Low-carbon Sources Research Articles

Neutronics design of shutdown and control systems for a Zero Power Experiments of chloride-based molten salt fast reactor.

Nuclear power's role as a reliable, baseload, low-carbon source and its importance in achieving clean energy goals are being increasingly recognized with growing urgency around decarbonization of the global energy systems. However, to deliver a long-term sustainable solution, it is essential to develop innovative nuclear technologies for improving the fuel utilization and reducing the nuclear waste disposal challenge. Zero Power Reactors (ZPR) are an essential initial step for developing new nuclear technologies because they allow for testing and refinement in a safe environment before large-scale deployment. This paper discusses the design of a ZPR experiments for the development of iMAGINE, a novel chloride-based molten salt reactor technology. The paper presents a detailed analysis of the neutronic design for the shutdown and control systems of an experimental ZPR based on the iMAGINE molten salt reactor technology. The study concludes that a split-core design with a lower corner reflector as an extension of the lower annular reflector offers the most robust ZPR configuration, offering optimum operational margins and maneuverability. This design ensures safety, regulatory compliance, and sufficient control and shutdown performance for the successful development of the iMAGINE technology.

The Slow Pace of Green Transformation: Underlying Factors and Implications

Concerns about climate change are a hot topic in the current debate about a sustainable future, and despite more than 30 years of international conferences, including the Intergovernmental Panel on Climate Change (IPCC) and the United Nations Climate Change Conference (COP), the annual usage amount of fossil fuel-based energy sources has remained largely unchanged, and the green transition to a carbon-free energy system is progressing at a much slower pace than anticipated. This paper presents an original approach that consists in addressing the green transition’s dilemmas by analyzing the complex interplay of strongly interwoven forces hindering the rapid adoption of so-called green energy sources scrutinized from a three-fold perspective: socio-psychological; political–strategic and territorial; and technological. Moreover, these forces are ranked according to the magnitude of their impact on the anticipated transition to green, and it is estimated by logistic fit extrapolation that the total share of the contribution of low-carbon sources might reach a maximum of about 25% among all energy sources in 2050. A final original picture is presented, summarizing how all the involved forces are acting upon the expected transition as well as their consequences.

Should We Have Selfish Microgrids?

Substantial breakthroughs in renewable energy have been made in order to reduce energy-induced climate change. Yet our reliance on these sources is still insufficient. The UK’s objective of attaining net-zero emissions by 2050 is highly dependent on shifting to an electrical system that exclusively relies on zero-carbon generation. This entails integrating renewable energy sources, along with other low-carbon sources such as nuclear power, into the energy mix. However, the primary barrier to incorporating additional renewable energy sources into the grid is their intermittent and volatile nature. Therefore, there is a pressing need to stabilise the generation of renewables and manage this volatility by enhancing the balancing mechanism between microgrids and the national grid. This paper examines previous research on microgrids and smart grids, specifically from a supply chain perspective. It has been observed that the majority of the current literature focuses on documenting selfish microgrids that strive to optimise performance at the microgrid level. However, there is an alternative approach that draws inspiration from the field of supply chain management. Consequently, it is possible to enhance a microgrid’s performance within the broader system that it belongs to by reconsidering the timing and location of storage utilisation.

Performance of bio-nest by modified basalt fiber carriers on the enhanced remediation of low-carbon and -nitrogen urban black-smelling water

ABSTRACT Biological contact oxidation reactors employing modified basalt fiber (MBF) were constructed to systematically investigate the impact of various hydraulic retention times (HRTs) and aeration durations on nitrogen and phosphorus removal in low carbon and polluted river water. The experimental findings underscored that configuring the HRT to 36 h and maintaining an aeration ratio of 1:2 yielded the most favorable outcomes for the removal of COD, NH4+ -N, total nitrogen (TN), and TP from synthetic low carbon, source-polluted river water. Detailed microbial sequencing elucidated the predominant bacterial phylum within the MBF reactor, identified as Proteobacteria. The dominant genera encompassed Pseudomonas, Aeromonas, and SM1A02. This microbial composition, marked by a high abundance of denitrifying genera, corroborated the robust denitrification capacity exhibited by the MBF reactors. The orchestrated combination of optimal operational parameters and the prevalence of key microbial taxa substantiate the efficiency of MBF reactors in effectively mitigating nitrogen and phosphorus in low carbon source river water.

