Aykan Karademir | Kocaeli University (original) (raw)

Papers by Aykan Karademir

Environmental Science and Pollution Research

Energy Sources, Part A: Recovery, Utilization, and Environmental Effects

Journal of Material Cycles and Waste Management, 2016

Waste Management & Research, 2016

Ecological problems arising after the construction and operation of a waste incineration plant ge... more Ecological problems arising after the construction and operation of a waste incineration plant generally originate from incorrect decisions made during the selection of the location of the plant. The main objective of this study is to investigate how the selection method for the location of a new municipal waste incineration plant can be improved by using a dispersion modelling approach supported by geographical information systems and multi-criteria decision analysis. Considering this aim, the appropriateness of the current location of an existent plant was assessed by applying a pollution dispersion model. Using this procedure, the site ranking for a total of 90 candidate locations and the site of the existing incinerator were determined by a new location selection practice and the current place of the plant was evaluated by ANOVA and Tukey tests. This ranking, made without the use of modelling approaches, was re-evaluated based on the modelling of various variables, including the concentration of pollutants, population and population density, demography, temporality of meteorological data, pollutant type, risk formation type by CALPUFF and re-ranking the results. The findings clearly indicate the impropriety of the location of the current plant, as the pollution distribution model showed that its location was the fourth-worst choice among 91 possibilities. It was concluded that the location selection procedures for waste incinerators should benefit from the improvements obtained by the articulation of pollution dispersion studies combined with the population density data to obtain the most suitable location.

Journal of the Air Waste Management Association, Jun 19, 2013

A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorin... more A study was conducted to observe the changes in polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) levels and congener profiles in the flue gas of a hazardous waste incinerator during two start-up periods. Flue gas samplings were performed simultaneously through Air Pollution Control Devices (APCDs) (including boiler outlet, electrostatic precipitator (ESP) outlet, wet scrubbers (WS) outlet, and activated carbon (AC) filter outlet) in different combustion temperatures during a planned cold (long) start-up and an unplanned warm (short) start-up. The results showed that PCDD/F concentrations could be elevated during the start-up periods up to levels 3-4 times higher than those observed in the normal operation. Especially lower combustion temperatures in the short start-ups may cause high PCDD/F concentrations in the raw flue gas. Assessment of combustion temperatures and Furans/Dioxins values indicated that surface-catalyzed de novo synthesis was the dominant pathway in the formation of PCDD/Fs in the combustion units. PCDD/F removal efficiencies of Air Pollution Control Devices suggested that formation by de novo synthesis existed in ESP also when in operation, leading to increase of gaseous phase PCDD/Fs in ESP Particle-bound PCDD/Fs were removed mainly by ESP and WS, while gaseous phase PCDD/Fs were removed by WS, and more efficiently by AC filter. This paper evaluates PCDD/F emissions and removal performances of APCDs (ESP, wet scrubbers, and activated carbon) during two start-up periods in an incinerator. The main implications are the following: (1) start-up periods increase PCDD/F emissions up to 2-3 times in the incinerator; (2) low combustion temperatures in start-ups cause high PCDD/F emissions in raw gas; (3) formation of PCDD/Fs by de novo synthesis occurs in ESP; (4) AC is efficient in removing gaseous PCDD/Fs, but may increase particle-bound ones; and (5) scrubbers remove both gaseous and particle-bound PCDD/Fs efficiently.

Journal of Selcuk University Natural and Applied Science, Nov 10, 2013

Journal of Environmental Science and Health Part a, Sep 24, 2010

An estimation and assessment of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo... more An estimation and assessment of the polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo furans (PCDD/Fs) exposure levels for the people living in Kocaeli, the most industrialized area of Turkey, are presented. The information is based on the results of PCDD/F analyses in the samples collected from various environmental media and the multimedia exposure assessment methodology. Exposure scenarios were constructed on a site-specific basis by combining the exposure pathways appropriate to the area, and the activity patterns of the people living in Kocaeli. The model showed that the exposure levels of PCDD/Fs were in the range of 3.7-13.1 pg I-TEQ.kg-1 bw for adult receptors, which are higher than the recommended TDI value of 2 pg TEQ.kg-1 bw. The PCDD/F intakes for rural receptors were estimated to be three times higher than those for urban and semi-urban receptors due mainly to the consumption of locally grown foods. The assessment of the contributions of various exposure pathways to the total exposure and the sensitivity analysis performed based on a probabilistic approach indicated that PCDD/F intakes for adult receptors are directly proportional to the locally grown fraction of plant groups consumed.

