Publications2010

STOCH ENVIRON RES RISK ASSESS (2010) 24:57–65

Title: Average mass concentrations of TSP, PM10 and PM2.5 in Erzurum urban atmosphere, Turkey
Authors: Hanefi Bayraktar, F. Sezer Turalioğlu, Gürdal Tuncel
Abstract:In this study, particulate matters (TSP, PM10, PM2.5 and PM10–2.5) which are hazardous for environment and human health were investigated in Erzurum urban atmosphere at a sampling point from February 2005 to February 2006. During sampling, two low volume samplers were used and each sampling period lasted approximately 24 h. In order for detection of representative sampling region and point of Erzurum, Kriging method was applied to the black smoke concentration data for winter seasons. Mass concentrations of TSP, PM10 and PM2.5 of Erzurum urban atmosphere were measured on average, as 129, 31 and 13 lg/m3, respectively, in the sampling period. Meteorological factors, such as temperature, wind speed, wind direction and rainfall were typically found to be affecting PMs, especially PM2.5. Air temperature did not seem to be significantly affecting TSP and PM10 mass concentrations, but had a considerably negative induction on PM2.5 mass concentrations. However, combustion sourced PM2.5 was usually diluted from the urban atmosphere by the speed of wind, soil sourced coarse mode particle concentrations (TSP, PM10) were slightly affected by the speed of wind. Rainfall was found to be decreasing concentrations to 48% in all fractions (TSP, PM10, PM10–2.5, PM2.5) and played an important role on dilution of the atmosphere. Fine mode fraction of PM (PM2.5) showed significant daily and seasonal variations on mass concentrations. On the other hand, coarse mode fractions (TSP, PM10 and PM10–2.5) revealed more steady variations. It was observed that fine mode fraction variations were affected by the heating in residences during winter seasons.

ENVIRON MONIT ASSESS(2010) 166:11–27

Title: Air pollution forecasting in Ankara, Turkey using air pollution index and its relation to assimilative capacity of the atmosphere
Authors: D. Deniz Genc, Canan Yesilyurt, Gurdal Tuncel
Abstract:Spatial and temporal variations in concentrations of CO,NO,NO2, SO2, andPM10, measured between 1999 and 2000, at traffic-impacted and residential stations in Ankara were investigated. Air quality in residential areas was found to be influenced by traffic activities in the city. Pollutant ratios were proven to be reliable tracers to differentiate between different sources. Air pollution index (API) of the whole city was calculated to evaluate the level of air quality in Ankara. Multiple linear regression model was developed for forecasting API in Ankara. The correlation coefficients were found to be 0.79 and 0.63 for different time periods. The assimilative capacity of Ankara atmosphere was calculated in terms of ventilation coefficient (VC). The relation between API and VC was investigated and found that the air quality in Ankara was determined by meteorology rather than emissions.

INTERNATIONAL JOURNAL OF CIVIL AND ENVIRONMENTAL ENGINEERING

Title: Enhanced Nutrients Removal in Conventional Anaerobic Digestion Processes
Authors:
Abstract:One of the main challenges for one phase anaerobic digestion processes is the high concentration of NH4+ and PO43- ions in the digested sludge supernatant. This project focuses on enhancing the removal of nutrients during the anaerobic digestion process through fixing both NH4+ and PO43- ions in the form of struvite (magnesium ammonium phosphate, MAP, MgNH4PO4.6H2O) within the anaerobic sludge. Batch anaerobic digestion tests showed that Mg2+ concentration in the range 279 – 812 mg/L had insignificant effect on CGP but incurred a slight increase in COD removal. The reactor that had soluble Mg2+:NH4 +:PO43- at a molar ratio of 1.28:1:00:1:00 achieved the best performance enhancement of 8% increase in COD removal and 32% reduction in NH4+ in the reactor supernatant. Overall, the results show that there is a potential to optimise conventional anaerobic digestion such that supernatant lean in P and N, and sludge rich in nutrients are obtained.

