This page has only limited features, please log in for full access.
In this study, the microbial community of nitrifying activated sludge adapted to Finnish climate conditions was studied to clarify the microbial populations involved in low-temperature nitrification. Microbial community analysis of five full-scale wastewater treatment plants (WWTPs) showed several differences compared to WWTPs from other countries with a similar climate. In particular, very low abundance of ammonium oxidizing bacteria (AOBs) (altogether ˂ 0.25% of total community) as well as typical NOBs (˂0.35%) and a high abundance of orders Cytophagales and Micrococcales was observed in all Finnish WWTPs. To shed light on the importance of autotrophic and heterotrophic nitrifying processes, laboratory studies of activated sludge were carried out with a presence of and a lack of organic carbon in wastewater at 10 ± 1 °C. Two different sludge retention times (SRTs) were compared to determine the effect of this operational parameter on low-temperature nitrogen removal. The important role of previously reported Candidatus Nitrotogaarctica for nitrite oxidizing in cold climate conditions was confirmed in both full-scale and laboratory scale results. Additionally, potential participation of Dokdonella sp. and Flexibacter sp. in nitrogen removal at low-temperatures is proposed. Operation at SRT of 100 days demonstrated more stable and efficient nitrogen removal after a sharp temperature decrease compared to 14 days SRT.
Antonina Kruglova; Jenni Kesulahti; Khoi Minh Le; Alejandro Gonzalez-Martinez; Anna Mikola; Riku Vahala. Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems. Water 2020, 12, 2450 .
AMA StyleAntonina Kruglova, Jenni Kesulahti, Khoi Minh Le, Alejandro Gonzalez-Martinez, Anna Mikola, Riku Vahala. Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems. Water. 2020; 12 (9):2450.
Chicago/Turabian StyleAntonina Kruglova; Jenni Kesulahti; Khoi Minh Le; Alejandro Gonzalez-Martinez; Anna Mikola; Riku Vahala. 2020. "Low-Temperature Adapted Nitrifying Microbial Communities of Finnish Wastewater Treatment Systems." Water 12, no. 9: 2450.
Inflow and infiltration (I/I) is a common problem in sanitary sewer systems. The I/I rate is also considered to be an important indicator of the operational and structural condition of the sewer system. Situation awareness in sanitary sewer systems requires accurate wastewater-flow information at a fine spatiotemporal scale. This study aims to develop artificial intelligence (AI)-based models (adaptive neurofuzzy inference system (ANFIS) and multilayer perceptron neural network (MLPNN)) and to compare their performance for identifying the potential inflow and infiltration of the sanitary sewer subcatchment of two pumping stations. We tested the performance of these AI models by using data gathered from two pumping stations through a supervisory control and data acquisition (SCADA) system. As a result, these two AI models produced similar inflow and infiltration patterns—both subcatchments experienced inflow and infiltration. On the other hand, the ANFIS had overall higher performance than that of the MLPNN model for modelling the I/I situation for the catchments. The results of the research can be used to support spatial decision making in sewer system maintenance.
Zhe Zhang; Tuija Laakso; Zeyu Wang; Seppo Pulkkinen; Suvi Ahopelto; Kirsi Virrantaus; Yu Li; Ximing Cai; Chi Zhang; Riku Vahala; Zhuping Sheng. Comparative Study of AI-Based Methods—Application of Analyzing Inflow and Infiltration in Sanitary Sewer Subcatchments. Sustainability 2020, 12, 6254 .
AMA StyleZhe Zhang, Tuija Laakso, Zeyu Wang, Seppo Pulkkinen, Suvi Ahopelto, Kirsi Virrantaus, Yu Li, Ximing Cai, Chi Zhang, Riku Vahala, Zhuping Sheng. Comparative Study of AI-Based Methods—Application of Analyzing Inflow and Infiltration in Sanitary Sewer Subcatchments. Sustainability. 2020; 12 (15):6254.
Chicago/Turabian StyleZhe Zhang; Tuija Laakso; Zeyu Wang; Seppo Pulkkinen; Suvi Ahopelto; Kirsi Virrantaus; Yu Li; Ximing Cai; Chi Zhang; Riku Vahala; Zhuping Sheng. 2020. "Comparative Study of AI-Based Methods—Application of Analyzing Inflow and Infiltration in Sanitary Sewer Subcatchments." Sustainability 12, no. 15: 6254.