Fast as a plane, clean as a train? Prospective life cycle assessment of a hyperloop system

Today, options to reduce the climate impacts of high-speed passenger transport over hundreds of kilometres are limited to using low-carbon synthetic fuels in aviation and high-speed trains. In the future, alternatives like battery electric airplanes might be available. Further, vehicles operating in near-vacuum tubes, so-called “hyperloop systems”, could represent an alternative. Our first-of-its-kind environmental life cycle assessment (LCA), considering its construction, operation, and end-of-life, shows that such a hyperloop system is energy-efficient and can exhibit very low greenhouse gas emissions (<8 g CO2/pkm) if low-carbon sources provide electricity for its operation and relatively high occupation rates can be realised. The environmental performance of a hyperloop system can be regarded as very similar to that of a train offering the same transport service. Compared to air travel, environmental burdens can be substantially reduced (<5% impact on climate change compared to conventional aircraft). This fundamental finding holds despite uncertainties regarding technical properties and design choices, which reflect the current development status of the hyperloop.

Energy transition in Poland and Spain against changes in the EU energy and climate policy

The European Union climate policy and the subsequent energy transition are expected to cause fundamental changes in individual EU countries, their economies, and industrial sectors. Furthermore, in order to achieve them, high financial outlays are essential. The main purpose of the article is to present a comparative analysis of the pace, directions, and main factors of the energy transition in Poland and Spain against the changes in the EU energy and climate policy. In particular, the subject of the study is the changes in the fuel structure of electricity generation (energy mix) and the changes in the concentration of energy generation. The analysis concentrates on Poland and Spain against the background of the group of EU27 countries. The study adopted a long-term perspective (1990–2020). The methodology used taxonomic measures of variability of structures and measures of concentration, as well as measures of descriptive and mathematical statistics. The result of the research proves that the EU common climate and energy policy has explicitly accelerated changes in the energy mix, both in the EU27 and in the studied countries, including those traditionally based on coal. The concentration analysis demonstrated an increase in diversification resulting in a significant increase in the share of renewable and low-carbon sources. The taxonomic analysis additionally proved that there was a parallel process towards making the energy mix of the studied countries more similar to the EU27. The limitation of the research is the adopted triangulation arrangement of the studied structures (EU27, EU15, countries that accessed the EU after 2004), enforced in this pilot research, but possible to expand the field of perception in subsequent research. What serves as a proof of the originality of the study is the fulfilment of research gaps in the long-term study of the degree of changes in the concentration of the energy mix structure of EU countries, and especially the study of the degree of intensity of its similarity. The application value of the study is its use in the energy policies of countries traditionally based on coal for the indication of the taken position, the goals, and ways to achieve them based on the experience of other countries.

Revealing the impacts of intermittent aeration on nitrogen and phosphorus removal in powder carrier system from interfacial thermodynamics and metagenomic analysis

Intermittent aeration strategy has attracted significant attention due to its benefits of low oxygen and carbon source consumption. However, the feasibility of intermittent aeration in the powder carrier process and its effect on micro-granule formation remain unclear. This study investigated the impacts of intermittent aeration on the powder carrier system through interfacial thermodynamics and metagenomic analysis. The results demonstrated that total nitrogen removal efficiency increased from 61.1 ± 2.6 % to 89.7 ± 3.7 % under intermittent aeration, while the PO43-–P removal efficiency increased from 47.6 ± 4.7 % to 81.6 ± 3.9 %. The interfacial free energy of micro-granules was reduced from –4.85 mJ/m2 to –16.03 mJ/m2 due to aeration mode, resulting in a larger micro-granule size (185.24 ± 15.25 μm) and enhanced aggregation ability. Significant enhancements in tryptophan-like substances and hydrophobic functional groups (β-sheet, protonated amines, and C-(C/H)) in EPS under intermittent aeration likely contributed to the increased hydrophobicity and reduced interfacial free energy. The abundances of norank_NS9_marine_group (4.17 %), norank_Comamonadaceae (4.57 %), and Terrimonas (3.44 %) were increased, further driving the synergy of nitrogen removal of simultaneous partial nitrification and denitrification and endogenous denitrification. Correlation analysis confirmed that intermittent aeration primarily affected gene expression involved in the partial nitrification process, and that denitrification genes were enriched by increased hydrophobic components and micro-granule size. These results provide deeper insights into the key influencing factors and mechanisms of the powder carrier system, and offer a theoretical basis for process optimization.

