| 1. |
- Anbalagan, Anbarasan, et al.
(författare)
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Continuous microalgae-activated sludge flocs for remediation of municipal wastewater under low temperature
- 2017
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Konferensbidrag (refereegranskat)abstract
- The operational performance of indigenous microalgae-activated sludge was evaluated regarding the nutrient removal efficiency using raw wastewater collected from Västerås wastewater treatment plant, Sweden at limited artificial surface lighting (290 μmol m-1 sec-1) and Nordic wastewater conditions (13°C). Additionally, the oxygen production and consumption, biomass concentration and its settling was evaluated during the symbiotic algal-bacterial interaction. The results confirmed oxygenic organic compound removal (COD removal of 65-94%) at higher (31-45 d) and lower (13-18 d) sludge retention time (SRT). Also, a complete removal of ammonium throughout the process and partial nitrite-nitrate removal at all SRTs (total nitrogen removal of 41- 62%) were observed. Likewise, a partial phosphorus (P)removal was observed in the effluent which provides an opportunity to capture free P fromthe effluent for recovery as fertiliser. Further, the microalgal growth was slower due to lightor inorganic carbon limitation or ammonium repression caused by higher internal recirculationas observed from ammonium and nitrite-nitrate levels in the PBR. Most importantly, effectivePBR biomass concentration based nutrient removal and relative sludge recirculation have tobe considered in the PBR design to avoid light limitation and activate symbiosis.
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| 2. |
- Anbalagan, Anbarasan, et al.
(författare)
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Continuous photosynthetic abatement of CO2 and volatile organic compounds from exhaust gas coupled to wastewater treatment : Evaluation of tubular algal-bacterial photobioreactor
- 2017
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Ingår i: Journal of CO2 Utilization. - : Elsevier Ltd. - 2212-9820 .- 2212-9839. ; 21, s. 353-359
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Tidskriftsartikel (refereegranskat)abstract
- The continuous abatement of CO2 and toluene from the exhaust gas by an indigenous microalgal-bacterial consortium was investigated in a pilot tubular photobioreactor interconnected to an absorption column using diluted centrate in seawater as a free nutrient source. The removal efficiency of CO2 and toluene was maximised in the vertical absorption column by identifying an optimum liquid to gas (L/G) ratio of 15. The photobioreactor supported steady-state nitrogen and phosphorus removals of 91 ± 2% and 95 ± 4% using 15% diluted centrate at 14 and 7 d of hydraulic retention time (HRT), respectively. A decrease in the removal efficiencies of nitrogen (36 ± 5%) and phosphorus (58 ± 10%) was recorded when using 30% diluted centrate at 7 d of HRT. The volumetric biomass productivities obtained at an HRT of 7 d accounted for 42 ± 11 and 80 ± 3 mg TSS L-1 d-1 using 15 and 30% centrate, respectively. Stable CO2 (76 ± 7%) and toluene removals (89 ± 5%) were achieved at an L/G ratio of 15 regardless of the HRT or centrate dilution. Hence, this study demonstrated the potential of algal-bacterial systems for the continuous removal of CO2 and volatile organic compounds from exhaust gas coupled with the simultaneous treatment of centrate.
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| 3. |
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| 4. |
- Ashihmina, Olga, et al.
(författare)
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REMEDIATION OF TNT USING PINE BARK IN A BATCH STUDY: COMETABOLIC REDUCTION AND SORPTION
- 2011
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Konferensbidrag (refereegranskat)abstract
- Water contaminated with 2,4,6-trinitrotoluene (TNT) is regulated as a hazardous material. The objective of this study was to evaluate two bioremediation methods, namely, sorption and anoxic degradation for the removal of TNT from contaminated water in 7-day long batch experiment. TNT was co-metabolized with glucose under oxygen-limiting conditions using a mixed inoculum culture from a wastewater treatment plant, enriched with glucose and TNT. By the third day of the experiment most of TNT was adsorbed onto the pine bark and 96-98% of TNT was degraded. The results also indicated that the concentration of glucose is an important factor for the effective degradation of TNT, which is consistent with earlier research; the content of 0.15% w/v resulted in a more rapid TNT removal in comparison with 0.50% w/v. Two metabolites; 2-amino-4,6-dinitrotoluene (2-ADNT) and 4-amino-2,6-dinitrotoluene (4-ADNT) were detected. The para nitro group of TNT was preferentially reduced compared to the ortho nitro group. On the seventh day of incubation the concentration of 4-ADNT had decreased by 10% and 2-ADNT was no longer detectable.
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| 5. |
- Jonfelt, Clara, et al.
(författare)
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Key parameters for modelling Anammox process with N2O emissions
- 2017
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Ingår i: French Federation of Biotechnology - Bioreactors Symposium 2017. - France.