Reducing water loss from water supply systems is often regarded as one of the most important ways to improve the resource efficiency of water supply services. However, the costs and impacts of water loss reduction efforts need to be weighed against the benefits to define the optimal water loss target level. To this end, we conducted a cost–benefit analysis of three investment-based leakage reduction methods: district metering, pressure reduction, and pipe renovations. Furthermore, we conducted uncertainty and sensitivity analysis to determine the most relevant data for leakage analysis and policymaking on a national level. The results indicate that water loss management might not be directly cost-beneficial to utilities operating with moderate leakage levels. Neither leakage percentage nor the Infrastructure Leakage Index (ILI) were suitable for leakage target setting for the Finnish utilities. The costs of investing in district metering or renovations were the most influential factors in the sensitivity analysis, but the results showed that the estimated values were sufficiently accurate for assessing leakage policies.
Suvi Ahopelto; Riku Vahala. Cost–Benefit Analysis of Leakage Reduction Methods in Water Supply Networks. Water 2020, 12, 195 .
AMA StyleSuvi Ahopelto, Riku Vahala. Cost–Benefit Analysis of Leakage Reduction Methods in Water Supply Networks. Water. 2020; 12 (1):195.
Chicago/Turabian StyleSuvi Ahopelto; Riku Vahala. 2020. "Cost–Benefit Analysis of Leakage Reduction Methods in Water Supply Networks." Water 12, no. 1: 195.
Survival models can support the estimation of the resources needed for future renovations of sewer systems. They are particularly useful, when a large share of network will need renovation. This paper studies modelling sewer deterioration in a context, where data are available for pipes selected for inspections due to suspected or experienced poor condition. We compare the random survival forest and the Weibull regression for modelling survival and find that both methods yield similar results, but the random survival forest performs slightly better. We propose a method for estimating the range in which the actual network survival curve lies. We conclude that in order to reach reliable results, a life span model needs to be constructed based on a random sample of pipes, which are then consecutively inspected and in addition, censoring and left truncation need to be accounted for. The inspection data applied in this paper had been collected with the aim of finding pipes in poor condition in the network. As a result, the data were biased towards poor condition and unrepresentative in terms of pipe ages.
Tuija Laakso; Teemu Kokkonen; Ilkka Mellin; Riku Vahala. Sewer Life Span Prediction: Comparison of Methods and Assessment of the Sample Impact on the Results. Water 2019, 11, 2657 .
AMA StyleTuija Laakso, Teemu Kokkonen, Ilkka Mellin, Riku Vahala. Sewer Life Span Prediction: Comparison of Methods and Assessment of the Sample Impact on the Results. Water. 2019; 11 (12):2657.
Chicago/Turabian StyleTuija Laakso; Teemu Kokkonen; Ilkka Mellin; Riku Vahala. 2019. "Sewer Life Span Prediction: Comparison of Methods and Assessment of the Sample Impact on the Results." Water 11, no. 12: 2657.
We mapped a large-scale wastewater treatment plant onto a complex network and we investigated how the structural properties of the graph evolve in time as the facility is operated. The Viikinmäki plant is mapped onto a dependence network in which the nodes are online process measurements and interconnectivity between nodes encodes pairwise correlations between the corresponding time series, as estimated over moving-windows. In this initial study, the construction of a graph of Viikinmäki is presented and results are discussed with the goal of understanding its usability as model for process interactions and encoder of latent structures.
Francesco Corona; Michela Mulas; Anna Mikola; Anna Kuokkanen; Mari Heinonen; Riku Vahala. Network representation and analysis of a large-scale wastewater treatment plant. IFAC-PapersOnLine 2019, 52, 364 -369.
AMA StyleFrancesco Corona, Michela Mulas, Anna Mikola, Anna Kuokkanen, Mari Heinonen, Riku Vahala. Network representation and analysis of a large-scale wastewater treatment plant. IFAC-PapersOnLine. 2019; 52 (1):364-369.
Chicago/Turabian StyleFrancesco Corona; Michela Mulas; Anna Mikola; Anna Kuokkanen; Mari Heinonen; Riku Vahala. 2019. "Network representation and analysis of a large-scale wastewater treatment plant." IFAC-PapersOnLine 52, no. 1: 364-369.
Sewer condition is commonly assessed using closed-circuit television (CCTV) inspections. In this paper, we combine inspection results, pipe attributes, network data, and data on pipe environment to predict pipe condition and to discover which factors affect it. We apply the random forest algorithm to model pipe condition and assess the variable importance using the Boruta algorithm. We analyse the impact of predictor variables on poor condition using partial dependence plots, which are a valuable technique for this purpose. The results can be used in screening pipes for future inspections and provide insight into the dynamics between predictor variables and poor condition.
Tuija Laakso; Teemu Kokkonen; Ilkka Mellin; Riku Vahala. Sewer Condition Prediction and Analysis of Explanatory Factors. Water 2018, 10, 1239 .
AMA StyleTuija Laakso, Teemu Kokkonen, Ilkka Mellin, Riku Vahala. Sewer Condition Prediction and Analysis of Explanatory Factors. Water. 2018; 10 (9):1239.