Microstructural, Electrical, and Tribomechanical Properties of Mo-W-C Nanocomposite Films.

This study investigates the phase composition, microstructure, and their influence on the properties of Mo-W-C nanocomposite films deposited by dual-source magnetron sputtering. The synthesised films consist of metal carbide nanograins embedded in an amorphous carbon matrix. It has been found that nanograins are composed of the hexagonal β-(Mo2 + W2)C phase at a low carbon source power. An increase in the power results in the change in the structure of the carbide nanoparticles from a single-phase to a mixture of the β-(Mo2 + W2)C and NaCl-type α-(Mo + W)C(0.65≤k≤1) solid-solution phases. The analysis of electrical properties demonstrates that the nanograin structure of the films favours the occurrence of hopping conductivity. The double-phase structure leads to a twofold increase in the relaxation time compared to the single-phase one. Films with both types of nanograin structures exhibit tunnelling conductance without the need for thermal activation. The average distance between the potential wells produced by the carbide nanograins in nanocomposite films is approximately 3.4 ± 0.2 nm. A study of tribomechanical properties showed that Mo-W-C films composed of a mixture of the β-(Mo2 + W2)C and α-(Mo + W)C(0.65≤k≤1) phases have the highest hardness (19-22 GPa) and the lowest friction coefficient (0.15-0.24) and wear volume (0.00302-0.00381 mm2). Such a combination of electrical and tribomechanical properties demonstrates the suitability of Mo-W-C nanocomposite films for various micromechanical devices and power electronics.

The operating temperature affects the efficiency and pathogenic risk of wastewater treatment enhanced by slurry

The insufficient availability of carbon sources in low carbon source wastewater has consistently hampered the nitrogen removal efficiency. This study explored the potential of using anaerobic digested slurry supernatant as an additional carbon source and examined the cost-effective temperature range. The results demonstrated that wastewater treatment within the temperature range of 28 °C to 38 °C could meet the discharge standards set by wastewater treatment plants. However, at 38 °C, the nitrogen-to-carbon consumption ratio decreased to 0.18 g N/g COD. Mechanistic analysis revealed that both excessively high and low temperatures reduced the diversity of microbial communities and influenced the composition of the microbial community through environmental selective pressures. Thauera, Acidovorax, Syntrophomonas, and Acidaminobacter were identified as the dominant genera for nitrogen removal at the temperature of 38 °C, 33 °C, 28 °C, and 23 °C, respectively. Furthermore, high temperature enhanced nitrogen removal performance by promoting microbial activity, microbial transmembrane substance transport process, and the abundance of key genes (HK, pgi1, pfkB, narG, narH, narI) at 38 °C. Importantly, factor score analysis confirmed that the risk of microbial pathogenicity was relatively low at 28 °C. This work provides valuable insights into the optimal temperature parameters and regulatory mechanisms for wastewater treatment systems utilizing slurry as a carbon source. It provides innovative ideas for the clean and safe development of low carbon source wastewater treatment technologies.

France's National Energy-Climate Plan: Critical presentation

France's National Energy-Climate Plan (PNEC), presented in October 2023, is structured around the Multiannual Energy Program (PPE) and the National Low-Carbon Strategy (SNBC). These documents describe France's energy and climate strategies for the next dec- ade, aiming for carbon neutrality by 2050 and a significant reduction in greenhouse gas emis- sions by 2030 (-50% compared to 1990). The plan focuses on increasing the share of renew- able energies and nuclear power, while reducing fossil fuel consumption. By 2030, 58% of energy consumption should come from low-carbon sources. The plan recognizes that there are a number of unanswered questions, such as how to guarantee sufficient flexibility, and how to determine the necessary investment in electricity grids. In addition, electricity market reform and the fight against energy poverty are essential elements in ensuring a just transition, a particularly sensitive subject in France since the Yellow Vests crisis.

