Due to toxicity inhibition and high external carbon costs, anaerobic/anoxic/oxic technologies for coking wastewater require efficient, low-carbon alternatives. Here we develop a strategy to effectively enhance the autotrophic nitrogen removal process in coking wastewater through a phased addition of diatomite porous material and an inorganic electron donor. Under long-term operation, diatomite increased biomass by 86% and induced micro-granular sludge with an average size of 196 μm. Nitrogen removal pathway analysis showed a shift from heterotrophic to autotrophic mode. Ultimately, SCN-- and FeS2-driven autotrophic denitrification contributed 25.6% and 27.9%, respectively. Enrichment of autotrophic sulfur-oxidizing nitrate-reducing bacteria, such as Sulfuritalea and Sulfurisoma, provided strong evidence. Additional pyrite supplementation ultimately increased total nitrogen removal from 77.7% to over 94.0% without external carbon. This study enhanced the in-situ autotrophic process of conventional systems for coking wastewater, offering a cost-effective pathway for energy-saving and carbon-reduction goals.

To address the challenges of low prediction accuracy and limited generalization capability in forecasting complex water quality at refineries, this study proposes a novel hybrid neural network model (CBG). This model integrates convolutional neural networks, bidirectional long short-term memory networks, and grey wolf optimization algorithms. The CBG model demonstrates excellent accuracy in predicting key pollutants such as chemical oxygen demand (COD), oil, and ammonia nitrogen (NH3-N). Its correlation coefficients reach 0.95, 0.89, and 0.91 respectively, and the nash sutcliffe efficiency coefficients stand at 0.91, 0.79, and 0.83 respectively, which are significantly superior to those of other benchmark models. Additionally, the study innovatively developed a comprehensive warning water quality index (WWQI). This index, together with the CBG model, forms an integrated prediction and warning framework that triggers alerts when water quality indices exceed pre-set thresholds. This framework provides a valuable tool for the early detection and proactive intervention of risks within the water systems of integrated refining and petrochemical enterprises. This study holds significant practical implications for enhancing water resource utilization and maintaining the stability of production operations. By providing intelligent early warning and proactive risk management tools, this research contributes to improving the operational safety and resource efficiency of industrial water circulation systems. This comprehensive approach provides a clear, quantifiable method for forward-thinking, science-based decision-making in water systems management for integrated refining and petrochemical enterprises, ultimately helping to drive more sustainable industrial practices.

Greenhouse gas (GHG) emissions from various household wastewater management systems were an important component of global GHG emissions, but there was still a lack of country-level GHG emission. In this study, global scale GHG emissions were estimated in a relatively comprehensive system boundary based on the revised emission factors. Firstly, the proportion of safely treated household wastewater varied by region, with most of this being processed through wastewater treatment plants. Then, the total global GHG emissions amounted to 519 MtCO2e, with an average intensity of 1.94 kgCO2e/m3. There were huge differences in GHG emissions and intensity between different countries. Due to differences in the factors affecting GHG emissions and intensity, high-GHG-intensity countries were entirely distinct from high-GHG-emissions countries. In various wastewater management systems, on-site septic tanks had the highest GHG intensity while wastewater treatment plants had the highest GHG emissions. Due to high emissions and potential for emission reductions from wastewater treatment plants, through technological improvements and sustainable management, household wastewater management could be carbon neutral as early as 2056, while in the baseline scenario, 627 MtCO2e would be emitted by 2060. This study revealed the GHG emissions from household wastewater management and offered crucial theoretical pathway towards carbon peaking and neutrality.