Chicago/Turabian StyleTuija Laakso; Teemu Kokkonen; Ilkka Mellin; Riku Vahala. 2018. "Sewer Condition Prediction and Analysis of Explanatory Factors." Water 10, no. 9: 1239.
We studied the seasonal variation of nitrite exposure in a drinking water distribution system (DWDS) with monochloramine disinfection in the Helsinki Metropolitan Area. In Finland, tap water is the main source of drinking water, and thus the nitrite in tap water increases nitrite exposure. Our data included both the obligatory monitoring and a sampling campaign data from a sampling campaign. Seasonality was evaluated by comparing a nitrite time series to temperature and by calculating the seasonal indices of the nitrite time series. The main drivers of nitrite seasonality were the temperature and the water age. We observed that with low water ages (median: 6.7 h) the highest nitrite exposure occurred during the summer months, and with higher water ages (median: 31 h) during the winter months. With the highest water age (190 h), nitrite concentrations were the lowest. At a low temperature, the high nitrite concentrations in the winter were caused by the decelerated ammonium oxidation. The dominant reaction at low water ages was ammonium oxidation into nitrite and, at high water ages, it was nitrite oxidation into nitrate. These results help to direct monitoring appropriately to gain exact knowledge of nitrite exposure. Also, possible future process changes and additional disinfection measures can be designed appropriately to minimize extra nitrite exposure.
Pirjo-Liisa Rantanen; Ilkka Mellin; Minna M. Keinänen-Toivola; Merja Ahonen; Riku Vahala. The Seasonality of Nitrite Concentrations in a Chloraminated Drinking Water Distribution System. International Journal of Environmental Research and Public Health 2018, 15, 1756 .
AMA StylePirjo-Liisa Rantanen, Ilkka Mellin, Minna M. Keinänen-Toivola, Merja Ahonen, Riku Vahala. The Seasonality of Nitrite Concentrations in a Chloraminated Drinking Water Distribution System. International Journal of Environmental Research and Public Health. 2018; 15 (8):1756.
Chicago/Turabian StylePirjo-Liisa Rantanen; Ilkka Mellin; Minna M. Keinänen-Toivola; Merja Ahonen; Riku Vahala. 2018. "The Seasonality of Nitrite Concentrations in a Chloraminated Drinking Water Distribution System." International Journal of Environmental Research and Public Health 15, no. 8: 1756.
The aim of this work was to study the performance and microbial community structure of a polar Arctic Circle aerobic granular sludge (AGS) system operating at low temperature. Thus, an AGS bioreactor was operated at 7, 5 and 3 °C of temperature using a cold-adapted sludge from Lapland. At 5 °C, it yielded acceptable conversion rates, in terms of nitrogen, phosphorous, and organic matter. However, under 3 °C a negligible nitrogen and phosphorous removal performance was observed. Below 5 °C, scanning electron microscopy studies showed a wispy, non-dense and irregular granular structure with a strong outgrowth of filamentous. Moreover, Illumina next-generation sequencing showed a heterogeneous microbial population where SM1K20 (Archaea), Trichosporon domesticum (Fungus), and Zooglea, Arcobacter and Acinetobacter (Bacteria) were the dominant phylotypes. Our study suggests that AGS technologies inoculated with North Pole sludge could be operated, in cold regions for a period longer than 3 months (winter season) under 5 °C of water temperature.
Alejandro Gonzalez-Martinez; Barbara Muñoz Palazon; Paula Maza-Márquez; Alejandro Rodriguez-Sanchez; Jesus Gonzalez-Lopez; Riku Vahala. Performance and microbial community structure of a polar Arctic Circle aerobic granular sludge system operating at low temperature. Bioresource Technology 2018, 256, 22 -29.
AMA StyleAlejandro Gonzalez-Martinez, Barbara Muñoz Palazon, Paula Maza-Márquez, Alejandro Rodriguez-Sanchez, Jesus Gonzalez-Lopez, Riku Vahala. Performance and microbial community structure of a polar Arctic Circle aerobic granular sludge system operating at low temperature. Bioresource Technology. 2018; 256 ():22-29.
Chicago/Turabian StyleAlejandro Gonzalez-Martinez; Barbara Muñoz Palazon; Paula Maza-Márquez; Alejandro Rodriguez-Sanchez; Jesus Gonzalez-Lopez; Riku Vahala. 2018. "Performance and microbial community structure of a polar Arctic Circle aerobic granular sludge system operating at low temperature." Bioresource Technology 256, no. : 22-29.
