Assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC):

Escobar, Isabel C.; Randall, Andrew A.

doi:10.1016/s0043-1354(01)00173-7

Cited by 141 publications

(65 citation statements)

References 18 publications

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“…It is well known that chlorination not only kills most bacterial cells but it also produces an increase in assimilable organic carbon (AOC) due to the reaction of free chlorine with the dissolved organic carbon (DOC) present in natural water (29). This AOC consists of a variety of low-molecular-weight compounds that provide substrates for the growth of heterotrophic bacteria (5,13). Therefore, substantial shifts in the community structure and composition can be expected after chlorination.…”

Section: Vol 72 2006 Microbial Community Dynamics In Drinking Watermentioning

confidence: 99%

Composition and Dynamics of Bacterial Communities of a Drinking Water Supply System as Assessed by RNA- and DNA-Based 16S rRNA Gene Fingerprinting

Eichler

Christen

Höltje

et al. 2006

Appl Environ Microbiol

188

174

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Bacterial community dynamics of a whole drinking water supply system (DWSS) were studied from source to tap. Raw water for this DWSS is provided by two reservoirs with different water characteristics in the Harz mountains of Northern Germany. Samples were taken after different steps of treatment of raw water (i.e., flocculation, sand filtration, and chlorination) and at different points along the supply system to the tap. RNA and DNA were extracted from the sampled water. The 16S rRNA or its genes were partially amplified by reverse transcription-PCR or PCR and analyzed by single-strand conformation polymorphism community fingerprints. The bacterial community structures of the raw water samples from the two reservoirs were very different, but no major changes of these structures occurred after flocculation and sand filtration. Chlorination of the processed raw water strongly affected bacterial community structure, as reflected by the RNA-based fingerprints. This effect was less pronounced for the DNA-based fingerprints. After chlorination, the bacterial community remained rather constant from the storage containers to the tap. Furthermore, the community structure of the tap water did not change substantially for several months. Community composition was assessed by sequencing of abundant bands and phylogenetic analysis of the sequences obtained. The taxonomic compositions of the bacterial communities from both reservoirs were very different at the species level due to their different limnologies. On the other hand, major taxonomic groups, well known to occur in freshwater, such as Alphaproteobacteria, Betaproteobacteria, and Bacteroidetes, were found in both reservoirs. Significant differences in the detection of the major groups were observed between DNA-based and RNA-based fingerprints irrespective of the reservoir. Chlorination of the drinking water seemed to promote growth of nitrifying bacteria. Detailed analysis of the community dynamics of the whole DWSS revealed a significant influence of both source waters on the overall composition of the drinking water microflora and demonstrated the relevance of the raw water microflora for the drinking water microflora provided to the end user.

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Section: Vol 72 2006 Microbial Community Dynamics In Drinking Watermentioning

confidence: 99%

Composition and Dynamics of Bacterial Communities of a Drinking Water Supply System as Assessed by RNA- and DNA-Based 16S rRNA Gene Fingerprinting

Eichler

Christen

Höltje

et al. 2006

Appl Environ Microbiol

188

174

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“…Appropriate methods are needed to monitor biological stability in drinking water systems. A conventional but indirect approach to measure biological stability is assessing the microbial growth potential of a water sample, using assimilable organic carbon (AOC) measurements, biodegradable dissolved organic carbon (BDOC), and pathogen growth potential (PGP) assays (Escobar and Randall, 2001;Hammes and Egli, 2005;Laurent et al, 2005a;Van der Kooij, 2000;Vital et al, 2010). These parameters have in some cases been related to the degree of growth or contamination observed in drinking water distribution systems and some guideline values for "biologically stable" water have been suggested for AOC in the absence of disinfectants (<10 mg/l; Van der Kooij, 2000) as well as in the presence of disinfectants (<100 mg/l; LeChevallier et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