The treatment of air pollutants in iron and steel industry was crucial for environmental protection, but this process generated GHG emissions. This study adopted the emission factor approach to assess the spatiotemporal variation and future trends of GHG emissions from air pollutants treatment in the global steel industry. In 2019, global GHG emission from air pollutants treatment in iron and steel industry reached 5.37×109 kg CO2e in 2019, comparable in scale to GHG emissions from wastewater and waste treatment. Among these, SO2 treatment accounted for the largest source of GHG emissions. Spatially, Asia accounted for 91

To reconcile the resource recovery and decarbonization trade-off in industrial wastewater treatment while meeting the United Nations Sustainable Development Goals, this study deciphers the operational mechanisms of globally representative steel-industry net-zero-liquid discharge (NZLD) system (220 m3/h) to propose a hierarchical four-stage framework. We reveal that Cl-/SO42- competition dynamically regulates nanofiltration membrane selectivity, while establishing quantitative links between oxygen atom signatures of dissolved organics and product purity. An experimentally-derived salinity-driven trade-off emerges: high salt levels enhance ion separation but suppress organic degradation due to radical scavenging. Life cycle impact assessment pinpoints carbon hotspots and demonstrates an 81.8% footprint reduction via renewable electricity. Under modelled scenarios, scaling this framework to treat China’s annual 1.50 billion m3 applicable Na+/Cl-/SO42--dominated high-salinity wastewater could potentially recover 1.43 billion m3 water, 8.11 million tonnes NaCl, and 5.09 million tonnes Na2SO4, saving USD 3.68 billion annually. This strategy provides a transferable blueprint for low-carbon resource recovery globally. Huaqiang Chu and colleagues propose a hierarchical four-stage framework based on a full-scale facility to optimize net-zero-liquid discharge and resource recovery from industrial wastewater. They reveal salinity-driven trade-offs between membrane separation and organic degradation, while renewable electricity reduces the system’s carbon footprint by 81.8%.

The biological treatment of coking wastewater faces challenges due to high toxicity, high nitrogen loading, and excessive carbon demand. This study comprehensively investigated the pollutant removal performance, microbial community diversity, and metabolic functions of 14 full-scale coking wastewater treatment systems (CWWs) in China, aiming to explore pollutant removal mechanisms to reduce environmental impacts. The dominant functional microorganisms exhibit significant variations across different CWWs. The core autotrophic sulfur-oxidizing denitrifiers Thiobacillus and Arcobacter drive the sulfur-driven autotrophic denitrification process, leading to higher nitrogen removal in mixotrophic systems. Deterministic factors influence microbial community structures, which can enable targeted community structure regulation. Based on sulfide-based pollutants such as thiocyanates, the contribution of sulfur-driven autotrophic denitrification processes to CWWs was revealed. By optimizing the allocation of electron donors, the construction of mixotrophic nitrogen removal systems can improve nitrogen removal efficiency while reducing carbon inputs and greenhouse gas emissions.

The steel industry faces dual challenges of extensive CO2 emissions and intricate wastewater management. This study investigated a novel microalgal platform using Chlorella pyrenoidosa for simultaneous CO2 utilization and valorization of cold-rolling emulsion wastewater. Optimal biomass production (1.80 ± 0.07 g/L) was achieved at 5 % CO2, whereas 20 % CO2 caused severe inhibition of growth and carbon fixation. Mechanistic investigation revealed that 20 % CO2 triggered systemic energy restriction, evidenced by depleted intracellular ATP and downregulated metabolic pathways (TCA cycle, oxidative phosphorylation). Furthermore, essential energy was diverted to counteract oxidative and acidification stress, upregulating multiple DNA repair pathways. Concurrently, 20 % CO2 triggered metabolic overflow that actively rerouted 16.8 % of carbon towards extracellular organic matter. A regulatory nexus was established: energy restriction drove overall inhibition, while energy reallocation induced carbon flow alteration. These insights provide a theoretical basis for engineering microalgae with enhanced tolerance for industrial carbon utilization and bioresource recovery.

