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Aerobic granular sludge (AGS) exhibits excellent resistance to adverse environment due to its unique layered structure. However, the mechanism about how salinity fluctuations in municipal wastewater impact AGS formation and its physicochemical properties has not been thoroughly revealed. In this study, AGS was cultivated under additional 0 % salinity (R1), additional 1.5 % constant salinity (R2), and additional 0-1.5 % fluctuant salinity (R3), respectively. The results indicate that increased salinity can enhance extracellular polymeric substances (EPS) production and improve sludge settleability, thereby facilitate AGS formation. However, the AGS experienced frequent environmental conversion between dehydration and swell due to salinity fluctuations, resulting in higher content of loosely-bond EPS and low settleability, which delayed the maturation of AGS for over 14 days. Additional salinity significantly inhibited the nitrification process, but the formation of AGS promoted the recovery of ammonia oxidation activity and facilitated the construction of short-range nitrification denitrification processes, resulting in over 16.0 % higher total nitrogen removal efficiency than R1. The microbial community analysis revealed that Thauera played an important role in the granulation process under salinity stress, due to its salt tolerance and EPS secretion abilities. As expected, the formation of AGS enhanced the salt resistance of microorganisms, allowing for the enrichment of functional bacteria, such as Flavobacterium and Candidatus_Competibacter. Generally, microorganisms required extended adaptation periods to cope with salinity fluctuations. Nevertheless, the resulting AGS proved stable and efficient wastewater treatment performance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Vermicomposting is an efficient bioconversion technology for recycling nutrients from organic waste materials. The biodegradability of raw materials has a significant impact on the earthworm transformation product. However, the management of carbon bioavailability is often overlooked during the vermicomposting process due to the varying degradability of C-rich source in different organic waste. This research aims to investigate the impact of different bioavailable carbon compositions on vermicomposting and to develop a strategy for efficient carbon management. The study involved systematic vermicomposting using four different biodegradable carbon sources (pineapple peels, rice straw, tomato straw, and sawdust) with varying carbon‑nitrogen ratios (ranging from 24 to 42). The earthworm production and vermicompost quality were comprehensively evaluated, along with the influence of carbon components on microbial community structure. The results indicated that the optimal vermicomposting treatments were achieved at PCM24, RCM30, TCM30, and MCM30 treatments. Maintaining an approximate ratio of 1:(0.5-1.3) between available and recalcitrant carbon components based on the optimal carbon‑nitrogen ratio was found to be optimal for regulating vermicomposting products. Increasing the proportion of available carbon enhanced the quality of vermicompost fertilizer, while a higher proportion of recalcitrant carbon could improve earthworm biomass production efficiency. Labile carbon proportion I (LCP1) and available carbon component (ACC) were identified as key indicators in influencing the formation of microbial community structure. Different carbon compositions led to the specific development and formation of microbial communities, further resulting in significant variations in vermicompost quality under the mediation of microbes. This study, for the first time, clarifies the impact of vermicomposting performance and microbial community from the perspective of carbon bioavailability, which is of great significance for the oriented regulation the vermicomposting efficiency and product in practice., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

In this work, the feasibility and performance of zero valent iron (ZVI) coupled anaerobic microorganisms in nitrogen removal under low organic carbon condition were investigated, through the comparison of mono-ZVI system and mono-cell system. Coupled system showed the highest total nitrogen (TN) removal efficiency of 67.85% with the addition of 15 g L−1 iron shavings at pH 7.0, which was higher than 29.62% in the mono-ZVI system and 43.86% in the mono-cell system. Besides, the activities of nitrate reductase (NAR), nitrite reductase (NIR), nitric oxide reductase (NOR) and nitrous oxide reductase (N 2 OR) were significantly improved at ZVI dosage of 15 g L−1 and pH 7.0, which contributed to the higher TN removal efficiency in coupled system. The extent of sludge granulation was greater in the coupled system than mono-cell system, which benefited to the high operational performance and stability of coupled system. The promoted generation of extracellular polymeric substances (EPS) and formation of iron oxides in the coupled system also took advantages on nitrogen removal through adsorption. In addition, ZVI could largely enrich the functional species related to nitrogen removal in the system at phyla and genera level, which could be reasoned for the enhanced nitrogen removal efficiency. In conclusion, this study will improve the understandings of nitrogen removal in the coupled system and be useful to ensure the application of ZVI-supported biological process in the remediation of farmland drainage. Unlabelled Image • Coupled bio-ZVI system presented better performance on nitrogen removal. • Optimum iron dosage and pH were discussed to reach the desirable nitrogen removal. • ZVI improves the activity of denitrifying enzymes including NAR, NIR, NOR and N 2 OR. • Functional microbes for nitrogen removal were enriched in the coupled system. [ABSTRACT FROM AUTHOR]

