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1.
J Hazard Mater ; 472: 134561, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38733784

RESUMO

Steroid estrogens (SEs) have garnered global attention because of their potential hazards to human health and aquatic organisms at low concentrations (ng/L). The ecosystems of plateau freshwater lakes are fragile, the water lag time is long, and pollutants easily accumulate, making them more vulnerable to the impact of SEs. However, the knowledge of the impact of SEs on the growth and decomposition of phytoplankton communities in plateau lakes and the eutrophication process is limited. This study investigated the effects and mechanisms of SEs exposure on dominant algal communities and the expression of typical algal functional genes in Erhai Lake using indoor simulations and molecular biological methods. The results showed that phytoplankton were sensitive to 17ß-estradiol (E2ß) pollution, with a concentration of 50, and 100 ng/L E2ß exposure promoting the growth of cyanophyta and chlorophyta in the short term; this poses an ecological risk of inducing algal blooms. E2ß of 1000 ng/L exposure led to cross-effects of estrogenic effects and toxicity, with most phytoplankton being inhibited. However, small filamentous cyanobacteria and diatoms exhibited greater tolerance; Melosira sp. even exhibited "low inhibition, high promotion" behavior. Exposure to E2ß reduced the Shannon-Wiener diversity index (H'), Pielou index (J), and the number of dominant algal species (S) in phytoplankton communities, leading to instability in community succession. E2ß of 50 ng/L enhanced the expression levels of relevant functional genes, such as ftsH, psaB, atpB, and prx, related to Microcystis aeruginosa. E2ß of 50 ng/L and 5 mg/L can promote the transcription of Microcystis toxins (MC) related genes (mcyA), leading to more MC production by algal cells.


Assuntos
Estradiol , Eutrofização , Lagos , Fitoplâncton , Poluentes Químicos da Água , Fitoplâncton/efeitos dos fármacos , Fitoplâncton/genética , Estradiol/toxicidade , Poluentes Químicos da Água/toxicidade , Diatomáceas/efeitos dos fármacos , Diatomáceas/genética , Diatomáceas/metabolismo , Diatomáceas/crescimento & desenvolvimento , Cianobactérias/genética , Cianobactérias/metabolismo , Cianobactérias/efeitos dos fármacos , Clorófitas/efeitos dos fármacos , Clorófitas/genética , Clorófitas/crescimento & desenvolvimento , Clorófitas/metabolismo
2.
Toxics ; 12(5)2024 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-38787101

RESUMO

To explore the contamination status and identify the source of the heavy metals in the sediments in the major inflow rivers of Dianchi Lake in China, sediment samples were collected and analyzed. Specifically, the distribution, source, water quality, and health risk assessment of the heavy metals were analyzed using correlation analysis (CA), principal component analysis (PCA), the heavy metal contamination factor (Cf), the pollution load index (PLI), and the potential ecological risk index (PERI). Additionally, the chemical fractions were analyzed for mobility characteristics. The results indicate that the average concentration of the heavy metals in the sediment ranked in the descending order of Zn > Cr > Cu > Pb > As > Ni > Cd > Hg, and most of the elements existed in less-mobile forms. The Cfwas in the order of Hg > Zn > Cd > As > Pb > Cr > Ni; the accumulation of Hg, Zn, Cd, and As was obvious. Although the spatial variability of the heavy metal contents was pronounced, the synthetical evaluation index of the PLI and PERI both reached a high pollution level. The PCA and CA results indicate that industrial, transportation, and agricultural emissions were the dominant factors causing heavy metal pollution. These results provide important data for improving water resource management efficiency and heavy metal pollution prevention in Dianchi Lake.