ENG. LIFE SCI.2010, 10, No. 6, 552–559

Title: Effect of operational parameters on anaerobic co-digestion of dairy cattle manure and agricultural residues: A case study for the Kahramanmaras- region in Turkey
Authors: Emrah Alkaya, Tuba Hande Erguder, Göksel N. Demirer
Abstract:The aim of this study was to investigate the effect of temperature and hydraulic retention time (HRT) on anaerobic co-digestion/biomethanation of cattle manure and agricultural residues (clover, grass and wheat straw). For this purpose, 12 semi-continuous reactors, fed with/without agricultural residues, were operated under varied temperature (10+, 20+ and 35±1C) and HRT (20 and 30 days) conditions. During the experimental study, all reactors were fed once on a daily basis and operated with an organic loading rate of 3 g volatile solids (VS)/Ld. Daily biogas production, pH, biogas composition, volatile fatty acids, chemical oxygen demand and solids’ (dry matter andVS) concentrations were analyzed. Results indicate that the effect of agricultural residue addition did not influence the rate and extent of biomethanation of cattle manure. An effect of temperature was clearly observed on reactor performance for both operational HRTs of 20 and 30 days. At 35±1C, reactors produced 299–324mL biogas/g VS added, whereas this value remained between 87–138mL biogas/g VS for the reactors run at 20+C. The results were comparable to the studies performed on anaerobic digestion of cattle manure in terms of both methane production yield (39–182mL CH4/g VS added) and dry matter reduction efficiencies (33–51%).

TRENDS IN ANALYTICAL CHEMISTRY, Vol. 29, No. 9, 2010

Title: Quality improvement in determination of chemical oxygen demand in samples considered difficult to analyze, through participation in proficiency-testing schemes
Authors: F. Raposo, V. Ferna´ndez-Cegrı´, M.A. De la Rubia, R. Borja, J. Beltra´n, C. Cavinato, M. Clinckspoor, G. Demirer, E. Diamadopoulos, J.C. Frigon, J. Koubova, M. Launay, R. Me´ndez, G. Menin, J. Noguerol, H. Uellehdahl,S. West
Abstract:Chemical oxygen demand (COD) is a critical analytical parameter in waste and wastewater treatment, more specifically in anaerobic digestion, although little is known about the quality of measuring COD of anaerobic digestion samples. Proficiency testing (PT) is a powerful tool that can be used to test the performance achievable in the participants laboratories, so we carried out a second PT of COD determination in samples considered ‘‘difficult’’ to analyze (i.e. solid samples and liquid samples with high concentrations of suspended solids). The results obtained (based on acceptable z-score values) may be considered satisfactory. When compared with the results of a previous similar scheme, the overall performance improved by around 30%, again demonstrating that analytical performance can be improved by regular participation in PT.

JOURNAL OF HAZARDOUS MATERIALS 181 (2010) 248–254

Title: The determination of fertilizer quality of the formed struvite from effluent of a sewage sludge anaerobic digester
Authors: Ayla Uysal, Y. Dilsad Yilmazel, Goksel N. Demirer
Abstract:The formation of struvite (MgNH4PO4·6H2O) in wastewater treatment plants can lead to scaling and thus operational problems reducing the treatment efficiency. However, struvite has significant commercial value as an agricultural fertilizer. Therefore, controlled struvite formation in wastewater treatment plants not only presents an opportunity to recover nutrients but also corresponds to the valorization of wastes. NH4–N and PO4–P removal and recovery from the effluent of a full-scale sewage sludge anaerobic digester via controlled struvite precipitation were investigated in this study. The effect of the residual heavy metal and micropollutant content of the formed struvite on fertilizer quality was also evaluated. Removal efficiencies of NH4–N, PO4–P and COD were 89.35%, 95% and 39.78% when Mg:N:P molar ratio was 1.5:1:1 and pH was 9.0. Mercury, nickel, zinc and chrome concentrations derived from struvite precipitation were below the regulatory limit for fertilizer usage in Turkey. The precipitate did not contain polychlorinated biphenyls (PCB). X-ray diffraction (XRD) analysis conducted on the precipitate indicated a struvite formation.