Irrigation with treated wastewater (TWW) has become a prevailing agricultural practice due to the scarcity of fresh water resources, which may have a significant impact on the microbial communities that are critical to many biogeochemical processes in soils. However, it is unclear whether there are links between soil microbial responses to long-term irrigation with different sources of wastewater and soil depth. Here we assess the influence of treated domestic (DTWW), leather industry (LTWW) and pharmaceutical (PTWW) wastewater on microbial communities in vertical soil profiles using high-throughput sequencing based on 16S rRNA and internal transcribed spacer (ITS) gene profiling. We found that microbial α-diversity in the vertical profiles of soils was significantly influenced by TWW irrigation. Bacteria and fungi in different soil depths showed distinct responses to TWW; irrigation with TWW markedly increased abundance of bacterial OTUs and inhibited abundance of fungal OTUs. β-diversity analysis showed that the effect of TWW irrigation on microbial communities was greater than the effect of soil depth, and microbes in subsurface soil were more sensitive to different sources of irrigation water. We also found that, based on β-diversity analysis, irrigation with treated industrial wastewater, including LTWW and PTWW, had a greater impact on microbial community structures than DTWW. TWW irrigation significantly affected the composition of indigenous soil microbial communities at different depths and might introduce exogenous microbes into the soil environment. Our work explicitly demonstrates the vertical responses of bacterial and fungal communities in soils to irrigation with TWW from different sources, which can provides insights into the microbial-dominated geochemical processes from the perspective of the entire soil profile under the context of wastewater irrigation. Unlabelled Image • Significant effect of treated wastewater (TWW) on microbial diversity, community structure and composition. • TWW exerted positive impact on bacterial abundance of OTUs and negative impact on fungal abundance of OTUs. • Microbial community structures were more markedly affected by industrial TWW irrigations than domestic TWW irrigation. • Effects of TWW irrigation on microbial communities were greater than that caused by soil depth. [ABSTRACT FROM AUTHOR]

Abstract Anammox-related processes are often applied for the wastewater treatment which contains both ammonium and antibiotics. Herein, the long-term effects of tetracycline (TC), at environmentally and industrially relevant concentrations, on the performance, anammox activity and microbial community of anammox reactors were investigated for 518 days. The control reactor (without TC exposure) was stable for nitrogen removal during the long-term operation (a nitrogen removal rate of 0.56 ± 0.05 kg-N·m−3·d−1). In the TC-added reactor, the nitrogen removal efficiency increased slightly at low TC levels (1–100 μg/L), whereas poor anammox performance occurred at high TC concentration (1000 μg/L). Furthermore, the concentrations of extracellular polymeric substances (EPS) were much higher at 10 μg/L than those in the control reactor (P < 0.01), whereas rapidly decreased at 1000 μg-TC/L. Furthermore, the reactor performance was highly consistent with the variations of the heme c contents. Consistently, exposure to TC changed the abundance of anammox bacteria, e.g., an increase in Candidatus Jettenia abundance occurred from 2.20 ± 0.97% (0–10 μg/L) to 12.13 ± 1.66% (100 μg/L). Similarly, the genus Denitratisoma , the most predominant denitrification bacteria, also had a higher abundance at a TC concentration of 100 μg/L (15.60 ± 6.42%) than other TC concentrations (5.40 ± 2.50% and 7.65 ± 0.55% at concentrations of 10 and 1000 μg/L, respectively). The results can explain why the exposure of anammox bacteria to a lower TC concentration (100 μg/L) resulted in a better nitrogen removal rate. In contrast, exposure to a high TC level (1000 μg/L) led to a decline in the abundance of anammox bacteria and denitrifiers (1.53 ± 0.64% and 8.18 ± 0.63%, respectively) but an increased abundance in the nitrifier population (8.07 ± 1.21%; P < 0.01). Therefore, this study can aid in the design and operation of anammox-based processes treating sewage and industrial wastewater. Graphical abstract Unlabelled Image Highlights • The anammox biofilm reactor showed an excellent removal efficiency of TC (≤100 μg/L). • The reactor performance was highly consistent with variations in the heme c content. • High TC concentration (1000 μg/L) decreased the abundance of denitrifier and anammox bacteria. • Nitrifier population exhibited an acclimation process to high level of TC. [ABSTRACT FROM AUTHOR]