3.
Food Chem ; 445: 138693, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38350197

RESUMO

The impacts of varying germination periods (0-72 h) on morphological properties, proximate composition, amino acid profile, GABA levels, antioxidant attributes, polyphenol content (both free and bound), and volatile compounds of quinoa were evaluated. Germination significantly increased the content of fiber, amino acids, GABA, polyphenols, and in-vitro antioxidant activities in quinoa. The optimal nutritional quality and antioxidant capacity of quinoa were observed during the 36-72 h germination period. We examined the dynamics of 47 phenolic compounds in quinoa during germination and noted a substantial rise in free phenolic acids and bound flavonoids post-germination. A total of 53 and 84 volatile compounds were respectively identified in ungerminated quinoa and germinated quinoa. It was found that the germination period of 24-48 h contributed to reducing the presence of undesirable flavors. TEM analysis revealed significant structural damage to the ultrastructure and relaxation of the cell wall in germinated quinoa grains.


Assuntos
Antioxidantes , Chenopodium quinoa , Antioxidantes/química , Chenopodium quinoa/química , Sementes/química , Polifenóis/análise , Valor Nutritivo , Ácido gama-Aminobutírico/análise , Germinação
4.
Chemosphere ; 350: 141061, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38159729

RESUMO

The diffusive gradients in thin films (DGT) technique serves as a passive sampling method, inducing analyte transport and concentration. Its application is widespread in assessing labile components of metals, organic matter, and nutrients across various environmental media such as water, sediments, and saturated soils. The DGT devices effectively reduce the porewater concentration through irreversible binding of solutes, consequently promoting the release of labile species from the soil/sediment solid phase. However, the precise quantification of simultaneous adsorption and desorption of labile species using DGT devices alone remains a challenge. To address this challenge, the DGT-Induced Fluxes in Soils and Sediments (DIFS) model was developed. This model simulates analyte kinetics in solid phases, solutions, and binding resins by incorporating factors such as soil properties, resupply parameters, and kinetic principles. While the DIFS model has been iteratively improved to increase its accuracy in portraying kinetic behavior in soil/sediment, researchers' incomplete comprehension of it still results in unrealistic fitting outcomes and an oversight of the profound implications posed by kinetic parameters during implementation. This review provides a comprehensive overview of the optimization and utilization of DIFS models, encompassing fundamental concepts behind DGT devices and DIFS models, the kinetic interpretation of DIFS parameters, and instances where the model has been applied to study soils and sediments. It also highlights preexisting limitations of the DIFS model and offers suggestions for more precise modeling in real-world environments.


Assuntos
Metais , Solo , Solo/química , Difusão , Cinética , Adsorção , Monitoramento Ambiental/métodos , Sedimentos Geológicos/química
5.
Langmuir ; 39(47): 16750-16759, 2023 11 28.
Artigo em Inglês | MEDLINE | ID: mdl-37963300

RESUMO

Low-molecular-weight peptide hydrogels can be formed by self-assembly through weak interactions, but the application of the hydrogel is influenced by its weak mechanical properties. Therefore, it is important to construct low-molecular-weight peptide hydrogels with excellent mechanical properties. In this work, we designed the pentapeptide molecule Fmoc-FFCKK-OH (abbreviated as FFCKK) with a sulfhydryl group, and another low-molecular-weight cross-linker N,N'-methylenebis(acrylamide) (MBA) was introduced to construct a hydrogel with excellent mechanical properties. The secondary structure change process of FFCKK and the assembly mechanism of hydrogel were analyzed using theoretical calculations and experimental characterizations. The occurrence of thiol-ene click chemistry provides covalent interaction in the hydrogel, and the synergistic effect ofcovalent interaction and hydrogen bonding improves the mechanical properties of the hydrogel by nearly 10-fold. The hydrogel was observed to be able to withstand a stress of 368 Pa and to break in a layer-by-layer manner by compression testing. The micromechanics of the hydrogels were characterized, and the excellent mechanical properties of the hydrogels were confirmed. The synergistic approach provides a new idea for the preparation of low-molecular-weight peptide hydrogels and facilitates the expansion of their potential applications in biomedical fields.


