Metagenomic Insight Reveals the Microbial Structure and Function of the Full-Scale Coking Wastewater Treatment System:Gene-Based Nitrogen Removal

Microbial communities play crucial roles in pollutant removal and system stability in biological systems for coking wastewater(CWW)treatment,but a comprehensive understanding of their structure and functions is still lacking.A five month survey of four sequential bioreactors,anoxic 1/oxic 1/anoxic 2/oxic 2(A1/O1/A2/O2),was carried out in a full-scale CWW treatment system in China to elucidate operational performance and microbial ecology.The results showed that A1/O1/A2/O2 had excellent and stable performance for nitrogen removal.Both total nitrogen(TN;(17.38±6.89)mgL1)and ammonium-nitrogen(NH4 t-N;(2.10±1.34)mg·L^(-1))in the final biological effluent satisfied the Chinese national standards for CWW.Integrated analysis of 16S ribosome RNA(rRNA)sequencing and metagenomic sequencing showed that the bacterial communities and metagenomic function profiles of A1 and O1 shared similar functional structures,while those of A2 significantly varied from those of other bioreactors(p<0.05).The results indicated that microbial activity was strongly connected with activated sludge function.Nitrosospira,Nitrosomonas,and SM1A02 were responsible for nitrification during the primary anoxic-oxic(AO)stage and Azoarcus and Thauera acted as important denitrifiers in A2.Nitrogen cycling-related enzymes and genes work in the A1/O1/A2/O2 system.Moreover,the hao genes catalyzing hydroxylamine dehydrogenase(EC 1.7.2.6)and the napA and napB genes catalyzing nitrate reductase(EC 1.9.6.1)played important roles in the nitrification and denitrification processes in the primary and secondary AO stages,respectively.The mixed liquor suspended solids(MLSS)/total solids(TS),TN removal rate(RR),total organic carbon(TOC)(RR),and NH_(4)^(+)t-N(RR)were the most important environmental factors for regulating the structure of core bacterial genera and nitrogen-cycling genes.Proteobacteria were the potential main participants in nitrogen metabolism in the A1/O1/A2/O2 system for CWW treatment.This study provides an original and comprehensive understanding of the microbial community and functions at the gene level,which is crucial for the efficient and stable operation of the full-scale biological process for CWW treatment.

A review of CFD simulation in pressure driven membrane with fouling model and anti-fouling strategy

Pressure-driven membrane filtration systems are widely utilized in wastewater treatment,desalination,and water reclamation and have received extensive attention from researchers.Computational fluid dynamics(CFD)offers a convenient approach for conducting mechanistic studies of flow and mass transfer characteristics in pressure-driven systems.As a signature phenomenon in membrane systems,the concentration polarization that accompanies the permeation process is a key factor in membrane performance degradation and membrane fouling intensification.Multiple fouling models(scaling,biofouling and colloidal particle fouling)based on CFD theory have been constructed,and considerable research has been conducted.Several representative antifouling strategies with special simulation methods,including patterned membranes,vibration membranes,rotation membranes,and pulsatile flows,have also been discussed.Future studies should focus on refining fouling models while considering local hydrodynamic characteristics;experimental observation tools focusing on the internal structure of inhomogeneous fouling layers;techno-economic model of antifouling strategies such as vibrational,rotational and pulsatile flows;and unfavorable hydraulic phenomena induced by rapidly changing flows in simulations.

RIM21基因缺失对拉格啤酒酵母絮凝性能的影响

拉格啤酒酵母是我国啤酒酿造的主要菌种。细胞絮凝是啤酒酵母重要的生产性状,在不影响发酵性能的情况下适度提高酵母的絮凝能力,有助于发酵结束时细胞和产物的分离,有利于工业化啤酒生产,具有较高的经济价值。前期在对一株工业用拉格啤酒酵母G03及其絮凝突变株的研究中,挖掘到一个可能影响啤酒酵母絮凝性的候选基因RIM21。为了验证该基因的作用,文中在G03中对RIM21进行了敲除,发现RIM21敲除后,酵母在11℃发酵条件下的絮凝性能增强,基因FLO5、Lg-FLO1及细胞壁完整性途径中的部分基因表达上调。同时,CO2失重、酒精度、发酵度等发酵指标未有明显变化。另外,发现RIM21的缺失增强了啤酒酵母对细胞壁抑制剂的耐性。研究结果为阐释低温发酵条件下啤酒酵母的絮凝调控机理及菌株絮凝性的改善提供了基础。

Biosorption of clofibric acid and carbamazepine in aqueous solution by agricultural waste rice straw

Due to their widespread use, clofibric acid （CA） and carbamazepine （CBZ） have been frequently detected simultaneously at relatively high concentrations in aquatic environments. In this study, agricultural waste rice straw was employed as a potentially low-cost, effective and easy-to-operate biosorbent （RSB） to remove CA and CBZ. The adsorption of both pharmaceuticals followed pseudo second-order kinetics, and intraparticle diffusion was an important rate-limiting step. The adsorption isotherms of both drugs were fit well with Freundlich model. The adsorption of CA onto RSB was exothermic and was more likely to be dominated by physical processes, while the adsorption of CBZ was endothermic. Solution pH was determined to be the most important factor for CA adsorption, such that the adsorption capacity of CA onto RSB increased with the decline of solution pH. In the lower range of solution pH below 3. l, the CA removal efficiency was enhanced with the increase of biosorbent dosage. The CBZ removal efficiency was enhanced with the increase of RSB dosage without pH control. The maximum adsorption capacities were 126.3 mg/g for CA and 40.0 mg/g for CBZ.

