The inhibitory effects of heavy metals and organic compounds on the net maximum specific growth rate of the autotrophic biomass in activated sludge

Juliastuti, Sri Rachmania; Baeyens, Jan; Creemers, Claude; Bixio, D.; Lodewyckx, E.

doi:10.1016/s0304-3894(03)00116-x

Cited by 100 publications

(74 citation statements)

References 24 publications

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“…AOB are highly sensitive to many environmental factors such as pH, temperature, and dissolved oxygen (DO) concentration [28,29,31]. Growth of AOB is also affected by industrial contaminants, including cyanide [3,11,16,17].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous effect of temperature, cyanide and ammonia-oxidizing bacteria concentrations on ammonia oxidation

Lim

Shin

et al. 2008

J Ind Microbiol Biotechnol

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For biological nitrification, a set of experiments were carried out to approximate the response of lag period along with ammonia oxidation rate with respect to different concentrations of cyanide (CN-) and ammonia-oxidizing bacteria (AOB), and temperature variation in laboratory-scale batch reactors. The effects of simultaneous changes in these three factors on ammonia oxidation were quantitatively estimated and modeled using response surface analysis. The lag period and the ammonia oxidation rate responded differently to changes in the three factors. The lag period and the ammonia oxidation rate were significantly affected by the CN- and AOB concentrations, while temperature changes only affected the ammonia oxidation rate. The increase of AOB concentration and temperature alleviated the inhibition effect of cyanide on ammonia oxidation. The statistical method used in this study can be extended to estimate the quantitative effects of other environmental factors that can change simultaneously.

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Section: Introductionmentioning

confidence: 99%

Simultaneous effect of temperature, cyanide and ammonia-oxidizing bacteria concentrations on ammonia oxidation

Lim

Shin

et al. 2008

J Ind Microbiol Biotechnol

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“…Ammonia oxidation is often a rate-limiting step in nitrogen removal in wastewater treatment plants (WWTP), as the AOB are influenced by various environmental factors such as light, dissolved oxygen, pH, and substrate concentrations (2,19,47,48) and easily inhibited by various organic compounds or heavy metals (24,26,34). Curtis and Sloan (8) postulated that autotrophic ammonia oxidation in WWTP is governed by a small metacommunity, leading to easy replicate sampling of the microbially diverse community, which is thought to be stable.…”

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confidence: 99%

Quantifying Community Dynamics of Nitrifiers in Functionally Stable Reactors

Wittebolle

Vervaeren

Verstraete

et al. 2008

Appl Environ Microbiol

183

137

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A sequential batch reactor (SBR) and a membrane bioreactor (MBR) were inoculated with the same sludge from a municipal wastewater treatment plant, supplemented with ammonium, and operated in parallel for 84 days. It was investigated whether the functional stability of the nitrification process corresponded with a static ammonia-oxidizing bacterial (AOB) community. The SBR provided complete nitrification during nearly the whole experimental run, whereas the MBR showed a buildup of 0 to 2 mg nitrite-N liter ؊1 from day 45 until day 84. Based on the denaturing gradient gel electrophoresis profiles, two novel approaches were introduced to characterize and quantify the community dynamics and interspecies abundance ratios: (i) the rate of change [⌬ t(week) ] parameter and (ii) the Pareto-Lorenz curve distribution pattern. During the whole sampling period, it was observed that neither of the reactor types maintained a static microbial community and that the SBR evolved more gradually than the MBR, particularly with respect to AOB (i.e., average weekly community changes of 12.6% ؎ 5.2% for the SBR and 24.6% ؎ 14.3% for the MBR). Based on the Pareto-Lorenz curves, it was observed that only a small group of AOB species played a numerically dominant role in the nitritation of both reactors, and this was true especially for the MBR. The remaining less dominant species were speculated to constitute a reserve of AOB which can proliferate to replace the dominant species. The value of these parameters in terms of tools to assist the operation of activated-sludge systems is discussed. Fernandez et al. (12) demonstrated that ecosystem stability encompasses a broad spectrum of definitions. These definitions resolve into two components: the measurable functional properties of the ecosystem and the change over time of the community composition. Frequently, only the functional parameters are evaluated (37), but recently attempts were made to relate (dys)functioning with the structure of a microbial community (13,25,46,49). It was found that highly dynamic communities can still maintain a stable ecosystem function (12, 25).Curtis and Sloan (8) postulated that the relationship between structure and function in a microbial community can be evaluated only through an understanding of the source of diversity from which the community is drawn, named the global reservoir or metacommunity. Up to now, diversity has been mainly measured statically, based on indices such as Shannon and Simpson indices. By adding Lorenz curves, a nonambiguous graphical presentation of species evenness can be provided (31,35,42), investigating interspecies abundance ratios and thus the internal community structure. Besides the importance of the community diversity and composition at one time point, the dynamics of microbial communities can play an important role in the functionality of a system (49). Nevertheless, due to infrequent sampling, the dynamics of functionally stable microbial communities has not yet been quantified in terms of a rate of change on a sho...

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“…Heavy metals, such as Cd 2ϩ (12,28), Hg 2ϩ , and Cu 2ϩ (30), are extensively used in industry (e.g., in the fabrication of pigments, batteries, and electronics), and improper disposal of the metals or their byproducts tends to contaminate the environment (40). These metals may inhibit nitrification in the reclamation of wastewater (4,5,27,44).…”

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confidence: 99%

Candidate Stress Genes ofNitrosomonas europaeafor Monitoring Inhibition of Nitrification by Heavy Metals

Park

Ely

2008

Appl Environ Microbiol

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Heavy metals have been shown to be strong inhibitors of nitrification in wastewater treatment plants. In this research, the effects of cadmium, copper, and mercury on Nitrosomonas europaea were studied in quasi-steadystate batch reactors. When cells were exposed to 1 M CdCl 2 , 6 M HgCl 2, or 8 M CuCl 2 , ammonia oxidation rates were decreased by about 90%. Whole-genome transcriptional and proteomic responses of N. europaea to cadmium were used to identify heavy metal stress response genes. When cells were exposed to 1 M CdCl 2 for 1 h, 66 genes (of the total of 2,460 genes) were upregulated, and 50 genes were downregulated more than twofold. Of these, the mercury resistance genes (merTPCADE) averaged 277-fold upregulation under 1 M CdCl 2 , with merA (mercuric reductase) showing 297-fold upregulation. In N. europaea cells exposed to 6 M HgCl 2 or to 8 M CuCl 2 , merA showed 250-fold and 1.7-fold upregulation, respectively. Cells showed the ability to recover quickly from Hg 2؉ -related toxic effects, apparently associated with upregulation of the mercury resistance genes and amoA, but no such recovery was evident in Cd 2؉ -exposed cells even though merTPCADE were highly upregulated. We suggest that the upregulation of merA in response to CdCl 2 and HgCl 2 exposure may provide a means to develop an early-warning indicator for inhibition of nitrification by these metals.

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The inhibitory effects of heavy metals and organic compounds on the net maximum specific growth rate of the autotrophic biomass in activated sludge

Cited by 100 publications

References 24 publications

Simultaneous effect of temperature, cyanide and ammonia-oxidizing bacteria concentrations on ammonia oxidation

Simultaneous effect of temperature, cyanide and ammonia-oxidizing bacteria concentrations on ammonia oxidation

Quantifying Community Dynamics of Nitrifiers in Functionally Stable Reactors

Candidate Stress Genes ofNitrosomonas europaeafor Monitoring Inhibition of Nitrification by Heavy Metals

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