| 1. |
- Sundberg, Carina, 1963-, et al.
(author)
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Ammonia oxidation and the corresponding bacterial communities in two overland flow areas treating landfill leachate or wastewater
- 2011
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In: Overland Flow and Surface Runoff. - : Nova Science Publishers, Inc.. - 9781611228687 ; , s. 346-
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Book chapter (peer-reviewed)abstract
- A high diversity of ammonium oxidising bacteria (AOB) has been observed in overland flow areas (OFA) treating ammonia-rich landfill leachate. The current section aimed to explore if treatment OFAs in general supports more diverse AOB communities than conventional treatment systems, or if it is a result of effluent composition. The potential ammonium oxidation and the AOB community composition were studied during three seasons in an OFA where one part received wastewater and the other landfill leachate. The AOB communities were investigated using group-specific PCR primers targeting the 16S rRNA gene, and analysed by DGGE and nucleotide sequencing. The potential ammonia oxidation, studied by short-time slurry incubation, was higher in the landfill OFA than in the wastewater area and highest in the litter layer. Higher activity correlated with the appearance of Nitrosomonas sp. belonging to cluster 7. Both overland flow areas supported a more diverse AOB community than in common wastewater treatment plants. Fifteen different AOB sequences were detected, but only three were observed in both OFAs, pointing to the impact of the effluent quality and/or the hydraulic load. The wastewater OFA, which received a higher load of effluents with 5-10 times lower ammonia concentrations, was dominated by AOB populations that are usually found in less favourable conditions.
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| 2. |
- Sundberg, Carina, 1963-, et al.
(author)
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Development of the community structure and activity of ammoniaoxidising bacteria in overland flow systems used to treat landfill leachates
- 2009
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In: Journal of Applied Microbiology. - 1364-5072 .- 1365-2672.
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Journal article (other academic/artistic)abstract
- Ammonium in landfill leachates can be nitrified in overland flow areas (OFA). We studied OFAs to investigate if changes occur in the ammonium oxidizing community as the ecosystem develops, and the influence of different operating conditions. Samples were collected from the macrophyte litter layers, the rhizospheres and the sediments in their associated settling ponds in May, August, and November during four years. Potential ammonia oxidation (PAO) was investigated by a short-term slurry incubation method. The composition of the ammonia-oxidising bacteria (AOB) communities was investigated by PCR, using a group-specific primer pair, followed by denaturing gradient gel electrophoresis and subsequent sequencing. A shift from a Nitrosomonas community to a mixture of Nitrosomonas and Nitrosospira was and a gradual increase in PAO was observed, but only in the litter layer in the youngest OFA. Both OFAs had diverse AOB communities belonging to six different clusters. Nitrosomonas clusters predominated in the OFA with higher PAO, whereas Nitrosospira clusters were more common in the OFA with lower PAO. There was a seasonal increase of AOB populations in the OFA that was not in use during winter, and a more stable composition of the AOB community and the PAO in the OFA with year-round application. Keywords: Ammonia-oxidising bacterial community; Landfill leachates; Nitrification; Overland flow; 16S rDNA; Denaturing gradient gel electrophoresis.
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| 3. |
- Sundberg, Carina, 1963-
(author)
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Nitrifyers in constructed wetlands treating landfill leachates
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Landfill leachate is produced many years after a landfill site closes. Hence, treatment by “natural methods”, as e.g. constructed wetlands, with low management requirements is attractive. Constructed wetlands usually provide both shallow and deep areas with aerobic and anaerobic zones, which is suitable for nitrification followed by denitrification of the ammonium-rich leachates. Full-scale treatment systems are influenced by climatic variables that affect the microbial community. Also, the operational strategy can have a considerable impact on both activity and composition of the microorganisms. Many studies have measured inflow/outflow water quality in treatment systems. Such “black box” studies describe the treatment efficiency but add little to an increased understanding of theorganisms performing the treatment or the spatial distribution of their activities and treatment processes.In this thesis we investigated seasonal and annual changes in potential nitrification and denitrification, and in the corresponding bacterial communities in constructed wetlands treating landfill leachates. Variations in the potential activity in full-scale systems were investigated over several years, using short-term incubation. The composition of the bacterial communities was investigated using a group-specific PCR primer pair targeting the 16S rRNA genes or a primer pair targeting the funtional gene nosZ. The PCR products were analysed by denaturing gradient gelelectrophoresis and subsequent nucleotide sequencing and phylogentic analysis.A stable ammonia-oxidising bacterial (AOB) community composition and potential ammonia-oxidation (PAO) were detected in the system with a year-round operation. On the other hand, changes in the AOB community composition which followed the operational schedule were detected in the overland flow area (OFA) running seasonally. Furthermore, the influence of operational strategy was indicated by a low PAO in the wastewater overland flow area and compact constructed wetland receiving high hydraulic loads, indicating the value of aeration. Higher PAO was detected in the OFAs where the hydraulic load followed literature guidelines.All systems supported diverse AOB communities, represented by several Nitrosomonas and Nitrosospira populations. The number of different populations detected in these wetlands was much higher than reported in municipal wastewater treatment plants, and differed from those in a parallel OFA treating municipal wastewater. Furthermore, the large variation in both potential activity and sequences detected in replicate samples suggests that such systems are spatially heterogenic.
