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Volume 11, Number 6, November 2020

In this study, household waste plastic garbage bag recycling industry wastewater was treated by a membrane process to recycle water for using in the bags washing process. Two different ultrafiltration (UP150 and UP005) and nanofiltration (NF270 and NF90) membranes were tested. The steady-state permeate flux was obtained 14.9 and 19.2 L/m2.h at 5 bar for UP150 and UP005 membranes, respectively. However, the steady-state permeate flux was 12.9 and 8.9 L/m2.h at 20 bar for NF270 and NF90 membranes, respectively. The chemical oxygen demand (COD) was also tested for all membrane permeates and the highest COD removal efficiency was obtained for NF90 membrane. Thus, optimization was carried out using NF90 membrane and the effect of transmembrane pressure (10, 20, 30 bar) and solution pH (5, 7, 9) on COD removal efficiency was tested. The results showed that the highest steady-state permeate flux (23.5 L/m2.h) and COD removal efficiency (95.1%) were obtained at 30 bar and pH 9. After the optimization of the membrane type and operating conditions, 75% recovery was obtained to re-use in the bags washing process. The concentrate stream was treated by an activated sludge process to manage membrane concentrate and to provide discharge standards. The maximum COD removal efficiency in biological treatment for membrane concentrate stream was 96.2% under steady-state condition using a sequencing batch reactor (SBR) operated at 10 days of sludge retention time and 12 h of hydraulic retention time. The proposed combined process including membrane and activated sludge processes was successfully used to recover wastewater.

Key Words
household waste plastic garbage bag recycling industry wastewater; water recovery; water reuse; membrane process; activated sludge

Ezgi Bezirhan Arikan, Yasin Ozay: Chemical Department of Environmental Engineering, Mersin University, Mersin, 33343, Turkey
Bahar Ozbey Unal, Yasin Ozay: Department of Environmental Engineering, Gebze Technical University, Kocaeli, 41440, Turkey
Bahar Ozbey Unal:Institute of Earth and Marine Sciences, Gebze Technical University, Kocaeli, 41400, Turkey
Vahid Vatanpour: Faculty of Chemistry, Kharazmi University, Tehran, Iran

Before discharge into sewage or living waters, dairy effluents need to be effectively treated to meet the requirements defined by environmental protection regulations. In addition to the commonly used technologies, membrane separation might offer a novel solution with many remarkable advantages. Although membrane fouling often limits its industrial scale application, module vibration can reduce membrane fouling. In this study, multi-stage membrane separations with ultrafiltration (UF), as pre-filtration, and nanofiltration (NF) were investigated. On the one hand, our aim was to separate the wastewater to reach the cleanest permeate possible, on the other hand to achieve the highest organic content in the smallest volume for further energetic utilization. Firstly, with one-stage separations the effects of Vibratory Shear Enhanced Processing (VSEP) on shear rate, fluxes and rejections were investigated. These tests revealed that vibration has a positive effect on fluxes and rejections. Secondly, two types of multi-stage UF/NF separation experiments were carried out and membrane fluxes, COD rejections and flux decreasing rates were examined. In type 1, permeates of nanofiltered UF permeates achieved the lowest organic load in purified wastewater to meet European environmental threshold limits for living waters. In type 2, concentrates of nanofiltered UF concentrates reached the highest possible volume reduction ratio (VRR) resulting in higher organic content in a smaller volume, which could increase the efficiency of biogas production as an alternative post-treatment for waste management.

Key Words
ultrafiltration; nanofiltration; VSEP; shear rate; multi-stage; dairy wastewater; biogas

Szabolcs Kertész, Szabolcs Gyula Szerencsés, Gábor Veréb, Zsuzsanna László:Department of Process Engineering, Faculty of Engineering, University of Szeged, H-6725 Szeged, Moszkvai krt. 9., Hungary
József Csanádi: Department of Food Engineering, Faculty of Engineering, University of Szeged, H-6725 Szeged, Moszkvai krt. 9., Hungary
Cecilia Hodúr: Institute of Environmental Science and Technology, University of Szeged, H-6725, Tisza Lajos krt. 103, Szeged, Hungary

In recent years, the generation of disinfectant by-products (DBPs) in drinking water system has been highlighted for their potential negative impact on humans. A commonly used disinfectant, chlorine, produces a by-product which is highly hazardous and a known carcinogen. This study investigated the toxic effects of DBPs from several organic matter as a function of contact time with chlorine-based disinfectants were investigated using zebrafish. The results indicated that the generation of DBPs was dependent on the composition of dissolved organic matter (DOM) in water. Suwannee river natural organic matter and experimental site water sample (complex DOM) were almost 2.5 times higher than that of a single dissolved organic matter, such as microcystin-LR (MCLR) at 120 min. The behavior of zebrafish was significantly affected by complex composition DOM. In vivo biomarker analysis result from lipid profile analysis, reaction in vivo showed different depending on the composition of the DOM. Through this study, the effect of DBPs were observed via lipid metabolic and movement changes in aquatic organisms can be considered as a new biomarker for the drinking water risk assessment.

