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Digital, Palm Oil Mill Effluent (POME) requires treatment before disposal due to its high organic matter content. In this study, the electrical performance and wastewater treatment efficiency were evaluated for Microbial Fuel Cells (MFC) treating unsterile POME with chemical oxygen demand (COD) from 200 to 10 000 mg/L. Since the inoculum type is a key factor in MFC performance, three types of sludge (methanogenic sludge (MS), facultative sludge (FS), and dry sludge (DS), obtained from the current POME treatment ponds were evaluated as inoculum. Dry sludge (DS) developed a maximum power output of 3.30 W/m3 by oxidizing 71% out of the COD provided by POME (1000 mg/L). Also, raw POME microbiota contributed to an enrichment of the community in DS inoculum along with the operation, in which Geobacter was the predominant genus reaching a current generation of 247 mA/m2 and a power density of 2.36 W/m3. Conversely, pure electrogenic (Shewanella sp.) inoculation led to a diversification process, resulting in a lower current generation of 52 mA/m2 and a power density of 0.10 W/m3. Consequently, microbial community dynamics revealed that MFC inoculation tends to a microbial equilibrium wherein generation of high current density was achieved by gradual microbial enrichment rather than external electrogenic invasion., Ciencias Exacta y Naturales

Bài báo trình bày tổng quan các phương pháp tiền xử lý để tăng cường quá trình phân hủy kỵ khí (PHKK) đối với chất thải rắn hữu cơ (CTRHC). Các phương pháp tiền xử lý như nhiệt học, hóa học, sinh học, cơ học, vật lý hay kết hợp làm tăng khả năng hòa tan của các thành phần hữu cơ và nâng cao hiệu suất của quá trình PHKK. Bài báo cung cấp thông tin về cơ chế, hiệu quả và hạn chế của các kỹ thuật tiền xử lý đồng thời cập nhật các kết quả đạt được về tiền xử lý CTRHC nhằm mục đích cải thiện quá trình PHKK. Dựa trên sự so sánh về cân bằng năng lượng, tính bền vững với môi trường cũng như hiệu quả về kinh tế, tiền xử lý nhiệt ở nhiệt độ thấp (50÷100ºC) và tiền xử lý kỵ khí hiệu quả hơn so với các phương pháp tiền xử lý khác.

Bioelectrochemical systems such as microbial fuel cells (MFCs) have gained extensive attention due to their abilities to simultaneously treat wastewater and generate renewable energy resources. Recently, to boost the system performance, the photoelectrode has been incorporated into MFCs for effectively exploiting the synergistic interaction between light and microorganisms, and the resultant device is known as photo-assisted microbial fuel cells (photo-MFCs). Combined with the metabolic reaction of organic compounds by microorganisms, photo-MFCs are capable of simultaneously converting both chemical energy and light energy into electricity. This article aims to systematically review the recent advances in photo-MFCs, including the introduction of specific photosynthetic microorganisms used in photo-MFCs followed by the discussion of the fundamentals and configurations of photo-MFCs. Moreover, the materials used for photoelectrodes and their fabrication approaches are also explored. This review has shown that the innovative strategy of utilizing photoelectrodes in photo-MFCs is promising and further studies are warranted to strengthen the system stability under long-term operation for advancing practical application.

Identifying the microbial composition in the evaluation of the effectiveness of anaerobic digestion for complex systems still poses a challenge with regard to the first three phases (hydrolysis, acidogenesis and acetogenesis). These phases are crucial in creating substrates for the methanogens to take in, which will affect biogas production. In this study, the microbial composition of the various chambers in the anaerobic digestion of chicken manure was investigated. The optimal living conditions of the microorganisms in the chambers corresponds well with their respective operating conditions (aerobic hydrolysis chamber to anaerobic digester chambers). Diversity of the microbial community for chicken manure was relatively simpler, consisting of mainly the genus of Lactobacillus compared to the main digestion chambers of a more complex community containing more class of Clostridia. This change in microbial diversity composition indicates on the amount and degree of anaerobic digestion occurring (chicken manure only has hydrolysis phase occurring while the main digesters has the first three phases of anaerobic digestion (hydrolysis, acidogenesis and acetogenesis) occurring). A comparison of the metagenomics vs metaproteomics mode of analysis revealed that the bacterial compositions between these two modes of analysis were quite comparable, with the main difference being the quantity of unclassified microorganisms each due to different database and techniques used. The quantity of volatile fatty acids detected in each respective chamber suggested the effectiveness of the microorganisms in assimilating the metabolites for their growth. Successful integration of these study modes would present a better understanding of the anaerobic digestion of complex systems.

