The treatment of oil-contaminated industrial wastewater remains a critical environmental and economic challenge. This study presents a comprehensive hydrodynamic analysis and design optimization of a horizontal oil-water separator, integrating an automated control system with a theoretical trajectory model for oil droplets. This study develops a mathematical model based on force balance (buoyancy versus drag) under laminar flow conditions to predict droplet trajectories as functions of key hydrodynamic and dimensional parameters: droplet radius, inlet velocity, separator diameter, mass flow rate, and Reynolds number. The model yields explicit expressions for terminal rise velocity, rise time, residence time, and minimum required separator length. Parametric analysis reveals that smaller droplets (50 & micro;m) dictate design requirements: at an inlet velocity of 0.005 m/s, a separator of radius 1.0 m requires a minimum length of 4.55 m to achieve complete separation, corresponding to a residence time of approximately 15 minutes. A critical mass flow rate of 0.5 kg/s is identified, below which buoyancy dominates and above which horizontal advection compromises efficiency. To maintain laminar conditions (Re < 2300), inlet velocity must not exceed 0.015 m/s for a 1.0 m diameter separator. The theoretical length-to-diameter ratio for the design droplet is approximately 2.3; applying a safety factor of 1.5-2.0 yields practical ratios of 3.4-4.6, aligning with industry standards (3:1 to 5:1). Quantitative design guidelines are summarized, including recommendations for separator diameter (>= 1.0 m), maximum inlet velocity (<= 0.015 m/s), and separator compartment sizing.
Anaerobic ammonia oxidation (Anammox) faces challenges in high salinity environments due to inhibited microbial activity, while upflow anaerobic sludge bed (UASB) reactors maintain a higher biomass concentration. To explore how the Anammox-USAB system responds to the high salinity (NaCl) environment, a UASB reactor seeded with heterotrophic nitrification sludge. The salinity was gradually increased from 0 to 40 g NaCl/L. The results show that, when salinity increased from 0 to 15 g NaCl/L, the conversion rate of ammonia nitrogen (NH4+-N) and total nitrogen (TN) decreased by about 25% and 22 %, respectively. At the same time, the ammonium removal load of unit sludge gradually stabilized at about 3.65 mg NH4+-N/g VSS over 10 g NaCl /L. When the salinity gradient increased to 30 g NaCl/L, microorganisms preferentially increased their polysaccharide (PS) content from 5.50 to 8.26 mg/g VSS to resist the high osmotic pressure environment. Notably, extracellular protein increased significantly, from 5.78 to 29.01 mg/g VSS to stabilize the cell structure and maintain metabolic activities at 40 g NaCl/L. With the increase of salinity, some salt-intolerant bacteria were inhibited or killed, resulting in a continuous decline in abundance while the abundance of salt-tolerant bacteria increased. The abundance of dominant species Candidatus Kuenenia and Halomonas increased from 5.97% and 0.53% to 12.29% and 12.17%, respectively. It could be seen that the Anammox-USAB system used the structural adjustment of the microbial itself and community as an adaptive strategy in response to the changes of the high-salinity environment.
In this work, the feasibility of air gap membrane distillation for breaking the butyric acid/water azeotrope is examined. The azeotropic mixture was passed through the set up equipped with a porous, hydrophobic PTFE membrane. The effect of various process variables, including feed temperature, feed flow rate, coolant temperature, coolant flow rate, and air gap width on total permeate flux, selectivity of butyric acid, and permeate and retentate concentration has been studied. Furthermore, EDS and FE-SEM were used to investigate how operating time impacts morphology of membrane. The SEM image of membrane was analysed with ImageJ software to determine the pore size distribution. The experimental findings indicate that the total flux increases from 0.54 to 9.81 kg/m2 h on increasing the feed temperature from 40 degrees C to 80 degrees C mm at air gap width of 3mm. Total flux decreases from 2.75 to 1.01 kg/m2h on increasing air gap width from 3 to 11 mm at flow rate of 4l/min. In addition, the total flux decreases from 0.54 to 0.40 kg/m2 h when the coolant temperature is increased from 4 degrees C to 20 degrees C for air gap of 3 mm. It was observed that the butyric acid selectivity in the permeate was less than one, indicating the higher butyric acid concentration in retentate relative to permeate.
