2 Displayed | Download in RIS Format
| Other project views: | All 7 publications | 3 publications in selected types | All 3 journal articles |
|---|
| Type | Citation | ||
|---|---|---|---|
|
|
He X, Zhang Q, Cooney MJ, Yan T. Biodegradation of fat, oil and grease (FOG) deposits under various redox conditions relevant to sewer environment. Applied Microbiology and Biotechnology 2015;99(14):6059-6068. |
R834871 (2014) R834871 (Final) |
Exit Exit |
|
|
Pagaling E, Yang K, Yan T. Pyrosequencing reveals correlations between extremely acidophilic bacterial communities with hydrogen sulphide concentrations, pH and inert polymer coatings at concrete sewer crown surfaces. Journal of Applied Microbiology 2014;117(1):50-64. |
R834871 (2013) R834871 (2014) R834871 (Final) |
Exit Exit |
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.