Browsing by Author "Dilek, Filiz B."

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Citation - WoS: 12
Citation - Scopus: 12
Removal of Pesticides From Secondary Treated Urban Wastewater by Reverse Osmosis
(Springer Heidelberg, 2023) Ates, Nuray; Uzal, Nigmet; Yetis, Ulku; Dilek, Filiz B.
The residues of pesticides that reach water resources from agricultural activities in several ways contaminate drinking water resources and threaten aquatic life. This study aimed to investigate the performance of three reverse osmosis (RO) membranes (BW30-LE, SW30-XLE, and GE-AD) in rejecting four different pesticides (tributyl phosphate, flutriafol, dicofol, and irgarol) from secondary treated urban wastewater and also to elucidate the mechanisms underlying the rejection of these pesticides. RO experiments were conducted using pesticide-spiked wastewater samples under 10 and 20 bar transmembrane pressures (TMP) and membrane performances were evaluated. Overall, all the membranes tested exhibited over 95% rejection performances for all pesticides at both TMPs. The highest rejections for tributyl phosphate (99.0%) and irgarol (98.3%) were obtained with the BW30-LE membrane, while for flutriafol (99.9%) and dicofol (99.1%) with the GE-AD membrane. The increase in TMP from 10 to 20 bar did not significantly affect the rejections of all pesticides. The rejection performances of RO membranes were found to be governed by projection area as well as molecular weight and hydrophobicity/hydrophilicity of pesticides. Among the membranes tested, the SW30-XLE membrane was the most prone to fouling due to the higher roughness.
Citation - WoS: 16
Citation - Scopus: 23
Recovery of Caustic From Mercerizing Wastewaters of a Denim Textile Mill
(desalination Publ, 2015) Varol, Cihangir; Uzal, Nigmet; Dilek, Filiz B.; Kitis, Mehmet; Yetis, Ulku
The objective of this study was to evaluate caustic recovery from mercerizing wastewater originating from a denim textile producing plant using membrane technology. For this purpose, ultrafiltration (UF) and nanofiltration (NF) processes were considered. In the first stage, in an attempt to control the possible membrane fouling, pretreatment alternatives of flocculation, centrifugation, and microfiltration were evaluated. These pretreatment application alternatives were unsuccessful as they did not provide considerable color and solids removal. In the second stage, UF and NF processes were tested using a tight UF membrane (GR95PP, Alfalaval) and three NF membranes (NP010 and NP030, Microdyn Nadir, and MPF34, Koch Membranes) to accomplish the caustic recovery without applying any pretreatment. The best performance was obtained with NP010 NF in terms of permeate flux along with color and COD rejections. Then, for this membrane the effects of transmembrane pressure (4.03 and 6.23 bar), cross-flow velocity (from 0.40 to 1.40 m/s), and feed temperature (20 and 40 degrees C) were investigated. Temperature positively affected the permeate flux without significant loss in recovery and rejections. Caustic stream produced had about 98-100% of NaOH in the feed at a concentration of 30-40 g/L and therefore was recyclable after a concentration process.