scholarly journals Natural organic matter and sulphate elimination from rainwater with nanofiltration technology and process optimisation using response surface methodology

Author(s):  
Börte Köse-Mutlu

Abstract In the current study, the effect of operating conditions including membrane characteristics and applied pressure on natural organic matter and sulphate removal of nanofiltration membranes for drinking water production was investigated. Water stress has been increasing all over the world due to population growth, climate change, and pollution; rainwater management stands out as one of the key solutions to this problem. Nanofiltration to treat rainwater stored in a cistern was studied. The objectives were sufficient treatment performance to overcome the taste problem and lower energy consumption. In this regard, three commercial nanofiltration membranes (NP010, NP030, and NF90) were used for the experiments carried out at 6–12 bar operating pressure regarding the response surface methodology. The correlation among the results of experiments and the model parameters were also calculated for all steps. According to the results, the effect of membrane characteristics was more abundant than the effect of the operating pressure. Finally, over 99% of natural organic matter and sulphate were eliminated in the optimum conditions. The results showed that it is possible to obtain treated rainwater with desired qualities, in a non-continuous NF plant operated at the pressure of 6 bar to reuse the rainwater and achieve water sustainability.

Desalination ◽  
2010 ◽  
Vol 253 (1-3) ◽  
pp. 38-45 ◽  
Author(s):  
Supatpong Mattaraj ◽  
Wongphaka Phimpha ◽  
Pakasit Hongthong ◽  
Ratana Jiraratananon

Author(s):  
André Gadelha de Oliveira ◽  
Jefferson Pereira Ribeiro ◽  
Eliezer Fares Abdala Neto ◽  
Ari Clecius Alves de Lima ◽  
Álvaro Amanajás Amazonas ◽  
...  

Abstract The use of the pulsed current can be an alternative to decrease the electrode polarization, as well as achieving lower energy consumption. This study investigated the electrocoagulation through pulsed current for the removal of natural organic matter from water. The experiments were carried out using Box–Behnken factorial design with the response surface methodology for the design of experiments, modeling and interpreting of the results. The electrocoagulation cell consisted of an acrylic reactor with 4 L capacity with four electrodes of aluminum, in parallel connection mode. The experimental independent variables studied were: current density (5.5 to 44.5 A m−2), electrodes spacing (2 to 7.6 mm), stirring rate (200 to 1,000 rpm), frequency (500 to 5,000 Hz), humic acid concentration (5 to 20 mg L−1) and NaCl (100 to 300 mg L−1) as supporting electrolyte, evaluating the residual apparent color (RAC) and electric energy consumption (EEC). The pH of the solution increased during the experiments, reaching basic values. The response surface regression procedure was employed to fit the second-order polynomial, and the model fitted well to the obtained values, reaching R2 0.9995 (RAC) and R2 0.9989 (EEC). The lowest RAC was 11.8 Hazen units (96.2% color removal), where the EEC was 0.393 kWh m−3.


2019 ◽  
Vol 46 (4) ◽  
pp. 299-307 ◽  
Author(s):  
Anirban Banik ◽  
Suman Dutta ◽  
Tarun Kanti Bandyopadhyay ◽  
Sushant Kumar Biswal

The paper investigates increasing permeate flux (%) of the disc membrane which can improve the quality of rubber industrial effluent of Tripura. Response surface methodology was used to optimize the independent influencing parameters to improve the permeate flux. The effect of different influencing parameters like operating pressure, membrane pore size, and inlet feed velocity on membrane permeate flux were studied to determine the optimum operating conditions within the predefined boundary. The experiments were pre-planned and designed according to central composite rotatable design, and second-order polynomial regression model was developed for regression and analysis of variance study. Results show the membrane has maximum permeate flux (%) when the operating pressure is 14.50 Pa, pore size is 0.20 μm, and inlet feed velocity is 2.10 m/s. The Pareto analysis in the study established that the inlet velocity was the most influential parameter in the model equation.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1775 ◽  
Author(s):  
Mohamad Rasool Malekbala ◽  
Soroush Soltani ◽  
Suraya Abdul Rashid ◽  
Luqman Chuah Abdullah ◽  
Umer Rashid ◽  
...  

In the present study, a sequence of experiments was performed to assess the influence of the key process parameters on the formation of a carbon nanofiber-coated monolith (CNFCM), using a four-level factorial design in response surface methodology (RSM). The effect of reaction temperature, hydrocarbon flow rate, catalyst and catalyst promoter were examined using RSM to enhance the formation yield of CNFs on a monolith substrate. To calculate carbon yield, a quadratic polynomial model was modified through multiple regression analysis and the best possible reaction conditions were found as follows: a reaction temperature of 800 °C, furfuryl alcohol flow of 0.08525 mL/min, ferrocene catalyst concentration of 2.21 g. According to the characterization study, the synthesized CNFs showed a high graphitization which were uniformly distributed on a monolith substrate. Besides this, the feasibility of carbon dioxide (CO2) adsorption from the gaseous mixture (N2/CO2) under a range of experimental conditions was investigated at monolithic column. To get the most out of the CO2 capture, an as-prepared sample was post-modified using ammonia. Furthermore, a deactivation model (DM) was introduced for the purpose of studying the breakthrough curves. The CO2 adsorption onto CNFCM was experimentally examined under following operating conditions: a temperature of 30–50 °C, pressure of 1–2 bar, flow rate of 50–90 mL/min, and CO2 feed amount of 10–40 vol.%. A lower adsorption capacity and shorter breakthrough time were detected by escalating the temperature. On the other hand, the capacity for CO2 adsorption increased by raising the CO2 feed amount, feed flow rate, and operating pressure. The comparative evaluation of CO2 uptake over unmodified and modified CNFCM adsorbents confirmed that the introduced modification procedure caused a substantial improvement in CO2 adsorption.


