Techno Press
Tp_Editing System.E (TES.E)
Login Search


mwt
 
CONTENTS
Volume 11, Number 2, March 2020
 

Abstract
The worldwide shortage of water resources is a major environmental issue. Using pure water for drinking and domestic purposes is a bigger issue than other environmental issues. Industrialization and Urbanization have even polluted rainwater. In China, when it rains, rainwater is stored on the roof or other sources of storage for daily use resulting in pollution. Several studies have been conducted to treat rainwater. The objective of this study is to evaluate the efficiency of constructed wetlands by using ACF as a medium. So, this study aims to treat rainwater in Wuhan city through a Composite Vertical Flow Constructed Wetlands. First, rainwater was stored in the tank while it flows out of the roof, further it is processed in constructed wetlands. The constructed wetlands is consisted with plants Calamus and Chives, adding ACF (prepared from luffa) has achieved great results in this study. Results show that the pollutants have been removed to a considerable level, there were significant differences in removal rates under different HRT at 6h, 9h and 12h respectively. Therefore, Composite Vertical Flow Constructed Wetlands is recommended for total nitrogen and Ammonia nitrogen and total phosphorus.

Key Words
CVFCW, ACF, wetlands-plants, water treatment, rainwater, Wuhan-China

Address
School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, P. R. China

Abstract
Membrane fouling is the main drawback of membrane technology. Frequent membrane cleaning and membrane replacement are, therefore, required to reduce membrane fouling that causes permeate flux reduction, lower rejection, or higher operating pressure. Studies have proved that the alteration of membrane properties is the key controlling factor in lessening membrane fouling. Among stimuli-responsive membranes, thermo-responsive membrane is the most popular, with a drastic phase transition and swelling-shrinking behavior caused by the temperature change. In this study, the thermo-responsive ability of two commercial membranes, PolyCera® Titan membrane and PolyCera® Hydro membrane, at different temperatures was studied on the antifouling function of the membrane in palm oil mill effluent (POME) treatment. The evaluation of the membrane's thermo-responsive ability was done through three cycles of adsorption (fouling) and desorption (defouling) processes in a membrane filtration process. The experimental result depicted that PolyCera® Hydro membrane had a higher membrane permeability of 67.869 L/m².h.bar than PolyCera® Titan membrane at 46.011 L/m².h.bar. However, the high membrane permeability of PolyCera® Hydro membrane was compensated with low removal efficiency. PolyCera® Titan membrane with a smaller mean pore size had better rejection performance than PolyCera® Hydro membrane for all tested parameters. On the other hand, PolyCera® Titan membrane had a better hydrodynamic cleaning efficiency than PolyCera® Hydro membrane regardless of the hydrodynamic cleaning temperature. The best hydrodynamic cleaning performed by PolyCera® Titan membrane was at 35°C with the flux recovery ratio (FRR) of 99.17 ± 1.43%. The excellent thermo-responsive properties of the PolyCera® Titan membrane could eventually reduce the frequency of membrane replacement and lessen the use of chemicals for membrane cleaning. This outstanding exploration helps to provide a solution to the chemical industry and membrane technology bottleneck, which is the membrane fouling, thus reducing the operating cost incurred by the membrane fouling.

Key Words
fouling; thermo-responsive; PolyCera®membrane; antifouling; POME treatment

Address
Teow Yeit Haan and Abdul Wahab Mohammad: Research Centre for Sustainable Process Technology (CESPRO), Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
Teow Yeit Haan, Loh Wei Chean and Abdul Wahab Mohammad: Department of Chemical and Process Engineering , Faculty of Engineering and Built Environment, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia

Abstract
The fouling of Nanofiltration membrane (NF) was examined using wastewater containing reactive black dye RB5 of 1500 Pt/Co color concentrations with 16890 mg/l TDS collected from El-alamia Company for Dying and Weaving in Egypt. The NF-unit was operated at constant pressure of 10 bars, temperature of 25°C, and flowrate of 420 L/min. SEM, EDX, and FTIR were used for fouling characterization. Using the ROIFA-4 program, the total inorganic fouling load was 1.07 mM/kg present as 49.3% Carbonates, 10.1% Sulfates, 37.2% Silicates, 37.2% Phosphates, and 0.93% Iron oxides. The permeate flux, recovery, salt rejection and mass transfer coefficients of the dye molecules were reduced significantly after fouling. The results clearly demonstrate that the fouling had detrimental effect on membrane performance in dye removal, as indicated by a sharp decrease in permeate flux and dye recovery 68%. The dye mass transfer coefficient was dropped dramatically by 34%, and the salt permeability increased by 14%. In this study, all the properties of the membrane used and the fouling that caused its poor condition are identified. Another study was conducted to regeneration fouled membrane again by chemical methods in another article (Abdel-Fatah et al. 2017).

