Publications by authors named "Nan-Qi Ren"

The production of waste leachate (WL) has been increasing annually with the growth of population and the improvement of living standards, but it has become a difficult task to treat and resource it. Furthermore, the shortage of energy is becoming more serious, so the development of renewable energy instead of expensive fossil fuels is especially essential for productive life. This study constructed a system to oxidize WL by ozone at different temperatures and used it as a culture substrate for microalgae to produce biodiesel.

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Sulfate-reducing bacteria (SRB) are anaerobic microorganisms that use sulfate as a terminal electron acceptor for the oxidation of organic compounds or H. These organisms can cause a serious problem in, for example, the offshore oil industry, due to the production of sulfide. Thus, it is of fundamental and practical importance to identify potent and selective inhibitors of SRB.

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Denitrifying anaerobic methane oxidation (DAMO) processes have been proven effective for nitrogen removal while contributing to the sustainable operation of wastewater treatment plants. However, it remains unclear whether DAMO-centric technologies can simultaneously remove nitrous oxide (NO). Here, we demonstrated high removal performance of nitrite and NO with methane as the electron donor over a prolonged period.

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Deciphering and mitigating dynamic greenhouse gas (GHG) emissions under environmental fluctuation in urban drainage systems (UDGSs) is challenging due to the absence of a high-prediction model that accurately quantifies the contributions of biological production pathways. Here we infused biological production pathways into the graph neural network (GNN) model architecture, developing ecological knowledge-infused GNN (EcoGNN-GHG) models to evaluate methane (CH) and nitrous oxide (NO) production in sewers and wastewater treatment plants (WWTPs). The EcoGNN-GHG model demonstrated high predictive accuracy, achieving an of 0.

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Chemicals of emerging concern (CECs) pose critical threats to both public health and the environment, emphasizing the urgent need for effective water treatment measures. Yet, the implementation of such intervention technologies often results in increased energy consumption and adverse environmental consequences. Here, we employ a comprehensive methodology that integrates multiple datasets, assumptions, and calculations to assess the human health and environmental implications of removing various CECs from source water.

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Carbon chain elongation offers a promising pathway for converting waste resources into caproate. However, challenges in yield and selectivity have limited its broader application. To address these limitations, anaerobically digested sludge-derived biochar (ADS-B) was incorporated into the carbon chain elongation process.

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Controlling the spread of antibiotic-resistance genes (ARGs) under antibiotic stress has become an increasingly urgent issue. Microalgae possess the capability to remove antibiotics while concurrently inhibiting ARGs. Microalgae-bacteria systems can produce significant quantities of extracellular polymeric substances (EPS).

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Manganese (Mn), abundant in the Earth's crust, can act as an oxidant or a reductant for diverse nitrogen biotransformation processes. However, the functional microorganisms and their metabolic pathways, as well as interactions, remain largely elusive. Here, a microbial consortium was enriched from a mixture of freshwater sediments and activated sludge by feeding ammonium, nitrate and Mn(II), which established manganese-driven co-removal of nitrate and ammonium with removal rates of 5.

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The microalgal-bacterial consortium (MBC) system is recognized as an advanced approach for nitrogen and phosphorus removal in wastewater treatment. However, the influence of microalgae on bacterial community dynamics and niche differentiation across varying seasonal conditions remains unexplored. In this study, we established a pilot-scale continuous-flow MBC system to disentangle, for the first time, the impact of microalgae on seasonal bacterial community succession by conducting monthly time-series sampling over a full seasonal cycle.

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Both mechanical models and machine learning-based models are widely utilized for real-time dynamic control; however, their implementation in the water sector often incurs significant data and computational costs. To address these challenges, this study introduces an innovative feature extraction method designed to enhance the cost-effectiveness of dynamic control in wastewater treatment plants. The proposed method extracts dynamic features from time-series data of key substrate variables to construct a data-driven model and develop real-time control strategies.

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Lignocellulosic biomass (LCB) is expected to play a critical role in achieving the goal of biomass-to-bioenergy conversion because of its wide distribution and low price. Biomass fermentation is a promising method for the sustainable generation of biohydrogen (bioH) from the renewable feedstock. Due to the inherent resistant structure of biomass, LCB needs to be pretreated to improve its digestibility and utilization.

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The dissemination of antibiotic resistance genes (ARGs) poses global environmental issues, and plasmid-mediated conjugation contributes substantially to the spread of ARGs. Quorum sensing (QS), an important cell-cell communication system that coordinates group behaviors, has potential as a feasible regulation pathway to inhibit the conjugation process. We examined the promoting effects of QS signal on conjugation, and this study is the first to report that QS inhibitors 2(3H)-benzofuranone and acylase I effectively repressed conjugation frequency of RP4 plasmid to 0.

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Anaerobic microorganisms are critical in regulating ethane in geothermal environments, where selenate and selenite are common contaminants. Although coupling ethane oxidation with selenate reduction has been demonstrated as feasible, such processes remain poorly explored in geothermal environments. This study addressed this gap by successfully enriching thermophilic anaerobic cultures capable of coupling ethane oxidation with selenate/selenite reduction, achieving selenate and selenite removal rate of 2.

