| 1. |
- Dalecka, Brigita, et al.
(författare)
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Bioaugmentation with fungi: An emerging strategy for removing pharmaceutical substances in wastewater treatment process by fluidized bed pelleted bioreactor
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Fungi have been shown to be effective candidates to remove pharmaceuticals. However, the pilot-scale application mainly deals with the strict growth conditions and competition between microbial community from wastewater. Thus, the bioaugmentation for removing the pharmaceuticals in municipal wastewater by T. versicolor and A. luchuensis using fluidized bed pelleted bioreactor was studied. To find the optimal performance of bioaugmentation two periodical biomass volume, 10 and 50 g per 1.25 L bioreactor, were tested. The removal of nutrients, pharmaceutical substances and changes in the pH value, laccase activity, and total microorganisms were analyzed. The results showed that bioaugmentation has an effect in removing NH 4 -N and lower accumulation of NO 3 -N, whereas PO 4 -3 -P and TOC did not show significant effect on the reduction of nutrient load. The results of removal efficiency for diclofenac, carbamazepine, and sulfamethoxazole showed that there was no significant effect on the removal while the highest removal efficiency (> 90%) for ibuprofen, ketoprofen, and metoprolol was achieved by both fungi with periodical addition with 50 g of biomass after an incubation time of 3 hours. Finally, the data analysis with AI-based experimental design indicated that A. luchuensis can be a promising fungus for pharmaceutical removal and implies as a promising approach for optimization of fluidized bed pelleted bioreactor. Overall, the obtained results and the use of an AI-based platform are a promising approach for optimization and operation of fluidized bed pelleted bioreactor.
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| 2. |
- Dalecka, Brigita, et al.
(författare)
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Isolation of Fungal Strains from Municipal Wastewater for the Removal of Pharmaceutical Substances
- 2020
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Ingår i: Water. - : MDPI. - 2073-4441. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Fungi have been shown to be promising candidates to be used in removal of pharmaceutical compounds during wastewater treatment processes. However, fungal growth, including removal efficiency, can be affected by several factors, such as temperature and the pH. The ability of fungal isolates to grow in the presence of carbamazepine, diclofenac, ibuprofen, and sulfamethoxazole was tested. Removal efficiency results indicated that a fungal isolate of Aspergillus luchuensis can completely (>99.9%) remove diclofenac from a synthetic wastewater media without a pH correction within 10 days of incubation. Furthermore, the results of the biosorption test for A. luchuensis indicate that this isolate uses the biosorption mechanism as a strategy to remove diclofenac. Finally, the results demonstrate that A. luchuensis can remove >98% of diclofenac in non-sterile wastewater without a pH correction immediately after biomass inoculation on biofilm carriers while Trametes versicolor requires an incubation period of at least 24 h to completely remove diclofenac. Therefore, this isolate is a promising candidate for use in removal of pharmaceutical compounds from wastewater with typical pH 7.8, minimizing a requirement of the pH correction.
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| 3. |
- Dalecka, Brigita, et al.
(författare)
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Removal of total phosphorus, ammonia nitrogen and organic carbon from non-sterile municipal wastewater with Trametes versicolor and Aspergillus luchuensis
- 2020
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Ingår i: Microbiological Research. - : Elsevier. - 0944-5013 .- 1618-0623. ; 241:126586, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Discharge of organic load from treated wastewater may cause environmental eutrophication. Recently, fungi have gained much attention due to their removal of pharmaceutical substances by enzymatic degradation and adsorption. However, the fungal effect in removing nutrients is less investigated. Therefore, two fungal species, the white-rot fungus T. versicolor as a laboratory strain and the mold A. luchuensis as an environmental isolate from the municipal wastewater treatment plant, were studied to determine the fungal potential for phosphorus, nitrogen, and the total organic carbon removal from municipal wastewater, carrying out a batch scale experiment to a fluidized bed pelleted bioreactor. During the batch scale experiment, the total removal (99.9 %) of phosphorus by T. versicolor was attained after a 6 hours-long incubation period while the maximal removal efficiency (99.9 %) for phosphorus from A. luchuensis was gained after an incubation period of 24 hours. Furthermore, both fungi showed that the pH adjustment to 5.5 kept the concentration of nitrogen constant and stabilized the total organic carbon reduction process for the entire incubation period. The results from the fluidized bed bioreactor demonstrated opposite tendencies on a nutrient removal comparing to a batch experiment where no significant effect on phosphorus, nitrogen, and total organics carbon reduction was observed. The obtained results from this study of batch and fluidized bed bioreactor experiments are a promising starting point for a successful fungal treatment optimization and application to wastewater treatment.