Abstract This study investigated nutrient removal kinetics and main influencing factors of natural pyrrhotite autotrophic denitrification (PAD), and nutrient removal performance and the microbial community in the PAD biofilter (PADB). Results demonstrated that both NO 3 − and PO 4 3− in wastewater were nearly completely removed, and biological N removal and chemical P removal took place simultaneously in the PAD process. NO 3 − removal kinetics of the PAD can be described with half-order kinetics. The PAD was effective across a wide temperature range of 11–34 °C, initial NO 3 −-N range of 13–52 mg·L−1 and PO 4 3−-P below 60 mg·L−1. Both NO 3 − and PO 4 3− decreased gradually with wastewater flowing along the PADB. The PADB operation results show that at 12 h HRT, when the PADB treated wastewater containing 30.95 ± 0.97 mg·L−1 of NO 3 − and 3.02 ± 0.10 mg·L−1 of PO 4 3−-P, the effluent contained 1.15 ± 2.08 and 0.09 ± 0.11 mg·L−1 of NO 3 −-N and PO 4 3−-P on average, respectively. In the PADB the dominant bacteria were Thiobacillus and Sulfurimonas , which used pyrrhotite as the electron donor to reduce NO 3 −. The relative abundance of Thiobacillus at the bottom of the PADB increased from 0.81% to 58.65% and that of Sulfurimonas decreased from 97.22% to 12.30%, with exposure to pyrrhotite. From the bottom to the top of the PADB, the relative abundance of Thiobacillus increased from 58.65% to 86.23% and Sulfurimonas decreased from 12.30% to 0.52%. Technologies based on the PAD are promising ways to control eutrophication. Graphical abstract Unlabelled Image Highlights • NO 3 −-N removal kinetics of the PAD can be described with half-order kinetics. • The main optimal parameters of the PAD fell in the range of municipal wastewater. • NO 3 − and PO 4 3− can be nearly completely removed from wastewater through the PADB. • The dominant bacteria in the PADB were Thiobacillus and Sulfurimonas. [ABSTRACT FROM AUTHOR]

Abstract The present work aimed to explore the potential of autochthonous microorganisms from an urban estuary and from activated sludge of an associated wastewater treatment plant (WWTP), for biodegradation of an antidepressant drug, paroxetine, and on a cholesterol-lowering agent, bezafibrate. These compounds were chosen as representatives of extensively used pharmaceuticals. Autochthonous microorganisms from the indicated sources were exposed to the target pharmaceuticals (1 mg/L) in co-metabolism with sodium acetate (500 mg/L) along a two-weeks period, for a total of 7 two-weeks periods (here referred as cycles). Exposures were carried out in batch mode, under different incubation conditions (agitation vs. static). Removal of pharmaceuticals was monitored at the end of each cycle, by analysing the culture medium. For paroxetine, fluoride ion release was also followed as an indicator of defluorination of the molecule. The structure of the bacterial communities was analysed by ARISA (Automated rRNA Intergenic Spacer Analysis), at the beginning of the experiment and at the end of the first and the last cycles to identify substantial changes associated with the time of exposure, the incubation conditions and the presence and type of pharmaceuticals. Incubation conditions affected not only the bacterial community structure, but also the biodegradation efficiency. At the beginning of the experiment, removal of target pharmaceuticals was found to be lower under agitation than under static conditions, but at the end of the experiment, results showed high removal of the pharmaceuticals from the culture medium (>97%) under both conditions, mainly by microbiological processes. For paroxetine, adsorption and abiotic processes also had an important influence on its removal, but defluorination only occurred in the presence of microorganisms. These results highlight that autochthonous microorganisms from estuarine sediments and WWTP sludge have high ability to remove the selected pharmaceuticals with relevant implications for the development of new bioremediation tools for environmental restoration. Graphical abstract Unlabelled Image Highlights • Potential of autochthonous microorganisms for bioremediation of pharmaceuticals tested • Microorganisms from a sediment and an activated sludge degraded paroxetine and bezafibrate • Microbial community structure changed to adapt to pharmaceuticals presence • Results are relevant for development of new bioremediation tools for environmental restoration. [ABSTRACT FROM AUTHOR]