Dissolved organic matter (DOM), known as a key to the aquatic carbon cycle, is influenced by abiotic and biotic factors. However, the compositional variation and these factors' effects on fluorescence DOM (FDOM) in urban rivers undergoing different anthropogenic pressure are poorly investigated. Herein, using fluorescence excitation-emission matrix and parallel factor analysis (EEM-PARAFAC), four FDOM components (C1, C2, C3, and C4) were identified in a less urbanized north river (NR) and a more urbanized west river (WR) of Jiulong River Watershed in Fujian province, China. C1, C2, and C4 were related to humic-like substances (HLS) and C3 to protein-like substances (PLS). HLS (63.9% in WR and 36.4% in NR) and PLS (62.7% in WR and 37.3% in NR) exhibited higher fluorescence in the more urbanized river. We also found higher PLS in winter, but higher HLS in summer for both rivers. Although the coefficient of variation indicated a difference in FDOM components stability to some extent between the two rivers, the typhoon event that occurred in summer had a stronger disruptive impact on the CDOM and FDOM of a more urbanized river than that of a less urbanized river. We explore abiotic and biotic factors' effects on FDOM using the partial least squares path model (PLS-PM). PLS-PM results revealed higher significant influences of biotic factors on FDOM in the more urbanized river. This study enhances our understanding of FDOM dynamics of rivers with different anthropogenic pressure together with the abiotic and biotic factors driving them.

Despite the growing awareness of antibiotic resistance genes (ARGs) spreading in the environment, there is a knowledge gap on the fate and transport of ARGs in particle-attached (PA) and free-living (FL) lifestyles in deep freshwater ecosystems experiencing seasonal hydrological changes. Here, we examined the ARG profiles using high-throughput quantitative PCR in PA and FL lifestyles at four seasons representing two hydrological seasons (i.e., vertical mixing and thermal stratification) in the Shuikou Reservoir (SR), Southern China. The results indicated that seasonal hydrological dynamics were critical for influencing ARGs in PA and FL fractions, and the transition of ARGs between the two lifestyles. Although both PA and FL ARG profiles were likely to be shaped by horizontal gene transfer, PA and FL ARGs had different responses to the changes in physico-chemicals (e.g., nutrients and dissolved oxygen) caused by seasonal hydrological dynamics. The particle-associated niche (PAN) index revealed that there were 94 non-conservative ARGs (i.e., no preferences for PA and FL), 23 conservative ARGs that preferred PA lifestyle, and 16 conservative ARGs for FL lifestyle. A sharp decline in the number of conservative ARGs in stratified seasons suggests a hydrological dynamics-dependent transition of ARGs between two lifestyles. Remarkably, the conservative ARGs (in PA or FL lifestyle) were more closely related to bacterial OTUs in their preferred lifestyle compared to their counterpart lifestyle, suggesting a lifestyle-dependent ARG enrichment. Altogether, these findings enhance our understanding of the role of seasonal hydrological changes in the dissemination of ARGs in different size fractions in deep aquatic ecosystems.

Antibiotic resistance genes (ARGs) are a well-known environmental concern. Yet, limited knowledge exists on the fate and transport of ARGs in deep freshwater reservoirs experiencing seasonal hydrological changes, especially in the context of particle-attached (PA) and free-living (FL) lifestyles. Here, the ARG profiles were examined using high-throughput quantitative PCR in PA and FL lifestyles during four seasons representing two hydrological phenomena (vertical mixing and thermal stratification) in the Shuikou Reservoir (SR), Southern China. The results indicated that seasonal hydrological dynamics were critical for influencing the ARGs in PA and FL and the transition of ARGs between the two lifestyles. ARG profiles both in PA and FL were likely to be shaped by horizontal gene transfer. However, they exhibited distinct responses to the physicochemical (e.g., nutrients and dissolved oxygen) changes under seasonal hydrological dynamics. The particle-association niche (PAN) index revealed 94 non-conservative ARGs (i.e., no preferences for PA and FL) and 23 and 16 conservative ARGs preferring PA and FL lifestyles, respectively. A sharp decline in conservative ARGs under stratified hydrologic suggested seasonal influence on the ARGs transition between PA and FL lifestyles. Remarkably, the conservative ARGs (in PA or FL lifestyle) were more closely related to bacterial OTUs in their preferred lifestyle than their counterparts, indicating lifestyle-dependent ARG enrichment. Altogether, these findings enhanced our understanding of the ARG lifestyles and the role of seasonal hydrological changes in governing the ARG transition between the lifestyles in a typical deep freshwater ecosystem.

The increasing-volume release of micropollutants into natural surface waters has raised great concern due to their environmental accumulation. Persisting micropollutants can impact multiple generations of organisms, but their microbially-mediated degradation and their influence on community assembly remain understudied. Here, freshwater microbes were treated with several common micropollutants, alone or in combination, and then transferred every 5 days to fresh medium containing the same micropollutants to mimic the repeated exposure of microbes. Metabarcoding of 16S rRNA gene makers was chosen to study the succession of bacterial assemblages following micropollutant exposure. The removal rates of micropollutants were then measured to assess degradation capacity of the associated communities. The degradation of micropollutants did not accelerate over time but altered the microbial community composition. Community assembly was dominated by stochastic processes during early exposure, via random community changes and emergence of seedbanks, and deterministic processes later in the exposure, via advanced community succession. Early exposure stages were characterized by the presence of sensitive microorganisms such as Actinobacteria and Planctomycetes, which were then replaced by more tolerant bacteria such as Bacteroidetes and Gammaproteobacteria. Our findings have important implication for ecological feedback between microbe-micropollutants under anthropogenic climate change scenarios.