Key Words
dissolve organic matter(DOM); disinfection byproducts(DBPs); toxicity assessment

Hyojik Yoon,Yongsuk Hong, Byoungsoo Kim, Sungpyo Kim:Department of Environmental Engineering, Korea University, Sejong 30019, Republic of Korea
Hyojik Yoon, Yongsuk Hong,Sungpyo Kim: Program in Environmental Technology and Policy, Korea University, Sejong 30019, Republic of Korea
Yunsu Lim: BKT Co. Ltd., 25 Yuseong-daero 1184 beon-gil, Yuseong-gu, Daejeon 34109, Republic of Korea
Sungkyu Maeng: Department of Civil and Environmental Engineering, Sejong University, Seoul 05006, Republic of Korea
Seokjong Byun: Department of Research and Development, Jeollanamdo Environmental Industries Promotion Institute,
Jeollanam-do 59205, Republic of Korea
Hyun-Chul Kim: Research Institute for Advanced Industrial Technology, Korea University, Sejong 30019, Republic of Korea
Byoungsoo Kim: Department of Clean Water Supply Facilities Maintenance, K-water, Daejeon 34350, Republic of Korea

Mosquitoes are extraordinary in their ability to penetrate the epidermis layer into human skin with a natural ultimate microneedle without pain, named mosquito’s fascicle. The mosquito usages a very small force to pierce into the skin. This force is at least four or three orders of magnitude smaller than the insertion force for a synthetic microneedle with an ultra-sharp tip to penetrate into the layer of human skin. In order to comprehend the piercing mechanism of the mosquito’s fascicle into the human skin tissue, using new techniques as the variational iteration method. to analysis of elastic stability for mosquito’s fascicle with the elastic foundation is conducted. Solutions for these types of problems are not a simple procedure since the equations of stability criteria are highly nonlinear. This study presents the application of the variational iteration method for obtaining the solutions for restrained mosquito’s fascicle. The study proves that the variational iteration method is a very efficient and promising approach in the elastic stability analysis of specified problems. A good agreement occurs between the present results and the experimental measurements.

Key Words
mosquito mouthparts; variational iteration method; instability analysis; microneedle; penetration

S. R. Mahmoud: GRC Department, Jeddah Community College, King Abdulaziz University, Jeddah, Saudi Arabia.
Habeeb M. Al-Solami, Naser Alkenani, Alawiah M. S. Alhebshi, Afaf S. Alwabli and Ahmed Bahieldin: Department of Biological Sciences, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia.

In the present research, batch adsorption of anionic dye such as Acid Black 1 (AB1) in aqueous solution onto biosorbent Acacia concinna was investigated at room temperature. The effect of various physico-chemical parameters such as contact time, adsorbent dosage, initial dye concentration and temperature on the percentage removal of dye were investigated. Adsorption kinetics was investigated using linear and nonlinear form of pseudo first-order and pseudo-second-order kinetic models but experimental data for adsorption of AB1 dye in aqueous mixture onto biosorbent Acacia concinna was fitted well to pseudo-second order model with maximum value of regression coefficient (0.9995). Linear and nonlinear forms of Langmuir, Freundlich, Tempkin, and Dubinin– Radushkevich (D–R) were used to reveal experimental data but experimental data for adsorption of AB1 dye in aqueous mixture onto biosorbent Acacia concinna fitted well to the Langmuir isotherm model with adsorption capacity 3.21✕10-4 Adsorption thermodynamic study showed that adsorption of AB1 dye onto adsorbent Acacia concinna was endothermic and spontaneous process. This study revealed that biosorbent Acacia concinna was good biosorbent for removal of dyes from aqueous solution.

Key Words
adsorption; acid black 1; pseudo second order; nonlinear isotherms; three parameter isotherms; acacia concinna

Aqsa Naz, Hina Masood, Samreen Ehsan: Department of Chemistry, The Government Sadiq College Women University, Bahawalpur 63000, Pakistan
Tayyab Tahir: Department of Chemistry, Government College University Faisalabad, Faisalabad 38000, Pakistan

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