Treatment of highly turbid water in disaster conditions using coagulation-flocculation process: modeling and optimization

Abstract In the present research, the coagulation-flocculation (CF) process was used to eliminate highly turbid water in disaster conditions. To better understand the efficiency of the system, the impact of various numerical factors namely; initial turbidity (10–350 NTU), pH (5–9), coagulant dosage (50–250 mg/L), rapid mixing (120–280 rpm), slow mixing (30–50 rpm), and sedimentation time (10–50 min) were optimized through the central composite design (CCD) under response surface methodology (RSM). Based on analysis of variance (ANOVA), the quadratic model was more suitable for the dataset with R2 = 0.85 for removing turbidity. Moreover, the results of the present study revealed that the highest turbidity removal (99.14%) was observed at pH (9), alum dosage (50 mg/L), initial turbidity (350 NTU), rapid mixing (280 rpm), slow mixing (50 rpm), and sedimentation time (50 min). Furthermore, the residual turbidity at the maximum efficiency of the system was 3 NTU.

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Investigating the feasibility of removing the rapid mixing unit in conventional surface water treatment and its effect on turbidity removal

Water Practice & Technology ◽

10.2166/wpt.2021.070 ◽

2021 ◽

Author(s):

Abolfazl Hessam ◽

Mohammad Hadi Mehdinejad

Keyword(s):

Water Treatment ◽

Surface Water ◽

Removal Efficiency ◽

Treatment Plant ◽

Test Method ◽

Turbid Water ◽

Turbidity Removal ◽

Rapid Mixing ◽

Surface Water Treatment ◽

Significant Difference

Abstract Coagulation and Flocculation processes play a major role in surface water treatment. The aim of this study was to eliminate the rapid mixing unit in the water treatment plant. This experimental study was conducted on turbid water. Turbid water was synthesized by kaolin powder. The conventional Jar Test method was used. The flocculation and sedimentation processes were performed on the turbid water without rapid mixing unit for getting the new optimal condition. When the PACl coagulant was used alone and in conjunction with chitosan, the percentages of turbidity removal in low, medium and high turbidities were obtained 86.7%, 95.8%, 97.8% and 86.67%, 95.73%, 98.26%, respectively. When the rapid mixing unit was emitted, the efficiency of turbidity removal in the low turbidity was reduced from 5.26% to 21.73%. But, in higher turbidity in two states (presence and absence of the rapid mixing units) did not have a significant difference. This study showed that the removal of the rapid mix unit on the removal efficiency of turbidity in the low turbidity is effective, but does not effect on higher turbid water. Also, to use PACl in conjunction with chitosan were effective on the removal efficiency and to reduce of residual aluminum.

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Turbid Water Treatment Using Deshelled Carica papaya Seed: Analysis Via Factorial Design

Biointerface Research in Applied Chemistry ◽

10.33263/briac126.77877795 ◽

2021 ◽

Vol 12 (6) ◽

pp. 7787-7795

Keyword(s):

Water Treatment ◽

Carica Papaya ◽

Turbid Water ◽

Turbidity Removal ◽

Coagulant Dosage ◽

Natural Coagulants ◽

Operational Factors ◽

Papaya Seeds ◽

Carica Papaya Seed ◽

Papaya Seed

Natural coagulants are proven to be a good alternative to conventional coagulants with the removal of various pollutants and are environmentally friendly. Despite its advantages, the least studies were carried out on local agro-wastes such as papaya seeds as natural coagulants concerning different operational factors. The study analyzes the main and interactions effect between the coagulant dosage, initial turbidity, and pH on deshelled Carica papaya seeds for turbid water treatment. A 2-level factorial design was used to investigate the main and interaction effects of the main operational factors, viz. coagulant dosage (50-200 mg/L), pH (3-7), and initial turbidity (100-500 NTU) on the turbidity removal of the synthetic turbid water. Based on individual performance, the results suggested that initial turbidity and pH are the most significant factors among the investigated operational factors. In combination, all interactions are significant, but the interaction between initial turbidity and pH is most significant, with 97.2% turbidity removal. Upon application of Carica papaya seed as a natural coagulant in water and wastewater treatment, these operating variables and their interactions are best to be considered.