An Activated Sludge Model #3 (ASM3)-based, pseudo-mechanistic model describing nitrous oxide (N2O) production was created in this study to provide more insight into the dynamics of N2O production, consumption, and emissions at a full-scale wastewater treatment plant (WWTP). N2O emissions at the studied WWTP are monitored throughout the plant with an FT-IR analyzer, while the developed model encountered N2O production in the biological reactors via both ammonia oxidizing bacteria (AOB) nitrification and heterotrophic denitrifiers. Additionally, the stripping of N2O was included by applying a KLa-based approach that has not been widely used before. The objective was to extend the existing ASM3-based model of the plant and assess how well the full-scale emissions could be predicted with the selected model. The validity and applicability of the model were tested by comparing the simulation results with the comprehensive online data. The results show that the ASM3-based model can be successfully extended and applied to modelling N2O production and emissions at a full-scale WWTP. These results demonstrate that the biological reactor can explain most of the N2O emissions at the plant, but a significant proportion of the liquid-phase N2O is further transferred during the process.
Kati Blomberg; Pascal Kosse; Anna Mikola; Anna Kuokkanen; Tommi Fred; Mari Heinonen; Michela Mulas; Manfred Lübken; Marc Wichern; Riku Vahala. Development of an Extended ASM3 Model for Predicting the Nitrous Oxide Emissions in a Full-Scale Wastewater Treatment Plant. Environmental Science & Technology 2018, 52, 5803 -5811.
AMA StyleKati Blomberg, Pascal Kosse, Anna Mikola, Anna Kuokkanen, Tommi Fred, Mari Heinonen, Michela Mulas, Manfred Lübken, Marc Wichern, Riku Vahala. Development of an Extended ASM3 Model for Predicting the Nitrous Oxide Emissions in a Full-Scale Wastewater Treatment Plant. Environmental Science & Technology. 2018; 52 (10):5803-5811.
Chicago/Turabian StyleKati Blomberg; Pascal Kosse; Anna Mikola; Anna Kuokkanen; Tommi Fred; Mari Heinonen; Michela Mulas; Manfred Lübken; Marc Wichern; Riku Vahala. 2018. "Development of an Extended ASM3 Model for Predicting the Nitrous Oxide Emissions in a Full-Scale Wastewater Treatment Plant." Environmental Science & Technology 52, no. 10: 5803-5811.
The emergence and spread of antibiotics resistance in wastewater treatment systems have been pointed as a major environmental health problem. Nevertheless, research about adaptation and antibiotics resistance gain in wastewater treatment systems subjected to antibiotics has not been successfully developed considering bioreactor performance, microbial community dynamics and microbial activity dynamics at the same time. To observe this in autotrophic nitrogen removal systems, a partial-nitritation biofilter was subjected to a continuous loading of antibiotics mix of azithromycin, norfloxacin, trimethoprim, and sulfamethoxazole. The effect of the antibiotics mix over the performance, bacterial communities and bacterial activity in the system was evaluated. The addition of antibiotics caused a drop of ammonium oxidation efficiency (from 50 to 5%) and of biomass concentration in the bioreactor, which was coupled to the loss of ammonium oxidizing bacteria Nitrosomonas in the bacterial community from 40 to 3%. Biomass in the partial nitritation biofilter experienced a sharp decrease of about 80% due to antibiotics loading, but the biomass adapted and experienced a growth by stabilization under antibiotics feeding. During the experiment several bacterial genera appeared, such as Alcaligenes, Paracoccus, and Acidovorax, clearly dominating the bacterial community with >20% relative abundance. The system reached around 30% ammonium oxidation efficiency after adaptation to antibiotics, but no effluent nitrite was found, suggesting that dominant antibiotics-resistant phylotypes could be involved in nitrification–denitrification metabolisms. The activity of ammonium oxidation measured as amoA and hao gene expression dropped a 98.25% and 99.21%, respectively, comparing the system before and after the addition of antibiotics. On the other hand, denitrifying activity increased as observed by higher expression of nir and nos genes (83.14% and 252.54%, respectively). In addition, heterotrophic nitrification cyt c-551 was active only after the antibiotics addition. Resistance to the antibiotics was presumably given by ermF, carA and msrA for azithromycin, mutations of the gyrA and grlB for norfloxacin, and by sul123 genes for sulfamethoxazole. Joined physicochemical and microbiological characterization of the system were used to investigate the effect of the antibiotics over the bioprocess. Despite the antibiotics resistance, activity of Bacteria decreased while the activity of Archaea and Fungi increased.
Alejandro Gonzalez-Martinez; Alejandro Margareto; Alejandro Rodriguez-Sanchez; Chiara Pesciaroli; Silvia Diaz-Cruz; Damia Barcelo; Riku Vahala. Linking the Effect of Antibiotics on Partial-Nitritation Biofilters: Performance, Microbial Communities and Microbial Activities. Frontiers in Microbiology 2018, 9, 354 .