Assuntos
Química Click , Hidrogéis , Hidrogéis/química , Compostos de Sulfidrila/química , Peptídeos/química
6.
Int J Biol Macromol ; 253(Pt 7): 127450, 2023 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-37844819

RESUMO

Chemical modification of sodium alginate (SA) polymer chains can increase its functional group species. Sodium periodate (SP) was usually used to oxidize the hydroxyl groups on the chain of SA to aldehyde groups, the preparation of oxidized sodium alginate (OSA) using SP is not only complicated, also limits the variety of functional groups on the chain of OSA. By contrast, we have developed an innovative strategy for OSA, in which ammonium persulfate (APS) was used to oxidize SA, providing a clear elucidation of the oxidizing process and mechanism. OSA/PAM hydrogels were synthesized using OSA, the hydrogels possess excellent adhesion properties to various non-metallic and metallic substrates. Tensile and compression tests show that the cross-linked OSA/PAM hydrogels have superior mechanical properties. We exploit OSA/PAM hydrogels as soil adhesive and water-retaining agents for wheat growth. OSA/PAM hydrogels significantly improve the survival time of wheat grown in brown loam soil under a water-shortage environment, and slow down the wilting of wheat in a water-shortage environment and prolong the survival time of wheat in sandy soils. Our trials should make hydrogels important for wheat cultivation in brown loam soils and the development of desert areas.


Assuntos
Adesivos , Triticum , Alginatos/química , Solo/química , Água/química , Hidrogéis/química
7.
Sci Total Environ ; 858(Pt 2): 159983, 2023 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-36356753

RESUMO

Lake sediment is an important organic carbon (OC) sink. Nevertheless, few studies have been conducted on sediment organic carbon (SOC) in lakes, and the effects of environmental variables on SOC pools remain poorly understood. We combined physicochemical and spectroscopic analyses to investigate the composition, distribution, and source of OC in surface sediments of Erhai Lake, southwest China, and explored the relationships between environmental variables and its SOC pool. The SOC pool consists of relatively high proportions of labile organic carbon fractions, mainly from algal production, which are rapidly decomposed and exhibit high turnover rates. The relative content of humus carbon ranges from 13.5 % to 20.5 %, with fulvic acid carbon predominating (average 52.95 %), indicating weak humification and a relatively active humus carbon pool. The dissolved organic matter in water column and sediments of Erhai Lake is largely influenced by endogenous production, with a great contribution from phytoplankton. Surface sediments contained more protein-like components than overlying waters (80.0 % vs. 63.0 %), attributed mainly to abundant algal deposition and intense bacterial metabolism. Among environmental variables, sediment chlorophyll a showed the strongest relationship with the SOC pool, and was associated with rapid decomposition and promotion of the humification process, which supported the conclusion that algae had an important influence on the SOC pool. The SOC pool in the southern region of the lake is mainly contributed by algae, other microorganisms, and sewage, exhibiting a greater potential to release organic matters into the water column. The center and northern SOC pools show relatively stable characteristics and stronger OC sink capacity, mainly because of the input of terrestrial refractory organic matters from runoff. Our data shed light on the OC storage mechanisms in the surface sediments of Erhai Lake and provide theoretical bases for enhancing the OC sink of sediments in the lake.


Assuntos
Lagos , Poluentes Químicos da Água , Lagos/química , Carbono/análise , Sedimentos Geológicos/química , Clorofila A/análise , Poluentes Químicos da Água/análise , Solo , Água/análise , China
8.
Chemosphere ; 299: 134377, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35364075