Microalgae-based biogas slurry treatment systems, which possess the dual capability of assimilating nutrients and sequestering CO2, are widely recognized as a promising technology. However, the complex composition of biogas slurry hinders microalgal metabolic activity and limits the system’s efficiency. In this study, a novel microbubbles-assisted Fe-C micro-electrolysis (MFC) system was proposed for biogas slurry pretreatment to overcome the bottleneck of utilizing microalgae in biogas slurry treatment. The MFC system significantly improved the electron transfer rate, which facilitated the oxidation of Fe(II) to Fe(III) and achieved self-accelerating coagulation, increasing the removal efficiencies of dissolved organic matter (DOM) and turbidity to 37.3% and 94.9%, respectively. The results revealed that rapid oxidation and continuous perturbation by microbubbles caused the formation of more single-corner coordination between FeO6 octahedrons, as well as inhibited the transformation of hydrotalcite to the highly crystalline mineral. The accumulation of hydrotalcite significantly enhances the adsorption of specific types of DOM by forming a more stable structure in the flocs. In addition, the MFC system effectively removed stressors (e.g., humic-like substances, aromatic compounds, and residual iron ions) of microalgae in biogas slurry and increased the maximum quantum conversion efficiency (Fv/Fm) of the photosynthetic system from 0.455 to 0.556. Consequently, the biomass of microalgae cultured in the biogas slurry treated by the MFC system was increased by 42.7% compared to the conventional Fe-C micro-electrolysis (CFC) system. Overall, this study demonstrates that MFC-driven oxidative synergistic self-accelerating coagulation is a promising process for the stabilization and sustainability of microalgae-based biogas slurry treatment.

Coking wastewater contains a complex mixture of organic substances that are challenging to decompose,including phenols,polycyclic aromatic hydrocarbons(PAHs),and nitrogen-containing heterocyclic compounds(NHCs).These pollutants pose potential threats to the ecological environment and are notoriously difficult to remove via traditional wastewater treatment technologies.In recent years,considerable attention has been directed towards developing more efficient methods for treating coking wastewater.This review provides a comprehensive overview of current advancements in coking wastewater treatment technologies,focusing on their sources,characteristics,pretreatment technologies,biochemical treatments,and advanced treatment technologies.Pretreatment technologies,such as chemical precipitation and biological treatment,are widely employed to remove these pollutants like oil,grease,and heavy metals.Biochemical treatment processes,including A/O and A2/O systems,effectively reduce COD and NH4+-N levels,yet show limited effectiveness in degrading refractory organics.Advanced treatment technologies,such as membrane separation and ozone-catalyzed oxidation,show promise in further improving treatment efficiency.Innovations in anti-fouling membranes have significantly extended membrane lifespans and reduced the risk of increased costs and operational interruptions caused by frequent cleaning.Furthermore,this review discusses the zero-discharge strategies for coking wastewater,emphasizing the importance of technologies aimed at reducing energy consumption and enhancing efficiency.Integrated processes can facilitate resource recovery while minimizing environmental impacts.Future research will focus on reducing energy consumption,improving resource recovery and reuse,and optimizing treatment processes to achieve green and low-carbon treatment of coking wastewater.By advancing these areas,researchers aim to unlock a more sustainable future for this critical sector.Collaboration between scientists and engineers will be essential for developing novel materials and catalysts that enhance reaction efficiencies while reducing costs.For instance,self-regenerating catalysts in ozone-catalyzed oxidation could significantly lower replacement frequencies and expenses,offering a practical pathway to cost-effective wastewater treatment.Optimization of process integration is equally crucial;intelligent combination of treatment steps can minimize energy consumption while maximizing resource recovery.A notable example is the coupling anaerobic digestion with membrane bioreactors,which can simultaneously produce biogas as an energy source and generate purified water for reuse.Moreover,the integration of digital technologies such as artificial intelligence(AI)and the Internet of Things(IoT)promises to revolutionize coking wastewater treatment.Real-time monitoring and control enabled by these technologies can streamline operations,ensuring optimal use of energy and resource.Through these advancements,the journey toward a more sustainable and efficient treatment process for coking wastewater will be accelerated,benefitting both the environment and industry.