AMA StyleAlejandro Gonzalez-Martinez, Alejandro Margareto, Alejandro Rodriguez-Sanchez, Chiara Pesciaroli, Silvia Diaz-Cruz, Damia Barcelo, Riku Vahala. Linking the Effect of Antibiotics on Partial-Nitritation Biofilters: Performance, Microbial Communities and Microbial Activities. Frontiers in Microbiology. 2018; 9 ():354.
Chicago/Turabian StyleAlejandro Gonzalez-Martinez; Alejandro Margareto; Alejandro Rodriguez-Sanchez; Chiara Pesciaroli; Silvia Diaz-Cruz; Damia Barcelo; Riku Vahala. 2018. "Linking the Effect of Antibiotics on Partial-Nitritation Biofilters: Performance, Microbial Communities and Microbial Activities." Frontiers in Microbiology 9, no. : 354.
Seven full-scale biological wastewater treatment systems located in the Polar Arctic Circle region in Finland were investigated to determine their Archaea, Bacteria and Fungi community structure, and their relationship with the operational conditions of the bioreactors by the means of quantitative PCR, massive parallel sequencing and multivariate redundancy analysis. The results showed dominance of Archaea and Bacteria members in the bioreactors. The activated sludge systems showed strong selection of Bacteria but not for Archaea and Fungi, as suggested by diversity analyses. Core OTUs in influent and bioreactors were classified as Methanobrevibacter, Methanosarcina, Terrestrial Group Thaumarchaeota and unclassified Euryarchaeota member for Archaea; Trichococcus, Leptotrichiaceae and Comamonadaceae family, and Methylorosula for Bacteria and Trichosporonaceae family for Fungi. All influents shared core OTUs in all domains, but in bioreactors this did not occur for Bacteria. Oligotype structure of core OTUs showed several ubiquitous Fungi oligotypes as dominant in sewage and bioreactors. Multivariate redundancy analyses showed that the majority of core OTUs were related to organic matter and nutrients removal. Also, there was evidence of competition among Archaea and Fungi core OTUs, while all Bacteria OTUs were positively correlated among them. The results obtained highlighted interesting features of extremely cold temperature bioreactors.
Alejandro Gonzalez-Martinez; Maija Sihvonen; Barbara Muñoz Palazon; Alejandro Rodriguez-Sanchez; Anna Mikola; Riku Vahala. Microbial ecology of full-scale wastewater treatment systems in the Polar Arctic Circle: Archaea, Bacteria and Fungi. Scientific Reports 2018, 8, 1 -11.
AMA StyleAlejandro Gonzalez-Martinez, Maija Sihvonen, Barbara Muñoz Palazon, Alejandro Rodriguez-Sanchez, Anna Mikola, Riku Vahala. Microbial ecology of full-scale wastewater treatment systems in the Polar Arctic Circle: Archaea, Bacteria and Fungi. Scientific Reports. 2018; 8 (1):1-11.
Chicago/Turabian StyleAlejandro Gonzalez-Martinez; Maija Sihvonen; Barbara Muñoz Palazon; Alejandro Rodriguez-Sanchez; Anna Mikola; Riku Vahala. 2018. "Microbial ecology of full-scale wastewater treatment systems in the Polar Arctic Circle: Archaea, Bacteria and Fungi." Scientific Reports 8, no. 1: 1-11.
This study examines zinc(II)–chitosan complexes as a bio-sorbent for phosphate removal from aqueous solutions. The bio-sorbent is prepared and is characterized via Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Point of Zero Charge (pHPZC)–drift method. The adsorption capacity of zinc(II)–chitosan bio-sorbent is compared with those of chitosan and ZnO–chitosan and nano-ZnO–chitosan composites. The effect of operational parameters including pH, temperature, and competing ions are explored via adsorption batch mode. A rapid phosphate uptake is observed within the first three hours of contact time. Phosphate removal by zinc(II)–chitosan is favored when the surface charge of bio-sorbent is positive/or neutral e.g., within the pH range inferior or around its pHPZC, 7. Phosphate abatement is enhanced with decreasing temperature. The study of background ions indicates a minor effect of chloride, whereas nitrate and sulfate show competing effect with phosphate for the adsorptive sites. The adsorption kinetics is best described with the pseudo-second-order model. Sips (R2 > 0.96) and Freundlich (R2 ≥ 0.95) models suit the adsorption isotherm. The phosphate reaction with zinc(II)–chitosan is exothermic, favorable and spontaneous. The complexation of zinc(II) and chitosan along with the corresponding mechanisms of phosphate removal are presented. This study indicates the introduction of zinc(II) ions into chitosan improves its performance towards phosphate uptake from 1.45 to 6.55 mg/g and provides fundamental information for developing bio-based materials for water remediation.