RESUMO

Dissolved organic matter (DOM) is a complex mixture of organic molecules that plays an important role in freshwater lake ecosystems. Excitation emission matrix-parallel factor analysis (EEM-PARAFAC) is an important tool for the identification and source analysis of DOM but is still inadequate for studying the differences and quantifying the contributions of different sources. Here, based on the maximum fluorescence intensities (Fmax) of the four fluorescent components (e.g., protein-like component C1, and the humic-like components C2, C3, C4) identified by EEM-PARAFAC, combined with large-scale data obtained from observations at Erhai Lake, we used partial least squares path modeling (PLS-PM) to improve the understanding of the migration and transformation mechanisms of DOM. The results showed that the phytoplankton and trophic state had greater impacts on DOM, while the impacts of sediment and inflow rivers were less significant. The results of the models that used nitrogen nutrients (N) and phosphorus nutrients (P) to separately indicate the trophic state suggested that the driving force of P on DOM was stronger than that of N in Erhai Lake. Among the four fluorescent components, the protein-like component with the largest relative proportion (41.98%) was mainly affected by phytoplankton, which was consistent with the autogenic characteristics obtained through spontaneous source index (BIX). The duality of the humic-like components was consistent with the duality of DOM through fluorescent index (FI). C3 had a higher sensitivity to the trophic state than the other components, and C2 received the greatest positive contribution from the rivers entering the lake. These results provide an improved insight into the influence of different sources on the behavior of DOM and demonstrate the potential of using PLS-PM to study the complex driving mechanism of aquatic biogeochemical parameters.


Assuntos
Lagos , Matéria Orgânica Dissolvida , Ecossistema , Análise Fatorial , Substâncias Húmicas/análise , Lagos/química , Espectrometria de Fluorescência , Qualidade da Água
9.
Bioprocess Biosyst Eng ; 45(1): 75-85, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34564754

RESUMO

Hyperthermophilic microorganisms play a key role in the hyper-thermophilic composting (HTC) technique. However, little information is available about the hyperthermophilic microorganisms prevalent in HTC systems, except for the Calditerricola satsumensis, Calditerricola yamamurae, and Thermaerobacter. To obtain effective hyper-thermophilic microorganisms, a continuous thermo-acclimation of the suitable thermophilic microorganisms was demonstrated in this study. Bacillus thermoamylovorans with high-temperature endurance (70 °C) were newly isolated from sludge composting, and an adequate slow heating rate (2 °C per cycle) was applied to further improve its thermostability. Finally, a strain with a maximum growth temperature of 80 °C was obtained. Moreover, structural and hydrophobic changes in cell proteins, the special amino acid content ratio, and the membrane permeability of the thermophilic bacterium after thermo-acclimation were evaluated for improved thermostability. In addition, the acclimated hyperthermophilic bacterium was further inoculated into the HTC system, and an excellent performance with a maximum operating temperature of 82 °C was observed.


Assuntos
Archaea/fisiologia , Fermentação , Fenômenos Fisiológicos Bacterianos , Temperatura Alta
10.
Sci Rep ; 11(1): 23234, 2021 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-34853397

RESUMO

To enhance the reducing sugar yield in enzymatic hydrolysis, various factors (NaOH concentration, solid content and pre-treatment time) that affect the pre-treatment process were investigated and evaluated based on the reducing sugar yield of the subsequent enzymatic hydrolysis. The enzymatic hydrolysis was based on the cellulase from Trichoderma reesi ATCC 26921, the optimum NaOH pre-treatment conditions were an NaOH concentration of 1.0% (w/w), a solid content of 5.0% (w/v) and a pre-treatment time of 60 min. Various parameters that affect the enzymatic hydrolysis of wheat straw, including the solid content, enzyme loading, pH and hydrolysis time, were investigated and optimized through a Box-Behnken design and response surface methodology. The predicted optimum conditions for enzymatic hydrolysis were a solid content of 8.0% (w/v), an enzyme loading of 35 FPU/g substrate, a temperature of 50 °C, a pH of 5.3 and a hydrolysis time of 96 h. The experimental result showed that the maximum reducing sugar yield was 60.73% (53.35% higher than the wheat straw without NaOH pre-treatment), which is in accordance with the predicted conditions.


