Effluent Flow Rate Research Articles

Evaluation of ion exchange material from sulfonated polystyrene waste synthesized for removal Cr3+ from aqueous solution by column experiment

The paper aims to study the effect of operating conditions in the column experiment with the ion exchange material which was prepared in optimum synthesized conditions. Polystyrene waste from disposable food packaging was dissolved in cyclohexane and sulfonated by sulfuric acid to synthesize cation exchange materials which were applied to remove Cr3+ in water by the ion exchange principle. The optimum conditions for this method were found out and described in previously published literature of the author. Characterization by SEM and Fourier Transforms Infrared (FT-IR) spectroscopy proved that the additional Sulfonic groups were presented. The efficiency of Cr3+ removal was highly affected by column bed height, initial ion concentrations and flow rate of effluent. The highest efficiency of material was 84.0% with a material bed height of 10 cm in the removal of Cr3+ from simulated wastewater containing initial Cr3+ concentration of 120 mg/l. The experimental data obtained from this study was consistent with Thomas and Yoon-Nelson kinetic models, which will be applied for column design in practical study and design. The results from this method can help reduce the plastic waste and easy to apply in practice for removal of Cr3+ in wastewater.
 Keywords: ion exchange; polystyrene waste; synthesize; chromium.

Full-Scale Performance Evaluations of Innovative and Manufactured Sediment Barrier Practices

Sediment barriers (SB) are devices typically installed along the perimeters of construction sites to intercept, capture, and contain pollutant discharge. Effective SBs minimize sediment transportation off-site by temporarily impounding stormwater and facilitating sediment capture upstream of the installation. Full-scale experiments were conducted on common, innovative, and manufactured SB practices used within the construction industry to better understand their performance. These practices consisted of two manufactured silt fence systems, three sediment retention barrier practices, and three manufactured sediment barrier products. Installation details for each practice were analyzed and amendments made to provide the most effective installations. Test observations indicated that a major failure mode of innovative and manufactured SB practices was flow bypass due to undermining. Performance-based comparisons of sediment retention rates, maximum impoundment depths, effluent flow rates, and treatment efficiencies were determined for each practice. Longevity tests were also conducted to evaluate characteristic changes over iterative storm events. Overall performance evaluations indicate practices that achieve impoundment depths greater than 1 ft (0.3 m) have consistent sediment capture rates of at least 90%. More importantly, impoundment depths greater than 1.5 ft (0.46 m) do not facilitate improved sediment capture rates. These observations suggest that optimized sediment capture is achieved when a SB practice has an effective upstream impoundment depth between 1 and 1.5 ft (0.3 and 0.46 m). Additionally, impoundment depths within this optimal zone reduce impoundment surface turbidity up to 60% when compared with turbidity levels along the bottom of the impoundment.

Utilization of Hydroturbines in Wastewater Treatment Plants

Wastewater treatment plants (WWTPs) are a significant energy consumer, yet there are several opportunities for implementing on-site power generation systems. Within the treatment process, the high flow rate of effluent is produced and discharged to a nearby water body by gravity. Thus, hydroturbines can be utilized to generate power in such an application due to a difference in elevation and high flow rate. This paper presents a case study of introducing a hydroturbine in a WWTP in Wisconsin and evaluating the power output in addition to determining the energy savings. The WWTP considered in this study has an effluent flow rate of 190 MGD (million gallons per day) and elevation difference of 3 m (10 ft) between the final stage of treatment and the discharge point. Based on the parameters above; hubless rim-drive Kaplan type hydroturbine (RDT) is the optimal choice to be used in such an application. The RDT is designed and optimized by using in-house code. A computational fluid dynamics (CFD) software is applied to evaluate the performance of the proposed model, and the system is simulated through homer software to validate the results generated by the CFD. The expected savings is estimated to be 1564 MWh/yr.