Maryam Roza Yazdani; Elina Virolainen; Kevin Conley; Riku Vahala. Chitosan–Zinc(II) Complexes as a Bio-Sorbent for the Adsorptive Abatement of Phosphate: Mechanism of Complexation and Assessment of Adsorption Performance. Polymers 2017, 10, 25 .
AMA StyleMaryam Roza Yazdani, Elina Virolainen, Kevin Conley, Riku Vahala. Chitosan–Zinc(II) Complexes as a Bio-Sorbent for the Adsorptive Abatement of Phosphate: Mechanism of Complexation and Assessment of Adsorption Performance. Polymers. 2017; 10 (1):25.
Chicago/Turabian StyleMaryam Roza Yazdani; Elina Virolainen; Kevin Conley; Riku Vahala. 2017. "Chitosan–Zinc(II) Complexes as a Bio-Sorbent for the Adsorptive Abatement of Phosphate: Mechanism of Complexation and Assessment of Adsorption Performance." Polymers 10, no. 1: 25.
In this study the influence of low-temperature (8°C), sludge retention time (SRT) and loading of spotlight wastewater micropollutants (MPs) on bacterial community of activated sludge was investigated with a special focus on nitrification. Two Sequencing batch reactors (SBR) and two membrane bioreactors (MBR) were operated with synthetic municipal-like wastewater receiving and not receiving ibuprofen, diclofenac, estrone and 17α-ethynylestradiol (EE2). Bacterial population studies were related to removal efficiencies of studied MPs. The results showed that studied bacterial communities significantly differed from all previously published nitrifying activated sludge communities. Exceptionally low concentration of autotrophic nitrifying bacteria were found (<0.5%) as well as no common heterotrophic nitrifies were presenting in activated sludge and therefore could not be related to the MPs removal. Additionally SRT had a spacious effect on the diversity of bacteria and bacterial population shifts under pressure of MPs. Growth of Firmicutes was suppressed by presence of MPs in all the reactors. Increase of MPs concentrations in wastewater improved the removal of EE2. Abundance of Delta- and Gammaproteobacteria showed positive correlation with diclofenac removal.
Antonina Kruglova; Alejandro Gonzalez-Martinez; Matilda Kråkström; Anna Mikola; Riku Vahala. Bacterial diversity and population shifts driven by spotlight wastewater micropollutants in low-temperature highly nitrifying activated sludge. Science of The Total Environment 2017, 605-606, 291 -299.
AMA StyleAntonina Kruglova, Alejandro Gonzalez-Martinez, Matilda Kråkström, Anna Mikola, Riku Vahala. Bacterial diversity and population shifts driven by spotlight wastewater micropollutants in low-temperature highly nitrifying activated sludge. Science of The Total Environment. 2017; 605-606 ():291-299.
Chicago/Turabian StyleAntonina Kruglova; Alejandro Gonzalez-Martinez; Matilda Kråkström; Anna Mikola; Riku Vahala. 2017. "Bacterial diversity and population shifts driven by spotlight wastewater micropollutants in low-temperature highly nitrifying activated sludge." Science of The Total Environment 605-606, no. : 291-299.
Chengyuan Su; Yuxiang Lu; Jingjing Qin; Peng Zheng; Rui Qiu; Menglin Chen; Riku Vahala; Yu Wang. Performance and microbial community structure characterization of a CIC anaerobic reactor for the treatment of cassava wastewater. Ecological Engineering 2017, 108, 114 -122.
AMA StyleChengyuan Su, Yuxiang Lu, Jingjing Qin, Peng Zheng, Rui Qiu, Menglin Chen, Riku Vahala, Yu Wang. Performance and microbial community structure characterization of a CIC anaerobic reactor for the treatment of cassava wastewater. Ecological Engineering. 2017; 108 ():114-122.
Chicago/Turabian StyleChengyuan Su; Yuxiang Lu; Jingjing Qin; Peng Zheng; Rui Qiu; Menglin Chen; Riku Vahala; Yu Wang. 2017. "Performance and microbial community structure characterization of a CIC anaerobic reactor for the treatment of cassava wastewater." Ecological Engineering 108, no. : 114-122.
Alejandro Rodriguez-Sanchez; Alejandro Margareto; Tatiana Robledo-Mahón; Elisabet Aranda; Silvia Diaz-Cruz; Jesus Gonzalez-Lopez; Damia Barcelo; Riku Vahala; Alejandro Gonzalez-Martinez. Performance and bacterial community structure of a granular autotrophic nitrogen removal bioreactor amended with high antibiotic concentrations. Chemical Engineering Journal 2017, 325, 257 -269.