Assuntos
Celulase , Açúcares/química , Triticum/química , Hidrólise , Caules de Planta/química , Hidróxido de Sódio/química , Trichoderma/enzimologia
11.
Foods ; 10(11)2021 Oct 27.
Artigo em Inglês | MEDLINE | ID: mdl-34828877

RESUMO

Sugar content and bacterial contamination levels are important indicators for the health and safety of food, respectively. Therefore, it is important to construct a method that can detect both glucose and bacterial activity. Herein, natural compounds (gallic acid and glucose oxidase) were assembled into nanozyme (GOx@GA-Fe (ii)) for mild cascade detection. The nanozyme catalyzes glucose to produce hydrogen peroxide, which is then converted to ·OH and oxidized colorless TMB from blue oxidized TMB. Under the optimal conditions, the method has a good linear relationship in the glucose concentration range of 1-500 µM (R2 = 0.993) with minimum detection concentration of 0.43 µM. Based on the glucose consumption of bacteria metabolism, the cascade reaction was then applied to detect the viability of 5 common bacteria. As such, a cascade method based on a natural self-assembled nanozyme was fabricated to monitor the quality of food.

12.
Environ Sci Pollut Res Int ; 28(38): 52625-52650, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34448139

RESUMO

Contamination of water streams by dyes and heavy metals has become a major problem due to their persistence, accumulation, and toxicity. Therefore, it is essential to eliminate and/or reduce these contaminants before discharge into the natural environment. In recent years, 3D graphene has drawn intense research interests owing to its large surface area, superior charge conductivity, and thermal conductivity properties. Due to their unique surface and structural properties, 3D graphene-based materials (3D GBMs) are regarded as ideal adsorbents for decontamination and show great potential in wastewater or exhaust gas treatment. Here, this minireview summarizes the recent progress on 3D GBMs synthesis and their applications for adsorbing dyes and heavy metals from wastewater based on the structures and properties of 3D GBMs, which provides valuable insights into 3D GBMs' application in the environmental field.


Assuntos
Grafite , Metais Pesados , Poluentes Químicos da Água , Adsorção , Corantes , Poluentes Químicos da Água/análise
13.
Bull Environ Contam Toxicol ; 105(6): 882-891, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-33175186

RESUMO

On-site sampling analysis and laboratory-scale experiments were conducted to study the pollution status and release potential of EDCs in Erhai Lake. We found that nitrogen and phosphorus pollution in Erhai Lake sediment were both at a high level, as well as EDCs pollution. The concentrations of BPA, E2α, E1, E2ß, EE2, and E3 were 36.84 ng/g(DW), 13.04 ng/g(DW), 128.97 ng/g(DW), 52.57 ng/g(DW), 18.48 ng/g(DW) and 5.36 ng/g(DW), respectively. The concentrations of E2α, E1, E2ß and EE2 in the bottom water were higher than the surface water due to the impact of sediment release. The results of the 20 days release test indicated that BPA release from the sediment had a greater correlation with the original concentration and the particle size of sediment, while the steroid EDCs had no obvious correlation with these two factors, probably due to the difference in hydrophobicity between them. Under hydraulic disturbance and aerobic conditions, the release process of EDCs was accompanied by a large amount of microbial degradation, and degradation amount > released amount. BPA was released quickly, 9.56% was released in 20 days, but only 3.37% of steroid EDCs released. In comparison, the release process of steroids was longer and posed a greater threat to aquatic ecology.


Assuntos
Compostos Benzidrílicos/análise , Monitoramento Ambiental , Estrogênios/análise , Fenóis/análise , Poluentes Químicos da Água/análise , China , Disruptores Endócrinos/análise , Poluição Ambiental/análise , Sedimentos Geológicos , Lagos , Nitrogênio/análise , Fósforo/análise
14.
Water Res ; 184: 116198, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712509

