Publications by authors named "Nan Qi Ren"

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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  • 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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  • 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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Ethane, the second most abundant gaseous hydrocarbon in vast anoxic environments, is an overlooked greenhouse gas. Microbial anaerobic oxidation of ethane can be driven by available electron acceptors such as sulfate and nitrate. However, despite nitrite being a more thermodynamically feasible electron acceptor than sulfate or nitrate, little is known about nitrite-driven anaerobic ethane oxidation.

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Article Synopsis
  • Overusing antibiotics has led to their presence in water, affecting tiny living things that help remove pollution.
  • A study found that a specific antibiotic called ciprofloxacin (CIP) made it much harder for these helpers, known as denitrifiers, to do their job, leading to more pollution emissions.
  • The denitrifiers tried to protect themselves from damage caused by CIP, using special pathways for energy, but they still couldn't completely stop the harm from the antibiotic.
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Sulfate-dependent ammonium oxidation (Sulfammox) is a critical process linking nitrogen and sulfur cycles. However, the metabolic pathway of microbes driven Sulfammox is still in suspense. The study demonstrated that ammonium was not consumed with sulfate as the sole electron acceptor during long-term enrichment, probably due to inhibition from sulfide accumulation, while ammonium was removed at ∼ 10 mg N/L/d with sulfate and nitrate as electron acceptors.

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Medium-chain fatty acids (MCFAs) production from waste activated sludge (WAS) by chain extension (CE) is a promising technology. However, the effects and mechanisms of CE process on the fate of antibiotic resistance genes (ARGs) remain unclear. In this study, the results showed that the removal efficiency of ARGs was 81.

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Nitrate/nitrite-dependent anaerobic methane oxidation (n-DAMO) process is a promising wastewater treatment technology, but the slow microbial growth rate greatly hinders its practical application. Although high-level nitrogen removal and excellent biomass accumulation have been achieved in n-DAMO granule process, the formation mechanism of n-DAMO granules remains unresolved. To elucidate the role of functional microbes in granulation, this study attempted to cultivate granules dominated by n-DAMO microorganisms and granules coupling n-DAMO with anaerobic ammonium oxidation (Anammox).

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Ciprofloxacin (CIP) has received considerable attention in recent decades due to its high ecological risk. However, little is known about the potential response of macrophytes and microbes to varying levels of CIP exposure in constructed wetlands. Therefore, lab-scale manganese ore-based tidal flow constructed wetlands (MO-TFCWs) were operated to evaluate the responses of macrophytes and microbes to CIP over the long term.

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Microplastics (MPs) pollution has emerged as a global concern, and wastewater treatment plants (WWTPs) are one of the potential sources of MPs in the environment. However, the effect of polyethylene MPs (PE) on nitrogen (N) removal in moving bed biofilm reactor (MBBR) remains unclear. We hypothesized that PE would affect N removal in MBBR by influencing its microbial community.

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The widespread use of microplastics (MPs) has led to an increase in their discharge to wastewater treatment plants. However, the knowledge of impact of MPs on macro-performance and micro-ecology in simultaneous nitrification, denitrification, and phosphorus removal (SNDPR) systems is limited, hampering the understanding of potential risks posed by MPs. This study firstly comprehensively investigated the performance, species interactions, and community assembly under polystyrene (PS) and polyvinyl chloride (PVC) exposure in SNDPR systems.

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A limited understanding of microbial interactions and community assembly mechanisms in constructed wetlands (CWs), particularly with different substrates, has hampered the establishment of ecological connections between micro-level interactions and macro-level wetland performance. In this study, CWs with distinct substrates (zeolite, CW_A; manganese ore, CW_B) were constructed to investigate the nutrient removal efficiency, microbial interactions, metabolic mechanisms, and ecological assembly for treating rural sewage with a low carbon-to-nitrogen ratio. CW_B showed higher removal of ammonia nitrogen and total nitrogen by about 1.

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