Ebubekir Yüksel

Reuse of reactive dyehouse wastewater by nanofiltration: process water quality and economical implications

This paper presents the permeate water quality and economy of reuse by nanofiltration membranes in reactive dyeing. Actual remazol dye bath wastewater, which contains high concentrations of NaCl at the level of 80 g/l, was studied during experiments. Experimental results showed that permeate samples were colorless and remained enough NaCl to be reused in reactive dye bath preparation again. Neutralization by HCl decreased the permeate flux and also increased the NaCl recovery. Permeate flux value was about 10 l/m2 h and Cl− rejection was achieved at the level of 10%. In addition, economical analyses were done based on experimental results and the payback period of the reuse system was calculated as less than 2 years.

Quality of the Bottom Sediment Prior to Dredging in the Golden Horn of Istanbul

Abstract The Golden Horn has experienced severe pollution due to uncontrolled domestic and industrial wastewater discharges until recent years. A restoration project has been developed by our universities, upon a request from Istanbul Metropolitan Municipality. Two principal alternatives for the dredging and disposal of the bottom sediments were considered: disposing on the land and disposing in the sea. Both of these alternatives include several sub-alternatives. Characterization of the sediment quality is crucially important for selecting the best alternative considering the cost, environmental impact and public acceptance. However, only a few and rather old studies were present with which it was not possible to get a comprehensive information on the critical sediment characteristics. Therefore, the aim of this study was determination of spatial distribution of sediment characteristics. The project area, at which the sediment quality determined, covers the part of the Golden Horn remaining at the upstream of Valide Sultan Bridge. The number of sampling stations were thirteen and the sediment samples were collected from 0.0 m, 5.0 m and 10.0 m from the bottom surface. The following parameters were measured on each sample: Total solids, organic matter, total phosphorus, TKN, oil and grease, total sulphur, and sediment oxygen demand (SOD). Sediment oxygen demand parameter was further divided into three fractions, namely, biological (SOD-B) and chemical (SOD-C). Average organic content of the bottom sediment was around 10% while ammonia and sulfur exhibit very high levels. It is found that the bottom sediment is well stabilized with very low organic content below 5.0 m from the bottom surface. It can be said that, removing the upper 5 m of the bottom sediment will be enough for creating a relatively stable bottom surface which will cause oxygen depletion in the overlaying water at acceptable levels. High SOD values of the bottom sediment makes the alternatives considering disposal in the Marmara Sea and Black Sea inapplicable. High SOD-C values, especially, indicate that the sediment will cause a tremendous reduction in the oxygen concentration in a very short time at any marine environment, and even it may create anaerobic conditions. Therefore, disposal of dredged sediment into abandoned mines 4 km from the Golden Horn by a pressure pipeline has been chosen as the best applicable alternative.

Comparative evaluation of the results for the synthetic and actual reactive dye bath effluent treatment by nanofiltration membranes.

Abstract In this study, the results of nanofiltration experiments carried out on reactive dye house wastewaters are presented. The experiments were performed using lab-scale membrane system. Permeate quality was appropriate to reuse permeate in dyeing process again. Pretreatment and neutralization were the parameters which are very important for the recovery of high amounts of salt and water at the permeate stream. In addition, use of HCl instead of H2SO4 for neutralization increased the NaCl recovery.

Treatment of winery wastewater by electrocoagulation process

Abstract Winery wastewater treatment by electrocoagulation (EC) process using aluminum (Al) and iron (Fe) electrodes was investigated. The effects of operational parameters such as initial pH, current density and electrolysis time were investigated separately. Chemical oxygen demand (COD), turbidity and color were used to measure the treatment efficiency. Electrode consumptions were calculated per m3 of wastewater. Amount of sludge produced by EC was also reported per m3 of wastewater. The optimum operating conditions were defined due to the initial pH, applied current density and operating time for Fe and Al electrodes. Maximum removal efficiencies were found at pH 7 for Fe electrode and pH 5.2 for Al electrode with current density of 300 A/m2 for both electrodes and with an operating time of 90 min and 120 min for Fe and Al electrodes, respectively. The removal efficiencies were found as 46.6% (COD), 80.3% (color) and 92.3% (turbidity) for Fe electrode while they were 48.5% for COD, 97.2% for color and ...