WASTE MANAGEMENT 30 (2010) 792–798 248–254

Title: Investigation of the effect of culture type on biological hydrogen production from sugar industry waste
Authors: Leyla Ozkan, Tuba H. Erguder, Goksel N. Demirer
Abstract:Aerobic biological treatment of opium alkaloid containing wastewater as well as the effect of gamma irradiation as pre-treatment was investigated. Biodegradability of raw wastewater was assessed in aerobic batch reactors and was found highly biodegradable (83–90% degradation). The effect of irradiation (40 and 140 kGy) on biodegradability was also evaluated in terms of BOD5/COD values and results revealed that irradiation imparted no further enhancement in the biodegradability. Despite the highly biodegradable nature of wastewater, further experiments in sequencing batch reactors (SBR) revealed that the treatment operation was not possible due to sludge settleability problem observed beyond an influent COD value of 2000 mg dm3. Possible reasons for this problem were investigated, and the high molecular weight, large size and aromatic structure of the organic pollutants present in wastewater was thought to contribute to poor settleability. Initial efforts to solve this problem by modifying the operational conditions, such as SRT reduction, failed. However, further operational modifications including addition of phosphate buffer cured the settleability problem and influent COD was increased up to 5000 mg dm3. Significant COD removal efficiencies (470%) were obtained in both SBRs fed with original and irradiated wastewaters (by 40 kGy). However, pre-irradiated wastewater provided complete thebain removal and a better settling sludge, which was thought due to degradation of complex structure by radiation application. Degradation of the structure was observed by GC/MS analyses and enhancement in filterability tests.

RADIATION PHYSICS AND CHEMISTRY79 (2010) 519–526

Title: Treatment of opium alkaloid containing wastewater in sequencing batch reactor (SBR)—Effect of gamma irradiation
Authors: Cavit B. Bural , Goksel N. Demirer , Omer Kantoglu, Filiz B. Dilek
Abstract:Aerobic biological treatment of opium alkaloid containing wastewater as well as the effect of gamma irradiation as pre-treatment was investigated. Biodegradability of raw wastewater was assessed in aerobic batch reactors and was found highly biodegradable (83–90% degradation). The effect of irradiation (40 and 140 kGy) on biodegradability was also evaluated in terms of BOD5/COD values and results revealed that irradiation imparted no further enhancement in the biodegradability. Despite the highly biodegradable nature of wastewater, further experiments in sequencing batch reactors (SBR) revealed that the treatment operation was not possible due to sludge settleability problem observed beyond an influent COD value of 2000 mg dm3. Possible reasons for this problem were investigated, and the high molecular weight, large size and aromatic structure of the organic pollutants present in wastewater was thought to contribute to poor settleability. Initial efforts to solve this problem by modifying the operational conditions, such as SRT reduction, failed. However, further operational modifications including addition of phosphate buffer cured the settleability problem and influent COD was increased up to 5000 mg dm3. Significant COD removal efficiencies (470%) were obtained in both SBRs fed with original and irradiated wastewaters (by 40 kGy). However, pre-irradiated wastewater provided complete thebain removal and a better settling sludge, which was thought due to degradation of complex structure by radiation application. Degradation of the structure was observed by GC/MS analyses and enhancement in filterability tests.