Abstract Tropical peatlands are globally important ecosystems with high C storage and are endangered by anthropogenic disturbances. Microbes in peatlands play an important role in sustaining the functions of peatlands as a C sink, yet their characteristics in these habitats are poorly understood. This research aimed to elucidate the responses of these complex ecosystems to disturbance by exploring greenhouse gas (GHG) emissions, nutrient contents, soil microbial communities and the functional interactions between these components in a primary and secondary peat swamp forest in Peninsular Malaysia. GHG measurements using closed chambers, and peat sampling were carried out in both wet and dry seasons. Microbial community phenotypes and nutrient content were determined using phospholipid fatty acid (PLFA) and inductively-coupled plasma mass spectrometry (ICP-MS) analyses respectively. CO 2 emissions in the secondary peat swamp forest were > 50% higher than in the primary forest. CH 4 emission rates were ca. 2 mg m−2 h−1 in the primary forest but the secondary forest was a CH 4 sink, showing no seasonal variations in GHG emissions. Almost all the nutrient concentrations were significantly lower in the secondary forest, postulated to be due to nutrient leaching via drainage and higher rates of decomposition. Cu and Mo concentrations were negatively correlated with CO 2 and CH 4 emissions respectively. Microbial community structure was overwhelmingly dominated by bacteria in both forest types, however it was highly sensitive to land-use change and season. Gram-positive and Gram-negative relative abundance were positively correlated with CO 2 and CH 4 emissions respectively. Drainage related disturbances increased CO 2 emissions, by reducing the nutrient content including some with known antimicrobial properties (Cu & Na) and by favouring Gram-positive bacteria over Gram-negative bacteria. These results suggest that the biogeochemistry of secondary peat swamp forest is fundamentally different from that of primary peat swamp forest, and these differences have significant functional impacts on their respective environments. Graphical abstract CO 2 emissions from secondary forest were twice that of what is observed in primary forest, while CH 4 emissions were very low in comparison. Almost all of the nutrients in surface peat were significantly lesser in secondary forest and exhibited correlations with GHG emissions. Microbial phenotypic community structure was significantly different between the forest types and showed significant seasonal variations. Unlabelled Image Highlights • Increased CO 2 , decreased CH 4 and nutrient content in secondary vs primary peat forest. • Bacteria dominate the microbial community structure in tropical peat forests. • Gram-negative and fungal relative abundance decreased in the secondary forest. • Cu and Mo concentrations correlated with decreased CO 2 & CH 4 emissions, respectively. • Gram-positive and Gram-negative correlated with CO 2 and CH 4 emissions, respectively. [ABSTRACT FROM AUTHOR]

Abstract Although effects of biochar application on soil microorganism have been increasingly reported, the direct evidences for demonstrating the contributions of biochar chemical and physical properties to soil microorganisms are still lacking. Herein, we partitioned corn-straw biochar (BC) into three fractions, including aqueous extractable substances (AE), organic extractable substances (OE) and the remaining solid (EBC) after these two extractions. These fractions and BC were added to purple soil for a 30-day incubation. Soil properties, microbial α-diversity indices and microbial community compositions were analysed after the incubation. The results showed the obvious changes in soil properties, along with higher available P, available K and total organic C, as well as, lower pH and available N than those of soil without biochar, were observed in the BC-treated soil. Illumina Miseq sequencing displayed a distinct difference between responses of bacteria and fungi to biochar application, in which fungal richness and diversity were increased, and no significant changes happened in bacterial richness. Furthermore, biochar had apparent effects on bacterial and fungal community compositions at phylum level, which were most close to the influences of AE and EBC, respectively. These results suggested that AE, improving soil nutrients (e.g., total N), played a pivotal role in changing bacterial phylum community composition. The EBC, regarded as physical structure and relatively recalcitrant compounds of BC, had a dominant contribution to the influence of biochar on the fungal community composition. Graphical abstract Unlabelled Image Highlights • Corn-straw biochar (BC) influenced purple soil properties during 1-month incubation. • The α-diversity indices of soil fungi were reduced by BC. • Bacterial and fungal community composition at phylum level was changed by BC. • Aqueous-extractable substance of BC is key factor of changing bacterial community. • Physical structure and recalcitrant C of BC is key role in changing fungal community. [ABSTRACT FROM AUTHOR]

