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| 2. |
- Abadikhah, Marie, 1992, et al.
(författare)
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Effect of anode material and dispersal limitation on the performance and biofilm community in microbial electrolysis cells
- 2023
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Ingår i: Biofilm. - 2590-2075. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- In a microbial electrolysis cell (MEC), the oxidization of organic compounds is facilitated by an electrogenic biofilm on the anode surface. The biofilm community composition determines the function of the system. Both deterministic and stochastic factors affect the community, but the relative importance of different factors is poorly understood. Anode material is a deterministic factor as materials with different properties may select for different microorganisms. Ecological drift is a stochastic factor, which is amplified by dispersal limitation between communities. Here, we compared the effects of three anode materials (graphene, carbon cloth, and nickel) with the effect of dispersal limitation on the function and biofilm community assembly. Twelve MECs were operated for 56 days in four hydraulically connected loops and shotgun metagenomic sequencing was used to analyse the microbial community composition on the anode surfaces at the end of the experiment. The anode material was the most important factor affecting the performance of the MECs, explaining 54–80 % of the variance observed in peak current density, total electric charge generation, and start-up lag time, while dispersal limitation explained 10–16 % of the variance. Carbon cloth anodes had the highest current generation and shortest lag time. However, dispersal limitation was the most important factor affecting microbial community structure, explaining 61–98 % of the variance in community diversity, evenness, and the relative abundance of the most abundant taxa, while anode material explained 0–20 % of the variance. The biofilms contained nine Desulfobacterota metagenome-assembled genomes (MAGs), which made up 64–89 % of the communities and were likely responsible for electricity generation in the MECs. Different MAGs dominated in different MECs. Particularly two different genotypes related to Geobacter benzoatilyticus competed for dominance on the anodes and reached relative abundances up to 83 %. The winning genotype was the same in all MECs that were hydraulically connected irrespective of anode material used.
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| 3. |
- Abadikhah, Marie, 1992, et al.
(författare)
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Evidence of competition between electrogens shaping electroactive microbial communities in microbial electrolysis cells
- 2022
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Ingår i: Frontiers in Microbiology. - : Frontiers Media SA. - 1664-302X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- In single-chamber microbial electrolysis cells (MECs), organic compounds are oxidized at the anode, liberating electrons that are used for hydrogen evolution at the cathode. Microbial communities on the anode and cathode surfaces and in the bulk liquid determine the function of the MEC. The communities are complex, and their assembly processes are poorly understood. We investigated MEC performance and community composition in nine MECs with a carbon cloth anode and a cathode of carbon nanoparticles, titanium, or stainless steel. Differences in lag time during the startup of replicate MECs suggested that the initial colonization by electrogenic bacteria was stochastic. A network analysis revealed negative correlations between different putatively electrogenic Deltaproteobacteria on the anode. Proximity to the conductive anode surface is important for electrogens, so the competition for space could explain the observed negative correlations. The cathode communities were dominated by hydrogen-utilizing taxa such as Methanobacterium and had a much lower proportion of negative correlations than the anodes. This could be explained by the diffusion of hydrogen throughout the cathode biofilms, reducing the need to compete for space.
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| 4. |
- Andersson, Patrik, 1974, et al.