Climate therapy: Developing a climate change charter for Cancer Trials Ireland (CTI).

e23214 Background: Climate change is a threat to human existence. Healthcare is the 5th leading cause of CO2 emissions globally, while clinical trials generate the equivalent of half the CO2 emissions of Denmark. Consequently, both enterprises represent significant, potentially modifiable, causes of climate change. In response to this climate toxicity (PMID 36773799), CTI launched the National Green Cancer Clinical Trials Initiative in 2022. A climate charter, which was to consist of a living document of actionable areas, was commissioned by the CTI board to implement them. Methods: Carbon footprint touch points of CTI’s activity on climate change were identified such as travel, procurement, energy use, financial management. An online scoping review of existing academic and non-academic sustainability initiatives, funding agency and national policy documents, peer reviewed and grey literature sources was conducted using the terms climate change and sustainability. Action points were categorised and collated. No exemplar climate charters for clinical trial organisations were identified in the search. Results: 5 pillars of interaction with sustainability initiatives were evident. These were education, engagement, empowerment, embedding, and emphasising. These pillars related to 8 themes for climate smart involvement by CTI staff and members. Personal commitment to sustainability at an individual level eg dietary choices, EU climate pact participation. Trial design and management eg sustainability assessment &amp; integration into protocols Recycling and waste management at central office and sites. Energy and water use eg optimise computing infrastructure, prioritise low carbon sources. Procurement and contracts eg promote green purchasing, integrate environmental and social sustainability clauses in contracts, sustainability assessment of financial services including pensions Meetings and conferences eg prioritising virtual meetings, select conference venues and accommodation with environmental certs. Commuting and business travel. Outreach eg, to University partners, trainees, network with Green Trial groups. Conclusions: The climate charter provides a structure to facilitate sustainability integration at CTI. This living document registers existing activities, highlights areas for engagement, facilitates horizon scanning and outreach to emerging initiatives, empowers staff , and demonstrates an organisational commitment to climate smart, clinical trial conduct.

Optimizing solar powered electrokinetic remediation of chromium contaminated groundwater: One step closer to a sustainable solution

Electrokinetic remediation (EKR) presents a promising solution for addressing soil and groundwater contamination challenges. However, practical viability is hindered by significant energy consumption and related expenses, necessitating a comprehensive sustainability approach beyond solely adopting renewable energy and low-carbon sources. This study aims to merge innovative solar-powered systems with a risk-based evaluation strategy for tackling chromium-contaminated groundwater, providing valuable insights into EKR economically viable and applicable approaches. Through the integration of environmental and electrical engineering expertise, this study introduces the Continuous Solar-powered Electrokinetic Remediation (CSER) system and risk-based energy efficiency (REF) evaluation approach, addressing intermittency issues while optimizing energy generation and minimizing costs. Experimental results demonstrate removal efficiencies ranging from 29.85% to 84.26%, highlighting the impact of intermittent current, voltage boosters, and electrolyte selection on risk reduction and energy consumption. While intermittent current intensifies the focusing phenomenon and reduces contaminant migration, it may offer promising results in specific cases, such as observed in the EK2 experiment. Conversely, the EK3 results reveal that the integration of conventional solar power with a voltage booster may enhance removal rates but often leads to unfavorable outcomes in risk reduction considering related higher energy consumption. However, CSER, with its utilization of constant current, proves more efficient in power generation, risk reduction, and energy usage compared to other systems. Integration of such a system with cost-effective and environmentally friendly chemical agents could significantly increase the REF index while minimizing related costs, thereby shifting EKR remediation techniques towards sustainable solutions for contaminated groundwater worldwide.