Abstract Autotrophic denitrification process is an effective strategy for treating sulfide and nitrate-enriched wastewater with low organic carbon. This study determined the sulfide oxidation and nitrate reduction rates and characterized the dominant bacteria and microbial community structure stimulated by micro-aerobic conditions in autotrophic denitrification system. With gradually increased sulfide concentration, the sulfide removal rate decreased to 37.8% at S2− = 600 mg/L, while the peak sulfide and nitrate removal rates (100% and 53.8%) were achieved at S2− = 800 mg/L with the air aeration rate of 20 mL/min. The Illumina sequencing results indicated that Thiobacillus accounted for 63% of total operational taxonomic units at generic level with sulfide concentration of 200 mg/L under anaerobic condition. However, Azoarcus , Thauera and Aliidiomorina became the dominant genera under micro-aerobic condition and their abundance significantly and positively related to the sulfide concentration and aeration rate (p < 0.05). According to the 16S metaproteomics functional composition prediction, one potential mechanism for autotrophic denitrifying under micro-aerobic condition was deduced that the oxidation of sulfide to thiosulfate further to sulfite was reinforced by trace oxygen, while the sulfite reductase activity was restrained. The decreased sulfide concentration weakened the toxicity inhibition on denitrifiers and accordingly the performance of autotrophic denitrification process was enhanced by micro-aerobic condition. Graphical abstract Unlabelled Image Highlights • The injection of trace oxygen has enhanced effect on autotrophic denitrification process. • Sulfide and nitrate removal rates peaked at 53.8% and 100% with aeration rate of 20 mL/min. • The abundance of Azoarcus , Thauera and Aliidiomorina were positively related to S2− and aeration rate (p < 0.05). • Oxidation of sulfide to thiosulfate further to sulfite was stimulated by trace oxygen. [ABSTRACT FROM AUTHOR]

Abstract We designed an indoor mesocosm experiment to investigate the long-term effects of exposure to clomazone, a widely used herbicide, on soil microbial communities and their nitrogen (N) cycling functions. Clomazone was applied to two typical soils from China at three concentrations: 0.8 (the recommended dosage), 8 and 80 mg kg−1 soil dry weight, and the mix was incubated for 90 days. Samples were removed periodically for assay with several techniques. The half-lives of clomazone in this experiment were 11–126 d. Results were significant only for the highest clomazone concentration. Next-generation sequencing of the 16S and 18S rDNA genes revealed that bacterial diversity significantly decreased whereas fungal abundance increased after day 60 but with no detectable effect on the microbial community. Hierarchical cluster and principal coordinates analysis revealed that the bacterial community structure was negatively impacted. Linear discriminant analysis of effect size identified Sphingomonas and Arthrobacter as the predominant bacterial species. Finally, we measured soil NH 4 + and NO 3 − concentrations and used real-time PCR to analyze the abundance of the N-cycling genes , nifH and amoA. In the first 30 days, the NO 3 −-N content and the number of ammonia-oxidizing bacteria increased. N 2 -fixing bacteria were inhibited after 60 days, but the NH 4 +-N concentration remained unchanged and was likely provided by ammoniation. Graphical abstract Unlabelled Image Highlights • The effects of clomazone on soil microorganism and N 2 -cycling have been studied. • High dosage clomazone decreased bacterial abundance and changed the composition. • Clomazone could increase fungal abundance. • High dosage clomazone significantly impact the abundance of nif H and amo A. [ABSTRACT FROM AUTHOR]