ITÜDERGISI/E SU KIRLENMESI KONTROLÜ Cilt:20, Sayı:2, 12-24 Kasım 2010

Title: Türkiye’de bir tekstil fabrikasında kimyasal madde değişimine yönelik ön değerlendirme
Authors: Ertan ÖZTÜRK, Göksel N. DEMİRER, Ülkü YETİŞ, Filiz B. DİLEK
Abstract:Kirlilik önleme çalışmalarında temel yaklaşımlardan birisi, kirletici özellikteki maddelerin daha az kirletici olanlar ile değiştirilmesidir. Bu çerçevede, biyolojik olarak kolay parçalanan maddelerin zor parçalananlara oranla uzun vadede daha az ekolojik problemlere neden olacağından hareketle, üretimde kullanılan kimyasal maddelerin biyodegradasyon özellikleri göz önüne alınması gereken önemli bilgilerden birisidir. Tekstil kimyasallarının toksik ve biyodegradasyon özellikleri konusunda yayınlanmış sınırlı sayıda çalışma bulunmaktadır. Kimyasalların biyodegradasyon potansiyellerini belirleme aşamasında, söz konusu kimyasala uygun yöntem seçilmesi önem arz etmektedir. Bu çalışmada, problemli kimyasalların ve alternatiflerinin biyodegradasyon potansiyellerini belirlemek amacıyla, OECD 302b (Zahn-Wellens) test metodu seçilmiştir. Testler, Türkiye’deki bir tekstil fabrikasında uygulanmakta olan reçetelerde kullanılan 2 adet kompleks yapıcı kimyasal madde (A ve B) ve kullanılma potansiyeli olan 1 adet kompleks yapıcı kimyasal maddenin (B*) biyodegradasyon potansiyellerini hem tek başlarına bulunmaları halinde var olan değerlerini doğrulamak, hem de birlikte kullanılmaları durumunda etkileşimlerini tespit etmek ve böylece, kimyasal değişikliğine karar verme aşamasında kullanmak amacıyla uygulanmıştır. Bu amaca yönelik olarak, kompleks oluşturan maddelerin farklı kombinasyonları ile kesikli reaktör deneyleri gerçekleştirilmiştir. Deneysel bulgular faktör analizi yöntemi ile istatistiksel analize tabi tutularak biyodegradasyon (bağlı değişken olarak) ve kompleks yapıcı madde konsantrasyonu (bağımsız değişken) arasındaki ilişki belirlenmiştir. Bu analizler, STATGRAPHIC istatistiksel yazılım programı kullanılarak yapılmıştır. Mümkün olabilecek kimyasal değişimine yönelik ön değerlendirme yapma amacıyla, doğrusal çoklu regresyon yöntemi ile matematiksel model oluşturulmuştur.

CLEAN – SOIL, AIR, WATER 2010, 38 (4), 387 – 393

Title: Effect of Initial Azo Dye Concentration and Biomass Acclimation on Sludge Digestion and Dye Co-treatment
Authors: Umay Gokce Ozkan-Yucel, Celal Ferdi Gokcay
Abstract:The effect of a reactive azo dye (the hydrolyzed form of Reactive Orange 107, HRO107) on the digestion of municipal waste sludge (WS) was studied. The study also focused on the effect of acclimation of the anaerobic mixed culture on dye treatment. Anaerobic batch assays were carried out in serum bottles under mesophilic conditions. Unacclimated and acclimated anaerobic mixed cultures were used for the study. Both unacclimated and acclimated anaerobic cultures completely reduced HRO107 during WS digestion. Inhibitory HRO107 concentration was found to be 800 mg/L for unacclimated mixed culture. Acclimation increased the inhibitory concentration level from 800 to 3200 mg/L. Sulfanilic acid and four other unidentified dye reduction end products were detected at the end of the assays. The results of this study indicated that anaerobic municipal WS digesters have the potential to be a cost efficient and effective pre treatment method.

WATER SCIENCE AND TECHNOLOGY—WST | 62.1 | 2010

Title: Application of the contingent valuation method in a developing country: a case study of the Yusufeli Dam in northeast Turkey
Authors: Emre Alp, Ülkü Yetis
Abstract:Hydroelectric power plants and dams often play an important role in developing countries in terms of their contribution to economy. In accordance with the energy policies of Turkish Republic, Yusufeli Dam and Hydroelectric Power Plant in Northeastern Turkey have been initiated. In this study, theContingent Valuation Method (CVM) was conducted in Yusufeli Village to determine the environmental costs of the Yusufeli Project. The purpose is to assess the willingness to pay (WTP) of Yusufeli Village residents for restoration of the environmental impacts of the dam project and also to investigate the underlying economic, psychological, and social motivations for WTP. WTP was calculated as US$761 per person which can further be used in the cost–benefit analysis. The results from thestudy suggest that application of the CVM in rural and urban areas located in the same region can show differences..