A multidisciplinary approach to select wind turbines for power-hydrogen production: Energy, exergy, economic, environmental under uncertainty prediction by artificial intelligence

A promising solution for carbon reduction in energy systems is the use of hydrogen formed by low-carbon sources. Hydrogen production from wind energy not only addresses industrial hydrogen demands but also mitigates environmental and intermittent challenges. In the present study, a novel framework is proposed in which the wind to hydrogen system is evaluated from energy, exergy, economic, environmental (4E), uncertainty aspects, and the best wind turbine is determined using a multi-criteria approach. At first, eight wind turbines are selected for the case study, and the system performance is analyzed from 4E aspects. Furthermore, to assess the uncertainty, the system’s performance is predicted for 3000 years using artificial intelligence, and the project successful probability and economic risk is evaluated using Monte Carlo simulation. The results showed that system’s energy (exergy) efficiency ranges 22–29 % (36–46 %). Additionally, the Levelized Cost of Hydrogen (Payback period) ranges 3.55–3.36 $/kg (6.3 to 9.8 years). Moreover, the proposed system saved 463,872–611,661 m3/yr of natural gas. The Monte Carlo simulation results also showed that the project successful probability ranges 80–93.8 %. Finally, the present framework identified the Gamsa G90 as the best wind turbine for hydrogen production. Overall, the present approach is comprehensive and can be applied for evaluation in other renewable applications.

Low-carbon transition paths and benefits for the power sector at city level: A case study in Zhengzhou, China

The power sector significantly contributes to global greenhouse gas emissions, making its transition to low-carbon energy crucial for achieving carbon neutrality. Zhengzhou, recognized as one of the China's "National Central Cities", has a high energy demand. Its power sector, which is primarily reliant on coal, is responsible for half of the city's CO2 emissions. The low emissions analysis platform (LEAP) model serves as an effective tool for exploring the power sector's transition to low-carbon sources. However, studies on the combined reduction in air pollutants and CO2 at the city level are scarce. This study focuses on Zhengzhou's power sector, examining the power composition, coal usage, CO2 and air pollutant emissions, social costs, and employment effects across five scenarios using LEAP. The five scenarios are the business-as-usual scenario, the reference scenario, the carbon neutrality scenario, and two optimization scenarios with different carbon peak and carbon neutrality time. CO2 emissions will peak in 2030 at 34.6 Mt in the reference scenario, and in 2022 at 32.4 Mt in the carbon neutrality scenario. Emissions in the reference and carbon neutrality scenarios will decrease by 64.8% and 75.2%, respectively, from those in the business-as-usual scenario due to emission reduction strategies. In the carbon neutrality scenario, coal power reformation is the most significant measure, accounting for 45.7% of the total CO2 reduction compared to that in the business-as-usual scenario, followed by the integration of external electricity (17.8%) and solar energy (13.6%). This scenario also demonstrated a strong synergistic effect on reducing air pollutants and CO2 emissions. Although the carbon neutrality scenario incurs costs 60.4 billion yuan higher than those of the reference scenario, its CO2 mitigation cost is 66.1 yuan/t lower. This indicated that more rapid CO2 reduction, despite higher economic inputs, is justified by ambitious CO2 reduction goals and environmental benefits. Enhancing the use of renewable energy technologies for research and development to lower costs could increase the economic feasibility of the carbon neutrality scenario. In the two optimization scenarios, complete elimination of CO2 and air pollutant emissions is achieved by 2060, with all the electricity generated from renewable sources, although issues of uncertainty and stability need to be addressed. The study also highlights that renewable energy development will significantly boost employment, with an estimated 1.19 million jobs in 2060 in the carbon neutrality scenario. Finally, the paper concludes with a sensitivity analysis and offers policy recommendations for the power sector's low-carbon transition.