Critical review of perovskites-based advanced oxidation processes for wastewater treatment: Operational parameters, reaction mechanisms,and prospects

In the field of advanced oxidation processes(AOPs) of wastewater, many materials can be used as heterogeneous catalysts. The role of these catalysts is to activate oxidants and generate reactive oxygen species(ROS) to decompose refractory pollutants. Perovskite oxide, an emerging catalyst in the field of AOPs, has been extensively studied in wastewater treatment. Nevertheless, the application of perovskite in AOP systems still faces some problems, such as leaching of metal ions, a small surface area, a low number of active sites, etc. Herein, this critical review comparatively examines the activation mechanisms of peroxymonosulfate, hydrogen peroxide, and peroxydisulfate. Furthermore, the formation pathways of oxidizing species based on recent advances in experimental and theoretical studies were evaluated. In addition, the impacts of water parameters and constituents such as initial p H, oxidant concentration, catalyst dosage,natural organic matter, halide, phosphate, and carbonate were discussed. Finally, a critical discussion and prospects of mechanism exploration and possible materials development are proposed to confront the existing challenges in the application of perovskite oxides in AOPs.

Technologies for pollutant removal and resource recovery from blackwater:a review

Blackwater(BW),consisting of feces,urine,flushing water and toilet paper,makes up an important portion of domestic wastewater.The improper disposal of BW may lead to environmental pollution and disease transmission,threatening the sustainabie development of the world.Rich in nutrients and organic matter,BW could be treated for resource recovery and reuse through various approaches.Aimed at providing guidance for the future development of BW treatment and resource recovery,this paper presented a literature review of BWs produced in different countries and types of toilets,including their physiochemical characteristics,and current treatment and resource recovery strategies.The degradation and utilization of carbon(C),nitrogen(N)and phosphorus(P)within BW are underlined.The performance of different systems was classified and summarized.Among all the treating systems,biological and ecological systems have been long and widely applied for BW treatment,showing their universality and operability in nutrients and energy recovery,but they are either slow or ineffective in removal of some refractory pollutants.Novel processes,especially advanced oxidation processes(AOPs),are becoming increasingly extensively studied in BW treatment because of their high efficiency,especially for the removal of micropollutants and pathogens.This review could serve as an instructive guidance for the design and optimization of BW treatment technologies,aiming to help in the fulfilment of sustainable human excreta management.

Carbamazepine degradation by heterogeneous activation of peroxymonosulfate with lanthanum cobaltite perovskite:Performance,mechanism and toxicity

The widely used carbamazepine(CBZ)is one of the most persistent pharmaceuticals and suffers insufficient removal efficiency by conventional wastewater treatment.A synthesized Co-based perovskite(LaCoO3)was used to activate peroxymonosulfate(PMS)in order to degrade CBZ.Results showed that LaCoO3 exhibited an excellent performance in PMS activation and CBZ degradation at neutral pH,with low cobalt leaching.The results of FT-IR and XPS verified the high structurally and chemically stability of LaCoO3 in PMS activation.Electron spin resonance(ESR)analysis suggested the generation of radical species,such as sulfate radicals(SO4·-)and hydroxyl radicals(·OH).Radical quenching experiments further revealed the responsibility of SO4·-as the dominant oxidant for CBZ oxidation.Ten products were detected via the oxidation of CBZ,with the olefinic double bond attacked by SO4·-as the initial step.Hydroxylation,hydrolysis,cyclization and dehydration were involved along the transformation of CBZ.The toxicity of CBZ solution was significantly reduced after treating by PMS/LaCoO3.

2D-material-integrated whispering-gallery-mode microcavity

Optical microcavities, which support whispering gallery modes, have attracted tremendous attention in both fundamental research and potential applications. The emerging of two-dimensional materials offers a feasible solution to improve the performance of traditional microcavity-based optical devices. Besides, the integration of two-dimensional materials with microcavities will benefit the research of heterogeneous materials on novel devices in photonics and optoelectronics, which is dominated by the strongly enhanced light–matter interaction.This review focuses on the research of heterogeneous two-dimensional-material whispering-gallery-mode microcavities, opening a myriad of lab-on-chip applications, such as optomechanics, quantum photonics, comb generation, and low-threshold microlasing.