Environmental Engineering and Management Journal

High resolution gas chromatography coupled with high resolution mass spectrometry systems are oft... more High resolution gas chromatography coupled with high resolution mass spectrometry systems are often used for the analyses of dioxins at low concentrations in environmental sample matrices such as soil, vegetation, sediment, air and food. Since the construction and operation costs of these systems are so expensive, the most of the laboratories in the developing countries haven't the systems with high resolution mass spectrometry. Thus, cheaper systems with similar sensitivity such as high resolution gas chromatography coupled with low resolution mass spectrometry systems in negative chemical ionization mode may be beneficial to assess the dioxin pollution levels in environmental samples before the elaborate studies on dioxin contamination and stochastic risk assessment. In this manuscript, 17 toxic congeners of dioxins were analyzed by a system with low resolution mass spectrometry. The sensitivity, stability and resolution power of the system for the analysis of dioxins were investigated. The calibration experiments in 3 different periods were studied and the minimum detection limits were determined by using the labeled and unlabeled standard solutions. The differences according to operation conditions of the ion source were examined and expounded by using relative response factor and relative standard deviation values obtained from sequential injections. Finally, it was performed a sample analysis program for some local food samples with the aim of observing the feasibility of the system on food samples that have very low level dioxin concentrations such as egg and cow's milk. It was found that the systems with low resolution mass spectrometry in negative chemical ionization mode are capable to fulfill the requirements for the environmental analyses of dioxins at ppt levels, with the exception of 2,3,7,8-TCDD showing lower sensitivity in negative chemical ionization. Thus, using the systems with low resolution mass spectrometry in negative chemical ionization mode may be recommended for the some environmental studies for dioxins in the absence of the systems with high resolution. On the other hand, the proposed methodology cannot be used for the direct analysis of dioxins without improvement of 2,3,7,8-TCDD detection and quantification.

Journal of Environmental Science and Health, Part A, 2006

Trace concentrations of a variety of chemicals remain in solid residues following combustion even... more Trace concentrations of a variety of chemicals remain in solid residues following combustion even in properly designed and operated incinerators. In the present study, the adsorbable organic halogen (AOX) levels of the solid residues, i.e., bottom ash, fly ash, and filter cake, were investigated during a 82-day of continuous operation of a Hazardous and Clinical Waste Incinerator. The distribution of halogens in the waste input prior to the incineration was also determined. The AOX levels measured in bottom ash, fly ash and filter cake were in the range of 0.014-1.879, 0.012-0.263, and 0.004-0.062 mg-Cl(-)/kg, respectively. The AOX levels are significantly low in the fly ash and filter cake due to the post-combustion process in the incinerator. At the end of the 82 days, the total AOX output in the bottom ash, fly ash, and filter cake were 571, 3.71, and 6.26 g, respectively. The partitioning of the total AOX in solid residues was 98.28, 0.64, and 1.08% for the bottom ash, fly ash and filter cake, respectively. This shows that the bottom ash is more contaminated with AOX than the other two residues.

Concentrations of Zn, Fe, Mn and Pb were determined in biota, sediment and sea water samples coll... more Concentrations of Zn, Fe, Mn and Pb were determined in biota, sediment and sea water samples collected seasonally from two stations in the Marmara Sea in Turkey. The levels of Fe and Mn in biota and Zn, Mn and Pb in sediment samples were higher than the previous studies. The order of heavy metal concentrations in all samples was: Fe > Mn > Zn > Pb.

Waste Management & Research, 2014

As studies on municipal solid waste management increased in recent years, many new mathematical m... more As studies on municipal solid waste management increased in recent years, many new mathematical models and approaches with a focus on determining the best treatment and disposal scenario were developed and applied. In this study, a mixed integer linear programming model was developed to be used as a facilitative tool for the cost minimisation of municipal solid waste management practices. Since municipal solid waste mass is a mixed composition of various types of waste components with different physical and chemical properties, the model was designed to include all the suitable treatment and disposal methods for these different waste components. The method alternatives with multiple waste inputs, such as aerobic biological treatment and the thermal processes, were divided into a number of inputs to remove their non-linear structures. This way, linear programming could be used, and the linear cost function could be minimised over a set of linear constraints with integer variables. The model was applied to the city of Kocaeli, which will require a new waste management application in the future, beginning from 2015. The results obtained for different haul distance constraints in the study area were presented and assessed. The results showed that all the information required for a comprehensive management task could be modelled by a linear optimisation model with a divided processes approach easily.