Investigation of effective parameters on adsorption of amoxicillin from aqueous medium onto activated carbon

In this study, the adsorption of amoxicillin onto activated carbon was investigated. The effect of particle size and the effluent flow rate was discussed as well as the kinetics and isotherm of adsorption equilibrium. The isotherm equilibrium studies showed that the Langmuir model was appropriate for describing the adsorption equilibrium of amoxicillin onto the activated carbon. Furthermore, the kinetics of adsorption fit the pseudo-second-order model while the highest adsorption amount occurred at pH = 5. Moreover, the change of particle size from 600 microns to 125 microns resulted in increasing the adsorption amount of 102 mg/g to 225 mg/g. Furthermore, the breakthrough curves indicated that the controlling mechanism of mass transfer was intra-particle diffusion. Also, by reducing the length of the bed from 6.8 to 3.4 cm, the breakpoint time decreased from 3.2 hours to 54 minutes at 300 ppm initial concentration. Eventually, the breakpoint time increased from 2 minutes to 55 minutes by decreasing the average particle diameter from 840 to 250 microns.

An Average Dwell-Time Method for Fault-Tolerant Control of Switched Time-Delay Systems and Its Application

This paper presents an average dwell-time method for fault-tolerant control of a class of uncertain switched linear time-delay systems and also designs an algorithm to determine the parameters pertaining to the dwell-time condition. Compared to the literature results, this paper features the following: 1) the proposed method is independent of switching polices if switchings are slow enough in the average sense; 2) the proposed control design guarantees exponential stabilization of this class of time-delay linear systems with actuator faults; and 3) this method treats all actuators in a unified manner without a need to identify which are faulty or healthy actuators. The proposed method is applied to the water pollution control problem, for the first time, to deal with different ratios of stream flow rates to effluent flow rates.

Head Loss Reduction in Surcharged Four-Way Junction Manholes

Head loss in surcharged four-way junction manholes is a factor that increases damage due to urban inundation; thus, the flow characteristics of such manholes must be analyzed to reduce the head loss. In this study, a physical model was constructed; this model included a manhole and a connection pipe, fabricated on a 1/5 scale by applying sewer facility standards to perform a physical model investigation. Numerical simulations were performed using the Fluent model to derive efficient benching designs that can reduce head loss. Physical model investigations were performed by varying the ratio of the lateral influent flow rate to the effluent flow rate as well as by varying the effluent flow rate and benching designs. The result of physical model investigations showed that the installation of half rectangular benching reduced the head loss coefficients by 7% and 10% on average compared with square and circular manholes, respectively. The installation of full rectangular benching reduced the head loss coefficients by 28% and 17% on average compared with square and circular manholes, respectively. Thus, the benching proposed herein can be installed and used to improve the drainage capacity of urban stormwater conduit facilities.

Application of Physical and Chemical Enhanced Backwashing to Reduce Membrane Fouling in the Water Treatment Process Using Ceramic Membranes.

This study investigated the improvement of operating efficiency through physical cleaning and chemical enhanced backwashing (CEB) using ceramic membranes with high permeability and chemical safety compared to organic membranes. The turbidity and DOC (Dissolved Organic Carbon) concentrations were selected to ensure that the degree of contamination was always constant. The operating pressures were fixed at 100, 200, and 300 kPa, and the filtration was terminated when the effluent flow rate decreased to 30% or less from the initial value. After filtration, backwashing was performed at a pressure of 500 kPa using 500 mL backwash water. The membrane was cleaned by dipping in NaOCl, and a new washing technique was proposed for steam washing. In this study, we investigated the recovery rate of membranes by selectively performing physical cleaning and CEB by changing the influent water quality and operating pressure conditions.

Investigating Three Different Models for Simulation of the Thermal Stage of an Industrial Split-Flow SRU Based on Equilibrium-Kinetic Approach with Heat Loss

Abstract Modified Claus process is the most important process that recovers elemental sulfur from H2S. The thermal stage of sulfur recovery unit (SRU), including the reaction furnace (RF) and waste heat boiler (WHB), plays a critically important role in sulfur recovery percentage of the unit. In this article, three methods including kinetic (PFR model), equilibrium and equilibrium-kinetic models have been investigated in order to predict the reaction furnace effluent conditions. The comparison of results with industrial data shows that kinetic model (for whole the thermal stage) is the most accurate model for simulation of the thermal stage of the industrial split-flow SRU. Mean absolute percentage error for the considered kinetic model is 4.59 %. For the first time, the consequences of considering heat loss from the reaction furnace on calculated molar flows are studied. The results show that considering heat loss only affects better prediction of some effluent molar flow rates such as CO and SO2, and its effect is not significant on the results. Eventually the effects of feed preheating on some important parameters like sulfur conversion efficiency, H2S to SO2 molar ratio and important effluent molar flows are investigated. The results indicate that feed preheating will reduce the sulfur conversion efficiency. It is also noticeable that by reducing the feed temperature to 490 K, H2S/SO2 molar ratio reaches to its optimum value of 2.

