Biodegradation of N-Nitrosodimethylamine
Date Issued
2010
Date
2010
Author(s)
Chien, Yu-Han
Abstract
Chlorination is the most common disinfection method to reduce the activities of pathogens in water treatment process due to its low-cost and effectiveness. However, with the existence of nature organic matters (NOMs), the application of chlorine-contained disinfectants may result in the formation of disinfection byproducts (DBPs) which are of particular concern considering their potential impact on people health.
One of the emerging DBPs, N-Nitrosodimethylamine (NDMA), is considered as a potent carcinogen. It is often found in finished water with chlorine or chloramine applied, especially in water with high nitrogen contents. Thus the removal of NDMA in water treatment process is crucial to ensure the safety of aquatic environment.
The removal of NDMA by physical-chemical process has been proved to be effective; however, with consideration of cost, physical-chemical technology may not be the best available strategy, promoting biodegradation as an alternative. Previous literature indicated that NDMA is biodegradable, but with limited information regarding functional bacteria provided.
The objective of this study is to identify the bacteria with capability to degrade NDMA. Three methanotrophs, i.e., Methylosinus trichosporium OB3b, Methylocystis parvus OBBP and isolated strain 05A-I-S2, as well as two activated sludges including one from Neihu municipal wastewater treatment plant and the other cultivated by tetramethylammonium hydroxide (TMAH) were chosen to examine their biodegradability of NDMA.
The result showed that NDMA was degradable by three methanotrophs through cometabolism along with expression of methane monooxygenase (MMO). Note that the efficiency of degradation was higher to methanotrophs with inducement of the soluble MMO (sMMO) than those with particulate MMO (pMMO) produced.
In addition, NDMA can also be biodegraded by both sources of sludge adopted in this study with only one pure strain isolated from the TMAH-cultivated sludge, Uncultured alpha proteobacterium UP2, being capable to utilize NDMA as the carbon source while biodegrading.
Subjects
N-Nitrosodimethylamine (NDMA)
Biodegradation
Methanotrophs
Methane Monooxygenase (MMO)
SDGs
Type
thesis
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