(författare)
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Framtidsbilder för samhällsbyggnad
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Framtidsbilder för samhällsbyggnad 2020De kommande 15 åren står institutionen för Bygg- och miljöteknik inför stora förändringar. Därför har institutionen initierat projektet Framtidsbilder 2020 där man engagerat en framtidspanel bestående av elva yngre disputerade forskare. Arbetet inleddes med ett breddgruppsmöte där 110 personer representerande institutionens personal och studenter deltog. Vid mötet identifierades ett antal trender och osäkra utvecklingar som påverkar framtiden inom samhällsbyggnadsområdet. Deltagarna bidrog också med idéer till en önskvärd utveckling, vilket har sammanställts och utgör grunden till en gemensam önskvärd framtid/vision för institutionen. Materialet från breddgruppsmötet har bearbetats av Framtidspanelen och resulterat i fyra scenarier som beskriver hur samhällsbyggnadsområdet kan se ut år 2020. Syftet med framtidsbilderna är att de ska vara vägledande för institutionens beslut och förhållningssätt under de kommande åren.Fyra scenarierTurning TorsoSamhället präglas av en ekonomi som är på uppgång, och av ett nytänkande och öppet samhälle. Materiell status och individualism är viktigt. Detta leder till en hög arbetsbelastning samt krav på exklusiva varor av hög kvali-tet. Det finns en stor medvetenhet om miljöpåverkan och klimatförändringar och lösningarna för att klara energiförsörjningen är innovativa.Eco-metropolenDet sveper en grön våg genom dagens samhälle. Under de senaste 15 åren har vi insett att jorden skall vara en bebolig plats även åt dem som kommer efter oss. Vi söker ständigt efter nya, mer förfinade metoder att tillvarata de resurser vi har. Samhället och individen är i balans. Ekonomin är god och vi är miljömedvetna, trygga och integrerade. Nytänkande premieras och icke- materialistiska värderingar står högt i kurs. Vi tänker individuellt, men agerar mer än gärna för kollektivets bästa. Utbildning är gratis TrädgårdsstadenEtt samhälle där vi lärt oss hantera stress, men känner oss otrygga och helst umgås i slutna sociala sammanhang. Vi bor enkelt inne i stan, eller gärna på landsbygden nära storstäderna. Minskade behov av högutbildade i samhället gör att vi har svårt att rekrytera studenter till teknikutbildningar. Det traditionella tankesättet leder till kulturkrockar med företag och personer från andra länder.Gated communitiesFörsämrad ekonomi och ökad egoism har lett fram till ett stressat, otryggt och segregerat samhälle. Accelererande klimatförändringar och ökad miljö-påverkan skrämmer oss, men trots det åtgärdar vi inte problemen, utan koncentrerar oss på konsekvenserna. Arbetslöshet i samhällsbyggnadssek-torn leder till sänkt status för samhällsbyggaren. Vi har därför svårt att rekrytera studenter, och även forskningen har låg status.
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| 5. |
- Burzio, Cecilia, 1991, et al.
(författare)
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Sorption of pharmaceuticals to foam and aerobic granular sludge with different morphologies
- 2024
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Ingår i: Resources, Environment and Sustainability. - : Elsevier BV. - 2666-9161. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- In biological wastewater treatment, the sorption process is an important removal pathway of organic micropollutants from the aqueous phase. Beyond the conventional sorption to biomass and particulate matter, organic molecules can also partition to gas bubbles commonly present in aerated biological processes. This study investigated the partitioning behavior of 21 selected pharmaceuticals to two types of aerobic granular sludge, and the foam generated by aeration. Batch sorption experiments were performed with biologically inactive granules of controlled diameters (0.5–1, 1–2, and >2 mm). Removal during sorption tests was observed for four positively charged micropollutants (sertraline, citalopram, clarithromycin, and erythromycin), four neutral compounds (levonorgestrel, estradiol, ethinylestradiol, and ketoconazole), and one negatively charged pharmaceutical (losartan). This highlights the importance of electrostatic interactions and lipophilic affinity with the solids. For some compounds, the removal increased with time, suggesting that sorption in thick biofilm is limited by molecular diffusion into the biofilm matrix. Furthermore, partitioning of pharmaceuticals to aeration-induced foam was confirmed in separate batch tests. Clarithromycin, erythromycin, ketoconazole, losartan, levonorgestrel, and ethinylestradiol exhibited concentrations in the foam 1.0–5.3 times higher than the initial test values, indicating potential adsorption at the liquid/gas interface for these compounds.
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| 6. |
- Modin, Oskar, 1980, et al.