Hydrothermal pretreatment (HTP) of sewage sludge (SS) has been shown to improve the subsequent biogas production by anaerobic digestion (AD), but the effect of catalysts on HTP performance was less explored. This study intended to investigate the SS pretreatment by wet air oxidation (WAO) with the addition of K2CO3 as a catalyst on the performance of methane production by AD. WAO was found to improve the solubilization of SS, the soluble chemical oxygen demand, dissolved organic carbon, and total dissolved nitrogen. The methane yield from WAO increased from 202 mL/gVSin with no catalyst added to 277 mL/gVSin with 10 wt% of K2CO3 added at 180 °C with 30 min of residence time. Under this pretreatment condition, the highest methane production rate could achieve 15.8 mL/gVSin day, and the percentage of methane reached 73%. The structure of the microbial community involved in the AD was affected by the residence time, working gas, and catalyst of the HTP process. The results showed that Bacteroidetes, Bacteroidia, and SC103 were the dominant phylum, class, and genus of bacteria, respectively, of almost all of the samples. In addition, the most abundant archaeal order was Methanosarcinales, while Methanosaeta was the dominant archaeal genus of most of the samples. However, Methanosarcina largely increased the relative abundance, corresponding to the amount of K2CO3 catalyst used. The findings in this study demonstrated the potential use of K2CO3 during WAO of SS and implied the link between shift of methanogen community and the enhanced methane yield in AD.

Two Gram-stain-negative, aerobic, motile and rod-shaped bacteria, one designated as strain AXBT, capable of degrading estrogens, and another, YL23T, capable of degrading estrogen and bisphenol A, were isolated from activated sludge in Xiamen City, PR China. The optimum temperature and pH of both strains were 25–35 °C and pH 7.0–8.0. While strain AXBT could tolerate 3 % (w/v) NaCl, YL23T could only grow between 0–1 % (w/v) NaCl. They contained ubiquinone-10 as the major quinone, spermidine as the major polyamine, summed feature 8 (comprising C18:1ω6c and/or C18:1ω7c) as the major fatty acids and diphosphatidylglycerol, phosphatidylcholine, phosphatidyldimethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol and sphingoglycolipid as the major polar lipids. The DNA G+C contents of strains AXBT and YL23T were 63.6 and 63.7 mol%, respectively. Based on the results of 16S rRNA gene sequence analysis, strains AXBT and YL23T belonged to the genus Sphingobium . Strain AXBT was most closely related to Sphingobium chlorophenolicum NBRC 16172T (97.5 %) and Sphingobium chungbukense DJ77T (97.2 %), and strain YL23T was most closely related to S. chlorophenolicum NBRC 16172T (97.4 %) and S. quisquiliarum P25T (97.1 %). Average nucleotide identity values between these two strains and S. chlorophenolicum NBRC 16172T, S. chungbukense DJ77T, Sphingobium chinhatense IP26T, Sphingobium quisquiliarum P25T and Sphingobium japonicum UT26ST were from 80.7 to 85.8 %. In conclusion, strains AXBT and YL23T represent novel species of the genus Sphingobium , for which the names Sphingobium estronivorans sp. nov. and Sphingobium bisphenolivorans sp. nov. are proposed, respectively. The type strains of S. estronivorans and S. bisphenolivorans are AXBT (=MCCC 1K01232T=DSM 102173T) and YL23T (=MCCC 1K02300T=DSM 102172T), respectively.

The plant microbial fuel cell (PMFC) is a novel technology that can be used to convert solar energy into electrical energy using microbes in the rhizosphere of plants. However, low power density is one of the major obstacles to the development of PMFCs. In this study, we show that the Trapa natans husk-derived carbon (TNH-GBG) is a potential sustainable electrode material for the Canna indica-based PMFCs. The results of the polarization curve measurements showed that the maximum power density of the PMFC utilizing the TNH-GBG-coated graphite felt as the electrodes could reach 55 mW m−2. This was considerably higher than that of the PMFC with pure graphite felt electrodes (22 mW m−2). The enhanced power density of the TNH-GBG was attributed to its high surface area and high content of oxygen-containing groups on the surface of carbon, which enhanced the hydrophilicity and possibly enhanced the microbial attachment, thereby reducing the activation polarization. Furthermore, when the PMFC (with TNH-GBG-coated graphite felt electrodes) was connected to an external load (1000 Ω), a power density of 20 mW m−2 was maintained for over 10 days, which is also higher than that of the PMFC with the graphite felt electrodes. The PMFC with the TNH-GBG-coated graphite felt electrodes shows a similar performance with the one with commercial activated carbon-coated graphite felt electrodes. However, the price of the TNH-GBG is only one-fifth of the commercially activated carbon. Furthermore, the TNH-based PMFC-supercapacitor system was assembled, and it demonstrated that TNH is a potential low-cost electrode material for sustainable power generation-energy storage applications.