Increasing salinity has important impacts on biogeochemical processes in estuary wetlands, with the potential to influence the soil respiration, dissolved organic carbon (DOC) and microbial population. However, it is unclear how soil respiration is related to changes in the DOC and microbial community composition with increasing salinity. In this study, soil cores were sampled from a brackish wetland in the Liaohe River estuary and treated by salinity solutions at four levels (fresh water, 3‰, 5‰, and 10‰). Samples of gas, water and soil were collected to determine the respiration rates and microbial community structure of the soil and the DOC leaching from the soil. Compared to the low-salinity treatments (fresh water and 3‰), the high-salinity treatments (5‰ and 10‰) decreased the soil respiration rates by 45–57% and decreased the DOC concentrations by 47–55%. However, no significant differences were observed within the low-salinity treatments nor the high-salinity treatments. There is a positive correlation between the soil respiration rates and DOC concentrations in all treatments, but it does not indicate a genetic cause-effect relationship between them. The microbial community structure varied with the salinity level, with higher β- and δ-Proteobacteria abundance, as well as higher Anaerolineae, and lower Clostridia abundance in the high-salinity treatments. The respiration rates were slightly negatively related to the richness of Proteobacteria and positively related to the richness of Clostridia. This study suggests that there may be a salinity threshold (3–10‰) impacting the organic carbon loss from estuarine brackish wetlands. In addition, the response of soil respiration to increasing salinity may be mainly linked to changes in the microbial community composition rather than changes in the DOC quantity. [ABSTRACT FROM AUTHOR]

In biologically active filters (BAFs), microorganisms acclimated on the media surface are the key players responsible for removing organic water contaminants. In this study, next generation sequencing by Illumina MiSeq was used to characterize the microbial community structures in the influent, effluent, and media of a set of bench-scale BAFs that have been demonstrated with high removal efficiency (>75%) of 16 contaminants of emerging concern (CECs), which include a variety of pharmaceuticals (e.g., sulfamethoxazole and ibuprofen), X-ray contrast agent (i.e., iopromide), and pesticides (e.g., atrazine) that are prevalently found in municipal waste streams. Proteobacteria and Planctomycetes were the most abundant phyla in filter media, while the influent and effluent samples were dominated by Proteobacteria , Actinobacteria , and Chlamydiae . Factorial and principal component analysis revealed microbial structures in the media were significantly affected by the operation conditions, including media type (GAC versus dual media anthracite sand), EBCT (10 versus 18 min), and pre-ozonation. Detrended correspondence analysis demonstrated media materials predominantly governed the structures of the acclimated biofilm in BAFs as they provide direct attachment surface. This is in line with the higher microbial activity and better treatment performance exhibited by GAC BAFs compared to the dual media BAFs, corroborating the importance of filter media selection to promote the acclimation of active and robust biofilm for efficient CEC removal. Principal component analysis revealed the significant influence from ozonation, which does not only break down CECs, but also stimulates microbes that grow on the ozonation products. Partial canonical correlation analysis further proved the shaping of biofilm communities on the BAF media is more associated with media type and ozonation compared to EBCT. Putative CEC degraders are predicted based on their dominance in the media and degradation capabilities reported in previous literature. This is the first study to examine the relationship between the microbial community structure and the BAF operating parameters, which are both aligned with the treatment performance exhibited by the BAFs. [ABSTRACT FROM AUTHOR]

Due to its widespread application and large-scale production, dibutyl phthalate (DBP) has become one of the most frequently identified phthalic acid esters (PAEs) in soils. The fate of DBP and its effects on microbial communities in soils with contrasting properties have seldom been studied. In this study, the degradation of DBP and its long-term effects on the soil microbial community were investigated in aquic cambisols and udic ferrosols. The half-lives of DBP in aquic cambisols and udic ferrosols were found to be 0.286–1.41 days and 0.870–20.4 days, respectively, indicating that DBP was degraded faster in aquic cambisols. In addition, the degradation of DBP in aquic cambisols was less vulnerable to adverse incubation conditions, including high DBP concentration, low temperature and low moisture. These results can be ascribed to the higher microbial abundance and activity in aquic cambisols than in udic ferrosols. During DBP degradation, the toxic metabolite monobutyl phthalate (MBP) was present only transiently and did not accumulate in the two soils. After 60 days of incubation, the degradation-resistant DBP residue concentrations were as high as 1.10 and 1.34 mg/kg, and the relative abundance of 8.51%–12.9% of bacterial genera and 5.59%–6.02% of fungal genera was significantly disturbed by DBP in both test soils. The results from this study highlight the need to comprehensively evaluate the environmental risks of degradation-resistant DBP residues and the impact of DBP contamination on soil microbial functions. [ABSTRACT FROM AUTHOR]