Sex and mortality in septic severe acute kidney injury

PurposeTo investigate the relationship between sex and mortality and whether menopause or the intensity of renal replacement therapy (RRT) modify this relationship in patients with severe septic acute kidney injury (AKI). Materials and methodsPost-hoc analysis of patients with sepsis included in the Randomized Evaluation of Normal versus Augmented Level renal replacement therapy (RENAL) trial. ResultsOf 724 patients, 458 (63.3%) were male and 266 (36.7%) were female. The mean delivered effluent flow rate was 25.6 ± 7.4 ml/kg/h (80 ± 15% of prescribed dose) in males and 27.4 ± 7.6 ml/kg/h (83 ± 15% of prescribed dose) in females (p = .01). A total of 237 (51.7%) males and 118 (44.5%) females died within 90 days of randomization (p = .06). The adjusted hazard ratio (HR) for 90-day mortality was significantly decreased in females as compared with males (HR 0.74, 95% CI 0.57 to 0.96, p = .02). The relationship between sex and mortality was not significantly altered by menopausal status (adjusted P value for interaction 0.99) or by RRT intensity allocation (adjusted P value for interaction 0.27). ConclusionsIn a cohort of patients with sepsis and severe AKI, female sex was associated with improved survival. The relationship between sex and survival was not altered by menopausal status or RRT intensity.

Formulation and application of a biosurfactant from Bacillus methylotrophicus as collector in the flotation of oily water in industrial environment

The present study describes the formulation of a biosurfactant produced by Bacillus methylotrophicus UCP1616 and investigates its long-term stability for application as a collector in a bench-scale dissolved air flotation (DAF) prototype. For formulation, the conservative potassium sorbate was added to the biosurfactant with or without prior heat treatment at 80 °C for 30 min. After formulation, the biosurfactant samples were stored at room temperature for 180 days and the tensioactive properties of the biomolecule were determined with different pH values, temperatures and concentrations of salt. Then, a central composite rotatable design was used to evaluate the influence of the independent variables (effluent flow rate and formulated biosurfactant flow rate) on the oil removal efficiency in the DAF prototype. The formulated biosurfactant demonstrated good stability in both conservation methods, with tolerance to a wide pH range, salinity and high temperatures, enabling its use in environments with extreme conditions. The efficiency of the formulated biomolecule through heating and addition of sorbate was demonstrated by the 92% oil removal rate in the DAF prototype. The findings demonstrate that the biosurfactant from Bacillus methylotrophicus enhances the efficiency of the DAF process, making this technology cleaner. This biosurfactant can assist in the mitigation and management of industrial effluents, contributing toward a reduction in environmental pollution caused by petroleum-based hydrocarbons.

Performance of the first stage of the French system of vertical flow constructed wetlands with only two units in parallel: influence of pulse time and instantaneous hydraulic loading rate.

The technology of vertical flow constructed wetlands - French system for treating raw wastewater depends on several hydraulic factors, one of them being the duration of the pulse feeding and the resulting instantaneous hydraulic loading rate. This paper analyses two scenarios in the same system, the first of a faster feeding by pump and the second of a slower feeding by siphon, both with instantaneous hydraulic loading rate values lower than the literature recommendations. The system treated raw wastewater from a population equivalent of 100 p.e. in Brazil, and was comprised by only the first stage and two units in parallel. The shorter duration of feeding time and higher instantaneous hydraulic loading rate were associated with significantly higher chemical oxygen demand and total Kjeldahl nitrogen removal efficiencies, but with no significant differences in terms of biochemical oxygen demand (BOD) and suspended solids (SS). Oxygen concentrations and redox potential in the effluent were evaluated, together with the effluent flow rate profiles. The removal efficiencies were associated with the accumulation of solids in the upper part of the filter resulting from seven years of operation and to the operating hydraulic conditions, which are important elements in the performance of the system.

