Engin G.O.,Gebze Institute of Technology |
Muftuoglu B.,Istanbul Water and Sewerage Administration |
Senturk E.,Gebze Institute of Technology
Desalination and Water Treatment | Year: 2012
During biosorption, removal is ensured by several mechanisms that occurred between living or nonliving microorganisms and transporting metal ions. In this study, the kinetics, equilibrium, and thermodynamics of the biosorption of Cu2+ onto dried activated sludge and Spirulina platensis from aqueous solution were investigated at different experimental conditions. The biosorption characteristics were investigated with respect to some of the significant parameters including the effect of pH, biosorbent dosage, and temperature. The Langmuir, Freundlich, and Temkin equilibrium adsorption models were studied. Results showed that Langmuir isotherm model fitted well the experimental data followed by the other isotherm models used. In order to determine the mechanism of the biosorption, kinetic models were applied. The results of the kinetic studies indicated that the biosorption processes fitted the pseudo-second-order model. The thermodynamic parameters were also calculated, and the values indicated that the biosorption process was spontaneous, exothermic, and more ordered in nature. © 2012 Desalination Publications.
Ogurlu M.,Istanbul Water and Sewerage Administration |
Bayram B.,Yildiz Technical University
Fresenius Environmental Bulletin | Year: 2014
Istanbul is one of the most crowded metropolitan areas of the world with an approximate population of 13 million. Fresh water is supplied to this megacity from seven reservoirs located on both the European and the Asian sides. Thus, protection of water resources is extremely important. Due to increase in water demand and to protect the existing water resources from pollution, it is necessary to hinder and almost stop any human activities such as construction works at the watersheds of these reservoirs. In this study, a web-based GIS system has been designed which allows to make queries by the property owners to get basic information about the status of their parcel. This system is designed to support the works of Istanbul Water and Sewerage Administration (ISKI). Using this system, the usage or construction-right and more spatial information of the parcels which are located in the protection zones of the reservoirs can be queried easily. The first version of the developed system has been activated by ISKI in 2008 and the last version has been completed in 2010. The developed web-based system has been visited by nearly 159,000 people and around 500,000 parcels were queried. In the year of 2011 this number has been doubled. © by PSP.
Uyak V.,Pamukkale University |
Soylu S.,Pamukkale University |
Topal T.,Pamukkale University |
Karapinar N.,Pamukkale University |
And 3 more authors.
Environmental Forensics | Year: 2014
This study presents the seasonal and spatial variations of trihalomethanes (THMs) and haloacetic acids (HAAs) in 30 sampling points within three water distribution systems of Istanbul City, Turkey. The effects of surface water quality, seasonal variation, and species differences were examined. The occurrence of chlorinated THMs and HAAs levels was considerably lower in the system in which raw water is subjected to pre-ozonation versus pre-chlorination. Seasonal analysis of the data indicated that the median concentration of four THMs (THM4) was higher than nine HAAs (HAA9) concentrations in all three distribution systems sampling points. For all distribution systems monitored, the highest median THM4 and HAA9 concentrations were observed in the spring and summer season, while the lowest concentrations of these disinfection byproduct (DBP) compounds were obtained in the fall and winter period. Due to the higher level of bromide in supplying waters of these two systems, moderate levels of brominated DBP species have been observed in the Kagithane and Buyukcekmece distribution systems districts. In fact, Spearman partial correlations (Spearman rank correlation coefficients [rs]) tend to be higher among analogues in terms of number and types of substituent, especially TCAA with TCM (rs 0.91), and DBAA with DBCM (rs 0.90). In contrast, the hydraulic (residence time and flow rate) and chemical mechanisms (hydrolysis, volatilization, and adsorption) affect the fate and transport of DBPs in distribution systems. Seasonal and spatial variations of DBPs presented in this study have important implications on regulatory issues and from an epidemiological point of view. © 2014 Taylor & Francis Group, LLC.
Gulec A.,Istanbul Water and Sewerage Administration |
Cevher O.,Sakarya University |
Ustel F.,Sakarya University |
Turk A.,Sakarya University |
And 2 more authors.
Materials Performance | Year: 2011
A study was conducted to compare the performance of sprayed coatings for ductile iron (DI) pipe. DI pipe samples were coated with zinc (Zn) and Zn/aluminum (Al) 85/15 to conduct the investigations. Structures coated using twin wire electric arc (TWEA) spray techniques were compared and their protective values evaluated, along with accelerated salt spray corrosion tests. The contribution of the surface oxide layer on DI to corrosion-resistance performance was investigated and some empirical studies were conducted on industrially produced pipe coatings and industrial results. The test sample surface, corrosion products and pitting corrosion were investigated by scanning electron microscopy (SEM) at the end of the corrosion test. The results of the investigations revealed that Zn and Zn/Al 85/15 coatings contain oxides and the Zn/Al alloy coating had relatively dense structure with less porosity.
Insel G.,Technical University of Istanbul |
Guder B.,Technical University of Istanbul |
Gunes G.,Istanbul Water and Sewerage Administration |
Ubay Cokgor E.,Technical University of Istanbul
Water Science and Technology | Year: 2012
The design and operational parameters of an activated sludge system were analyzed treating the municipal wastewaters in Istanbul. The design methods of ATV131, Metcalf & Eddy together with model simulations were compared with actual plant operational data. The activated sludge model parameters were determined using 3-month dynamic data for the biological nutrient removal plant. The ATV131 method yielded closer sludge production, total oxygen requirement and effluent nitrogen levels to the real plant after adopting correct influent chemical oxygen demand (COD) fractionation. The enhanced biological phosphorus removal (EBPR) could not easily be predicted with ATV131 method due to low volatile fatty acids (VFA) potential. © IWA Publishing 2012.