This study focuses on investigating the efficacy of corn bran, serving as a natural biosorbent, in the biosorption of Pb(II) and Cd(II) ions. The FTIR, XRD, SEM, and pHpzc were used to characterize the biosorbent. The aim of examining the impact of contact time, pH, biosorbent dose, initial concentration, and temperature was to thoroughly comprehend how these factors affect the biosorption process. The equilibrium was defined through the Langmuir and the Freundlich isotherm models. The Langmuir model exhibited a satisfactory linear correlation (R2 = 0.999 for Pb and R2 = 0.989 for Cd), than the Frundlich isotherm. At the optimal conditions for each metal, the maximum loading capacity (qmax) was 40.98 mg/g and 29.41 mg/g for Pb(II) and Cd(II) ions, respectively. These results emphasize the possibility of utilizing corn bran as a low-cost and eco-friendly material for removing lead and cadmium ions. The biosorption capacity of lead and cadmium ions in a single system was higher than in a binary system, at optimum conditions. Over 99.18 % and 97.54 % of lead and cadmium ions were successfully recovered through desorption using 0.5M HNO3. The examination of thermodynamic parameters (Delta Ho, Delta So, and Delta Go) suggests that the biosorption process is exothermic, spontaneous, and favorable.
Massive amounts of kitchen wastewater mainly composed of organic colloidal matter is produced by the food service industry. In this study, the performance of nanocomposite membrane incorporated by multi-walled carbon nanotubes (MWCNTs) are evaluated. The effect of non-acidic oxidative reagents (NH4OH:H2O2) and diameter of MWCNTs was studied. Membrane characterization including surface functional groups, porosity and pore size, surface hydrophilicity, and membrane morphology was conducted. The results showed that the higher NH4OH/H2O2 ratio (3:1) introduced more oxygen-containing functional groups on the oxidized MWCNTs (OMWCNTs). The large diameter of MWCNTs (20-30 nm) tend to produce nanocomposite membrane with bigger pore size and the oxidation of MWCNTs has further enhanced the membrane hydrophilicity. The highest membrane water permeability (245.50 L/m(2) h bar) was attained by nanocomposite membrane (M2c) modified by larger diameter OMWCNTs with higher NH4OH/H2O2 ratio (3:1). In terms of kitchen wastewater treatment, all nanocomposite membrane showed improved pollutant rejection for suspended solids (SS) (96.48-98.74%), turbidity (98.88-100%), color (61.54-66.67%), chemical oxygen demand (COD) (28.42-38.92%), and total dissolved solids (TDS) (3.57-36.70%). Besides, the M2c nanocomposite membrane showed the highest antifouling performance compared to other nanocomposite membranes. This enhancement was attributed to the increased surface negative charge and formation of loose foulant layer on the membrane surface.
The hydrodynamic performance optimization of sports water systems is a mandatory consideration to improve the efficiency in sports hydration. In the given research, the concept of nanocomposites structures is proposed as a method of improving fluid delivery and structural integrity of high-performance hydration pipelines in the context of competitive sports environments. We also discuss the application of nano-engineered concrete pipelines created in the research and development of nano-conduits in polymers as portable and submersible sports hydration to inspired by the advances in nano-engineered concrete pipelines to pump fluids on a mass scale. The governing equations of motion are developed using classical shell theory and Hamilton principle and the fluid-structure interactions are modeled according to the framework of Navier Stokes equations. The successful material properties of the nanocomposites are estimated with the assistance of the Mori-Tanaka method. They are determined by taking dynamic simulations, which are based on the numerical techniques such as the differential quadrature method (DQM) and the Newmark method, to the system in response to various loads, such as fluid pressure changes and external dynamic disturbances. Results show nanoparticle reinforcement compound to increase rigidity, reduce peak deflections and augmenting resistance to vibrational instabilities, however the mass of internal fluids has an overwhelming influence on modal behaviors. The parametric studies indicate that the hydrodynamic efficiency is highly dependent on geometrical ratios (thickness/ radius, length/ radius) and boundary conditions and volumes fractions of nanoparticles. The findings indicate that optimized nanocomposite pipelines are applicable to minimize the energy losses incurred in the transportation of fluids, as well as provide structural stability in the dynamic application by athletes in next-generation athletic sports hydration technologies.