2004 ◽  
Vol 4 (5-6) ◽  
pp. 215-222 ◽  
Author(s):  
A.R. Costa ◽  
M.N. de Pinho

Membrane fouling by natural organic matter (NOM), namely by humic substances (HS), is a major problem in water treatment for drinking water production using membrane processes. Membrane fouling is dependent on membrane morphology like pore size and on water characteristics namely NOM nature. This work addresses the evaluation of the efficiency of ultrafiltration (UF) and Coagulation/Flocculation/UF performance in terms of permeation fluxes and HS removal, of the water from Tagus River (Valada). The operation of coagulation with chitosan was evaluated as a pretreatment for minimization of membrane fouling. UF experiments were carried out in flat cells of 13.2×10−4 m2 of membrane surface area and at transmembrane pressures from 1 to 4 bar. Five cellulose acetate membranes were laboratory made to cover a wide range of molecular weight cut-off (MWCO): 2,300, 11,000, 28,000, 60,000 and 75,000 Da. Severe fouling is observed for the membranes with the highest cut-off. In the permeation experiments of raw water, coagulation prior to membrane filtration led to a significant improvement of the permeation performance of the membranes with the highest MWCO due to the particles and colloidal matter removal.


1996 ◽  
Vol 34 (9) ◽  
pp. 149-156 ◽  
Author(s):  
C. Ratanatamskul ◽  
K. Yamamoto ◽  
T. Urase ◽  
S. Ohgaki

The recent development of new generation LPRO or nanofiltration membranes have received attraction for application in the field of wastewater and water treatment through an increasingly stringent regulation for drinking purpose and water reclamation. In this research, the application on treatment of anionic pollutants (nitrate, nitrite, phosphate, sulfate and chloride ions) have been investigated as functions of transmembrane pressure, crossflow velocity and temperature under very much lower pressure operation range (0.49 to 0.03 MPa) than any other previous research used to do. Negative rejection was also observed under very much low range of operating pressure in the case of membrane type NTR-7250. Moreover, the extended Nernst-Planck model was used for analysis of the experimental data of the rejection of nitrate, nitrite and chloride ions in single solution by considering effective charged density of the membranes.


2021 ◽  
Vol 14 ◽  
pp. 117862212110281
Author(s):  
Ahmed S. Mahmoud ◽  
Nouran Y. Mohamed ◽  
Mohamed K. Mostafa ◽  
Mohamed S. Mahmoud

Tannery industrial effluent is one of the most difficult wastewater types since it contains a huge concentration of organic, oil, and chrome (Cr). This study successfully prepared and applied bimetallic Fe/Cu nanoparticles (Fe/Cu NPs) for chrome removal. In the beginning, the Fe/Cu NPs was equilibrated by pure aqueous chrome solution at different operating conditions (lab scale), then the nanomaterial was applied in semi full scale. The operating conditions indicated that Fe/Cu NPs was able to adsorb 68% and 33% of Cr for initial concentrations of 1 and 9 mg/L, respectively. The removal occurred at pH 3 using 0.6 g/L Fe/Cu dose, stirring rate 200 r/min, contact time 20 min, and constant temperature 20 ± 2ºC. Adsorption isotherm proved that the Khan model is the most appropriate model for Cr removal using Fe/Cu NPs with the minimum error sum of 0.199. According to khan, the maximum uptakes was 20.5 mg/g Cr. Kinetic results proved that Pseudo Second Order mechanism with the least possible error of 0.098 indicated that the adsorption mechanism is chemisorption. Response surface methodology (RSM) equation was developed with a significant p-value = 0 to label the relations between Cr removal and different experimental parameters. Artificial neural networks (ANNs) were performed with a structure of 5-4-1 and the achieved results indicated that the effect of the dose is the most dominated variable for Cr removal. Application of Fe/Cu NPs in real tannery wastewater showed its ability to degrade and disinfect organic and biological contaminants in addition to chrome adsorption. The reduction in chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solids (TSS), total phosphorus (TP), total nitrogen (TN), Cr, hydrogen sulfide (H2S), and oil reached 61.5%, 49.5%, 44.8%, 100%, 38.9%, 96.3%, 88.7%, and 29.4%, respectively.


Membranes ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 70
Author(s):  
Jasir Jawad ◽  
Alaa H. Hawari ◽  
Syed Javaid Zaidi

The forward osmosis (FO) process is an emerging technology that has been considered as an alternative to desalination due to its low energy consumption and less severe reversible fouling. Artificial neural networks (ANNs) and response surface methodology (RSM) have become popular for the modeling and optimization of membrane processes. RSM requires the data on a specific experimental design whereas ANN does not. In this work, a combined ANN-RSM approach is presented to predict and optimize the membrane flux for the FO process. The ANN model, developed based on an experimental study, is used to predict the membrane flux for the experimental design in order to create the RSM model for optimization. A Box–Behnken design (BBD) is used to develop a response surface design where the ANN model evaluates the responses. The input variables were osmotic pressure difference, feed solution (FS) velocity, draw solution (DS) velocity, FS temperature, and DS temperature. The R2 obtained for the developed ANN and RSM model are 0.98036 and 0.9408, respectively. The weights of the ANN model and the response surface plots were used to optimize and study the influence of the operating conditions on the membrane flux.


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