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| 4. |
- Sundberg, Carina, 1963-, et al.
(author)
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Overland flow systems for treatment of landfill leachates : Potential nitrification and structure of the ammonia-oxidising bacterial community during a growing season
- 2007
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In: Soil Biology and Biochemistry. - : Elesevire. - 0038-0717 .- 1879-3428. ; 39:1, s. 127-138
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Journal article (peer-reviewed)abstract
- Overland flow systems are useful for treating landfill leachates, because they provide favourable conditions for nitrification and they are easy to maintain. However, little is known about the microbial communities in such systems or the nitrification capacity of those microorganisms. In this study, seasonal variations in potential nitrification and in community composition of nitrifying bacteria were investigated in two overland flow areas receiving leachate from landfills at Korslöt and Hagby, Sweden. Samples were collected in the settling ponds sediment and at two depths in the overland flow areas (the macrophyte litter layer and the rhizosphere) in May, August and November 2003. A short-term incubation method was used to measure potential oxidation of ammonia and nitrite (designated PAO and PNO). The ammonia-oxidising bacterial (AOB) community was investigated using a 16S rRNA gene approach that included PCR amplification and analysis of PCR products by denaturing gradient gel electrophoresis (DGGE), followed by nucleotide sequencing and phylogenetic analysis. PAO was determined in the range 5–2700 (NO2−+NO3−)-N g−1 dw d−1 and PNO in the range 60–2000 μg NO2−-N g−1 dw d−1. At Korslöt, PAO and PNO showed similar temporal variation in the different ecosystems, whereas no such relationship was noticed at Hagby. Considering both sites, there was no obvious change in the composition of the AOB community over the growing season. However, the composition did differ between the ecosystems: Nitrosomonas-like sequences were more common in the ponds, and in the litter layers they were found as often as Nitrosospira-like sequences, whereas Nitrosospira-like sequences were more common in the rhizospheres. Altogether, we found nine different AOB sequences, five Nitrosomonas-like and four Nitrosospira-like, which belonged to clusters 0, 2, 3b, 6a, 6b and 7. There was no apparent relationship between the number of AOB populations and the PAO in different soil layers and sediments.
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| 5. |
- Ziels, Ryan M., et al.
(author)
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Microbial rRNA gene expression and co-occurrence profiles associate with biokinetics and elemental composition in full-scale anaerobic digesters
- 2018
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In: Microbial Biotechnology. - : Wiley-Blackwell Publishing Inc.. - 1751-7907 .- 1751-7915. ; 11:4, s. 694-709
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Journal article (peer-reviewed)abstract
- This study examined whether the abundance and expression of microbial 16S rRNA genes were associated with elemental concentrations and substrate conversion biokinetics in 20 full-scale anaerobic digesters, including seven municipal sewage sludge (SS) digesters and 13 industrial codigesters. SS digester contents had higher methane production rates from acetate, propionate and phenyl acetate compared to industrial codigesters. SS digesters and industrial codigesters were distinctly clustered based on their elemental concentrations, with higher concentrations of NH3-N, Cl, K and Na observed in codigesters. Amplicon sequencing of 16S rRNA genes and reverse-transcribed 16S rRNA revealed divergent grouping of microbial communities between mesophilic SS digesters, mesophilic codigesters and thermophilic digesters. Higher intradigester distances between Archaea 16S rRNA and rRNA gene profiles were observed in mesophilic codigesters, which also had the lowest acetate utilization biokinetics. Constrained ordination showed that microbial rRNA and rRNA gene profiles were significantly associated with maximum methane production rates from acetate, propionate, oleate and phenyl acetate, as well as concentrations of NH3-N, Fe, S, Mo and Ni. A co-occurrence network of rRNA gene expression confirmed the three main clusters of anaerobic digester communities based on active populations. Syntrophic and methanogenic taxa were highly represented within the subnetworks, indicating that obligate energy-sharing partnerships play critical roles in stabilizing the digester microbiome. Overall, these results provide new evidence showing that different feed substrates associate with different micronutrient compositions in anaerobic digesters, which in turn may influence microbial abundance, activity and function.
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