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Application of improved rapid mixing for enhanced removal of dissolved organic matter and DBPFP (disinfection by-product formation potential) control

Water Science & Technology Water Supply ◽

10.2166/ws.2006.030 ◽

2006 ◽

Vol 6 (1) ◽

pp. 49-57 ◽

Cited By ~ 3

Author(s):

H.C. Kim ◽

S. Lee ◽

S.J. Byun ◽

M.J. Yu

Keyword(s):

Organic Matter ◽

Product Formation ◽

Turbidity Removal ◽

Rapid Mixing ◽

Potential Control ◽

Coagulant Dosage ◽

Uniform Dispersion ◽

Hydrophilic Fraction ◽

The Difference ◽

Hydrophobic Fraction

Dispersion of metal coagulant should be completed in a fraction of a second before the metal hydroxide precipitate has formed. For this reason, so-called pump diffusion flash mixing (PDFM) has been proposed, and PDFM is one reasonable method to quickly disperse the hydrolyzing metal salts. In this study, we attempt to understand the difference of removal characteristics of natural organic matter (NOM) between PDFM and conventional rapid mixing (CRM) in a water treatment system, and to enhance the removal of NOM through the improved mixing process. Dissolved organic carbon (DOC) and turbidity removal by PDFM was higher than those by CRM, while specific ultraviolet absorbance (SUVA) of treated water by PDFM was higher than that by CRM. NOM was more effectively removed by PDFM compared to CRM due to quick and uniform dispersion of coagulants. Though the hydrophilic fraction found as major faction in bulk NOM from Han River water is enriched in haloacetic acid precursor sites as compared to hydrophobic fraction, the hydrophilic fraction was more effectively removed by PDFM rather than CRM. Therefore, PDFM is effective and innovative process in reduction of DOC and DBPFPs as well as turbidity, and requires lower coagulant dosage compared to CRM.

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Sustained release biodegradable solid lipid microparticles: Formulation, evaluation and statistical optimization by response surface methodology

Acta Pharmaceutica ◽

10.1515/acph-2017-0034 ◽

2017 ◽

Vol 67 (4) ◽

pp. 441-461

Author(s):

Muhammad Hanif ◽

Hafeez Ullah Khan ◽

Samina Afzal ◽

Asif Mahmood ◽

Safirah Maheen ◽

...

Keyword(s):

Entrapment Efficiency ◽

Quadratic Model ◽

Release Mechanism ◽

Scanning Calorimetry ◽

Glyceryl Monostearate ◽

Solid Lipid ◽

Solid Lipid Microparticles ◽

Lipid Microparticles ◽

The Impact ◽

Central Composite

Abstract For preparing nebivolol loaded solid lipid microparticles (SLMs) by the solvent evaporation microencapsulation process from carnauba wax and glyceryl monostearate, central composite design was used to study the impact of independent variables on yield (Y1), entrapment efficiency (Y2) and drug release (Y3). SLMs having a 10-40 μm size range, with good rheological behavior and spherical smooth surfaces, were produced. Fourier transform infrared spectroscopy, differential scanning calorimetry and X-ray diffractometry pointed to compatibility between formulation components and the zeta-potential study confirmed better stability due to the presence of negative charge (-20 to -40 mV). The obtained outcomes for Y1 (29-86 %), Y2 (45-83 %) and Y3 (49-86 %) were analyzed by polynomial equations and the suggested quadratic model were validated. Nebivolol release from SLMs at pH 1.2 and 6.8 was significantly (p < 0.05) affected by lipid concentration. The release mechanism followed Higuchi and zero order models, while n > 0.85 value (Korsmeyer- Peppas) suggested slow erosion along with diffusion. The optimized SLMs have the potential to improve nebivolol oral bioavailability.

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Optimization of Initial Turbidity and Coagulant Concentration to Remove Turbidity Using Moringa oleifera Seed

Journal of Korean Society of Environmental Engineers ◽

10.4491/ksee.2020.42.2.47 ◽

2020 ◽

Vol 42 (2) ◽

pp. 47-54

Author(s):

Bong Min Kim ◽

Hee Yun Lee ◽

Johng-Hwa Ahn

Keyword(s):

Response Surface ◽

Surface Analysis ◽

Moringa Oleifera ◽

Response Surface Analysis ◽

Synthetic Wastewater ◽

Optimal Conditions ◽

Turbidity Removal ◽

Mixing Speed ◽

Rapid Mixing ◽

Slow Mixing

Objective:Coagulation of Moringa oleifera seeds was studied to determine the optimal conditions in treating a turbid water.Method:Jar-test experiments were performed at various rapid mixing (90-250 rpm; 1-2 min), slow mixing (10-60 rpm; 10-50 min), initial turbidity (100-500 NTU), coagulant doses (200-1,500 mg/L), and pH (2-12) in synthetic wastewater. Response surface analysis was used to optimize the coagulation in jar-test experiments.Results and Discussion:The optimal conditions for turbidity removal with M. oleifera were 200 rpm of rapid-mixing speed for 1 min, 40 rpm of slow-mixing speed for 20 min, and pH 8. The coagulation efficiency was found to be dependent on initial turbidity of water samples. Highest turbidity removals (96.5%) were obtained for water with very high initial turbidity (500 NTU). The effects of initial turbidity and coagulant dose were successfully analyzed by the response surface analysis. Within the design boundaries, turbidity removal was more sensitive to changes in initial turbidity than to changes in coagulant dose.Conclusions:The quadratic model between initial turbidity and coagulant for turbidity removal was shown. M. oleifera can be used as a potential coagulant especially for high turbidity water.