Loofah sponge crosslinked polyethyleneimine loaded with biochar biofilm reactor for ecological remediation of oligotrophic water: Mechanism, performance, and functional characterization

The removal of complex pollutants from oligotrophic water is an important challenge for researchers. In this study, the HCl-modified loofah sponge crosslinked polyethyleneimine loaded with biochar (LS/PEI@biochar) biofilm reactor was adapted to achieve efficient removal of complex pollutants in oligotrophic water. On the 35 d, the average removal efficiency of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), calcium (Ca2+), and phosphate (PO43--P) in water was 51, 95, 81, and 77 %, respectively. Additionally, it effectively used a low molecular weight carbon source. Scanning electron microscopy (SEM) results showed that the LS/PEI@biochar biocarrier had superior biofilm suspension performance. Meanwhile, analysis of the biocrystals confirmed Ca2+ and PO43- removal through the generation of CaCO3 (calcite and vaterite) and Ca5(PO4)3OH. This study demonstrated that the system has great efficiency and application prospect in treating oligotrophic water on the laboratory scale, and will be further validated for practical application on large-scale oligotrophic water.

Comprehensive carbon footprint analysis of wastewater treatment: A case study of modified cyclic activated sludge technology for low carbon source urban wastewater treatment

To reduce pollution and carbon emissions, a quantitative evaluation of the carbon footprint of the wastewater treatment processes is crucial. However, micro carbon element flow analysis is rarely focused considering treatment efficiency of different technology. In this research, a comprehensive carbon footprint analysis is established under the micro carbon element flow analysis and macro carbon footprint analysis based on life cycle assessment (LCA). Three wastewater treatment processes (i.e., anaerobic anoxic oxic, A2O; cyclic activated sludge technology, CAST; modified cyclic activated sludge technology, M-CAST) for low carbon source urban wastewater are selected. The micro key element flow analysis illustrated that carbon source mainly flows to the assimilation function to promote microorganism growth. The carbon footprint analysis illustrated that M-CAST as the optimal wastewater treatment process had the lowest global warming potential (GWP). The key to reduce carbon emissions is to limit electricity consumption in wastewater treatment processes. Under the comprehensive carbon footprint analysis, M-CAST has the lowest environmental impact with low carbon emissions. The sensitivity analysis results revealed that biotreatment section variables considerably reduced the environmental impact on the LCA and the GWP, followed by the sludge disposal section. With this research, the optimization scheme can guide wastewater treatment plants to optimize relevant treatment sections and reduce pollution and carbon emissions.

Techno-Economical Assessment for Combined Production of Hydrogen, Heat, and Power from Residual Lignocellulosic Agricultural Biomass in Huesca Province (Spain)

Nowadays, great emphasis is rightly given in the scientific community to hydrogen production from electrolysis. However, to achieve the politically stated target ambitions, all low-carbon sources for hydrogen production must be considered. The present work proposes a local production system of negative carbon hydrogen from lignocellulosic residual biomass using gasification and gas separation through H2-selective membranes as enabling technologies. The feedstock is pruning. In addition, the system produces heat and power for a Renewable Energy Community (REC) to increase the economic feasibility of hydrogen production via their sale. A modular basic plant is sized, based on a simplified system envisaged for RECs under the current regulatory framework in Spain (electrical renewable output of 100 kW). A network of these modular basic plants in the province of Huesca (Aragón) is simulated to create a system of hydrogen refueling stations for mobility in that area. A Levelized Cost of Hydrogen (LCOH) is proposed, comprehending the whole production chain from “field to tank”, which is significant in areas where there is no infrastructure for the production and distribution of hydrogen for automotive purposes. The resulting LCOH for the whole system is 8.90 EUR/kg. Sensitivity analysis potentially values a lower LCOH, which unveils that hydrogen mobility can be largely competitive with diesel one.

Tax Regulation of Countries in the Framework of Greening Business (using the example of the Russian Federation and the EU)