Forward osmosis (FO) is an innovative membrane process with growing potential. Mathematical models for predicting water flux in forward osmosis (FO) are valuable for understanding the system behavior and helpful in optimizing the performance. This work explores the relationship between water flux key governing parameters, namely water permeability, solute resistance and mass transfer coefficient which affect the water flux behavior. The influence of these parameters on water flux behavior is analyzed, highlighting how water permeability governs the water transport capacity, solute resistance dictates the rejection of solutes, and the mass transfer coefficient reflects the impact of external boundary layers. For both orientations the membrane active layer faces the feed solution (AL-FS) and the membrane active layer faces the draw solution (AL-DS), water flux increases with an increase in water permeability since water flux is directly proportional to the membrane water permeability as given by the basic flux equations. The mass transfer coefficient, whether on the feed side (AL-FS mode) or on the draw side (AL-DS mode), does not significantly influence the enhancement of water flux associated with increased membrane water permeability. On the other hand, solute resistance has a pronounced effect on the water flux with an increase in water permeability. At higher values of solute resistance, the increase in water flux resulting from enhanced water permeability becomes progressively limited, due to the intensified internal concentration polarization that diminishes the effective osmotic driving force.
This study investigates the effects of ultraviolet (UV) irradiation on the structural, chemical, and performance characteristics of polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs), with and without chemical treatment using hydrogen peroxide (H2O2) or polyethylene glycol (PEG). Membranes were exposed to UV light for 10, 20, and 30 minutes. Characterization techniques including SEM, FTIR, EDS, NMR, and AFM revealed that short-term UV treatment preserved the chemical integrity of the membranes and caused no significant surface damage, especially in chemically pretreated samples. PEG and H2O2 treatments enhanced membrane resistance to UV-induced degradation. Surface hydrophilicity improved with UV exposure, as indicated by reduced water contact angles and increased porosity. The treated membranes exhibited increased permeability 52.6 LMH to 82.3 LMH after 30 minutes of UV exposure, especially in H2O2-modified samples, while maintaining Methylene blue (MB) rejection of 75%. In contrast, PEG-modified membranes showed reduced permeability (from 49.8 LMH to 29.2 LMH) with UV exposure due to partial pore blocking. Mechanical strength varied with treatment, showing slight improvements in H2O2-treated samples and reductions in raw and PEG-treated ones. These findings demonstrate that UV post-treatment, especially when combined with H2O2, provides a clean and effective modification route to enhance PVDF HFMs, leading to improved hydrophilicity, permeability, and stability for water treatment applications.
Algal organic matters (AOMs) generated during algal blooms is known to lead to deterioration of water quality. In this study, the amounts of AOMs produced by two cyanobacteria such as Anabaena sp. and Oscillatoria sp. were measured during their growth, respectively. The results showed that AOM production continued from the exponential growth phase to the death phase. During the death phase, AOM production seemed to be sustained due to intracellular organic matter (IOM) released by dead cells. It was found that the specific UV absorbance (SUVA) values of extracellular organic matter (EOM) were relatively higher than those of IOMs in two algal species. Meanwhile, LC-OCD and XAD analyses were performed to understand the physicochemical characteristics of AOMs produced during the algal growth phases. The XAD analysis indicated that AOMs generated by both algal species had a high proportion of hydrophilic substances compared to hydrophobic and transphilic ones. The LC-OCD analysis showed that the order of high content of main components of AOMs was were high-molecular-weight biopolymers, humic-like substances, and building blocks.