Laminar-flow microfluidic microbial fuel cell (LMMFC) has attracted attention due to the advantage of the liquid-liquid interface between anolyte and catholyte without the use of membrane as a separator resulting in less fabrication cost. Unlike previous studies of LMMFC using syringe pumps, this study proposes the use of osmotic pumps to feed anolyte and catholyte in the microchannel without any additional power supply. The osmotic pump was constructed with two cylindrical chambers separated by a forward osmosis membrane, with the initial draw solution concentration of 90 g l

This study investigated the torrefaction of de-oiled Jatropha seed residue after a two-stage sequential process consisting of mechanical screw pressing and solvent extraction using n-hexane (denoted as JMS). The optimal torrefaction temperature (Tr) and torrefaction time (tr) were determined in the ranges of 260–300 °C and 10–60 min, respectively, so to achieve a better heating value and satisfactory energy densification (ED) with acceptable mass loss. Thermogravimetric analysis was employed to elucidate the thermal decomposition behaviors of JMS. By comparison with the torrefaction of Jatropha seed residue after mechanical oil extraction by screw pressing only (namely, JMET), the results indicated that the ED of the torrefaction of JMS yielding the torrefied product JMST (two-stage product) was higher than that of the torrefaction of JME giving the torrefied product JMET (single-stage product). Further, it was found that JMET contained some tar, which was attributed to a thermal reaction in the residual oil in JME during torrefaction. The tar/oil content of JMET was about 1.0–1.8 wt.% in the determined optimal conditions. Thus, the enhanced recovery of the residual oil is advantageous not only because it allows obtaining more oil from Jatropha seed residue with a positive net energy gain but also because it prevents the formation of tar in torrefied biomass products.

The attenuation of 10 mixed antibiotics along with nutrients in a continuous flow mode by four freshwater microalgae (Haematococcus pluvialis, Selenastrum capricornutum, Scenedesmus quadricauda, and Chlorella vulgaris) was examined in membrane photobioreactors (MPBRs). At lab-scale, consistent removal of both antibiotic and nutrient was shown by H. pluvialis and S. quadricauda, respectively. The system exhibited better performance with enhanced removal at HRT 24 h compared to 12 h and 48 h. The highest removal efficiency of antibiotics was observed in H. pluvialis MPBR, with the mean antibiotic removal values of 53.57%- 96.33%. Biodegradation was the major removal pathway of the antibiotics in the algal-MPBR (AMPBR), while removal by bioadsorption, bioaccumulation, membrane rejection, and abiotic was minor. Then, the bacterial feature was studied and showed significant influence from system hydrodynamics. The kinetics of continuous flow antibiotic removal followed Stover-Kincannon and Grau second-order models, which revealed great potential of AMPBR to withstand antibiotic load. The latter coupled with the computational fluid dynamic simulation was successfully applied for the residual antibiotic prediction and potential system optimization. Overall, these results provide an important reference for continuous flow antibiotic removal using AMPBR.

The high-volume release of micropollutants into natural surface waters has raised concern due to their environmental accumulation. Persisting micropollutants can impact multiple generations of organisms via press disturbances, but their microbially-mediated degradation and the influence on community assembly remain understudied. Here, freshwater microbial communities in microcosms were treated with four common micropollutants, alone or in combination, and then transferred in stages to fresh medium containing the same level of micropollutants to mimic the recurrent exposure of microbes under environmentally relevant conditions. Our results showed that the degradation of micropollutants was closely linked to the community succession, and that recurrent exposure to micropollutants enhanced the degradation capacity. The partitioning analysis of ecological processes revealed that community assembly was dominated by stochastic processes during early exposure, via random community changes, and by deterministic processes later in the exposure. Analyzing individual taxa abundances over time revealed two distinct bacterial responses, in which a larger proportion of sensitive than tolerant taxa was present in the disturbed communities, and the abundances of the most sensitive taxa were significantly associated with micropollutant degradation. This study clearly showed that microbial communities are generally vulnerable to persisting micropollutants in aquatic environments, which has important implications for pollution management, especially regarding microbial dynamics and ecosystem functioning in micropollutant removal.