ENVIRONMENTAL TECHNOLOGY Vol. 31, No. 6, May 2010, 633–640

Title: Application of ADM1 model to a full-scale anaerobic digester under dynamic organic loading conditions
Authors: U.G. Ozkan-Yucel and C.F. Gökçay
Abstract:The IWA Anaerobic Digestion Model No. 1 (ADM1) was used to simulate the full-scale anaerobic sludge digester of Ankara Central Wastewater Treatment Plant. The digester is a completely mixed, once through continuous flow type which is being fed with a primary and secondary sludge mixture. The variability and unpredicted nature of the primary sludge composition was expected to challenge the model. A one-year dynamic data set from the digester was used for model calibration and validation in the study. The standard ADM1 model was corrected in the study with regard to nitrogen and carbon mass balances. A good correlation between the measured and simulated data was obtained for biogas yield, total volatile fatty acids and pH after heuristically calibrating stoichiometric and kinetic parameters of the ADM1 model. The simulation is sensitive to influent composition.

CURRENT ANALYTICAL CHEMISTRY, 2010, 6, 66-71

Title: Comparison of Source Regions Affecting SO42- and NO3- Concentrations at the Eastern Mediterranean and Black Sea Atmospheres
Authors: G. Doğan, G. Güllü, D. Karakaş, and G. Tuncel
Abstract:In this study, source regions of atmospheric sulfate and nitrate in rural areas at the Black Sea and the Mediterranean coasts of Turkey are compared. Stations on the Black Sea and Mediterranean Sea are located at Amasra and Antalya regions, respectively. Source regions of SO4 2- and NO3- are determined by using potential source contribution function (PSCF). Statistical significance of source regions assigned by PSCF were assured using bootstrapping with 3000 iterations. Source regions affecting sulfate and nitrate concentrations at the Mediterranean and Black Sea regions have some similarities and differences. Emissions from source regions in Russia and Balkan countries affect both the Mediterranean and Black Sea basins.

CHEMOSPHERE 81 (2010) 992–999

Title: Spatial distribution and source apportionment of PCBs in sediments around Izmit industrial complexes, Turkey
Authors: Kadir Gedik, Filiz DemircioĞlu, Ipek Imamoğlu
Abstract:The spatial distribution, degree of pollution and major sources of PCBs were evaluated in surficial sediments within the heavily urbanized and industrialized Izmit Bay and its main freshwater inputs. RPCB concentrations range from 2.90 to 85.4 ng g-1 in marine sediments and from ND to 47.7 ng g-1 in freshwater sediments. Results suggest that high concentrations of RPCBs were localized around a chlor-alkali plant and an industry that handles bulk liquid, dry and drummed chemicals, and petroleum products in the Bay. Using a chemical mass balance receptor model (CMB), major sources of PCBs in the region were investigated. The CMB model identified Aroclor 1254 and 1260 to be the major PCB sources in marine sediments and the less chlorinated Aroclor 1248 and 1242 as the major PCB sources in freshwater sediments. The potential sources for the PCBs were briefly discussed in terms of their use in various industrial applications.