RESUMO

Porous metal-organic frameworks (MOFs) have drawn increasing attention as promising phosphate adsorbents. Yet the potential agglomeration of MOFs particles and the difficult collection process largely thwarted their application. Meanwhile, adsorbents regeneration might destroy MOFs structures due to the use of strong alkaline solution. In this work, we reported a strategy for designing and fabricating an electrode to remove phosphate based on MIL-101 derived metal/carbon via a two-step carbonization step, which not only introduced C doping but also created a stable structure. With the assistance of electric field, the migration and capture of phosphate anions were greatly enhanced. Under 1 V condition, the material exhibited a high maximum removal capacity of 97.73 mg P/g. Adsorption kinetics and parameters for phosphate at different conditions were analyzed. Langmuir and Freundlich isotherms were employed to validate the adsorption data. More importantly, the regeneration of electrode was achieved in a more facile and efficient way than micro/ nanoparticles adsorbents by simple voltage control. Such an intriguing approach may provide a new platform to further expand the use of MOFs for adsorption process.


Assuntos
Estruturas Metalorgânicas , Adsorção , Eletrodos , Cinética , Fosfatos
15.
Environ Sci Process Impacts ; 22(1): 217-226, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31898705

RESUMO

In the rhizosphere, plant root exudates can mediate the toxicity of antibiotics on microorganisms, yet the mechanisms are poorly understood. To simulate the antibiotic contamination of global rivers and lakes, the current study investigated the effects of two antibiotics (ofloxacin at 8.69 × 104 ng L-1 and tetracycline at 8.62 × 104 ng L-1) and their binary combination (8.24 × 104 ng L-1 ofloxacin and 7.11 × 104 ng L-1 tetracycline) on bacterial communities in micro-polluted constructed wetlands with and without artificial root exudates. The two antibiotics had no significant effects on the removal of excess carbon and nitrogen from the microcosms treated with and without exudates. Furthermore, with regard to bacterial community structure, antibiotic exposure increased the bacterial richness of bulk and exudate treated microcosms (P < 0.05). However, a significant increase (P < 0.05) in bacterial diversity elicited by ofloxacin and antibiotic mixture exposure was only observed in microcosms with exudates. In exudate treated microcosms, ofloxacin promoted the relative abundance of Arthrobacter spp., which are ofloxacin-resistant bacterial species, which significantly varied from what was observed in microcosms free of exudates. Moreover, tetracycline, ofloxacin and their combination all significantly increased the relative abundance of nitrogen cycling bacteria Rhizobacter spp. and Rhizobium spp., and decreased the relative abundance of antibiotic-resistant bacteria Pseudomonas spp. Simultaneously, with regard to bacterial community functions, the functional profiles (Kyoto Encyclopedia of Genes and Genomes) showed that the pathways of amino acid and carbohydrate metabolism were enhanced by antibiotics in microcosms with exudates. The findings illustrate that antibiotics not only alter the bacterial structure and composition but also change their functional properties in constructed wetlands, and these interruption effects could be affected by root exudates of plants, which may further reveal the ecological implication of plants in constructed wetlands.


Assuntos
Antibacterianos , Microbiota , Rizosfera , Áreas Alagadas , Antibacterianos/toxicidade , Microbiota/efeitos dos fármacos , Nitrogênio , Raízes de Plantas/microbiologia
16.
Environ Monit Assess ; 191(6): 365, 2019 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-31089888

RESUMO

Accurately measuring and estimating trends and variations in nutrient levels is a significant part of managing emerging eutrophic lakes in developing countries. This study developed an integrated approach containing Seasonal Trend Decomposition using Loess (STL) and a dynamic nonlinear autoregressive model with exogenous input (NARX) network to decompose and estimate the nutrient concentrations in Lake Erhai, a preliminary eutrophic lake in China. The STL decomposition results indicated that total nitrogen (TN) concentration of Lake Erhai progressively descended from 2006 to 2014, except for some agriculture area. The total phosphorus (TP) concentration showed an increasing trend from 2006 to 2013 and then decreased in 2014, but in the area near the tourist attractions, TP increased continuously from 2011 to 2014. Seasonal variations in TN and TP indicated that the lowest water quality of Lake Erhai occurred from July to October. Based on results obtained with STL, TP was selected as the sensitive parameter, as it showed a significant deterioration trend, and the area near the tourist attractions was selected as the sensitive area. Three variables (DO, pH, and water temperature) were selected as input parameters to estimate TP using the dynamic NARX model. The NARX modeling results demonstrated that it can accurately estimate TP concentrations with low root-mean-square error (0.0071 mg/L). The study establishes a new approach to better understand trends and variations in nutrient levels and to better refine estimates by identifying more easily accessible physical parameters in a preliminary eutrophic lake.