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| 4. |
- Dalecka, Brigita, 1990-
(författare)
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Wastewater treatment from pharmaceutical substances with filamentous fungi
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The ever-increasing concern about the widespread occurrence of pharmaceutical substances in the aquatic environment has been recognized as an emerging environmental issue as it can cause undesirable effects on the ecosystem and human health. The current wastewater treatment methods are not designed to treat municipal wastewater from the contamination of various pharmaceutical substances. As a result, pharmaceuticals can enter the environment and pose a threat to life forms. Therefore, it is important to enhance the classical wastewater treatment process in order to meet the challenges by advancing the technologies. Currently, the biological treatment method with filamentous fungi has been considered a promising, cost- effective, and environmentally friendly method for removing pharmaceutical substances from municipal wastewater. The thesis “Wastewater treatment from pharmaceutical substances with filamentous fungi” demonstrates the potential application of fungi in removing pharmaceutical substances and their expedience to incorporate into the classical municipal wastewater treatment process. The investigation focused on selecting suitable fungal strains that could adapt without adjusting physico-chemical parameters and compete with the microbial community in the municipal wastewater. Further, the thesis investigated whether fungal strains could reduce nutrients and pharmaceutical substances in lab-scale and pilot-scale setup and the mechanisms of pharmaceutical substance removal. The thesis consists of two main stages. In the first stage, the batch- scale experiments were carried out under laboratory conditions, finding out the most suitable fungal strains for the removal of pharmaceutical substances from wastewater. The results demonstrated that fungi compete with each other since higher removal efficiency was observed if the fungi were grown individually. Batch-scale experiments showed that Trametes versicolor a laboratory strain and Aspergillus luchuensis an environmental isolate from a municipal wastewater treatment plant – can be a promising strain for removing pharmaceutical substances in a non-sterile municipal wastewater treatment without the adjustment of pH level. Therefore, these strains were used for further study. In the second stage, the pilot-scale system with a fungal fluidized bed pelleted bioreactor was developed. The results demonstrated that a high potential to remove phosphorus from municipal wastewater efficiently and successfully under a batch scale experiment with non-sterile municipal wastewater while the results from the fluidized bed bioreactor did not demonstrate any significant decrease of phosphorus. Additionally, the fluidized pelleted bioreactor was optimized to perceive bioaugmentation as a strategy with the frequent addition of fungal biomass. The results from the optimization process showed that bioaugmentation is a relatively efficient approach to build on fungi in the fluidized pelleted bioreactor. Furthermore, the results from the AI-based platform with modeling study showed that optimization of bioaugmentation with fungi increases the removal efficiency of pharmaceutical substances from non-sterile municipal wastewater. The author of this study showed that both the literature review and the results from the batch and pilot-scale experiments provided new knowledge that can be used for future investigations of wastewater treatment with fungi. The thesis will help to improve and better understand the possible application of fungi in the municipal wastewater treatment process. The thesis is written in English and consists of 68 pages, 14 figures, 4 tables, and 133 literature sources were used for the development of the thesis.
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| 5. |
- Juhna, Talis
(författare)
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Aspects of drinking water supply in areas of humic water
- 2002
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The thesis investigated several aspects that are important for drinking water supply from waters with high amounts of humic substance (humic water). The results showed that the composition of humic substances is important in their sorption to aquifer material during surface water artificial recharge through infiltration basins to groundwater. The more acidic fraction of humic substances was less effectively sorbed than the more hydrophobic fraction. The removal of the former fraction from the recharged groundwater was effective using weak base anion exchange resin. A high total number of bacteria in presence of cyanobacteria in the subsurface below the infiltration indicated that significant decrease of biodegradation of organic matter, during water passage from blooming humic lake to groundwater, is not likely. Because of high amounts of microbially assimilable organic carbon in humic water and its low reduction during chemical treatment, bacterial growth in drinking water distribution systems was dependent on the phosphorus concentration. In the distributed water bacteria were forming biofilm on the pipe surfaces. To reduce the biofilm growth fairly high doses of chlorine were needed. The anion exchange resin was successfully used to determine concentrations of iron-humic complexes in humic groundwater. According to this analysis a significant part of iron in drinking water, produced by artificial recharge from a humic lake, was bound to humic substances.