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The carbon-neutral target presents a significant challenge for the sewage sludge treatment and disposal (SSTD) industry, necessitating strategic planning for a low-carbon transition. However, flexible and comprehensive carbon emission analysis tools to support this goal remain lacking. This study presents a carbon emission analysis tool to evaluate the carbon emission characteristics and future mitigation potentials of SSTD.

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Article Synopsis
  • The study investigated how nano-magnetite improves dissimilatory iron reduction (DIR) in sewage, specifically focusing on the formation of vivianite, a common product of DIR.
  • Incorporation of nano-magnetite increased the abundance of beneficial bacteria like Comamonas and Geobacter and significantly boosted microbial protein content during the DIR process.
  • The findings highlighted nano-magnetite's role in enhancing electron transfer by creating conductive pathways, promoting vivianite recovery, and advancing the understanding of mineral-microbe interactions in nutrient recovery.
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Global monitoring of persistent organic pollutants (POPs) has intensified following regulatory efforts aimed at reducing their release. In this context, we compiled over 10,000 POP measurements, reported from 1980 to 2023, to assess the effectiveness of these legislative measures in the global marine environments. While a general decreasing trend in legacy POP concentrations is evident across various maritime regions, highlighting the success of source control measures, the Arctic Ocean and its marginal seas have experienced a rise in POP levels.

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Heavy metal pollution in the cold region is serious, affecting human health and aquatic ecology. This study investigated the ability of microalgae to remove heavy metals (HMs) and produce lipid at low temperature. The removal efficiency of different HMs (Cd, Cu, Cr and Pb), cell growth and lipid synthesis of microalgae were analyzed at 15 °C.

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Article Synopsis
  • The Integrated Fixed-Film Activated Sludge (IFAS) system enhances the traditional activated sludge process by combining the benefits of attached and suspended sludge for improved nutrient removal.
  • A study utilized metagenomic analysis to evaluate the roles of attached sludge (AS) and suspended sludge (SS), revealing that AS is crucial for nitrogen (N) reduction, while SS plays a significant role in phosphorus (P) release and uptake.
  • Key findings highlighted that AS has higher levels of nitrate and nitrite reductase activity, whereas SS exhibits more activity in phosphatase enzymes, with different microbial communities and gene expressions affecting N and P removal efficiencies in the IFAS system.
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Article Synopsis
  • Plastics aging decreases resistance to microbial degradation, and the mealworm Tenebrio molitor can biodegrade polystyrene (PS) effectively, but how aging affects this process is not well-studied.
  • In a 24-day study, various pre-treatments (freezing with UV, UV only, and freezing) were used on PS microplastics, resulting in slightly better PS consumption and mass reduction compared to pristine PS.
  • The study found that while aging treatments slightly improved PS biodegradation, they significantly affected the gut microbial diversity of the mealworms and their metabolic pathways, showing their capacity to adapt to altered PS plastics.
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The report demonstrated that a member of cockroach family, Blaptica dubia (Blattodea: Blaberidae) biodegraded commercial polystyrene (PS) plastics with M of 20.3 kDa and M of 284.9 kDa.

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The aim of this study was to investigate the effects of various concentrations of antioxidants, including butyl hydroxy anisd (BHA), butylated hydroxytoluene (BHT), fulvic acid (FA), melatonin (MT), glycine betaine (GB) and putrescine (Put), on growth and lipid synthesis of microalgae under low-temperature (15 ℃). Changes in biochemical indicators, reactive oxygen species (ROS) level, glutathione (GSH) content and antioxidant enzyme activities were also studied. The results indicated that the maximum biomass concentration (1.

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The main pressing problems should be solved for heterogeneous catalysts in activation of peroxymonosulfate (PMS) are sluggish mass transfer kinetics and low intrinsic activity. Here, oxygen vacancies (Vo)-rich of CoO nanosheets were anchored on the superficies of spirulina-based reduced graphene oxide-konjac glucomannan (KGM) aerogel (R-CoO/SRGA). The porous structure and superhydrophilicity conferred by KGM maximized the diffusion and transport of reactant.

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Applied voltage is a crucial parameter in hybrid microbial electrolysis cells-anaerobic digestion (MEC-AD) systems for enhancing methane production from waste activated sludge (WAS). This study explored the impact of applied voltage on the initial biofilm formation on electrodes during the MEC-AD startup using raw WAS (Rr) and heat-pretreated WAS (Rh). The findings indicated that the maximum methane productivity for Rr and Rh were 3.

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In recent years, there has been significant interest in photocatalytic technologies utilizing semiconductors and photosensitizers responsive to solar light, owing to their potential for energy and environmental applications. Current efforts are focused on enhancing existing photocatalysts and developing new ones tailored for environmental uses. Anthraquinones (AQs) serve as redox-active electron transfer mediators and photochemically active organic photosensitizers, effectively addressing common issues such as low light utilization and carrier separation efficiency found in conventional semiconductors.

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