Feasibility and superiority of the bioelectrochemical system integrated with biocontact oxidation (BES-BCO) for degradation and/or mineralization of azo dyes have been confirmed. In this study, the effects of hydraulic retention time (HRT), applied voltage, and dissolved oxygen (DO) concentration at the bioanode on the performance of BES-BCO and traditional BES were investigated. Using the response surface methodology, the optimum values of HRT, applied voltage, and DO concentration at the bioanode of BES-BCO were investigated to obtain the maximum decolouration and COD removal efficiency and minimum specific energy consumption (SEC). The microbial community structure in BES-BCO was studied for analyzing the change following the introduction of oxygen. The optimised solution was an applied voltage of 0.59 V, HRT of 12 h, and DO concentration of 0.96 mg/L at the bioanode. Under such conditions, the DE, COD removal efficiency, and SEC values were 94.62 ± 0.63%, 89.12 ± 0. 32%, and 687.57 ± 3.86 J/g, respectively. In addition, after changing from BES to BES-BCO, the bacterial community structure of the bioanode underwent significant changes. Several aerobic aniline-degrading bacteria and anode-respiration bacteria (ARB) were found to dominate the community of the anode biofilm. The results showed that the removal of azo dye degradation by-products was closely correlated with the o-bioanode and the BCO bacterial community structure. [ABSTRACT FROM AUTHOR]

In this study, impacts of nanoplastic on the pure and mixed anaerobic digestion systems were investigated. Results showed the growth and metabolism of Acetobacteroides hydrogenigenes were partly inhibited by nanoplastic existed in the pure anaerobic digestion system. The anaerobic digestion of sewage sludge was also obviously inhibited by nanoplastic existed in the mixed anaerobic digestion system. Both the methane yield and methane production rate of the mixed anaerobic digestion system showed negative correlation with the nanoplastic concentration. Compared with anaerobic digestion system without nanoplastic, methane yield and maximum daily methane yield at the nanoplastic concentration of 0.2 g/L decreased for 14.4% and 40.7%, respectively. In addition, the start-up of mixed anaerobic digestion system was prolonged by addition of nanoplastic. Microbial community structure analysis indicated the microbial community structures were also affected by nanoplastic existed in the system. At the nanoplastic concentration of 0.2 g/L, the relative abundances of family Cloacamonaceae, Porphyromonadaceae, Anaerolinaceae and Gracilibacteraceae decreased partly. Conversely, the relative abundances of family Anaerolinaceae , Clostridiaceae , Geobacteraceae , Dethiosulfovibrionaceae and Desulfobulbaceae improved partly. [ABSTRACT FROM AUTHOR]

Rapidly developing industry raises concerns about the environmental risks of silver nanoparticles (AgNPs), but the effects of AgNPs on the performance and microbial community in the constructed wetlands remain unclear. In this study, long-term exposure of AgNPs in two VFCWs was conducted to determine the effects of AgNPs on the pollutant removal and microbial community structure. Before exposing AgNPs, the water quality of effluent was better in planted wetland (CW2), compared with unplanted wetland (CW1). After continuous exposure of 100 μg/L AgNPs, the COD (chemical oxygen demand) removal of two CWs had no difference. However, addition of AgNPs reduced the nitrogen and phosphorus removal in two CWs, with decreasing average removal efficiencies of ammonia nitrogen from 46.31% to 32.09% and 59.66% to 51.06%, total nitrogen from 57.76% to 43.78% and 67.35 to 60.58%, total phosphorus from 71.29% to 59.31% and 67.35% to 60.58%, respectively. The vegetable wetlands showed higher resistances to AgNPs loading than unplanted wetlands. In addition, AgNPs accumulated in the wetland substrate, especially in the soil layer with the silver concentration of approximately 4.32 μg/g. The small portion of silver was found in plant tissues, and plants played a minor role to remove the AgNPs from wastewater. Moreover, the constructed wetlands could effectively remove the AgNPs from the synthetic wastewater. The illumine high-throughput sequencing results demonstrated the variations of the bacterial community structure at the exposure of AgNPs. The results showed that the dominant phyla were Proteobacteria , Acidobacteria and Bacteroidetes . Compared with unplanted wetlands, the contents of several nitrifying bacteria such as Candidatus Nitrososphaera (AOA) and Nitrospira (NOB) at genus level increased, leading to the higher nitrogen removal in the planted wetlands. [ABSTRACT FROM AUTHOR]

