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.