BİYOLOJİ BİLİMLERİ ARAŞTIRMA DERGİSİ 3 (2), 33-38

Title: Meteorolojik Koşulların Mogan Gölü Su Kalitesine Etkileri
Authors: Firdes Yenilmez, Fatih Keskin, Ayşegül Aksoy
Abstract:Bu çalışmada sıcaklık, yağış, günlük güneşlenme şiddeti, gibi meteorolojik değişkenlerin ve su kalitesi parametrelerinin aralarındaki ilişkiler Mogan Gölü için incelenmiştir. Çözünmüş oksijen, pH, toplam azot, toplam fosfor ve diğer su kalitesi parametreleri dikkate alınmıştır. Çalışmada 2007-2008 periyoduna ait veriler kullanılmıştır. Su kalite parametrelerinin birbiriyle ve de meteorolojik değişkenlerle olan ilişkileri korelasyon analizi ve temel bileşenler analizi yardımıyla incelenmiştir. Sonuçlar meteorolojik koşulların Mogan Gölü’ndeki su kalitesini etkilediğine işaret etmiştir

TOP December 2010, Volume 18, Issue 2,303-320

Title: Evaluation of the genetic algorithm parameters on the optimization performance: a case study on pump-and-treat remediation design
Authors: Gamze Güngör-Demirci, Ayşegül Aksoy
Abstract:In this study, the impacts of different crossover and encoding schemes on the performance of a genetic algorithm (GA) in finding optimal pump-and-treat (P&T) remediation designs are investigated. For this purpose, binary and Gray encodings of the decision variables are tested. Uniform and two-point crossover schemes are evaluated for two different crossover probabilities. Analysis is performed for two P&T system optimization scenarios. Results show that uniform crossover operator with Gray encoding outperforms the other alternatives for the complex problem with higher number of decision variables. On the other hand, when a simpler problem, which had a lower number of decision variables, is solved, the efficiency of GA is independent of the encoding and crossover schemes.

CLEAN 2010, 38 (2), 117 – 128

Title: An Assessment of the Spatial Distribution of Polychlorinated Biphenyl Contamination in Turkey
Authors: Kadir Gedik, İpek İmamoğlu
Abstract:This study summarizes the relevant information regarding the spatial distribution of polychlorinated biphenyls (PCBs) in various environmental (e. g., soil, sediment, air, water) and biological (e. g., fish, mussel, adipose tissue, milk) media in Turkey. The information sources used for this purpose, in addition to the scientific literature, were; official import records, governmental reports on monitoring of organochlorines, and reports prepared by international organizations. PCBs were never produced in Turkey; however they were imported and used within equipment or otherwise. The number of studies conducted on the topic is increasing significantly throughout the years and especially in the last decade. Evidence of PCB pollution was compared with the available background monitoring results from the region and other parts of the world, as well as relevant legislative standards. Overall, the presence of a number of important local PCB contamination sources is indicated as a result of this assessment.

SEPERATION SCIENCE and TECHNOLOGY, 45: 331–338, 2010

Title: Nanofiltration and Reverse Osmosis for Reuse of Indigo Dye Rinsing Waters
Authors: Nigmet Uzal, Levent Yilmaz, and Ulku Yetis
Abstract:A membrane based treatment strategy was developed for the possible recycling of rinsing wastewater from indigo dyeing to the process itself. Performances of three different nanofiltration (NF) (NF 270 and NF 90, Dow Film Tech, USA and NF 99, Alfa Laval, Denmark) and two different reverse osmosis (RO) (HR 98 PP and CA 995 PE, Alfa Laval, Denmark) membranes were investigated with wastewater collected from the first post-rinsing tank of indigo dyeing process of a denim manufacturing plant. Dead-end microfiltration with a 5 mm filter was employed to remove coarse particles and minimize fouling of further NF and RO membranes. For NF and RO, a lab scale plate-and-frame membrane module was operated at a pressure of 5.07 bar and at a 0.62 m/s cross-flow velocity. The permeate quality from all the tested NF and RO membranes was acceptable for reuse in terms of COD and color. However, only the permeate from HR 98 PP RO and NF 90 membranes were with an acceptable conductivity. On the other hand, NF 270 membrane was superior to all the other NF and RO membranes in terms of the permeation rate. Flux declines obtained for all membranes were higher than 50% but fouling was not considerable and completely reversible. The good performance of NF 270 in terms of permeate quality (permeate conductivity, color, and COD values were 4.3 mS/cm, 8 Pt-Co, and 87 mg/L, respectively) together with a higher flux makes this membrane preferable over the other membranes to recycle denim textile rinsing wastewaters.