Assuntos
Monitoramento Ambiental/métodos , Eutrofização , Modelos Químicos , Poluentes Químicos da Água/análise , Poluição Química da Água/estatística & dados numéricos , Agricultura , China , Lagos/química , Nitrogênio/análise , Fósforo/análise , Estações do Ano , Temperatura , Qualidade da Água
17.
Water Environ Res ; 91(9): 843-854, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30844095

RESUMO

Throughout rural regions, large amounts of domestic wastewater are discharged into natural bodies of water without treatment. A well-designed subsurface wastewater infiltration (SWI) system is an effective wastewater pollution removal strategy for small and remote communities due to its low energy consumption, low operational cost, and good performance. This paper describes the types of structures and purification mechanisms of SWI systems, focusing on the design of substrate materials and the optimization of different operation modes including the hydraulic loading rate, pollutant loading rate, intermittent operation, aeration, and shunting distribution. The challenges and trends in the development of SWI systems are also discussed. PRACTITIONER POINTS: The construction and purification mechanisms of SWI system are described. The design of substrates and the optimization of operation modes are focused. The challenges and the development trends for the system are further introduced.


Assuntos
Águas Residuárias , Purificação da Água , Nitrogênio , Eliminação de Resíduos Líquidos
18.
Environ Sci Pollut Res Int ; 26(11): 10621-10630, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30762179

RESUMO

To investigate the effects of antibiotics on nitrogen removal and uptake by wetland plants, four typical macrophyte species, Cyperus alternifolius L., Typha angustifolia L., Lythrum salicaria L., and Acorus calamus L., were grown in hydroponic cultivation systems and fed wastewater polluted with 10 µg L-1 Ofloxacin (OFL) and Tetracycline (TET). Biomass production, nitrogen mass concentration, chlorophyll content, root exudates, and nitrogen removal efficiency of hydroponic cultivation were investigated. The results indicated that in all hydroponic systems, NH4+-N was entirely removed from the hydroponic substrate within 1 day and plant nitrogen accumulation was the main role of the removed NO3-. OFL and TET stimulated the accumulation of biomass and nitrogen of A. calamus but significantly inhibited the NO3--N removal ability of L. salicaria (98.6 to 76.2%) and T. augustifolia (84.3 to 40.2%). This indicates that A. calamus may be a good choice for nitrogen uptake in wetlands contaminated with antibiotics. OFL and TET improved the concentrations of total organic carbon (TOC), total nitrogen (TN), organic acid, and soluble sugars in root exudates, especially for oxalic acid. Considering the significant correlation between TOC of root exudates and nitrogen removal efficiency, the TOC of root exudates may be an important index for choosing macrophytes to maintain nitrogen removal ability in wetlands contaminated with antibiotics.