Effect of nitrate concentration on filamentous bulking under low level of dissolved oxygen in an airlift inner circular anoxic-aerobic incorporate reactor

This laboratory research investigated a possible cause of filamentous bulking under low level of dissolved oxygen conditions （dissolved oxygen value in aerobic zone maintained between 0.6-0.8 mgO2 /L） in an airlift inner-circular anoxic-aerobic reactor. During the operating period, it was observed that low nitrate concentrations affected sludge volume index significantly. Unlike the existing hypothesis, the batch tests indicated that filamentous bacteria （mainly Thiothrix sp.） could store nitrate temporarily under carbon restricted conditions. When nitrate concentration was below 4 mg/L, low levels of carbon substrates and dissolved oxygen in the aerobic zone stimulated the nitrate-storing capacity of filaments. When filamentous bacteria riched in nitrate reached the anoxic zone, where they were exposed to high levels of carbon but limited nitrate, they underwent denitrification. However, when nonfilamentous bacteria were exposed to similar conditions, denitrification was restrained due to their intrinsic nitrate limitation. Hence, in order to avoid filamentous bulking, the nitrate concentration in the return sludge （from aerobic zone to the anoxic zone） should be above 4 mg/L, or alternatively, the nitrate load in the anoxic zone should be kept at levels above 2.7 mg NO-3N/g SS.

Characteristics of dynamic membrane filtration:structure,operation mechanisms,and cost analysis

Dynamic membrane technology represents a promising substitution for conventional membrane bioreactor system,which owns the merits of flexible and comparably cheap materials,easy for backwash,good antifouling property,etc.It has been over half a century since the principle of dynamic membranes was first reported,whereas the development and popularization are still limited.This paper makes a review on characteristics of dynamic membranes,including development and application,mechanism,structure and materials,operation conditions,membrane fouling,dynamic membrane cleaning,and cost analysis,attempting to give clues on promotions and perspectives exhibited of this technology.

Macrophage-evading and tumor-specific apoptosis inducing nanoparticles for targeted cancer therapy

Extended circulation of anticancer nanodrugs in blood stream is essential for their clinical applications.However,administered nanoparticles are rapidly sequestered and cleared by cells of the mononuclear phagocyte system(MPS).In this study,we developed a biomimetic nanosystem that is able to efficiently escape MPS and target tumor tissues.The fabricated nanoparticles(TM-CQ/NPs)were coated with fibroblast cell membrane expressing tumor necrosis factor(TNF)-related apoptosis inducing ligand(TRAIL).Coating with this functionalized membrane reduced the endocytosis of nanoparticles by macrophages,but increased the nanoparticle uptake in tumor cells.Importantly,this membrane coating specifically induced tumor cell apoptosis via the interaction of TRAIL and its cognate death receptors.Meanwhile,the encapsulated chloroquine(CQ)further suppressed the uptake of nanoparticles by macrophages,and synergized with TRAIL to induce tumor cell apoptosis.The vigorous antitumor efficacy in two mice tumor models confirmed our nanosystem was an effective approach to address the MPS challenge for cancer therapy.Together,our TM-CQ/NPs nanosystem provides a feasible approach to precisely target tumor tissues and improve anticancer efficacy.

Zero-valent iron doped carbons readily developed from sewage sludge for lead removal from aqueous solution

Low-cost but high-efficiency composites of iron-containing porous carbons were prepared using sewage sludge and ferric salts as raw materials. Unlike previous time- and energy-consuming manufacturing procedures, this study shows that pyrolyzing a mixture of sludge and ferric salt can produce suitable composites for lead adsorption. The specific surface area, the total pore volume and the average pore width of the optimal composite were 321 m^2/g, 0.25 cm^3/g, and 3.17 nm, respectively. X-ray diffraction analysis indicated that ferric salt favored the formation of metallic iron, while Fourier transform infrared spectroscopy revealed the formation of hydroxyl and carboxylic groups. The result of batch tests indicated that the adsorption capacity of carbons activated with ferric salt could be as high as 128.9 mg/g, while that of carbons without activation was 79.1 mg/g. The new manufacturing procedure used in this study could save at least 19.5 k J of energy per gram of activated carbon.

Construction and application of the Synechocystis sp.PCC6803-ftnA in microbial contamination control in a coupled cultivation and wastewater treatment

Inspired by iron fertilization experiments in HNLC（high-nitrate, low-chlorophyll） sea areas,we proposed the use of iron-rich engineered microalgae for microbial contaminant control in iron-free culture media. Based on the genome sequence and natural transformation system of Synechocystis sp. PCC6803, ftn A（encoding ferritin） was selected as our target gene and was cloned into wild-type Synechocystis sp. PCC6803. Tests at the molecular level confirmed the successful construction of the engineered Synechocystis sp. PCC6803-ftn A. After Fe3＋-EDTA pulsing, the intracellular iron content of Synechocystis sp. PCC6803-ftn A was significantly enhanced, and the algae was used in the microbial contamination control system. In the coupled Synechocystis sp. PCC6803-ftn A production and municipal wastewater（MW, including Scenedesmus obliquus and Bacillus） treatment, Synechocystis sp. PCC6803-ftn A accounted for all of the microbial activity and significantly increased from 70% of the microbial community to 95%.These results revealed that while the stored iron in the Synechocystis sp. PCC6803-ftn A cells was used for growth and reproduction of this microalga in the MW, the growth of other microbes was inhibited because of the iron limitation, and these results provide a new method for microbial contamination control during a coupling process.