Microeukaryotes play a significant role in biogeochemical cycling and can serve as bioindicators of water quality in freshwater ecosystems. However, there is a knowledge gap on how freshwater microeukaryotic communities are assembled, especially that how terrestrial microeukaryotes influence freshwater microeukaryotic assemblages. Here, we used a combination of 18S rRNA gene amplicon sequencing and community-based microbial source tracking (MST) approaches (i.e., SourceTracker and FEAST) to assess the contribution of microeukaryotes from surrounding environments (i.e., soils, river sediments, swine wastewater, influents and effluents of decentralized wastewater treatment plants) to planktonic microeukaryotes in the main channel, tributaries and reservoir of a peri-urban watershed, China in wet and dry seasons. The results indicated that SAR (~ 49% of the total communities), Opithokonta (~ 34%), Archaeplastida (~ 9%), and Amoebozoa (~ 2%) were dominant taxa in the watershed. The community-based MST analysis revealed that sewage effluents (7.96 – 21.84%), influents (2.23 – 13.97%), and river sediments (2.56 – 11.71%) were the major exogenous sources of riverine microeukaryotes. At the spatial scale, the downstream of the watershed (i.e., main channel and tributaries) received higher proportions of exogenous microeukaryotic OTUs compared to the upstream reservoirs, while at the seasonal scale, the sewage effluents and influents contributed higher exogenous microeukaryotes to river water in wet season than in dry season. Moreover, the swine and domestic wastewater led to the presence of Apicomplexa in wet season only, implying rainfall runoff may enhance the spread of parasitic microeukaryotes. Taken together, our study provides novel insights into the immigration patterns of microeukaryotes and their dominant supergroups between terrestrial and riverine habitats.

Summary Steroid hormones modulate development, reproduction and communication in eukaryotes. The widespread occurrence and persistence of steroid hormones have attracted public attention due to their endocrine‐disrupting effects on both wildlife and human beings. Bacteria are responsible for mineralizing steroids from the biosphere. Aerobic degradation of steroid hormones relies on O2 as a co‐substrate of oxygenases to activate and to cleave the recalcitrant steroidal core ring. To date, two oxygen‐dependent degradation pathways – the 9,10‐seco pathway for androgens and the 4,5‐seco pathways for oestrogens – have been characterized. Under anaerobic conditions, denitrifying bacteria adopt the 2,3‐seco pathway to degrade different steroid structures. Recent meta‐omics revealed that microorganisms able to degrade steroids are highly diverse and ubiquitous in different ecosystems. This review also summarizes culture‐independent approaches using the characteristic metabolites and catabolic genes to monitor steroid biodegradation in various ecosystems., Aerobic degradation of steroid hormones relies on O2 as a co‐substrate of oxygenases to activate and to cleave the recalcitrant steroidal core ring. To date, two oxygen‐dependent degradation pathways—the 9,10‐seco pathway for androgens and the 4,5‐seco pathways for estrogens—have been characterized. Under anaerobic conditions, denitrifying bacteria adopt the 2,3‐seco pathway to degrade different steroid structures.

Due to the lack of wastewater treatment facility in Pakistan, the wastewater is directly discharged via urban drains, which might cause a high load of contaminants of emerging concerns and potential environmental risks. The present study focused on the occurrence and risk assessment of 52 pharmaceuticals and personal care products (PPCPs) of diversified classes in the water and sediment samples of urban drains and canal of Lahore, Pakistan. Non-steroidal anti-inflammatory drugs were the predominant PPCPs detected in the wastewater of urban drains and surface water of canal. The highest concentration was observed for acetaminophen, with median concentration of 13,880 ng/L followed by caffeine with median concentration of 6200 ng/L. Antibiotics were the predominant PPCPs in the sediment samples with highest concentration of ofloxacin (median value of 1980 μg/kg) followed by ciprofloxacin and oxytetracycline. Spatial variation showed that the population density has significant correlation with the level of many PPCPs in surface water while one of the drainage systems is affected by the direct wastewater discharge from the nearby industrial area. Ecological risk assessment in terms of risk quotient revealed that most of the PPCPs may cause high risk to the aquatic community. This high risk may lead to further contamination of food and crops, therefore enforcement of environmental legislations for treatment of wastewater is recommended.

Natural and synthetic estrogens have been widely detected in wastewater treatment plant (WWTP) influent and effluent as well as in the corresponding receiving aqueous environment and other ecosystems. Microalgae can be used to remove nitrogen and phosphorus in wastewater, but the species-dependent removal of estrogens needs further investigation. In this study we investigated estrone, 17β-estradiol and 17α-ethynylestradiol removals and transformation products by four common microalgae Haematococcus pluvialis, Selenastrum capricornutum, Scenedesmus quadricauda, and Chlorella vulgaris. It was found that H. pluvialis, S. capricornutum and S. quadricauda could more effectively remove all three estrogens in synthetic wastewater effluent. The estrogenic activities i.e. 17β-estradiol equivalency determined by yeast estrogenic screening assay showed substantial estrogenic activity reductions after biotransformation by H. pluvialis, S. capricornutum, and S. quadricauda. Quadrupole Time-of-flight Mass Spectrometry results identified several possible ring-cleavage metabolites as well as their metabolic pathways, which had not been reported yet, confirming the estrogen degradation rather than mere absorption or uptake by microalgae. The findings demonstrate that not only can some specific bacteria degrade estrogens, but also the widely living microalgae are able to degrade these emerging pollutants, suggesting that microalgae could be an advanced treatment of WWTPs to remove nutrients and estrogens.