In the past three decades, the role of environmental protection in the environmental and climate agenda, which shapes the trends of “green” economic development, has been continuously increasing. The purpose of this study is to examine this issue in the context of the experience of the European Union (EU) and regulatory principles of taxation to prevent the effects of climate change. Using the example of the EU and the Russian Federation, the reaction of a system for economic regulation of greenhouse gas emissions, which is at the initial stage, is considered. A SWOT-analysis of Russia’s “green” exports to the EU countries has been carried out, which contains forecasts of a decline in demand for Russian oil and oil products, coal, gas and metals and an increase in demand for electricity from low-carbon sources. Taking into account the extremely high carbon intensity of all Russian exports and its product and country structure, it is suggested that notable damage may occur after 2026 if the Carbon Border Adjustment Mechanism (CBAM) expands its product mix and scope. In the presence of significant risks for the Russian Federation in the context of hydrogen energy development, the drivers for increasing competitiveness and the corresponding positions of our country in the conditions of decarbonization are determined, PEST-analysis of the Russian economy on the way to the “green” market course is carried out. The practical significance of the study lies in the proposal to use the experience of tax regulation in the EU countries as part of greening business in the Russian economy.

Isolation and application of Bacillus thuringiensis LZX01: Efficient membrane biofouling mitigation function and anti-toxicity potential

Significant progress has been made in mitigating membrane biofouling by microbial quorum quenching (QQ). More efficient and survivable QQ strains need to be discovered. A new strain named Bacillus thuringiensis LZX01 was isolated in this study using a low carbon source concentration “starving” method from a membrane bioreactor (MBR). LZX01 secreted intracellular lactonase to enable QQ behavior and was capable of degrading 90 % of C8-HSL (200 ng/mL) within 30 min, which effectively delayed biofouling by inhibiting the growth of bacteria associated with biofouling and improving the hydrophilicity of bound extracellular polymeric substances. As a result, the membrane biofouling rate of MBR adding LZX01 was four times slower than that of the control MBR. Importantly, LZX01 maintains its QQ activity even in environments contaminated with typical toxic pollutants. Therefore, with high efficiency, toxicity resistance, and easy culture, LZX01 holds great potential and significant promise for biofouling control applications.

The synthesis of ectoine enhance the assimilation of ammonia nitrogen in hypersaline wastewater by the salt-tolerant assimilation bacteria sludge

In contrast to nitrification-denitrification microorganisms that convert ammonia nitrogen in hypersaline wastewater into nitrogen for discharge, this research utilizes sludge enriched with salt-tolerant assimilation bacteria (STAB) to assimilate organic matter and ammonia nitrogen in hypersaline wastewater into ectoine - a biomass with high economic value and resistance to external osmotic pressure. The study investigates the relationship between the synthesis of ectoine and nitrogen removal efficiency of STAB sludge in three sequencing batch reactors (SBR) operated at different salinities (50, 75, and 100 g/L) and organic matter concentrations. The research reveals that, under low concentration carbon sources (TOC/N = 4, NH4+-N = 60 mg/L), the ammonia nitrogen removal efficiency of SBR reactors increased by 14.51 % and 17.25 % within 5 d and 2 d, respectively, when salinity increased from 50 g/L to 75 g/L and 100 g/L. Under high concentration carbon sources (TOC/N = 8, NH4+-N = 60 mg/L), the ammonia nitrogen removal efficiency of STAB sludge in the three reactors stabilized at 80.20 %, 76.71 %, and 72.87 %, and the total nitrogen removal efficiency was finally stabilized at 80.47 %, 73.15 %, and 65.53 %, respectively. The nitrogen removal performance by ammonium-assimilating of STAB sludge is more sustainable under low salinity, while it is more short-term explosive under high salinity. Moreover, the intracellular ectoine concentration of STAB sludge was found to be related to this behavior. Empirical formulas confirm that STAB sludge synthesizes ectoine from nutrients in wastewater through assimilation, and intracellular ectoine has a threshold defect (150 mg/gVss). The ectoine metabolism pathways of STAB sludge was constructed using the Kyoto Encyclopedia of Genes and Genomes (KEGG). The ammonia nitrogen in sewage is converted into glutamic acid under the action of assimilation genes. It then undergoes a tricarboxylic acid cycle to synthesize the crucial precursor of ectoine - aspartic acid. Subsequently, ectoine is produced through ectoine synthase. The findings suggest that when the synthesis of intracellular ectoine reaches saturation, it inhibits the continuous nitrogen removal performance of STAB sludge under high salinity. STAB sludge does not actively release ectoine through channels under stable external osmotic pressure.