AMA StyleAlejandro Rodriguez-Sanchez, Alejandro Margareto, Tatiana Robledo-Mahón, Elisabet Aranda, Silvia Diaz-Cruz, Jesus Gonzalez-Lopez, Damia Barcelo, Riku Vahala, Alejandro Gonzalez-Martinez. Performance and bacterial community structure of a granular autotrophic nitrogen removal bioreactor amended with high antibiotic concentrations. Chemical Engineering Journal. 2017; 325 ():257-269.
Chicago/Turabian StyleAlejandro Rodriguez-Sanchez; Alejandro Margareto; Tatiana Robledo-Mahón; Elisabet Aranda; Silvia Diaz-Cruz; Jesus Gonzalez-Lopez; Damia Barcelo; Riku Vahala; Alejandro Gonzalez-Martinez. 2017. "Performance and bacterial community structure of a granular autotrophic nitrogen removal bioreactor amended with high antibiotic concentrations." Chemical Engineering Journal 325, no. : 257-269.
An aerobic granular sludge system has been started-up and operated at 7°C temperature using cold-adapted activated sludge as inoculum. The system could form granular biomass due to batch operation allowing for just 5-3min of biomass sedimentation. Scanning electron microscopy showed that fungi helped in the granular biomass formation in the early stages of the granule formation. The removal performance of the system was of 92-95% in BOD5, 75-80% in COD, 70-76% in total nitrogen and 50-60% in total phosphorous. The bacterial community structure from cold-adapted activated sludge changed during the operational time, leading to a final configuration dominated by Microbacteriaceae members Microbacterium and Leucobacter, which were strongly correlated to biomass settling velocity and bioreactor performance, as suggested by multivariate redundancy analyses. This experiment showed that aerobic granular sludge systems could be successfully started-up and operated, with high performance, under low operational temperatures when using cold-adapted biomass as inoculum.
Alejandro Gonzalez-Martinez; Barbara Muñoz Palazon; Alejandro Rodriguez-Sanchez; Paula Maza-Márquez; Anna Mikola; Jesus Gonzalez-Lopez; Riku Vahala. Start-up and operation of an aerobic granular sludge system under low working temperature inoculated with cold-adapted activated sludge from Finland. Bioresource Technology 2017, 239, 180 -189.
AMA StyleAlejandro Gonzalez-Martinez, Barbara Muñoz Palazon, Alejandro Rodriguez-Sanchez, Paula Maza-Márquez, Anna Mikola, Jesus Gonzalez-Lopez, Riku Vahala. Start-up and operation of an aerobic granular sludge system under low working temperature inoculated with cold-adapted activated sludge from Finland. Bioresource Technology. 2017; 239 ():180-189.
Chicago/Turabian StyleAlejandro Gonzalez-Martinez; Barbara Muñoz Palazon; Alejandro Rodriguez-Sanchez; Paula Maza-Márquez; Anna Mikola; Jesus Gonzalez-Lopez; Riku Vahala. 2017. "Start-up and operation of an aerobic granular sludge system under low working temperature inoculated with cold-adapted activated sludge from Finland." Bioresource Technology 239, no. : 180-189.
Antibiotics are found globally in the environment at trace levels due to their extensive consumption, which raises concerns about the effects they can have on non-target organisms, especially environmental micro-organisms. So far the majority of studies have focused on different aspects of antibiotic resistance or on analyzing the occurrence, fate, and removal of antibiotics from hospital and municipal wastewaters. Little attention has been paid to ecotoxicological effects of antibiotics on aquatic micro-organisms although they play a critical role in most ecosystems and they are potentially sensitive to these substances. Here we review the current state of research on the toxicological impacts of antibiotics to aquatic micro-organisms, including proteobacteria, cyanobacteria, algae and bacteria commonly present in biological wastewater treatment processes. We focus on antibiotics that are poorly removed during wastewater treatment and thus end up in surface waters. We critically discuss and compare the available analytical methods and test organisms based on effect concentrations and identify the knowledge gaps and future challenges. We conclude that, in general, cyanobacteria and ammonium oxidizing bacteria are the most sensitive micro-organisms to antibiotics. It is important to include chronic tests in ecotoxicological assessment, because acute tests are not always appropriate in case of low sensitivity (for example for proteobacteria). However, the issue of rapid development of antibiotic resistance should be regarded in chronic testing. Furthermore, the application of other species of bacteria and endpoints should be considered in the future, not forgetting the mixture effect and bacterial community studies. Due to differences in the sensitivity of different test organisms to individual antibiotic substances, the application of several bioassays with varying test organisms would provide more comprehensive data for the risk assessment of antibiotics. Regardless of the growing concerns related to antibiotics in the environment, there are still evident knowledge gaps related to antibiotics, as there is only limited or no ecotoxicological data on many potentially harmful antibiotics.