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| 6. |
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| 7. |
- Juhna, Talis
(författare)
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Sorption of humic substances and microbial activity in the course of artificial recharge of groundwater
- 1999
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Sorption of humic subtances and metal-humate complexes on aquifer material taken from basins used for artificial recharge of groundwater was studied in batch scale experiments. Distribution of bacteria attached to the material from uppermost layer and from the horizons below the infiltration basin were measured in the field studies. Sorption of aquifer material was heterogeneous in respect to the different position and depth in the infiltration basin. Sorption depended on the numerous factors including composition of the filter sand and properties of humic matter. The heavy metals retarded during artificial groundwater recharge was in the form of metal-humate complexes, dominantly in anionic form or as particulate matter. Sorption of humic substances on the aquifer material was substantially enhanced due to the forming of complexes with heavy metals. Total bacterial number was greatest on the upper most layer of infiltration basin. Slight decreases of bacterial number was observed down to the depth of two meters. There were no significant differences in ratio among major physiological groups of heterotrophic bacteria between layer investigated. The smallest seasonal variation of bacteria was found in the deeper layer below infiltration basin.
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| 8. |
- Juhna, Talis, et al.
(författare)
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Sorption of humic substances on aquifer material at artificial recharge of groundwater
- 2003
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Ingår i: Chemosphere. - 0045-6535 .- 1879-1298. ; 51:9, s. 861-8
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Tidskriftsartikel (refereegranskat)abstract
- Experiments in batch equilibrium system were carried out to evaluate the importance of physical and chemical factors determining the sorption efficiency of humic substances (HS) on aquifer material, which has been used for artificial recharge of groundwater (ARG) in drinking water production. Results showed that an increase of the amount of clay in the aquifer material and a decrease of pH in water increased the sorption efficiency. The sorption of higher molecular weight, more hydrophobic and aromatic HS (Aldrich and forest soil humic acids) were greater than the sorption of acidic HS (river fulvic acids), either on the aquifer material or to its representative sorbing phases, clay and organic matter. The sorption on the aquifer material was largely due to physical sorption (hydrophobic attractions). This study showed the importance of HS composition on their removal during ARG and contributed to an understanding of the HS sorption mechanisms in this process
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| 9. |
- Juhna, Talis, et al.
(författare)
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Water-Quality Changes in Latvia and Riga 1980–2000: Possibilities and Problems
- 2001
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Ingår i: Ambio. - : Royal Swedish Academy of Sciences. - 0044-7447 .- 1654-7209. ; 30:4-5, s. 306-14
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Tidskriftsartikel (refereegranskat)abstract
- Long-term changes in the environmental quality of water in Latvia (chemical composition of inland waters, wastewater treatment, and drinking-water treatment practices and quality) as a response to socioeconomic changes have been studied. Water composition, the major factors influencing water chemistry, and human impacts (wastewater loading) were studied to determine changes that occurred after recent reductions in pollution emissions, particularly nutrient loading, to surface waters. After 1991, (Latvia regained independence in 1991) inland water quality has begun to improve mainly as a result of decreases in nutrient loads from point and nonpoint sources and substantial efforts in the area of environmental protection. The situation differs, however, for drinking-water treatment, where practices have also changed during the whole period from 1980 till 2000. More stringent drinking-water-quality standards and novel insights regarding changes in water quality in the distribution network, necessitate further improvements in public water supply, and place this particular water issue among Latvia's main priorities.
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| 10. |
- Lavrinovičs, Aigars, et al.
(författare)
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Increasing Phosphorus Uptake Efficiency by Phosphorus-Starved Microalgae for Municipal Wastewater Post-Treatment
- 2021
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Ingår i: Microorganisms. - : MDPI. - 2076-2607. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- Four microalgal species, Chlorella vulgaris, Botryococcus braunii, Ankistrodesmus falcatus, and Tetradesmus obliquus were studied for enhanced phosphorus removal from municipal wastewater after their exposure to phosphorus starvation. Microalgae were exposed to phosphorus starvation conditions for three and five days and then used in a batch experiment to purify an effluent from a small WWTP. After 3-day P-starvation, C. vulgaris biomass growth rate increased by 50% and its PO4 removal rate reached > 99% within 7 days. B. braunii maintained good biomass growth rate and nutrient removal regardless of the P-starvation. All species showed 2-5 times higher alkaline phosphatase activity increase for P-starved biomass than at the reference conditions, responding to the decline of PO4 concentration in wastewater and biomass poly-P content. The overall efficiency of biomass P-starvation on enhanced phosphorus uptake was found to be dependent on the species, N/P molar ratio in the wastewater, as well as the biomass P content.
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