THERMOCHIMICA ACTA 510 (2010) 195–201

Title: Investigation of co-combustion characteristics of low quality lignite coals and biomass with thermogravimetric analysis
Authors: M. Varol, A.T. Atimtay, B. Bay, H. Olgun
Abstract:In this study, combustion and co-combustion characteristics of three biomass fuels and three Turkish lignite coals were investigated by using a thermo gravimetric analyzer. There are just a few studies investigating the co-combustion characteristics of coal and biomass, and the synergistic effect of their various combinations on the peak temperatures and burnout times. Results of this study have shown that low rank coals can be burned with biomass very beneficially. As the VM content of the coal increases, the ignition temperature decreases and the maximum combustion rate is reached at lower temperatures. About 80–90% of the fuel is combusted as the combustion of volatile matter. As the biomass content of the fuel mixture increases, the ignition temperatures of the mixtures are found to be very close to that of the biomass. Therefore, it can be said that biomass in the mixture starts to burn first and then coal follows. .

BIORESOURCE TECHNOLOGY 101 (2010) 6177–6184

Title: Effect of freeboard extension on co-combustion of coal and olive cake in a fluidized bed combustor
Authors: Onur Akpulat, Murat Varol, Aysel T. Atimtay
Abstract:In this study, flue gas emissions and combustion efficiencies during combustion and co-combustion of olive cake and coal were investigated in a bubbling fluidized bed. Temperature distributions along the combustion column and flue gas concentrations of O2, CO, SO2 and NOx were measured during combustion experiments. Two sets of experiments were performed to examine the effect of fuel composition, excess air ratio and freeboard extension on flue gas emissions and combustion efficiency. The results of the experiments showed that coal combustion occurs at lower parts of the combustion column whereas olive cake combustion takes place more in the freeboard region. As olive cake percentage in the fuel mixture increased, CO emissions increased, SO2 and NOx emissions decreased. Additionally, flue gas emissions could be lowered with the freeboard extension while burning biomass or biomass/coal mixtures. Noticeable decrease in CO emissions and slight increase in combustion efficiencies were observed with a column height of 1900 mm instead of 900 mm.

CLEAN TECHN ENVIRON POLICY (2010) 12:43–52

Title: Combustion of agro-waste with coal in a fluidized bed
Authors: Aysel T. Atimtay
Abstract:In this study, a review of the studies done on the co-combustion of some agro-waste in a bubbling fluidized bed combustor (BFBC) having an inside diameter of 102 mm and a height of 900 mm is given. The agro-waste used to investigate the co-combustion characteristics were peach and apricot stones produced as a waste from the fruit juice industry, and olive cake produced as a waste from the olive oil industry. These are typical wastes for a Mediterranean country. A lignite coal was used for co-combustion. On-line concentrations of O2, CO, CO2, SO2, NOx and total hydrocarbons (CmHn) were measured in the flue gas during combustion experiments. Variations of emissions of various pollutants were studied by changing the operating parameters (excess air ratio, fluidization velocity and fuel feed rate). Temperature distribution along the bed was measured with thermocouples. Emissions were also monitored from the exhaust. Various combinations of coal and biomass mixtures were tested. During the combustion tests, it was observed that the volatile matter from the biomass quickly volatilizes and mostly burns in the freeboard. The temperature profiles along the bed and the freeboard also confirmed this phenomenon. It was found that as the volatile matter of the biomass increases, combustion takes place more in the freeboard region. Better combustion conditions occur at higher excess air ratios. The results showed that co-combustion with these three proposed biomasses lowers the SO2 and NOx emissions considerably. CO and hydrocarbon emissions are lower at the higher excess air ratios.