A novel method for efficiently removing low levels of ammonium contamination from the aqueous solution using clinoptilolite in a high-gravity rotating packed bed (HGRPB) was developed. Our batch experiments have shown that irregular clinoptilolite gave better ammonium removal efficiencies due to higher specific surface area, and the adsorption data fitted better using pseudo-second-order adsorption kinetics than pseudo-first-order adsorption kinetics. HGRPB experiments have demonstrated that increasing rotating speeds will improve ammonium removal due to higher mass transfer of ammonium between the liquid and solid phases. The removal efficiency was 90% at the end of the fifth cycle (∼54 min) at a rotating speed of 1500 rpm using irregular clinoptilolite, with an initial ammonium concentration of 12.5 mg-N/L in distilled water and a flow rate of 180 mL/min. However, the removal efficiency was obviously lower in pond water than that in distilled water because of possible competitive adsorption of other cations in the pond water, suggesting modification of clinoptilolite to increase its selectivity for ammonium will be critical. This study has demonstrated the potential of using clinoptilolite in the HGRPB system to remove low levels of ammonium contamination in water and warrants the research need of HGRPB for biphasic liquid–solid adsorption processes.

In the present study, 13 endocrine disrupting compounds (EDCs) and their transformation products (TPs) were monitored in Jiulong River and its estuary, China in different seasons. The analytes included antimicrobials [triclosan (TCS) and triclocarbon (TCC)]; estrogens [estrone (E1), estradiol (E2), estriol (E3) and ethinylestradiol (EE2)]; alkylphenol ethoxylates [4-n-nonylphenol (NP) and 4-n-octylphenol (OP)] and the TPs [methyl triclosan (MeTCS), carbanilide (NCC), dichlorocarbanilide, 4-hydroxy estrone (4-OH E1) and 4-hydroxy estradiol (4-OH E2)]. A significant seasonal variation was observed for most EDCs. Approximately, 79% of the total E2 residues were detected in the normal season in comparison with the wet season to indicate recalcitrant behavior of E2 during the normal season. Risk assessment revealed that E2 was most potent among the EDCs to cause highest risk to both vertebrate and invertebrate aquatic species, whereas, E1, EE2, MeTCS and TCS also showed relatively high risk for some surface water aquatic species.

Triclosan (TCS) is a synthetic chlorinated aromatic compound and a typical antibacterial agent widely used in a diverse range of personal care products. Generally, after normal use, TCS is flushed ...

The plant microbial fuel cell (PMFC) is considered as a sustainable technology in which plants, microbes, and electrochemical cells are the major components and have the synergistic effect on electricity generation. Recent study has demonstrated the use of the PMFC system for remediation of hexavalent chromium (Cr(VI)) contaminated soils; however, the electrokinetic effects, fate of Cr and microbial community shift after long-term operation of PMFCs still need to be unveiled. In this study, PMFCs with spiking 50 mg/kg Cr(VI) were operated over 10 months and chemical and microbial characteristics of different locations of PMFC systems were investigated. Distinct chemical and microbial properties for different locations of soil samples were observed within PMFCs. For instance, the pH values of soils around the cathode and anode (cathode and anode soils) in PMFCs with Chinese pennisetum (Chinese pennisetum PMFCs) were 7.03 ± 0.15 and 6.09 ± 0.05 respectively, showing significantly higher pH values of cathode soils than those of anode soils. The electrical conductivity (EC) of cathode and anode soils in Chinese pennisetum PMFCs was 78.00 ± 5.61 and 156.25 ± 7.89 μs/cm respectively, showing significantly lower ECs of cathode soils than those of anode soils. The total Cr of cathode and anode soils in Chinese pennisetum PMFCs was 65.75 ± 3.77 and 84.29 ± 2.87 mg/kg respectively, showing significantly lower total Cr of cathode soils than that of anode soils. The permutational multivariate analysis of variance test of results of 16S rRNA gene high-throughput sequencing revealed that microbial communities in anode and cathode samples had significant difference in compositions. The stratified chemical and microbial characteristics between anode and cathode were primarily driven by the bioelectrochemical processes and electrokinetic effects within PMFCs. The findings in this study help to better understand the underlying effects of operating PMFCs and will be beneficial for future application of PMFCs in the remediation of heavy metal-contaminated soils.

Food waste (FW) contributes to a great proportion in the municipal solid waste and is generated during disposal from different life cycles of food processing and consumption. FW treatment is a big challenge and there is an urgent need to develop a suitable treatment technology. The microbial fuel cell (MFC) is a promising bioelectrochemical technology using bacteria as the catalyst, which has been developed to effectively generate bioelectricity from diverse organic wastes. The present study investigated the treatment of food waste collected from a Chinese canteen using MFCs under different conditions. It was observed that the highest closed circuit voltage and maximum power density obtained were 775 ± 21 mV and 422 mW m−2, respectively, when using food waste with nutrient medium as the anolyte and permanganate as the catholyte. Under this condition, biodegradation processes in the MFCs could achieve 69 ± 18% COD, 88 ± 5% carbohydrate, 76 ± 9% protein, 65 ± 8% TOC and 71 ± 8% total nitrogen removal. Microbial community analysis using 16S rRNA gene high-throughput sequencing showed Firmicutes, Bacteroidetes and Proteobacteria were the dominant phyla and Geobacter was the most abundant genus. Therefore, our microbial community results suggested that the mixture of exoelectrogenic and fermentative bacteria have a pronounced effect on MFCs system treating FW while affecting on organic degradation and energy production. A power management system was used to demonstrate that electricity from FW-fed MFCs can be successfully harvested to provide intermittent electricity to loads. Overall, this study demonstrated the potential of using MFCs for food waste treatment to achieve electricity production and waste reduction.