Ultrafast monolithic HPLC method for simultaneous quantification of the anticancer agents, imatinib and sorafenib: Application to tablet dosage forms

Purpose : To develop and validate a simple ultrafast monolithic high performance liquid chromatography (HPLC) method for the simultaneous quantification of two anti-cancer agents, imatinib and sorafenib, in pure form and tablet preparations. Method : Chromatographic separation was accomplished using Chromolith flash RP-18 HPLC-column (25 - 4.6 mm; macropores, 2 μm; mesopores, 13 – 15 nm). The optimum mobile phase composition of ammonium acetate buffer (10 mM, pH 8.5) and methanol at ratio of 35:65 v/v was used. Effluent flow rate was adjusted to 1.0 mL/min and the analysis was performed at 250 nm wavelength. The developed method was evaluated for specificity, linearity, precision and accuracy. Results : The method offered a linear relationship over the concentration range of 1 - 16 μg/ml (correction coefficient, R 2 = 0.9999) for both analytes. Limit of detection (LOD) was 0.1891 and 0.1888 μg/ml while limit of quantification (LOQ) was 0.6303 and 0.6294 μg/ml for imatinib and sorafenib, respectively. Mean recovery was within 100 ± 2 %. The utility of the new method was demonstrated by its successful use for the analysis of commercially available tablet formulations of both drugs. Conclusion : The developed method is fast and economical, and is being recommended for routine analysis of imatinib and sorafenib in bulk drug and tablet dosage forms in quality control laboratories. Keywords : RP-HPLC, Chromolith, Imatinib, Sorafenib, Validation, Quality control

PERMEATION OF BENTONITE SUSPENSIONS THROUGH LOOSE SANDY SOIL

Over the past years, the levee breach flood disaster caused by underseepage has become an alarming problem in Bangladesh. The underseepage phenomenon beneath the earthen embankments may be controlled by treating the underlying granular soil with grout suspensions delivered by permeation (permeation grouting), resulting in a less permeable deposit. Drawing on this physical link, a permeameter was fabricated to investigate the permeation of bentonite suspension through the granular soil medium. The variation of injection time of stopping grout flow, injected grout weight, penetration distance with bentonite fraction for a constant pressure grout injection were studied. The time dependent effluent flow rate variation were also monitored in the laboratory. The experimental results showed that grouting operation worked efficiently for a certain range of bentonite fraction. The individual parameters like injection time, penetration distance, injected grout weight decreased with the increase of bentonite concentration. The effluent flow rate reduction became much prominent as the test proceeded towards the end that justified the effectiveness of permeation. Finally, a grout concentration was proposed considering the cost and other factors like penetration distance, injection time etc. for the sand used in this investigation.

Quantitative determination of clobetasone butyrate in bulk and cream formulation by a validated stability-indicating reversed-phase HPLC method

A simple isocratic reversed-phase HPLC method for quantification of clobetasone in bulk and cream dosage forms has been developed. Chromatographic analysis was accomplished on an C18 column utilizing a mixture of methanol and water (84:16 v:v, pH = 6.0) as mobile phase. An effluent flow rate of 1 mL/min was adjusted and the detection was made at 240 nm wavelength. The method was evaluated according to ICH guidelines Q2 R1 for linearity, specificity, sensitivity, precision and accuracy. The method exhibited good linearity with correlation coefficient (r2) of 0.9993 over the concentration range from 5 to 50 μg/mL. The recoveries of the test drug from the cream sample was found to be 98.56 to 99.51% and the limit of detection and quantification were calculated as 0.85 and 2.83 μg/mL, respectively, suggesting the accuracy and sensitivity of the developed method. The precision was demonstrated by a low percentage of relative standard deviation (<1%) from six independent assay analysis performed for the cream formulation. Stability indicating property of the proposed method was demonstrated by performing the analysis of forced degradation samples. The developed method can be used for estimation of the clobetasone butyrate in bulk and pharmaceutical formulations for routine analysis in the quality control laboratories.

Factors affecting serum concentration of vancomycin in critically ill oliguric pediatric patients receiving continuous venovenous hemodiafiltration.