Surface water quality deterioration presents critical challenges for drinking water production in arid regions, where sustainable treatment solutions are essential. This study investigates Opuntia ficus-indica (OFT) mucilage as a natural coagulant aid for turbidity removal from Ain Zada dam water in northeastern Algeria. We systematically evaluated coagulation-flocculation parameters including pH (4-10), four coagulants (aluminum sulfate, aluminum chloride, ferric sulfate, ferric chloride) at 100-500 mg L-1, mixing conditions, settling time, pre-chlorination, and OFT mucilage (10-150 mL). Jar tests on water with 74-201 NTU turbidity revealed mixed organic-inorganic composition (60-70% organic colloids). A key finding is coagulant-specific compatibility with OFT mucilage: aluminum-based coagulants showed significant enhancement (aluminum sulfate improved from 57.69% to 75.77%; aluminum chloride from 68.61% to 81.85% with 10 mL mucilage per liter), while iron-based coagulants exhibited reduced efficiency (ferric sulfate decreased from 76.19% to 70.59%; ferric chloride from 79.62% to 74.43%), indicating fundamentally distinct chemical interactions between metal hydroxide surface chemistry and anionic mucilage polysaccharides. Pre-chlorination enhanced treatment to 82.85% removal while enabling 75% coagulant dose reduction. This work provides mechanistic insights into cactus-derived biopolymer integration in conventional water treatment, establishing design guidelines for sustainable implementation in arid regions where Opuntia ficus-indica is abundant.
Cesium (Cs) contamination in water, particularly after nuclear incidents, poses significant environmental and health risks. This study aimed to evaluate and compare the effectiveness of various coagulants-alum, ferric chloride (FeCl3), poly aluminum chloride (PAC), and poly aluminum hydroxide chloride silicate (PACl)-with and without turbidity-inducing materials, as well as the Cs removal efficiency of Prussian blue (PB). Laboratory-scale jar tests were conducted using raw water spiked with Cs-133 and analyzed using ICP-MS. FeCl3 achieved the highest removal among coagulants (13.5%), while turbidity-inducing materials increased Cs removal to 37% due to increased particle-mediated adsorption and flocculation. PB demonstrated the highest efficiency (>99.9% removal at 10 mg/L), although its combination with PACl did not further enhance removal. These findings confirm PB as the most promising adsorbent for Cs removal and show that turbidity-enhancing strategies can improve coagulation outcomes. Further optimization of PB handling, immobilization, and large-scale implementation is needed to ensure safe and practical adoption in water treatment facilities.
The treatment of oil-contaminated industrial wastewater presents a significant challenge due to its associated environmental and economic implications. While this research proposes a simple automated system, based on three valve separator controlled by conductivity sensor, it explores the fundamental principles governing the separation and removal of immiscible oils from wastewater, offering a practical approach to separator design. This article examines the factors influencing oil-water separation efficiency, including key physical properties of the oil (density and viscosity), oil droplet size, and the flow rate of the influent water. Furthermore, the importance of optimized operating conditions, such as maintaining the flow stability within the laminar system, is addressed. The impact of minimum influent water flow rate on oil separator dimensions, specifically length and width, and the relationship between these dimensions and flow regime stability are also investigated. A theoretical analysis of spherical oil droplet trajectory, incorporating relevant influencing parameters, is presented for the design and dimensioning of the oil separator. A two-compartment oil separator model is presented. The first compartment functions as a sludge collector, facilitating the sedimentation of solids such as seeds and mud. The second compartment enables oil-water separation via flotation and decantation, exploiting the lower density of oils relative to the wastewater. The oil separator incorporates an inlet and two outlet ports, each equipped with solenoid valves for automated control. These valves are actuated by a conductivity sensor. A process flow diagram detailing the automated operation of the three solenoid valves is provided.