Pia Välitalo; Antonina Kruglova; Anna Mikola; Riku Vahala. Toxicological impacts of antibiotics on aquatic micro-organisms: A mini-review. International Journal of Hygiene and Environmental Health 2017, 220, 558 -569.
AMA StylePia Välitalo, Antonina Kruglova, Anna Mikola, Riku Vahala. Toxicological impacts of antibiotics on aquatic micro-organisms: A mini-review. International Journal of Hygiene and Environmental Health. 2017; 220 (3):558-569.
Chicago/Turabian StylePia Välitalo; Antonina Kruglova; Anna Mikola; Riku Vahala. 2017. "Toxicological impacts of antibiotics on aquatic micro-organisms: A mini-review." International Journal of Hygiene and Environmental Health 220, no. 3: 558-569.
Maryam Roza Yazdani; Amit Bhatnagar; Riku Vahala. Synthesis, characterization and exploitation of nano-TiO 2 /feldspar-embedded chitosan beads towards UV-assisted adsorptive abatement of aqueous arsenic (As). Chemical Engineering Journal 2017, 316, 370 -382.
AMA StyleMaryam Roza Yazdani, Amit Bhatnagar, Riku Vahala. Synthesis, characterization and exploitation of nano-TiO 2 /feldspar-embedded chitosan beads towards UV-assisted adsorptive abatement of aqueous arsenic (As). Chemical Engineering Journal. 2017; 316 ():370-382.
Chicago/Turabian StyleMaryam Roza Yazdani; Amit Bhatnagar; Riku Vahala. 2017. "Synthesis, characterization and exploitation of nano-TiO 2 /feldspar-embedded chitosan beads towards UV-assisted adsorptive abatement of aqueous arsenic (As)." Chemical Engineering Journal 316, no. : 370-382.
Human urine contains significant amounts of N (nitrogen) and P (phosphorus); therefore it has been successfully used as fertilizer in different crops. But the use of urine as fertilizer has several constraints, such as, the high cost of transportation, an unpleasant smell, the risk of pathogens, and pharmaceutical residue. A combined and improved N stripping and P precipitation technique is used in this study. In this technique, Ca(OH)2 is used to increase the pH of urine which converts ammonium into ammonia gas and precipitate P as Ca-P compound. The ammonia gas is stripped and passed into the sulfuric acid where ammonium sulfate and hydrogen triammonium disulfate is formed. The experiment was performed using 700 mL of urine and the pH of the urine was increased above 12. Our results showed that 85–99% of N and 99% of P (w/w) can be harvested from urine in 28 h at 40 °C and in 32 h at 30 °C. The harvested N (13% N w/w) and P (1.5% P w/w) can be used as mineral fertilizer. The economic assessment of the technique showed that the extraction of N and P from 1 m3 of pure urine can make a profit of €2.25.
Surendra K. Pradhan; Anna Mikola; Riku Vahala. Nitrogen and Phosphorus Harvesting from Human Urine Using a Stripping, Absorption, and Precipitation Process. Environmental Science & Technology 2017, 51, 5165 -5171.
AMA StyleSurendra K. Pradhan, Anna Mikola, Riku Vahala. Nitrogen and Phosphorus Harvesting from Human Urine Using a Stripping, Absorption, and Precipitation Process. Environmental Science & Technology. 2017; 51 (9):5165-5171.
Chicago/Turabian StyleSurendra K. Pradhan; Anna Mikola; Riku Vahala. 2017. "Nitrogen and Phosphorus Harvesting from Human Urine Using a Stripping, Absorption, and Precipitation Process." Environmental Science & Technology 51, no. 9: 5165-5171.
Jukka Sirkiä; Tuija Laakso; Suvi Ahopelto; Ossi Ylijoki; Jari Porras; Riku Vahala. Data utilization at finnish water and wastewater utilities: Current practices vs. state of the art. Utilities Policy 2017, 45, 69 -75.
AMA StyleJukka Sirkiä, Tuija Laakso, Suvi Ahopelto, Ossi Ylijoki, Jari Porras, Riku Vahala. Data utilization at finnish water and wastewater utilities: Current practices vs. state of the art. Utilities Policy. 2017; 45 ():69-75.
Chicago/Turabian StyleJukka Sirkiä; Tuija Laakso; Suvi Ahopelto; Ossi Ylijoki; Jari Porras; Riku Vahala. 2017. "Data utilization at finnish water and wastewater utilities: Current practices vs. state of the art." Utilities Policy 45, no. : 69-75.