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Optimization and Quality by Design Approach for Piroxicam Fast Dissolving Tablet Formulations Using Box-Behnken Design

Current Drug Therapy ◽

10.2174/1574885514666190409102614 ◽

2020 ◽

Vol 15 (2) ◽

pp. 152-165

Author(s):

Harekrishna Roy ◽

Sisir Nandi ◽

Ungarala Pavani ◽

Uppuluri Lakshmi ◽

Tamma Saicharan Reddy ◽

...

Keyword(s):

Quality By Design ◽

Methyl Cellulose ◽

Statistical Technique ◽

Quadratic Model ◽

Contour Plot ◽

Compression Technique ◽

Disintegration Time ◽

Box Behnken Design ◽

The Impact ◽

The Relationship

Background: The present study deals with the formulation and optimization of piroxicam fast dissolving tablets and analyzes the impact of an independent variable while selecting the optimized formulation utilizing Quality by Design (QbD) and Box-Behnken Design (BBD). Methods: Seventeen formulations were prepared by direct compression technique by altering the proportion of cross carmellose sodium, spray dried lactose and hydro propyl methyl cellulose (HPMC K4M). The BBD statistical technique was used to optimize formulations and correlate the relationship among all the variables. Also, the powder mixture characteristics and tablet physiochemical properties such as hardness, friability, drug content, Disintegration Time (DT) and dissolution test were determined using 900 ml of 0.1N HCl (pH-1.2) at 37 ± 0.5°C. Results: Significant quadratic model and second order polynomial equations were established using BBD. To find out the relationship between variables and responses, 3D response surface and 2D contour plot was plotted. A perturbation graph was also plotted to identify the deviation of the variables from the mean point. An optimized formula was prepared based on the predicted response and the resulting responses were observed to be close with the predicted value. Conclusion: The optimized formulation with the desired parameter and formulation with variables and responses can be obtained by BBD and could be used in the large experiment with the involvement of a large number of variables and responses.

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Optimizing Adsorption of 17α-Ethinylestradiol from Water by Magnetic MXene Using Response Surface Methodology and Adsorption Kinetics, Isotherm, and Thermodynamics Studies

Molecules ◽

10.3390/molecules26113150 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3150

Author(s):

Mengwei Xu ◽

Chao Huang ◽

Jing Lu ◽

Zihan Wu ◽

Xianxin Zhu ◽

...

Keyword(s):

Response Surface Methodology ◽

Response Surface ◽

Quadratic Model ◽

Adsorption Efficiency ◽

Process Variables ◽

Adsorption Time ◽

Initial Concentration ◽

Independent Variables ◽

The Impact ◽

Adsorbent Dose

Magnetic MXene composite Fe3O4@Ti3C2 was successfully prepared and employed as 17α-ethinylestradiol (EE2) adsorbent from water solution. The response surface methodology was employed to investigate the interactive effects of adsorption parameters (adsorption time, pH of the solution, initial concentration, and the adsorbent dose) and optimize these parameters for obtaining maximum adsorption efficiency of EE2. The significance of independent variables and their interactions were tested by the analysis of variance (ANOVA) and t-test statistics. Optimization of the process variables for maximum adsorption of EE2 by Fe3O4@Ti3C2 was performed using the quadratic model. The model predicted maximum adsorption of 97.08% under the optimum conditions of the independent variables (adsorption time 6.7 h, pH of the solution 6.4, initial EE2 concentration 0.98 mg L−1, and the adsorbent dose 88.9 mg L−1) was very close to the experimental value (95.34%). pH showed the highest level of significance with the percent contribution (63.86%) as compared to other factors. The interactive influences of pH and initial concentration on EE2 adsorption efficiency were significant (p < 0.05). The goodness of fit of the model was checked by the coefficient of determination (R2) between the experimental and predicted values of the response variable. The response surface methodology successfully reflects the impact of various factors and optimized the process variables for EE2 adsorption. The kinetic adsorption data for EE2 fitted well with a pseudo-second-order model, while the equilibrium data followed Langmuir isotherms. Thermodynamic analysis indicated that the adsorption was a spontaneous and endothermic process. Therefore, Fe3O4@Ti3C2 composite present the outstanding capacity to be employed in the remediation of EE2 contaminated wastewaters.