Membrane wettability is crucial for filtration performance when treating feedwater containing inorganic particles, organic macromolecules, and microorganisms. Superhydrophilic membranes excel in resisting fouling during filtration, while superhydrophobic membranes are prized for their self-cleaning properties during maintenance. To address these contrasting needs, we herein propose a novel strategy by developing membranes with switchable superhydrophilicity and superhydrophobicity, enabling on-demand antifouling and self-cleaning. This membrane was created by electrodepositing copper oxides onto a copper mesh, resulting in the formation of hierarchical micro- and nanoscale structures. By applying a reduction voltage of -20 V, the copper oxides were converted into hydrophilic metallic copper, transforming the mesh into a superhydrophilic membrane. This transformation not only facilitated water permeation but also effectively repelled foulants during filtration. Remarkably, the gravity-driven permeation flux of the superhydrophilic membrane reached as high as 30,000 L·m-2·h-1. Furthermore, this superhydrophilic membrane demonstrated reasonable separation efficiency, achieving removal rates of 60.0% for total suspended solids, 93.1% for Melosira, and 83.0% for poly(vinyl alcohol). Upon heating at 100 °C for 1 h, the membrane surface reverted to a superhydrophobic state, enabling self-cleaning during membrane maintenance. With its facile preparation and smart electro- and thermo-responsive properties, this copper-based membrane, featuring reversibly switchable wettability, holds great promise for scalable applications in water treatment.

Livestock wastewater (LW) is characterized by the significant presence of organic matter, nitrogen (N), and phosphorus (P), as well as heavy metals (HMs), antibiotics, endocrine disruptors (EDCs), microplastics (MPs), and antibiotic resistance genes (ARGs). Microalgae-based technologies present a promising alternative for the bioremediation of LW, as they can efficiently eliminate pollutants while simultaneously utilizing renewable resources. However, microalgae-based LW treatment in remediating multiple contaminants of emerging concern (CECs) has been comprehensively evaluated by few articles. Consequently, the impact of inhibitory components in LW on microalgae and the response of microalgae to such exposure remain unclear. This review provides a critical and updated overview of the potential use of microalgae as LW bioremediation agents for the simultaneous removal of conventional pollutants and CECs. Several models and algorithms have been suggested as viable approaches for improving microalgal growth through the optimization of cultivation parameters. The effects of the inhibitory components in LW on microalgae and the removal mechanisms of hazards were comprehensively illustrated, highlighting the behavior of CECs (e.g., antibiotics, EDCs, MPs, and ARGs). Moreover, conventional and cutting-edge strategies for improving the performance of microalgae-based LW treatment, including pretreatment, optimization of the cultivation mode and light, genetic engineering, random mutagenesis, and microalgae-microbial fuel cells, were further discussed. Furthermore, perspectives for further improvement were proposed. Importantly, research should focus on verifying the specific removal mechanisms of CECs at the cellular level, distinguishing the combined effect of pollutants in LW, optimizing multi-objective microalgae-based LW treatment, and developing more sustainable and user-friendly strategies.

Zero liquid discharge (ZLD) strategy provides significant potential for industrial brine treatment. Still, the application has been constrained by the inadequate water recovery and membrane fouling of its membranebased brine concentration system. Herein, a pilot-scale system was established that integrated pretreatment, reverse osmosis (RO), nanofiltration (NF), and disk tube reverse osmosis (DTRO), and demonstrated over a 6-month operation for the first application in treating steel industry brine. Meanwhile, novel insights were offered into the spatial evolution of DTRO membrane fouling. The overall ZLD system reached ultra-efficient water recovery at 91% with relatively low energy consumption (7.27 kWh/m(3)). The RO and NF units concentrated the brine and selectively separated ions of different valences, simultaneously eliminating various contaminants. The DTRO unit enriched the highly saline NF permeate with a remarkable 7.5-fold concentration effect, producing an extremely hypersaline brine salinity (138,472 +/- 34,804 mg/L, Cl-/SO42- mass ratio of 56) that ultimately yielded ultra-pure NaCl salt. Additionally, DTRO special fouling patterns revealed a distinctive "W"-shaped fluctuation in humic acid along the device water flow, with concurrent reduction in iron/aluminum oxides leading to their deposition at the outlet. This synergistic fouling, coupled with silicon, coincides with the transformation of silica colloids into silicate compounds. The multistage membrane-based strategy and the spatial membrane fouling evolution pattern proposed and investigated in this work provide a highly efficient and cost-effective solution for industrial brine treatment with ZLD.