Forward Osmosis (FO) is the subject of many current studies, given existing and future conditions around the world. This work is the continuation of the series of research that implicates Artificial Neural Networks in the processes of membrane separation. Three databases (with the same size of 193 points), two learning algorithms, two function transfers, five subdivisions of the database, and eleven (11) inputs were used with the aim to extract the optimal QSPR-NN model which is chosen based on the best values of coefficient of correlation (R) and the Root Mean Squared Error (RMSE). QSPR-NN (Quantitative Structure-Property Relationships-Neural Networks) model obtained was characterized by eleven (11) neurons on the input layer, fourteen (14) neurons in the hidden layer, and one (1) neuron in the output layer, the Bayesian regularization (Trainbr) was the learning algorithm, tangent sigmoid (Tansig), and purelin were the transfers functions for the hidden and output layers respectively. The performance of the QSPR-NN optimal model obtained was demonstrated with a higher value of (R = 0.9895) and low Root Mean Squared Error (RMSE = 4.3683%), and other errors as RER and RPD more than 2.5 and equal to 21.4356 and 3.4290 respectively, the (NSE) more than 0.9. Furthermore, the comparison with other work in the same orientation demonstrated the excellence of our model developed in this work compared to the others.
The escalating pollution from pharmaceutical wastewater, notably tetracycline (TC), demands innovative treatment solutions. This study explores a membrane aerated biofilm reactor (MABR) for TC biodegradation and simultaneous removal of total nitrogen (TN), ammonia nitrogen (NH4+-N), and total phosphorus (TP). The MABR employed polypropylene hollow fiber membranes (0.2 mu m pore size) to develop stratified biofilms enabling microbial synergy: aerobic nitrifiers degraded NH4+-N while anoxic denitrifiers reduced TN. Optimal conditions (0.122 MPa aeration, 16-h HRT, 0.4 mg/L TC) achieved 70% TC degradation, 90% NH4+-N removal, 88% TN removal, 75% TP removal, and 93% COD removal. Microbial analysis confirmed TC mineralization via synergistic biofilm communities, minimizing toxic byproducts. The system's energy-efficient oxygen diffusion (direct membrane aeration) and high contaminant-removal efficiency underscore its cost-effectiveness. These findings position MABR as a sustainable, non-toxic solution for complex wastewater treatment.
The ANAMMOX process offers energy-efficient nitrogen removal but remains vulnerable to biomass loss due to the slow growth of ANAMMOX bacteria. This study evaluated the potential for performance recovery after biomass washout by supplementing with supernatant from a stable ANAMMOX reactor. A 5L reactor experienced intentional Mixed Liquor Suspended Solid(MLVSS) loss and was operated under reduced nitrogen loading. Recovery was initiated by adding 4 L of filtered supernatant. Reactor performance improved rapidly, with MLVSS increasing from 340 mg/L to 590 mg/L and Nitrogen Removal Rate(NRR) from 0.076 to 0.1832 kg-N/m3/day within 8 days. Sponge-type carrier media also showed biomass accumulation. The results suggest that the supernatant contained components that stimulated ANAMMOX activity, enabling fast recovery. Supernatant supplementation may offer a practical strategy for restoring ANAMMOX performance after biomass loss.
A model for water quality index is proposed. This index is based on the input quality variables such as concentration of turbidity, chlorophyll-a, ATP, absorbance at 260 nm and TOC. The index can be used for estimation of water quality before SWRO since the existing water quality metrics such as SDI and its derivatives do not provide reliable estimation for potential fouling. The impact of input variables was approximated by the second order function. The level of impact of input variables (such as concentration of chlorophyll-a; ATP; absorbance; TOC and turbidity) is characterized by weight factors. The target function-Z (Xj) was assumed to be proportional to the probability of membrane fouling that, in turn, proportional to SDI. The target function implies cumulative-composite structure. It includes imbedded sub-models f (Xj) for different fouling factors, X1-X5. The proposed model can be applied in different characteristic locations such as seawater intake, the points before and after pretreatment. The developed model can represent mathematical background for the software for monitoring and management of feed water quality in desalination. Individual weight factors and target function in real time can be used as a component in the early warning system.