Vancomycin is known to be unintentionally eliminated by continuous renal replacement therapy, and the protein bound fraction of vancomycin is also known to be different in adults and children. However, there are only a few studies investigating the relationship between the dose of continuous venovenous hemodiafiltration (CVVHDF) parameters and serum concentration of vancomycin in pediatric patients. The aim of this study was to determine clinical and demographic parameters that significantly affect serum vancomycin concentrations. This retrospective cohort study was conducted at a pediatric intensive care unit in a tertiary university children’s hospital. Data from oliguric patients who underwent CVVHDF and vancomycin therapeutic drug monitoring were collected. The correlation between factors affecting serum concentration of vancomycin was analyzed using mixed effect model. A total of 177 serum samples undergoing vancomycin therapeutic drug monitoring were analyzed. The median age of study participants was 2.23 (interquartile range, 0.3–11.84) years, and 126 (71.19%) were male patients. Serum concentration of vancomycin decreased significantly as the effluent flow rate (EFR; P < 0.001), dialysate flow rate (DFR; P = 0.009), replacement fluid flow rate (RFFR; P = 0.008), the proportion of RFFR in the sum of DFR and RFFR (P = 0.025), and residual urine output increased. The adjusted R2 of the multivariate regression model was 0.874 (P < 0.001) and the equation was as follows: Vancomycin trough level (mg/L) = (0.283 × daily dose of vancomycin [mg/kg/d]) + (365.139 / EFR [mL/h/kg])–(15.842 × residual urine output [mL/h/kg]). This study demonstrated that the serum concentration of vancomycin was associated with EFR, DFR, RFFR, the proportion of RFFR, and residual urine output in oliguric pediatric patients receiving CVVHDF.

Three-Stage Anaerobic Sequencing Batch Reactor (ASBR) for Maximum Methane Production: Effects of COD Loading Rate and Reactor Volumetric Ratio

A three-stage anaerobic sequencing batch reactor system was developed as a new anaerobic process with an emphasis on methane production from ethanol wastewater. The three-stage anaerobic sequencing batch reactor system consisted of three bioreactors connected in series. It was operated at 37 °C with a fixed recycle ratio of 1:1 (final effluent flow rate to feed flow rate) and the washout sludge from the third bioreactor present in the final effluent was allowed to be recycled to the first bioreactor. The pH of the first bioreactor was controlled at 5.5, while the pH values of the other two bioreactors were not controlled. Under the optimum chemical oxygen demand loading rate of 18 kg/m3d (based on the feed chemical oxygen demand load and total volume of the three bioreactors) with a bioreactor volumetric ratio of 5:5:20, the system provided the highest gas production performance in terms of yields of both hydrogen and methane and the highest overall chemical oxygen demand removal. Interestingly, the three-stage anaerobic sequencing batch reactor system gave a much higher energy production rate and a higher optimum chemical oxygen demand loading rate than previously reported anaerobic systems since it was able to maintain very high microbial concentrations in all bioreactors with very high values of both alkalinity and solution pH, especially in the third bioreactor, resulting in sufficient levels of micronutrients for anaerobic digestion.

EXPERIMENTAL INVESTIGATION ON BEHAVIOUR OF CROSS-FLOW THERMAL EFFLUENT DISCHARGE IN FREE SURFACE FLOW

Thermal discharges such as from power stations or industries into rivers causing degradation of water quality. A study was conducted in the laboratory to investigate the changes of the ambient temperature caused by thermal effluent discharged into the flow. A cross–flow thermal effluent is discharged from the bed of the channel. Thermal effluent flow rates of 0.133 liter/s and 0.05 liter/s and ambient flow rates of 20 liter/s and 10 liter/s were used in the study. Observation of thermal mixing process in the channel is concentrated in the near-field zone. The thermal dispersion patterns were observed along the channel through the isothermal lines; while the changes of ambient temperature are studied from the experimental data. The results indicate that the temperature changes are drastic in the near-field mixing zone. Then it gradually reduces along the channel until reaches the far-field mixing zone. Lower layer of the flow experiences high excess temperature compared to middle and upper layers of the flow. Meanwhile, larger effluent flow rate produces higher excess temperature in the receiving water body than small effluent flow rate. Based on experimental data, equations of excess temperature and dispersion were established.