Unmineable coal accounts for over 90% of the world’s fossil fuel resources. Fortunately, many coal seams contain indigenous microorganisms capable of utilizing the coal as a carbon source to produce secondary biogenic coalbed natural gas. However, coal bioavailability has been shown to be a significant factor that limits the extent of bioconversion. In this study, we have analyzed the rate and yield of the biogas production and assessed the gas potential, carbon balance, stable carbon isotopes, microbial communities, and microbial pathways changes resulting from the hydrogen peroxide pretreatment with the Wyoming’s Powder River Basin subbituminous coal. The results showed that coal pretreated with hydrogen peroxide can significantly enhance the bioavailability of coal for enhancing the biogas production, with a peak yield of 552.6 μmol/g coal (437.1 Scf/ton coal) at the day 184. The stable carbon isotopic analysis indicated that the δ13C values of the methane and carbon dioxide were much less negative than the published field data. This suggested that the enrichment or depletion of the precursor 13C could contribute to the shift of the carbon isotopic composition in the subsequence processes. Therefore, the data should be used with cautions for interpreting genesis of the thermogenic/biogenic methane and the methanogenic pathways. The methanogenic pathways were also investigated with re-fed experiment and microbial community analysis. The results indicated that the hydrogenotrophic pathway was not active in the original inoculum became activated after the gas production. The microbial community analysis demonstrated that the obligate hydrogenotrophic methanobacterium was the most dominant methanogens in the microcosms after the gas production. This suggested that the chemical treatment of coal has impacts on the microbial structure during the subsequent methane production phase.

Excessive quantities of nitrates in the aquatic environment can cause eutrophication and raise water safety concerns. Therefore, identification of the sources of nitrate is crucial to mitigate nitrate pollution and for better management of the water resources. Here, the spatiotemporal variations and sources of nitrate were investigated by stable isotopes (δ

Sewage sludge (SS) is an organic biomass from wastewater treatment plants, but the use of SS to produce bio-based chemicals under acid-catalyzed hydrolysis (ACH) processes is not well investigated. In this study, ACH processes were performed at 120, 150, and 180 °C using sulfuric acid (H2SO4) with concentrations of 0–0.5 M within a reaction time of 90–180 min to produce bio-based chemicals from SS. The results showed that the reaction temperature, reaction time, and concentrations of H2SO4 affected the yields of sugars, levulinic acid (LA), and 5-hydroxymethylfurfural (HMF). The highest xylose and glucose yields were 7.69 mol% and 5.22 mol% at 120 °C with 0.5 M H2SO4 during the 180 min of reaction time, respectively. Besides, under the ACH process at 180 °C and 180 min, the yield of LA reached a maximum value of 0.48 mol% at 0.5 M H2SO4, and the highest yield of HMF was 1.66 mol% at 0.1 M H2SO4. The data obtained also indicated that the ACH process led to an increase in soluble chemical oxygen demand, dissolved organic carbon, and total dissolved nitrogen. Fluorescence excitation-emission matrix of dissolved organic matter and thermogravimetric analysis of the treated SS further supported the enhanced solubilization of SS after ACH process, especially under higher reaction temperature and concentrations of H2SO4. Although the lower yields of bio-based chemicals might restrict the downstream recovery of the target products, the largely improved SS solubilization by ACH suggests that acid-catalyzed hydrothermal hydrolysis process has potential as an alternative pretreatment method of SS.

Understanding the underlying mechanism that drives the microbial community mediated by substrates is crucial to enhance the biostimulation in trichloroethene (TCE)-contaminated sites. Here, we investigated the performance of stable TCE-dechlorinating consortia by monitoring the variations in TCE-related metabolites and explored their underlying assembly mechanisms using 16S rDNA amplicon sequencing and bioinformatics analyses. The monitoring results indicated that three stable TCE-dechlorinating consortia were successfully enriched by lactate-containing anaerobic media. The statistical analysis results demonstrated that the microbial communities of the enrichment cultures changed along with time and were distinguished by their sample sources. The deterministic and stochastic processes were simultaneously responsible for shaping the TCE-dechlorinating community assembly. The indicator patterns shifted with the exhaustion of the carbon source and the pollutants, and the tceA-carrying Dehalococcoides, as an indicator for the final stage samples, responded positively to TCE removal during the incubation period. Pseudomonas, Desulforhabdus, Desulfovibrio and Methanofollis were identified as keystone populations in the TCE-dechlorinating process by co-occurrence network analysis. The results of this study indicate that lactate can be an effective substrate for stimulated bioremediation of TCE-contaminated sites, and the reduction of the stochastic forces or enhancement of the deterministic interventions may promote more effective biostimulation.