A Review of State-of-the-Art Technologies in Dye-Containing Wastewater Treatment – The Textile Industry Case

Recently, new single or hybrid/combined processes have attracted much attention for treatment of textile and dyeing wastewaters. These processes which may be termed as “state of the art technologies” are membrane separation processes, ultra‐ sonic, photochemical and electrochemical processes. Although the conventional methods still have been tried with some new materials such as, new adsorbents or coagulants, employing the new generation methods such as, electrocagulation-elec‐ trooxidation, sonooxidation or photo oxidation are gaining in popularity when the treatment of textile wastewaters is discussed. The purpose of the book chapter is to bring an overview on the new treatment methods for textile wastewaters, one of the most important source of environmental pollution. Despite the fact that there is no uniform standard currently, many countries have legalized some strict discharging standards and scientists and researchers face new technologies including electrical, sonic, magnetic, optical and thermal methods. Although many researches on treat‐ ment of synthetic or real wastewaters with various methods are available, very few researches have been carried out on the cutting-edge technologies. Moreover, there are a lot of review article or book chapters on textile wastewater treatment process‐ es individually based on each conventional process such as coagulation, adsorption, chemical oxidation, and biological decolorization. Therefore, in this part of the book, following major and minor titles are stated truly on the aforementioned new technologies. Besides, these parts are not only about cutting-edge technologies, but also related with conventional methods and their new applications in colored wastewater treatment area briefly.

Recent developments in forward osmosis membrane bioreactors: a comprehensive review

AbstractForward osmosis or osmotic membrane bioreactor (FOMBR) has attracted great attention for wastewater treatment and reuse since conceptually introduced as a process. It has been proposed to reduce the high energy consumption in the conventional MBR, has lower membrane fouling propensity, and produce higher quality water. Moreover, RO process can be used after FOMBR to reconcentrate the diluted DS to be used for FO again. Besides significant advantages, when compared to conventional MBRs; lower water flux, concentration polarization, and salt accumulation because of high retention of FO in the bioreactor still remains as major drawbacks and challenges of FOMBR systems that need to be solved. In the last few years, many advances in development of FOMBR are stated to overcome the drawbacks of the system. The researches focused on manufacturing of high performance FO membranes and orientation, utilizing various different draw solutions providing required osmotic pressure and minimum reverse salt flux, a...

A hardware test setup for grid connected and island operation of micro hydro power generation systems

This paper presents a micro hydro power generation hardware setup, established via a research project at Gebze Institute of Technology (GIT), Turkey. This project is founded by the government and aims to increase utilization of potential for small, local hydro power generation. The hardware setup consists of a newly designed cross flow type hydro turbine, two different generators (asynchronous and synchronous up to 20 kW power range) and all equipment necessary for grid connected operation and islanding. The setup can be used for two purposes: primarily performance tests of newly designed micro hydro turbines, and research and development studies to provide new regulations and technical guidelines regarding to energy management and grid connected and island (stand-alone) operation which concern for distributed generation versatility. The hardware setup offers a similar environment to that of real site which can easily be adapted to the clients test and turbine evaluation requirements.

Ozonation in direct filtration

Abstract The effects of pre-ozonation on the effluent quality and the head losses through a deep filter were investigated using two identical deep bed filters receiving the same raw water. One of the influents to the filters was pre-ozonated and the other was aerated using identical contact chambers and diffusers. It was observed that the pre-ozonated filter resulted in significantly better effluent quality. It was found that the delay time after the pre-ozonation process has an important effect in direct filtration. The shorter the delay time, the less is the head loss and the better is the effluent quality. Indices that calculate Specific Energy (cm of head required per gram of solids captured) in deep bed filters were developed. The Filterability Index given in the literature and the Specific Energy values were used to compare the performance of the two identical filters receiving the same raw water. It was shown that the pre-ozonated water required on average 1.1 times more specific energy compared to the same aerated water and the experiments with short ozone delay times had on average 4.9 times less specific energy compared to the long delay experiments.

An experimental investigation on the hydraulic behavior of declining rate filtration

ABSTRACT Hydraulic behavior of declining rate filtration (DRF) was investigated by means of pilot-scale experiments. A bank of four declining rate filters was constructed and operated. The common water level in the filters, individual filter velocities, and head losses in the filters were carefully monitored and recorded as functions of time. Many of the previous studies on DRF employed either a single average filtration velocity or a single coagulant dosage. In this study, however, filter runs were repeated treating the same water at several different filtration rates and coagulant dosages. Using such an experimental matrix of several different rates and coagulant dosages allowed an evaluation of the behavior of the declining rate filtration system under different operating conditions and the effects of the mentioned variables on various hydraulic characteristics of the DRF system. The validity of certain simplifying assumptions used in design calculations was also tested in these experiments. It is beli...