Key Words
membrane fouling; flux decline; nanofiltration; wastewater; ROIFA-4 software

Address
National Research Center, Chemical Engineering and Pilot Plant Department, Cairo, Egypt

Abstract
Submerged Membrane bioreactor (SMBR) is one of the last techniques that allow a high quality of treated industrial effluents by coupling biological treatment and membrane separation. Thus, this research was an effort to evaluate performance of a SMBR treating a model textile wastewater (MTWW). Different SMBR operating parameters like mixed liquor suspended solids (MLSS) and Dissolved oxygen concentration, hydraulic retention time (HRT), and nutrients addition (N and P) have been investigated. MTWW (influent to the SMBR) was generated using the reactive azo-dye, Novacron blue FNG (100mg/L feed concentration). Results of MTWW treatment using SMBR under optimal operating conditions (MLSS, 4.2-13.3g/L; HRT, 4 days; pH, 6.9-7.2; conductivity, 400-900 µS/cm and temperature, 19.4-22.2 °C) showed that COD and blue colour treatment performances are between 94-98% and 30-80%, respectively. It is concluded that SMBR can be used in large scale textile wastewater treatment plants to improve effluent quality in order to meet effluent discharge standards.

Key Words
dye removal; model textile dye wastewater; mixed liquor; submerged membrane bioreactor; wastewater treatment

Address
Marwa Guembri, Mohamed Neifar, Atef Jaouaniand Hadda-Imene Ouzari: Laboratoire des Microorganismes et Biomolécules Actives (LR03ES03), Faculté des Sciences de Tunis,
Université de Tunis El Manar, 2092 Tunis, Tunisia
Neila Saidi:Centre de Recherches et des Technologies des Eaux, Laboratoire Eau, Membranes et Biotechnologies de l`Environnement (LR15CERTE04), Technopôle Borj-Cédria Route Touristique de Soliman BP 273-8020 Soliman, Tunisia
Mohamed Neifar: University of Manouba, ISBST, BVBGR-LR11ES31, Biotechpole of Sidi Thabet, Ariana, Tunisia
Marc Heran: Institut Européen des Membranes IEM, UMR-5635, Université Montpellier, ENSCM, CNRS,
Place Eugène Bataillon, 34095 Montpellier cedex 5, France


Abstract
The current study focused on the preparation of low-cost PVC-based adsorbing membrane. Metakaolin, as available adsorbent, was embedded into the PVC matrix via solution blending method. The as-prepared PVC/metakaolin mixed matrix membranes were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), pure water permeability and contact angle measurements. The results confirmed the improvement of PWP and hydrophilicity due to the presence of metakaolin in the PVC matrix. Additionally the structure of PVC membrane was changed due to the incorporation of metakaolin in the polymer matrix. The static adsorption capacity of all samples was determined through dye removal. The effect of metakaolin dosage (0-7%) and pH (4, 8, 12) on dye adsorption capacity was investigated. The results depicted that the highest adsorption capacity was achieved at pH of 4 for all samples. Additionally, adsorption data were fitted on Langmuir, Freundlich, and Temkin models to determine the appropriate governing isotherm model. Finally, the dynamic adsorption capacity of the optimum PVC/metakaolin membrane was studied using dead-end filtration cell. The dye removal efficiency was determined for pure PVC and PVC/metakaolin membrane. The results demonstrated that PVC/metakaolin mixed matrix membrane had a high adsorption capacity for dye removal from aqueous solution.

Key Words
metakaolin; wastewater treatment; membrane adsorber; ultrafiltration; cationic dye

Address
Department of Chemical Engineering, University of Gonabad, Gonabad, Iran

Abstract
Prechlorination could increase the removal efficiency of Synedra, but there was no significant effect of increasing the amount of chlorine added. However, a removal efficiency of greater than 80% was noted when ozone was injected at concentrations greater than 2 mg/L. Also, it was found that on addition of polyamine, a removal efficiency of 80% or more could be achieved. As a result of the analysis of field operation data from the water treatment plants G and B, it was found that at water treatment plant G, the filter run time decreased to 10 hours or less when only coagulant was injected, but the filter run time increased to around 40 hours when polyamine (3 mg/L) was also injected. The Synedra population in the raw water subsequently increased to 2,340 cells/mL, and the filter continued running for more than 20 hours. At water treatment plant B, the average Synedra removal efficiency was 56% when only coagulant was injected, and the filter run time decreased drastically with the increasing population of Synedra in the raw water. However, the removal efficiency of Synedra reached 79% when polyamine was injected together with the coagulant, 90% when ozone was also injected, and 95% when polyamine and ozone were injected together and the filter continued running for over 50 hours. The filter run time was maintained at 60 hours when a Synedra population of 6,890 cells/mL flowed into the Paldang water source, but the filter run time with Synedra at 1,960 cells/mL decreased rapidly from 65 hours to 35 hours when the ratio of the size of the individual Synedra reaching 250 µm or more, increased from 38% to 94%. Therefore, the size of the Synedra is considered to be a factor that significantly influences filter clogging, as well as the size of the Synedra population.