We examined the uncertainty of the resistivity method in cavity studies using a synthetic cavity model set at six-different depths. Conceptual models were simulated to generate synthetic resistivity data for dipole-dipole, pole-dipole, Wenner-Schlumberger, and pole-pole arrays. The 2D geoelectric models were recovered from the inversion of the synthetically measured resistivity data. The highest anomaly effect (1.46) and variance (24400) in resistivity data were recovered by dipole-dipole array, while the pole-pole array obtained the lowest anomaly effect (0.60) and variance (2401) for the target cavity T1. The anomaly effect and variance were linearly associated with the quality of the inverted models. The steeper anomaly gradient of resistivity indicated more distinct cavity boundaries, while the gentler gradient prevents the inference of the cavity boundaries. The recovered model zone above the depth of investigation index of 0.1 has shown relatively higher sensitivity. Modeling for dipole-dipole array provided the highest model resolution and anomaly gradient that shows a relatively distinct geometry of the cavity anomalies. On the contrary, the pole-dipole and Wenner-Schlumberger arrays recovered good model resolutions and moderate anomaly gradient but determining the anomaly geometries is relatively challenging. Whereas, the pole-pole array depicted the lowest model resolution and anomaly gradient with less clear geometry of the cavity anomalies. At deeper depths, the inverted models showed a reduction in model resolutions, overestimation in anomaly sizes, and deviation in anomaly positions, which can create ambiguity in resistivity model interpretations. Despite these uncertainties, our modeling specified that the 2D resistivity imaging is a potential technique to study subsurface cavities.

Sewage and fecal pollution cause antibiotic resistance genes (ARGs) pollution in urban lagoons. Seasonality also affects ARG dynamics. However, knowledge of factors controlling ARG community assembly across seasons is still limited. Here, we revealed the seasonal variation of ARGs and depict the underlying assembly processes and drivers via high-throughput quantitative PCR in an urban lagoon, China. A higher richness and abundance of ARGs were observed in summer and winter compared to spring and fall (Kruskal-Wallis test, P 0.05). Both ARG and prokaryotic communities were mainly governed by stochastic processes, however, these processes drove ARGs and prokaryotes differently across seasons. Stochastic processes played a more dominant role in shaping ARG communities in summer (average stochasticity: 83%) and winter (75%), resulting in a stable antibiotic resistome. However, no such seasonal pattern of stochastic processes was determined for prokaryotes, indicating a decoupling of the assembly process of ARGs and prokaryotes. Moreover, fecal microorganisms (e.g., Bacteroidetes and Faecalibacterium) mediated the stochastic processes of ARG profiles, via enhancement of prokaryotic biomass and mobile genetic element abundances. The tnpA-07 transposase was the key for the horizontal gene transfer. These findings will enhance our understanding of how fecal pollution shapes ARG community assembly in urban lagoons.

A bisphenol A-degrading bacterium, designated as strain H4T, was isolated from surface seawater, which was sampled from the Jiulong River estuary in southeast PR China. Strain H4T is Gram-stain-negative, aerobic, short rod-shaped, lacking bacteriochlorophyll a, motile with multifibrillar stalklike fascicle structures and capable of degrading bisphenol A. Growth of strain H4T was observed at 24–45 °C (optimum, 32 °C), at pH 5.5–9 (optimum, pH 7.0) and in 0–7 % NaCl (optimum, 2 %; w/v) . The 16S rRNA gene sequence of strain H4T showed highest similarity to Croceicoccus pelagius Ery9T (98.7 %), Croceicoccus sediminis (98.3 %), Croceicoccus naphthovorans PQ-2T (98.1 %) and Croceicoccus ponticola GM-16T (97.6 %), followed by Croceicoccus marinus E4A9T (96.7 %) and Croceicoccus mobilis Ery22T (96.0 %). Phylogenetic analysis revealed that strain H4T fell within a clade comprising the type strains of Croceicoccus species and formed a phyletic line with them that was distinct from other members of the family Erythrobacteraceae . The sole respiratory quinone was quinone 10 (Q-10). The predominant fatty acids (>5 % of the total fatty acids) of strain H4T were summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c), summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c), C17 : 1 ω6c and C14 : 02-OH. The genomic DNA G+C content was 62.8 mol%. In the polar lipid profile, phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, two unidentified phospholipids, two sphingoglycolipids and three unknown lipids were the major compounds. Based on the genotypic and phenotypic data, strain H4T represents a novel species of the genus Croceicoccus , for which the name Croceicoccus bisphenolivorans sp. nov. is proposed. The type strain is H4T (=DSM 102182T=MCCC1 K02301T).