A microbiology-based multi-parametric approach towards assessing biological stability in drinking water distribution networks

et al. 2013

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a b s t r a c tBiological stability of drinking water implies that the concentration of bacterial cells and composition of the microbial community should not change during distribution. In this study, we used a multi-parametric approach that encompasses different aspects of microbial water quality including microbial growth potential, microbial abundance, and microbial community composition, to monitor biological stability in drinking water of the non-chlorinated distribution system of Zü rich. Drinking water was collected directly after treatment from the reservoir and in the network at several locations with varied average hydraulic retention times (6e52 h) over a period of four months, with a single repetition two years later. Total cell concentrations (TCC) measured with flow cytometry remained remarkably stable at 9.5 (AE 0.6) Â 10 4 cells/ml from water in the reservoir throughout most of the distribution network, and during the whole time period. Conventional microbial methods like heterotrophic plate counts, the concentration of adenosine tri-phosphate, total organic carbon and assimilable organic carbon remained also constant.Samples taken two years apart showed more than 80% similarity for the microbial communities analysed with denaturing gradient gel electrophoresis and 454 pyrosequencing.Only the two sampling locations with the longest water retention times were the exceptions and, so far for unknown reasons, recorded a slight but significantly higher TCC (1.3 (AE 0.1) Â 10 5 cells/ml) compared to the other locations. This small change in microbial abundance detected by flow cytometry was also clearly observed in a shift in the microbial community profiles to a higher abundance of members from the Comamonadaceae (60% vs.2% at other locations). Conventional microbial detection methods were not able to detect changes as observed with flow cytometric cell counts and microbial community analysis. Available online at www.sciencedirect.com journal home page: www.elsevier.com/loca te/watres w a t e r r e s e a r c h 4 7 ( 2 0 1 3 ) 3 0 1 5 e3 0 2 5 0043-1354/$ e see front matter ª

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“…Humic acids may cause color, taste, and odor problems and the formation of carcinogenic disinfection byproducts when they are present in drinking water [1,2]. In addition, humic acids may promote bacterial growth in the drinking water supply, posing an increasing risk to human health [3,4].…”

Section: Introductionmentioning

confidence: 99%

Enhanced adsorption of humic acids on ordered mesoporous carbon compared with microporous activated carbon

Liu

Wan

et al. 2011

Enviro Toxic and Chemistry

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Humic acids are ubiquitous in surface and underground waters and may pose potential risk to human health when present in drinking water sources. In this study, ordered mesoporous carbon was synthesized by means of a hard template method and further characterized by X-ray diffraction, N2 adsorption, transition electron microscopy, elemental analysis, and zeta-potential measurement. Batch experiments were conducted to evaluate adsorption of two humic acids from coal and soil, respectively, on the synthesized carbon. For comparison, a commercial microporous activated carbon and nonporous graphite were included as additional adsorbents; moreover, phenol was adopted as a small probe adsorbate. Pore size distribution characterization showed that the synthesized carbon had ordered mesoporous structure, whereas the activated carbon was composed mainly of micropores with a much broader pore size distribution. Accordingly, adsorption of the two humic acids was substantially lower on the activated carbon than on the synthesized carbon, because of the size-exclusion effect. In contrast, the synthesized carbon and activated carbon showed comparable adsorption for phenol when the size-exclusion effect was not in operation. Additionally, we verified by size-exclusion chromatography studies that the synthesized carbon exhibited greater adsorption for the large humic acid fraction than the activated carbon. The pH dependence of adsorption on the three carbonaceous adsorbents was also compared between the two test humic acids. The findings highlight the potential of using ordered mesoporous carbon as a superior adsorbent for the removal of humic acids.

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Assimilable organic carbon (AOC) and biodegradable dissolved organic carbon (BDOC):

Cited by 141 publications

References 18 publications

Composition and Dynamics of Bacterial Communities of a Drinking Water Supply System as Assessed by RNA- and DNA-Based 16S rRNA Gene Fingerprinting

Composition and Dynamics of Bacterial Communities of a Drinking Water Supply System as Assessed by RNA- and DNA-Based 16S rRNA Gene Fingerprinting

A microbiology-based multi-parametric approach towards assessing biological stability in drinking water distribution networks

Enhanced adsorption of humic acids on ordered mesoporous carbon compared with microporous activated carbon

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