Key Words
Synedra; filter clogging; filter run time; polyamine, ozone

Address
Dae-Keun Seo: Korea Water Resources Corporation, 200 Sintanjin-Ro, Daedeok-Gu, Daejeon, 34350 Republic of Korea
2Dept. Environmental Engineering, Kangwon National University, 1 Kangwondaehak-gil, Chuncheon-Si, Gangwon-Do,
24341 Republic of Korea

Abstract
ACF preparation from different materials has been attached with great attention during these years. This study was conducted to prepare activated carbon fiber (ACF) from luffa through the processes i.e pre-treatment, pre-oxidation and carbonization activation. Besides, this study also characterizes the ACF and its effect, i.e effect of pre-oxidation time and temperature also activation time and temperature on the compressive strength of ACF were investigated. The results from SEM, BET, FTIR and XRD show that the ACF is very efficient. The products under the optimum conditions had a specific surface area of 478.441 m2 /g with an average pore diameter of 3.783nm, and a pore volume of 0.193 cm3 /g. The surface of the luffa fiber is degummed and exposed, which is beneficial to the subsequent process and the increase of product properties. The compressive strength of HP-ACF was prepared under the optimum conditions, which can reach 0.2461 MPa. ACF is rich in micro-pores and has a good application prospect in the field of environmental protection.

Key Words
Luffa, Activated carbon fibers, Surface oxidation, Pyrolysis, Porous structure

Address
School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, P. R. China

Abstract
In this study, the performance and antifouling properties of polysulfone (PSf) and polyvinylidene fluoride/polyvinylpyrrolidone (PVDF/PVP) membranes in a membrane bioreactor (MBR) were investigated. The membranes were prepared via phase inversion method, and then characterized by a set of analyses including contact angle, porosity and water flux and applied in a lab-scale MBR system. Soluble microbial product (SMP), extracellular polymeric substance (EPS), FTIR, gel permission chromatography (GPC) and particle size distribution (PSD) analyses were also carried out for MBR system. The results showed that the MBR with PSf membrane had higher hydrophobic organic compounds which resulted in formation of larger flocs in MBR. However, in this MBR had high compressibility coefficient of cake layer was higher (n=0.91) compared to MBR with PVDF/PVP membrane (n=0.8); hence, the fouling was more profound. GPC analysis revealed that compounds with molecular weight lower than 2 kDa are more formed on PSf membrane more than PVDF/PVP membrane. The results of FTIR analysis confirmed the presence of polysaccharide and protein compounds on the cake layer of both membranes which was in good agreement with EPS analysis. In addition, the results showed that their concentration was higher for the cake on PSf membrane.

Key Words
PVDF/PVP; PSf; Cake layer specification; MBR

Address
Hossein Hazrati, Naser Karimi and Yoones Jafarzadeh: 1Faculty of Chemical Engineering, Sahand University of Technology, Tabriz, Iran
Hossein Hazrati: Environmental Engineering Research Center, Sahand University of Technology, Tabriz, Iran

Abstract
The effectiveness of in situ sediment capping as a technique for heavy metal risk mitigation in Hyeongsan River estuary, South Korea was studied. Sites in the estuary were found previously to show moderate to high levels of contamination of mercury, methylmercury and other heavy metals. A 400 m x 50 m section of the river was selected for a thin layer capping demonstration, where the total area was divided into 4 sections capped with different combinations of capping materials (zeolite, AC/zeolite, AC/sand, zeolite/sand). Pore water concentrations in the different sites were studied using diffusive gradient in thin film (DGT) probes. All capping amendments showed reduction in the pore water concentration of the different heavy metals with top 5 cm showing %reduction greater than 90% for some heavy metals. The relative maxima for the different metals were found to be translated to lower depths with addition of the caps. For two-layered cap with AC, order of placement should be considered since AC can easily be displaced due to its relatively low density. Investigation of methylmercury (MeHg) in the site showed that MeHg and %MeHg in pore water corresponds well with maxima for sulfide, Fe and Mn suggesting mercury methylation as probably coupled with sulfate, Fe and Mn reduction in sediments. Our results showed that thin-layer capping of active sorbents AC and zeolite, in combination with passive sand caps, are potential remediation strategy for sediments contaminated with heavy metals.

Key Words
GIS; concentration of nitrite; Najaf Abad; groundwater sources

Address
Javad Tabatabaei: 1Department of petroleum engineering and geology, Islamic Azad University
Leila Gorji: Department of Geology, Islamic Azad University


Techno-Press: Publishers of international journals and conference proceedings.       Copyright © 2020 Techno-Press
P.O. Box 33, Yuseong, Daejeon 34186 Korea, Tel: +82-42-828-7996, Fax : +82-42-828-7997, Email: info@techno-press.com