(författare)
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A relationship between phages and organic carbon in wastewater treatment plant effluents
- 2022
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Ingår i: Water Research X. - : Elsevier BV. - 2589-9147. ; 16
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Tidskriftsartikel (refereegranskat)abstract
- With stringent effluent requirements and the implementation of new processes for micropollutant removal, it is increasingly important for wastewater treatment plants (WWTPs) to understand the factors affecting effluent quality. Phages (viruses infecting prokaryotes) are abundant in the biological treatment processes. They can contribute to organic carbon in the treated effluent both because they are organic in nature and occur in the effluent and because they cause lysis of microorganisms. Today very little is known about the effects of phages on effluent quality. The goal of this study was, therefore, to determine the relationship between phages and organic carbon in WWTP effluents. We also examined the diversity, taxonomy, and host-association of DNA phages using metagenomics. Effluent samples were collected from four WWTPs treating municipal wastewater. Significant differences in both organic carbon and virus-like particle concentrations were observed between the plants and there was a linear relationship between the two parameters. The phage communities were diverse with many members being taxonomically unclassified. Putative hosts were dominated by bacteria known to be abundant in activated sludge systems such as Comamonadaceae. The composition of phages differed between the WWTPs, suggesting that local conditions shape the communities. Overall, our findings suggest that the abundance and composition of phages are related to effluent quality. Thus, there is a need for further research clarifying the association between phage dynamics and WWTP function.
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| 7. |
- Neth, Maria, 1980, et al.
(författare)
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A collaborative planning process to develop future scenarios for wastewater systems
- 2022
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Ingår i: Journal of Environmental Management. - : Elsevier BV. - 0301-4797 .- 1095-8630. ; 316
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Tidskriftsartikel (refereegranskat)abstract
- Wastewater infrastructure has a long lifetime and is subject to changing conditions and demands. When plans are made to upgrade or build new infrastructure, transdisciplinary planning processes and a robust analysis of future conditions are needed to make sustainable choices. Here, we provide a stepwise collaborative planning process in which future scenarios are developed together with local stakeholders and expert groups. The process was implemented at one of the largest wastewater treatment plants (WWTPs) in Scandinavia. With a combination of workshops and the use of a web-based digital tool, future scenarios including flows, pollutant loads, and treatment requirements could be created. Furthermore, sustainability prioritizations affecting the WWTP, were identified. The future scenarios developed for the WWTP in the case study, predict stricter and new regulations, constant or lower future loads and ambiguous future flows. The highest ranked sustainability priority was low resource and energy consumption together with low CO2 footprint. The quantified future scenarios developed in the planning process were used as input to a process model to show the consequences they would have on the WWTP in the case study. Applying this collaborative process revealed future scenarios with many, sometimes conflicting, expectations on future WWTPs. It also highlighted needs for improvements of both the collection system and the WWTP.
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| 8. |
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| 9. |
- Wilen, Britt-Marie, 1966, et al.
(författare)
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Large scale tertiary filtration – results and experiences from the discfilter plant at the Rya WWTP in Sweden
- 2016
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Ingår i: Water Practice and Technology. - : IWA Publishing. - 1751-231X. ; 11:3, s. 547-555
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Tidskriftsartikel (refereegranskat)abstract
- This paper summarizes the results and experiences from the full-scale discfilter plant at the Rya WWTP. In 2010 the WWTP was extended with post-denitrification and a discfilter plant for tertiary filtration of the effluent in order to meet the new discharge limits of 10 mg total nitrogen and 0.3 mg/l of total phosphorus. The disc filters receive effluent from both the moving bed biofilm reactor (MBBR) and the secondary settlers. The disc filters are equipped with filter cloths with 15 ?m pore openings. The concentration of suspended solids was generally kept below 5 mg/l and total phosphorus was
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| 10. |
- Almstrand, Robert, et al.
(författare)
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Three-dimensional stratification of bacterial biofilm populations in a moving bed biofilm reactor for nitritation-anammox.
- 2014
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Ingår i: International Journal of Molecular Sciences. - : MDPI AG. - 1661-6596 .- 1422-0067. ; 15:2, s. 2191-206
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Tidskriftsartikel (refereegranskat)abstract
- Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers.
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