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Konferensbidrag (refereegranskat)abstract
- In this paper, a sensitivity analysis and a calibration were applied to a recent published model used to replicate N2O emissions in an Anammox process of a moving-bed biofilm reactor (MBBR). The model used in this study was designed to replicate a one-stage nitrification-Anammox system in a MBBR at Hammarby-Sjöstad pilot plant (Stockholm, Sweden), whichtreats of anaerobic digestion liquor. The aeration was intermittently (45/15 minutes - on/off). During the aeration, a 1.5 mg/L DO set-point was set. Three main measurements wereobtained: NH4 in water, N2O in both water and gas phase.The sensitivity analysis was done via the one-at-a-time method, where one parameter at a timeis changed (in our case, 10%) from its nominal value and the model output is quantified. Next,the most sensitive parameters were used in the model calibration. Results indicate that the biofilm porosity (η [-]), biofilm density (ρ [gTS/m3]), maximum biofilmthickness (Lmax [mm]) and boundary layer thickness of the biofilm (L0 [μm]) were the mostsensitive parameters of the model. These parameters performed the model calibration.
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| 6. |
- Kanders, Linda, et al.
(författare)
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Sinks and sources of anammox bacteria in a wastewater treatment plant - screening with qPCR
- 2018
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 78:2, s. 441-451
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Tidskriftsartikel (refereegranskat)abstract
- The deammonification process, which includes nitritation and anammox bacteria, is an energyefficient nitrogen removal process. Starting up an anammox process in a wastewater treatment plant (WWTP) is still widely believed to require external seeding of anammox bacteria. To demonstrate the principle of a non-seeded anammox start-up, anammox bacteria in potential sources must be quantified. In this study, seven digesters, their substrates and reject water were sampled and quantitative polymerase chain reaction (qPCR) was used to quantify both total and viable anammox bacteria. The results show that mesophilic digesters fed with nitrifying sludge (with high sludge ages) can be classified as a reliable source of anammox bacteria. Sludge hygienization and dewatering of digestate reduce the amount of anammox bacteria by one to two orders of magnitude and can be considered as a sink. The sampled reject waters contained on average >4.0 × 104 copies mL1 and the majority of these cells (>87%) were viable cells. Furthermore, plants with side-stream anammox treatment appear to have higher overall quantities of anammox bacteria than those without such treatment. The present study contributes to the development of sustainable strategies for both startup of anammox reactors and the possibility of improving microbial management in WWTPs.
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| 7. |
- Krustok, Ivo, et al.
(författare)
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CULTIVATION OF INDIGENOUS ALGAE FOR INCREASED BIOGAS PRODUCTION
- 2013
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Konferensbidrag (refereegranskat)abstract
- There is an increased demand for biogas in the society and one way to meet this is to use cultivated microalgae as fermentation substrate. In the present study, a co-digestion experiment was established where municipal food waste was fermented with harvested microalgae cultivated in lake water. The experiment was carried out as a laboratory batch experiment with fermentation bottles, where 0, 12, 25 and 37% of the food waste was replaced with harvested microalgae, respectively. The results showed that the biogas production was generally improved after addition of microalgae. During the first 25 days of fermentation, replacement of 12% food waste with microalgae gave the highest biogas production rate. However, higher proportions of microalgae (25% and 37%) slightly decreased the gas production rate compared to 12% and compared to using food waste alone.
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| 8. |
- Krustok, Ivo, et al.
(författare)
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Cultivation of microalgae for potential heavy metal reduction in a wastewater treatmet plant
- 2012
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Konferensbidrag (refereegranskat)abstract
- Sorption capacity of microalgae in 10 different mixtures of wastewater and lake water was evaluated for their ability to reduce heavy metal concentrations in wastewater. Cu, Zn and Ba concentrations were mostly reduced whereas Al and As concentrations actually increased in some samples. Co and Ni concentrations were more reduced in samples with pure wastewater compared to samples with wastewater/lake water mixtures. Hence, a mixture of wastewater and lake water seemed to decrease the metal reduction process in the water. Finally, for Fe and Mn concentrations, there was no significant difference between samples with pure wastewater and wastewater/lake water mixture. In positive cases reduction of heavy metal concentrations in the samples with 50-70% of wastewater worked best.
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| 9. |
- Mara, Grube, et al.
(författare)
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Application of FT-IR Spectroscopy for Investigation of Pink Water Remediation by Pine Bark
- 2015
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Ingår i: Open Biotechnology Journal. - : Bentham Science Publishers Ltd.. - 1874-0707. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- This study demonstrates the application of FT-IR spectroscopy for investigating the remediation of pink water with the low cost adsorbent pine bark. The removal of 2,4,6-trinitrotoluene (TNT) from pink water by adsorption to pine bark was accompanied by a reduction in intensities of peaks at 1544 and 1347 cm-1 in the spectra of acetonitrile extracts of the pine bark. Hierarchial cluster analysis differentiated samples with high (30-180 mg/L) and low (0-4 mg/L) TNT concentrations, demonstrating the potential of this approach as a quick screening method for the control of the removal of TNT from pink water. The amount of lignin in pine bark was inversely proportional to the size of the pine bark particles, while the concentration of phenolic hydroxyl groups increases with increasing size of pine bark particles. FT-IR spectra showed that as well as TNT, pine bark can also adsorb nitramine explosives such as RDX and HMX.
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| 10. |
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