The growing water demand requires advanced treatment technologies to efficiently remove recalcitrant organic compounds from wastewater for its reuse. This study evaluated and compared the performance of various advanced oxidation processes (AOPs) for total organic carbon (TOC) removal, focusing on UV-based systems. Among the tested methods, UV/PS and UV/TiO2/Persulfate (PS) achieved the highest TOC removal efficiencies of 89.1% and 92.6%, respectively, under optimized conditions. The UV/TiO2/PS process, which combines persulfate activation with TiO2 photocatalysis, demonstrated superior performance under conditions 1 g/L persulfate, 1 g/L TiO2, and 39 W UV output, making it a promising option for wastewater reuse. Non-UV-based AOPs, including US/H2O2 and US/PS, also exhibited high TOC removal efficiencies (87.8% and 81.9%, respectively) due to ultrasonic cavitation. However, their high energy intensity requirements challenges for process scalability. O3/H2O2 achieved moderate efficiency (70.5%), while Fenton-based processes (Fenton and Ultrasound (US)/Fenton) showed lower efficiencies (59.5% and 71.6%) due to their sensitivity to pH conditions. Overall, UV-based systems outperformed others in efficiency and adaptability, with UV/TiO2/PS identified as the most effective for treating recalcitrant pollutants. In the UV/PS and UV/TiO2/PS systems, sulfate ion generation confirmed effective persulfate activation, resulting in sulfate radical formation. Compared to Fenton-based processes, which generate substantial sludge, these systems represent an environmentally favorable alternative.
This study develops a quantitative structure-property relationship (QSPR) model using a hybrid neural network and particle swarm optimization (PSO) to predict the gas separation performance of 120 polymers of intrinsic microporosity (PIMs). Over 5000 descriptors, including topological, constitutional, functional groups, and geometrical properties, were computed using alvaDesc software. Genetic algorithm optimization combined with partial least squares regression was used to select relevant descriptors for predicting PIM permeability to N2, CH4, and CO2. A hybrid neural network model with particle swarm optimization-based backpropagation (PSO-BP) algorithms was used for permeability prediction, and the results were compared to experimental published data. The PSO-BP model showed promising results, with root mean squared error (RMSE) values of 0.0048, 0.000743, and 0.0045 for CO2, N2, and CH4, permeabilities respectively. Key descriptors for predicting PIM permeability are associated with multiple physicochemical properties, including GATS, 3D Morse, TDB, SpMax, MATS, CATS3D, RDF, and ATS descriptors. CO2 permeability prediction requires more 3D descriptors than N2 and CH4.
Biomass waste treatment via carbonization has drawn considerable attention due to its applications such as a solid fuel and an adsorbents for wastewater. The characteristics of carbonized products can be influenced by various factors including selection of biomass waste, carbonization temperature, duration, and pretreatment technologies adopted during the process. Indeed, the conversion of biomass waste into the carbonized product presents the sustainable approach to deal with increasing biomass waste responding to the growing energy demands and the need for emerging contaminant removal. This paper provides a brief review of current re-search trends and advancements in biomass carbonization, along with proposed carbonization system design for a sustainable approach. Emphasis is placed on the value-added products through carbonized biomass waste, highlighting its significance towards a sustainable society along with the carbon-neutral system.
This study aimed to discover the potential application of the draw solution system based on trisodium alpha-DLalanine diacetate (MGDA draw solution) in forward osmosis (FO) desalination systems through the optimization of some important operational parameters, the investigation of fouling behaviours after long-term operation and the efficiency of mitigating strategies, and the analytical of some key quality properties of the produced freshwater. Optimization results suggested that in the investigated range, inlet temperature was the main operational parameters that influence the osmosis performance of the MGDA draw solution. Under the optimized operational parameters (inlet pressure difference = 0.4 bar on the feed side, inlet temperature = 30 degrees C, and feed side inlet flow rate = 250 mL.min-1), the osmosis performance obtained were Jw = 9.996 +/- 0.192 LMH and Rds = 0.3580 +/- 0.0020 g.L-1. Furthermore, experimental results also emphasized the advantages of MGDA solution, which were low tendency of membrane fouling and the relatively ease of membrane cleaning. Finally, experiments on real brackish water samples confirmed the potential application of the MGDA draw solution in FO desalination systems, with the produced freshwater meeting key requirements as recommended in the National Technical Regulation QCVN 01-1:2018/BYT.