Membrane separation technology has emerged as a highly energy-efficient method for microalgae enrichment and harvesting in wastewater treatment. However, membrane fouling caused by algal cells and stratified extracellular polymeric substances (EPS) remains a critical barrier to its industrial-scale application. This study meticulously investigates the micro process of algae-derived pollutants stacking to the membrane surface affected by stratified EPS. The fouling process resulting from algal cell particle deposition and cake layer formation are clearly simulated using a semi-coupled computational method of Computational Fluid Dynamics (CFD)-Discrete Element Method (DEM) for the first time. The results reveal that the hydrophilic component and spatial network structure of soluble EPS (S-EPS) effectively impede the algae-membrane adhesion, and enable the algal cake layer exhibit "dynamic membrane" characteristic to enhance the organic matter retention. In contrast, bound EPS (B-EPS) with higher protein content exhibits a stronger fouling potential and adhesion tendency of algal cells. The influence of stratified EPS on the variation of thermodynamic interaction with contact scale in the sphere-plane/sphere-sphere model is inventively conducted. Based on different algal cell filtration modes, a sequential increase in the eigenvalue n was observed by delaminating EPS layer by layer, indicative of a more severe membrane pore blockage. The semi-coupled CFD-DEM method provides a quantitative analysis of the deposition process, offering spatial resolution and force analysis for algal-derived pollutants. Additionally, we propose a novel calculation method to reverse the deposition process based on the particle stress, providing a valuable reference for simulating membrane-based microalgae harvesting under the influence of stratified EPS.

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) mgL-1) and ammonium-nitrogen (NH4+-N; (2.10 +/- 1.34) mgL-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 NH4+-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.

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.

Based on microalgae biological treatment technology, the microalgae-bacteria symbiosis system can not only efficiently realize sewage recycling, but also utilize the interactions between microalgae and bacteria to enhance the pollutant removal capacity of the treatment system and recover synthetic biomass. Bacterial-algal symbiotic systems can also be coupled with CO_2 fixation, and the combination of high CO_2 concentration in industrial flue gas for microalgae cultivation can simultaneously achieve carbon reduction and reduce the energy consumption of additional aeration of microalgae to supplement CO_2, which is in line with the development needs of "carbon neutral" . This article presents a systematic introduction of the mechanism, interaction forms and influencing factors of bacterial-algal symbiotic system in wastewater treatment and resource recovery process, and a summary of the potential of bacterial-algal engineering in pollutant degradation, CO_2 fixation and recovery of microalgal biomass products. The study of nutrient exchange, information transfer and genetic adaptation between bacteria and algae reveales that the selection of suitable symbiotic bacteria and algae combination culture can effectively enhance the pollutant removal and CO_2 fixation efficiency in wastewater. The effect of symbiosis on the accumulation of biological components (protein, lipid, carbohydrate, etc.) of algae is enhanced and selective. The selection of algae species and corresponding symbiotic bacteria, the adjustment of inoculation ratio and culture conditions can improve the efficiency of industrial scale harvesting of microalgae and further processing of biofuel and medical health food products. Bacterial-algal symbiosis is coupled with wastewater treatment, CO_2 fixation and biomass energy recovery in one. This article presents a critical review of development and progress of wastewater treatment and resource recovery surrounding microalgae-bacteria consortia. The development of the synthetic multi-functional system based on the consortium facilitates building an integrated sewage treatment and resource recovery processing mode featuring in low-carbon, economical and sustainable.