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Kinetics and Equilibrium of Radioactive Metal Adsorption onto Sugarcane Bagasse Waste: Comparison of Batch and Column Adsorption Modes

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2019-1418 ◽

2021 ◽

Vol 235 (3) ◽

pp. 281-294

Author(s):

Abida Kausar ◽

Haq Nawaz Bhatti ◽

Munawar Iqbal

Keyword(s):

Sugarcane Bagasse ◽

Flow Rate ◽

Breakthrough Curves ◽

Quadratic Model ◽

Waste Biomass ◽

Initial Concentration ◽

Bed Height ◽

Column Adsorption ◽

Central Composite ◽

Bagasse Waste

Abstract Sugarcane bagasse waste biomass (SBWB) efficacy for the adsorption of Zr(IV) was investigated in batch and column modes. The process variables i.e. pH 1–4 (A), adsorbent dosage 0.0–0.3 g (B), and Zr(IV) ions initial concentration 25–200 mg/L (C) were studied. The experiments were run under central composite design (CCD) and data was analysed by response surface methodology (RSM) methodology. The factor A, B, C, AB interaction and square factor A2, C2 affected the Zr(IV) ions adsorption onto SBWB. The quadratic model fitted well to the adsorption data with high R2 values. The effect of bed height, flow rate and Zr(IV) ions initial concentration was also studied for column mode adsorption and efficiency was evaluated by breakthrough curves as well as Bed Depth Service and Thomas models. Bed height and Zr(IV) ions initial concentration enhanced the adsorption of capacity of Zr(IV) ions, whereas flow rate reduced the column efficiency.

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Optimization of Supercritical Extraction Conditions of Senna Alata and Evaluation of Biological Activity

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.11.15937 ◽

2018 ◽

Vol 7 (3.11) ◽

pp. 94

Author(s):

Istikamah Subuki ◽

Aiman Nabilah Abdul Malek ◽

Saidatul Husni Saidin ◽

Mazura Md. Pisar

Keyword(s):

Crude Extract ◽

Extraction Process ◽

Quadratic Model ◽

Total Flavonoids ◽

Inhibition Activity ◽

Backward Elimination ◽

Total Flavonoids Content ◽

Senna Alata ◽

Central Composite ◽

Experimental Runs

Supercritical fluid extraction (SFE) offer faster extraction process, decreased solvent usage and more selectivity on desired compounds. In this present study, the influence of pressure (100, 200 and 300 bar) and temperature (40, 50 and 60˚C) on the Senna alata crude yield were investigated with fixed supercritical carbon dioxide (SC-CO2) at the flow rate of 35 g/min. The parameters were optimised and modelled using response surface methodology (RSM) and central composite design (CCD). The analysis of variance (ANOVA) experimental design consists of 13 experimental runs with 5 replicates at the central points. Well-fitting quadratic model were successfully established for crude extract through backward elimination. The optimum crude extract yield pointed out by RSM was at the pressure of 300 bar and temperature 40˚C respectively. Extraction yields based on SC-CO2 varied in the range of 0.28 to 3.62%. The highest hyaluronidase inhibition activity and total flavonoids content obtained by S.alata crude extracts were 41.19% and 52.53% w/w, respectively. SC-CO2 proves to have great potential for extraction of yield, hyaluronidase inhibition activity and total flavonoids content for S.alata.

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EGR cylinder deactivation strategy to accelerate the warm-up and restart processes in a Diesel engine operating at cold conditions

International Journal of Engine Research ◽

10.1177/14680874211039587 ◽

2021 ◽

pp. 146808742110395

Author(s):

José Galindo ◽

Vicente Dolz ◽

Javier Monsalve-Serrano ◽

Miguel Angel Bernal Maldonado ◽

Laurent Odillard

Keyword(s):

Steady State ◽

Diesel Engine ◽

Internal Combustion Engines ◽

Cold Start ◽

Pollutant Emissions ◽

Oxidation Catalyst ◽

Maximum Efficiency ◽

Warm Up ◽

Cylinder Deactivation ◽

The Impact

The aftertreatment systems used in internal combustion engines need high temperatures for reaching its maximum efficiency. By this reason, during the engine cold start period or engine restart operation, excessive pollutant emissions levels are emitted to the atmosphere. This paper evaluates the impact of using a new cylinder deactivation strategy on a Euro 6 turbocharged diesel engine running under cold conditions (−7°C) with the aim of improving the engine warm-up process. This strategy is evaluated in two parts. First, an experimental study is performed at 20°C to analyze the effect of the cylinder deactivation strategy at steady-state and during an engine cold start at 1500 rpm and constant load. In particular, the pumping losses, pollutant emissions levels and engine thermal efficiency are analyzed. In the second part, the engine behavior is analyzed at steady-state and transient conditions under very low ambient temperatures (−7°C). In these conditions, the results show an increase of the exhaust temperatures of around 100°C, which allows to reduce the diesel oxidation catalyst light-off by 250 s besides of reducing the engine warm-up process in approximately 120 s. This allows to reduce the CO and HC emissions by 70% and 50%, respectively, at the end of the test.

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