Combustion Science and Technology, 2014

Environmental science and pollution research international, Jan 17, 2014

Perfluorooctane sulfonic acid (PFOS) and related substances have been listed as persistent organi... more Perfluorooctane sulfonic acid (PFOS) and related substances have been listed as persistent organic pollutants (POPs) in the Stockholm Convention. Countries which have ratified the Convention need to take appropriate actions to control PFOS use and release. This study compiles and enhances the findings of the first inventory of PFOS and related substances use in Turkey conducted within the frame of the Stockholm Convention National Implementation Plan (NIP) update. The specific Harmonized Commodity Description and Coding System (Harmonized System (HS)) codes of imported and exported goods that possibly contain PFOS and 165 of Chemical Abstracts Service (CAS) numbers of PFOS-related substances were assessed for acquiring information from customs and other authorities. However, with the current approaches available, no useful information could be compiled since HS codes are not specific enough and CAS numbers are not used by customs. Furthermore, the cut-off volume in chemical database...

Causes, Impacts and Solutions to Global Warming, 2013

Journal of the Air & Waste Management Association, 2014

This study includes an application of the first two phases of a new three-phased decision-making ... more This study includes an application of the first two phases of a new three-phased decision-making structure that was developed to overcome the problems related to ecological safety and social justice in site selection applications. It was conducted on a current site selection problem related to the municipal solid waste disposal facilities in Kocaeli, the most industrialized region of Turkey. In order to assess the deficiencies of the legal site selection procedures related to ecological safety, two different decision tree modes were applied separately. The first mode (&amp;quot;Legislation&amp;quot;) concerns the current buffer zone applications given in the regulations, while the second one (&amp;quot;Proposed&amp;quot;) includes the applications of the new decision-making structure proposed in this study. Since it was assumed that the subjective tendencies of the decision makers on the weightings would have a significant effect on the final decision, these two modes were assessed by employing two different weighting models. The results were obtained from all of the scenarios related to selection of suitable sites with three different area requirements (15, 250, and 500 acres) for the solid wastes generated in the Kocaeli region. The results showed that the possible changes in the decision structure could cause significant differences in the final decision related to selection of the most suitable sites. The most highest and lowest differences were at the &amp;quot;Legislation&amp;quot; mode for 15 acres and 500 acres, respectively. Furthermore, the results obtained in the study showed that the possible differentiations in the criteria weightings could also cause significant differences in the suitability ranking. Therefore, to get a reliable final decision, a statistical assessment of these differentiations should be made. The results showed that the possible changes in the decision structure could cause significant differences in the final decision related to selection of the most suitable sites. Furthermore, the results obtained in the study showed that the possible differentiations in the criteria weightings could also cause significant differences in the suitability ranking. Therefore, to get a reliable final decision, a statistical assessment of these differentiations should be made.

Journal of the Air & Waste Management Association, 2013

Environmental Science and Pollution Research, 2013

This study evaluates PCDD/F pollution in the surface sediments of Izmit Bay (Turkey) and assesses... more This study evaluates PCDD/F pollution in the surface sediments of Izmit Bay (Turkey) and assesses the possible sources of PCDD/F inputs to the bay. The results showed that concentrations of toxic PCDD/F congeners in the sediments varied between 0.45 and 255 ng WHO 2005 -TEQ/kg dry weight. Pollution mapping shows that PCDD/F levels in the central section of Izmit Bay are much higher than those in the eastern and the western sections. Sediments collected from the northern part of the central section showed very high PCDD/F concentrations. The samples reveal three different congener profiles dominated by OCDF, 1,2,3,4,6,7,8-HpCDF, and OCDD respectively. The dominance of OCDF in the sediment samples taken from the central section was attributed to the former production of vinyl chloride monomer in the area, while that of 1,2,3,4,6,7,8-HpCDF was attributed to the (previously unknown) use of a chlorophenol-based fungicide in the region. The OCDD dominated group was explained by the use of pentachlorophenol. The results indicate that historic industrial discharges are the main contributor to the PCDD/F pollution in the sediments.

PAH and PCB concentrations were determined in mussel samples collected from Izmit Bay at the east... more PAH and PCB concentrations were determined in mussel samples collected from Izmit Bay at the east of marmara Sea. The samples were taken from ten points in spring season and analyzed by gas chromatography after ultrasonic extraction. Total PAH concentrations varied between 2.5-13.9 ng.g-wet wt., while the total PCB concentrations were between 4.2-140.7 ng.g-wet wt. The results indicates a considerable pollution problem in the bay, especially with respect to PCBs. 1 2 2 1 1 3 1 2 3 1 1 Introduction Izmit Bay, located in Northeastern Marmara Sea, has strongly been affected by growing populations and industrialization since 1960s. The study presents the first results of PAH/PCB analyses in the mussel samples in the framework of a pollution monitoring project in Izmit Bay.