Assuntos
Acorus/efeitos dos fármacos , Antibacterianos/farmacologia , Cyperus/efeitos dos fármacos , Lythrum/efeitos dos fármacos , Nitrogênio/metabolismo , Typhaceae/efeitos dos fármacos , Acorus/crescimento & desenvolvimento , Acorus/metabolismo , Transporte Biológico/efeitos dos fármacos , Biomassa , Cyperus/crescimento & desenvolvimento , Cyperus/metabolismo , Hidroponia , Lythrum/crescimento & desenvolvimento , Lythrum/metabolismo , Nitrogênio/análise , Ofloxacino/análise , Ofloxacino/farmacologia , Typhaceae/crescimento & desenvolvimento , Typhaceae/metabolismo , Águas Residuárias/química , Poluentes da Água/análise , Poluentes da Água/farmacologia , Áreas Alagadas
19.
Sci Total Environ ; 656: 503-511, 2019 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-30522033

RESUMO

Constructed wetlands (CWs) have emerged as a promising technology for the purification of micro-polluted water. However, their nitrogen removal performance can be significantly degraded by design, operational, and environmental factors. The present study investigates the effects of ofloxacin (OFL: 0.1, 10, and 1000 µg L-1) and plants (Cyperus alternifolius L. and Typha angustifolia L.) on nitrogen removal in a micro-polluted CW system over a duration of 12 weeks. The effects were evaluated by investigating NH4-N and NO3-N removal efficiency, nitrification genes (amoA-AOA and amoA-AOB), denitrification genes (nirK and nirS), fungal 18S rRNA gene and microorganism community structure. The results showed that in unplanted CWs, OFL increased the NH4-N removal efficiency (from 72.6% to 80.7-82.1%), the abundances of amoA-AOA, nirS, nirK and fungal 18S rRNA gene, and the bacterial diversity but decreased the abundance of both amoA-AOB and bacterial richness. In contrast, both the nitrogen removal efficiency (83.4-89.5% for NH4-N and 33.8-38.5% for NO3-N) and bacterial diversity/richness were not significantly affected by OFL in planted CWs. In planted systems, OFL increased the relative abundance of Arthrobacter, Pseudomonas, and Enterococcus, which are proven antibiotic-resistant bacteria. This study showed that CWs are able to remove nitrogen from antibiotic-contaminated micro-polluted water, which might primarily be attributed to the presence of plants that protect the microorganism community.


Assuntos
Cyperus/metabolismo , Microbiota , Nitrogênio/metabolismo , Ofloxacino/metabolismo , Typhaceae/metabolismo , Poluentes Químicos da Água/metabolismo , Antibacterianos/metabolismo , Cyperus/microbiologia , Genes Bacterianos , Typhaceae/microbiologia , Eliminação de Resíduos Líquidos , Áreas Alagadas
20.
Sci Total Environ ; 607-608: 676-682, 2017 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-28709102

RESUMO

Bisphenol A (BPA) has caused widespread concern among scholars as a result of its estrogenic toxicity. It exists mainly in natural waters, sediments, and soil, as well as sewage and wastewater sludge. Considering that BPA is a common environmental pollutant that is removed along with chemical oxygen demand (COD), nitrogen, and phosphorus in drainage treatment systems, it is important to research the fate of BPA in sewage treatment systems. In this research, laboratory batch experiments on soil degradation and adsorption were conducted with 14C-BPA, aiming to discuss the transport and degradation characteristics of BPA in both simulated facilities and a soil trench. Based on the experimental results, the Freundlich model could be applied to fit the isothermal adsorption curve of the BPA in soil. A low mobility characteristic of BPA was discovered. The mineralization rate of BPA was fast and that of the reaction showed small fluctuations. After degradation, 21.3 and 17.7% of the BPA groups (the experimental group treated with ammonia oxidase (AMO) inhibitor and the control group) were converted into 14CO2, respectively. This indicates that the nitrification and degradation of BPA had a certain competitive relationship. Besides, nitrification did not significantly affect the soil residue of BPA. Through the soil trench test, the average removal rate of BPA in the soil trench was 85.5%. 14CO2 was discharged via the mineralization of BPA, accounting for 2.5% of the initial input. BPA easily accumulated in the bottom soil of the soil trench. BPA and its metabolites in the effluent accounted for 14.5% of the initial dosage. The residual extractable BPA and its metabolites in the soil accounted for 51.3%, and the remaining part of the unextractable residue represented 19.8% of the initial radioactive dosage.

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