Coking wastewater is typical industrial wastewater produced in the process of coal coking. The notion of Zero Liquid Discharge (ZLD) presents a paradigm aimed at mitigating waste generation and optimizing resource recovery. However, the implementation of ZLD in the realm of industrial wastewater treatment remains inadequately investigated and researched. We undertook an investigation into a ZLD treatment system applied to coking wastewater within a steel plant, which had been in operation for a span of four years, where the core steps are membrane concentration separation and thermal crystallization. The treatment efficiency of each unit was studied using the method of on-site sampling and detection. In comparison to the initial phase, the separation effectiveness of NF unit on different valence ions demonstrated sustained stability, the average rejection rate of SO42− was approximately 96%, whereas the rejection rate of Cl− was near 0. Conversely, under the influence of long-term operation and membrane fouling, the efficiency of the membrane concentration unit had a downward trend, with problems such as the deterioration of membrane, loss of ion rejection capability, and degradation of reclaimed water. The water recovery rate has decreased to 48.9% and the average ion retention rate has decreased to 85% in the membrane concentration unit. Nonetheless, the resultant by-products continued to align with the steel plant's recycling requirements. In addition, the Life cycle Assessment (LCA) method was used to assess environmental impact during operation. Subsequent analysis led to that reagents and electricity consumed in pretreatment and advanced treatment had a significant impact for negative EI. The impact of pretreatment on ODP accounted for 27.64%, and the impact on ADP accounted for 20.72%. The impact of advanced treatment on ADP accounted for 16.25%, the impact on EP accounted for 21.74%, and the impact on ET accounted for 27.06%. Meanwhile, the recovered water and salt during operation generate considerable environmental benefits and dominate the evaluation of the entire operating process. This work furnishes a valuable point of reference for pertinent ZLD investigations, while unveiling the pronounced capacity of ZLD to contribute substantially to waste management and the betterment of environmental consequences.

炼焦行业是水污染物排放的主要行业之一,国家和地方已开始高度关注其水污染排放标准.为了解我国炼焦行业废水排放的标准体系,围绕污染物控制和管理水平改善目标,系统研究了美国、欧盟、日本等国家与我国炼焦行业废水的污染物排放标准,从排放标准的建立体系、排放限值等方面进行了对比分析.结果表明,国外相关标准的执行有很强的法律支撑;日本地方政府在标准实施中具有很强的能动性;美国及欧盟将排放限值与处理技术相结合,且排放要求更加严格.结合我国现行标准体系提出了以下几点建议:提高相关废水处理技术,积极推进最佳可行技术(Best Available Technology,BAT)体系建设,及时更新排放标准和加强相关标准法律效力,以期为焦化废水排放和污染物控制提供依据,为我国炼焦行业减排方案制定和废水排放标准的修订与实施工作提供参考.

The establishment of a multi-stage membrane system that integrates different membrane technologies has been regarded as an essential process in industry brine recycling. Although membrane fouling has been intensively studied, in particular, on single membrane unit at the lab-scale, the actual fouling behavior in multi-stage integrated pilot systems has not yet been fully understood. In this study, membrane fouling was systematically investigated in a pilot-scale RO-NF process by monitoring the surface properties of fouling layer and the deposition behavior of foulants. Distinct spatial fouling variation along the flow direction of the multi-stage integrated system was observed. At the first stage of the RO process, severe fouling occurred on the membrane surface under the synergistic interaction of several organic and inorganic foulants, resulting in a rough and thick cake layer. The membrane fouling at the second RO stage became less severe. During the following NF process, the amounts of metal oxides/hydroxides and organic foulants depositing on the membrane surface decreased. The results indicated that the foulants firstly deposited on the front stage of the integrated RO-NF process. Overall, the observations for spatially varied membrane fouling help to advance understanding of membrane technologies to achieve zero liquid discharge in the steel industry.

反渗透工艺在世界范围内广泛应用于海水淡化、废水处理和医药生产等领域.计算流体力学(CFD)的模拟能描述出多种流体的流动、传质和传热等相关物理过程,可以在反渗透膜组件的模拟中可视化流体流动情况和膜污染情况,对膜组件的设计与应用过程具有指导意义.文中综述了卷式反渗透膜组件中的流道隔网优化和膜污染过程的CFD模拟研究进展,以及一些特殊形式膜组件中CFD的应用可行性和成果,并提出了CFD模拟应用于优化反渗透膜性能可能的研究方向.