The aim of this study was to reveal the mechanisms on how biochar reduces bioaccumulation of polycyclic aromatic hydrocarbons (PAHs) in tuberous vegetables. Corn straw-derived biochar pyrolyzed at 300 °C (CB300) or bamboo-derived biochar pyrolyzed at 700 °C (BB700) was amended into PAH-contaminated soil planted with carrot ( Daucus carota L.). After 150 days, 2% CB300 or 2% BB700 amendments significantly reduced the bioaccumulation of PAHs in carrot root ( p < 0.05), especially for high-molecular-weight PAHs. In the non-rhizosphere, either CB300 or BB700 suppressed PAH dissipation and decreased the bioavailability via adsorption processes. Compared to the control, the total concentration of PAHs in the rhizosphere was higher in the 2% BB700 treatment but the bioavailable concentration was lower. This indicates that BB700 decreased the bioavailability of PAHs primarily via immobilization (adsorption processes). By contrast, the total and bioavailable PAH concentrations were both lower in the 2% CB300 treatment than those in the control. The abundance of bacteria such as Arthrobacter and Flavobacterium and the total number of genes playing important roles in microbial PAH degradation processes increased significantly ( p < 0.05), which were likely responsible for the rapid dissipation of PAHs in the 2% CB300 treatment in the rhizosphere. These results indicate that CB300 decreased the PAH bioavailability primarily via increasing degradation of PAHs by indigenous microorganisms. The two biochars both showed better effectiveness at reducing the bioavailability of high-molecular-weight PAHs than the low-molecular-weight PAHs in the rhizosphere. Therefore, the mechanisms on how biochar reduces the PAH uptake into carrot are dependent on the type of biochar (e.g., pyrolysis temperature and feedstock) and root presence. [ABSTRACT FROM AUTHOR]

The degradation characteristics of carbendazim (CBD) and chlortetracycline (CTC) in individual and combined treatments, and dynamics of soil microbial structural and functional diversity as well as their potential relations were studied during three repeated treatments using different concentrations. The results showed that the degradation half-life of CBD at concentrations of 3 mg/kg and 6 mg/kg obviously increased, but that of CTC at levels of 1 mg/kg and 10 mg/kg decreased with increasing treatment frequency. Soil microbial activity and functional diversity displayed the suppression trend in CBD treatment and the suppression-recovery-stimulation trend in CTC and CBD + CTC treatments, which were consistent with the findings of decreased degradation rate of CBD and increased degradation rate of CTC. 16S amplicon sequencing analysis revealed five potentially dominant CTC-resistant microbial genera including Bacillus , Actinobacillus , Pseudomonas , Mycobacterium , and Corynebacterium , which may mainly carry major facilitator superfamily transporter protein, ribosomal protection protein, and other proteins encoded by tetA , tetB , tetC , tetH , tetL , tetM , tetO , tetV , tetW , tetX , tetZ , tet33 , and tet39 . These five dominant genera may jointly contribute to the elevated bacterial community resistance to CTC. Our findings provided a better understanding of microbial community structure and function changes in repeatedly treated soils with CBD and CTC. [ABSTRACT FROM AUTHOR]

The widespread utilization of silver nanoparticles (AgNPs) in industrial and commercial products inevitably raises the release into wastewater that might cause potential negative impacts on sewage treatment system. In this paper, long-term exposure experiments at four levels were conducted to determine whether AgNPs caused adverse impacts on nutrient removals in sequencing batch reactors (SBRs) and changes of microbial community structure. Compared with the control reactor (without AgNPs), carbon, nitrogen and phosphorus removal in presence of 0.1 mg/L AgNPs was no difference. However, presence of 1.0 and 10 mg/L AgNPs decreased the average removal efficiencies of COD from 95.4% to 85.2% and 68.3%, ammonia nitrogen from 98.8% to 71.2% and 49%, SOP from 97.6% to 75.5% and 54.1%, respectively. It was found that AgNPs could accumulate in sludge with the distribution coefficients of 39.2–114 L/g, inhibit the protein and polysaccharide production in EPS, reduce the SOUR of sludge, and greatly increase LDH release from microbial cells. The illumina high-throughput sequencing results indicated that AgNPs concentration changed the structures of bacterial communities, associating with the effects of AgNPs on reactor performance. Sequence analyses showed that Proteobacteria , Bacteroidetes and Acidobacteria were the dominant phyla. It was notable that AgNPs addition reduced the contents of several nitrifying bacteria at genera level in sludge, leading to the lower removal of nitrogen. [ABSTRACT FROM AUTHOR]