Spinning Disc Technology – Residence Time Distribution and Efficiency in Textile Wastewater Treatment Application

The spinning disc (SD) technology has received increased attention in the last years due to its enhanced fluid flow features resulting in improved property transfers. The actual study focuses on characterization of the flow within a spinning disc system based on experimental data used to establish the residence time distribution (RTD) and its dependence on the feeding liquid flowrate and the disc rotational speed. To obtain these data, an inert tracer (sodium chloride) was injected as a pulse input in the liquid stream entering the disc and the salt concentration of the liquid leaving the disc was continuously recorded. The obtained data indicate that an increase in the liquid flowrate from 10 L/h to 30 L/h determines a narrower RTD function. Also, at rotational speed of 200 rpm, the residence time distribution is broader than that for 500 rpm and 800 rpm. The RTD data suggest that depending on the needed flow characteristics, one can choose a certain flowrate and rotational speed domain for its application. Also, the SD technology was used to process textile wastewater treated with bentonite (as both coagulation and discoloration agent) in order to investigate whether the quality indicators such as the total suspended solid content, turbidity and discoloration, can be improved. The experimental results are promising since the discoloration and the removals of suspended solids attained values of over 40%, and respectively, 50 %, depending on the effluent flowrate (10 l/h and 30 L/h), and the disc rotational speed (200 rpm, 550 rpm and 850 rpm) without any other addition of chemicals, or initiation of other simultaneous treatment processes (e.g., advanced oxidative, or reductive, or biochemical processes). This recommends spinning disc technology as a suitable and promising tool to improve different wastewater characteristics.

Treatment dose and the elimination rates of electrolytes, vitamins, and trace elements during continuous veno-venous hemodialysis (CVVHD).

During continuous renal replacement therapy, achievement of recommended treatment dose is important. However, relevant substrate loss may occur and recommended nutrition during critical illness could not be sufficient for higher dialysis doses. We investigated the correlation of dialysis dose and substrate loss for a broad range of dialysis doses. Forty critically ill patients with acute kidney injury undergoing citrate CVVHD were included in this prospective study. Three different corresponding blood flow (BF) and dialysate flow (DF) rates were applied (BF/DF: 100ml/min, 2000ml/h; 80ml/min, 1500ml/h; 120ml/min, 2500ml/h). Delivered effluent flow rate (DEFR) was calculated and correlated with losses of vitamins, electrolytes, and trace elements during recommended nutritional supplementation. For folic acid, vitamin B12, zinc, inorganic phosphate, and magnesium, no correlation of losses and DEFR was detected. For ionized calcium, a correlation was observed and additional substitution was required. Clinically relevant loss of folic acid, vitamin B12, zinc, inorganic phosphate, and magnesium was not observed for differently used dialysis doses of CVVHD, and the loss was covered sufficiently by daily recommended nutritional supplementation. Increased loss of ionized calcium for higher dialysis doses occurred during citrate CVVHD. Therefore, a strict protocol must maintain calcium homeostasis to avoid calcium depletion.

Enhanced removal of methylene blue dye from its aqueous solutions using humic acid-functionalized alumina nanoparticles

Recently, greater emphasis has been laid on the designing of nano-materials to improve the efficiency of treatment processes. Therefore, in the wake of technological improvement, a novel adsorbent humic acid-functionalized alumina (HAFA) nanoparticles were designed and have been tested for their decolorisation potential for methylene blue dye from aqueous solutions. HAFA nanoparticles were synthesized by the precipitation method and the qualitative aspect of the synthesized nanoparticles were explored by using various techniques, namely N2 adsorption–desorption measurements, Fourier transform infrared spectroscopy, X-ray diffraction analysis, scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis and zero point charge analysis. The effects of different parameters like pH value, initial contact time and concentration of the adsorbent solution were investigated to optimized the removal of methylene blue. Rate constants determination were explored by employing pseudo-first-order, and pseudo-second-order kinetic models and the latter was found to be the best simulated. Moreover, for gaining insight into the adsorption interaction, sorption data were further interpreted through Weber–Morris and Boyd models. The adsorption equilibrium data were best elucidated by Freundlich’s isotherm model and the maximum adsorption capacity of the HAFA nanoparticles was evaluated as 438.4 mg/g at 323 K. An adsorbent reusability study suggested that HAFA nanoparticles could be efficiently used for up to five cycles without compromising the adsorption capacity. Moreover, column investigation was also conducted, and results suggested that the breakthrough time could be easily enhanced by controlling the column bed height and effluent flow rate. A maximum breakthrough of 23 h was achieved with a column bed height of 7.5 cm.