BIORESOURCE TECHNOLOGY 101 (2010) (2010) 8984–8992

Title: Ultrasonic pretreatment and subsequent anaerobic digestion under different operational conditions
Authors: Onur Güven Apul, F. Dilek Sanin
Abstract:In this study ultrasonic pretreatment was investigated in order to improve anaerobic digestion. First, the most effective sonication time was selected during the preliminary studies conducted on waste activated sludge samples. Then the optimal time selected was confirmed running batch anaerobic reactors. In the last part of the experiments, the effect of sonication was investigated for different operational conditions of semi-continuous digesters. Preliminary studies showed 15 min of sonication increased 50 mg/L initial soluble COD concentration up to a value of 2500 mg/L. Batch anaerobic digester results indicated that the increased soluble substrate improved anaerobic biodegradability concurrently, again with the maximal improvement observed for 15 min of sonication. Results from semi-continuous reactors indicated that at SRT of 15 days and OLR of 0.5 kg/m3 d, ultrasonic pretreatment improved the daily biogas production, methane production and volatile solids reduction significantly when compared to control system. During the operation of reactors at 7.5 days of SRT, pretreatment helped to keep the reactors working. A simple economical analysis of the system was performed using the data obtained during the laboratory study.

INDOOR AIR, 2010; 20: 112–125

Title: Indoor/outdoor concentrations and elemental composition of PM10/PM2.5 in urban/industrial areas of Kocaeli City, Turkey
Authors: B. Pekey, Z.B. Bozkurt, H. Pekey, G. Doğan, A. Zararsız, N. Efe, G. Tuncel
Abstract:This study presents indoor/outdoor PM2.5 and PM10 concentrations measured during winter and summer in 15 homes in Kocaeli, which is one of the most industrialized areas in Turkey. Indoor and outdoor PM2.5 and PM10 mass concentrations and elemental composition were determined using an X-ray fluorescence spectrometer. Quantitative information was obtained on mass concentrations and other characteristics such as seasonal variation, indoor/ outdoor (I/O) ratio, PM2.5/PM10 ratio, correlations and sources. Average indoor and outdoor PM2.5 concentrations were 29.8 and 23.5 µg/m3 for the summer period, and 24.4 and 21.8 µg/m3 for the winter period, respectively. Average indoor and outdoor PM10 concentrations were 45.5 and 59.9 µg/m3 for the summer period, and 56.9 and 102.3 µg/m3 for the winter period, respectively. A varimax rotated factor analysis (FA) was performed separately on indoor and outdoor datasets in an effort to identify possible heavy metal sources of PM2.5 and PM10 particle fractions. FA of outdoor data produced source categories comprising polluted soil, industry, motor vehicles, and fossil fuel combustion for both PM fractions, while source categories determined for indoor data for both PM2.5 and PM10 comprised industry, polluted soil, motor vehicles, and smoking, with an additional source category of cooking activities detected for the PM2.5 fraction.

WASTE MANAGEMENT 30 (2010) 72–81

Title: A decision support system for assessing landfill performance
Authors: Başak Çelik, Sertan Girgin, Adnan Yazıcı, Kahraman Ünlü
Abstract:Designing environmentally sound landfills is a challenging engineering task due to complex interactions of numerous design variables; such as landfill size, waste characteristics, and site hydrogeology. Decision support systems (DSS) can be utilized to handle these complex interactions and to aid in a performancebased landfill design by coupling system simulation models (SSM). The aim of this paper is to present a decision support system developed for a performance-based landfill design. The developed DSS is called Landfill Design Decision Support System – LFDSS. A two-step DSS framework, composed of preliminary design and detailed design phases, is set to effectively couple and run the SSMs and calculation modules. In preliminary design phase, preliminary design alternatives are proposed using general site data. In detailed design phase, proposed design alternatives are further simulated under site-specific data using SSMs for performance evaluation. LFDSS calculates the required landfill volume, performs landfill base contour design, proposes preliminary design alternatives based on general site conditions, evaluates the performance of the proposed designs, calculates the factor of safety values for slope stability analyses, and performs major cost calculations. The DSS evaluates the results of all landfill design alternatives, and determines whether the design satisfies the predefined performance criteria. The DSS ultimately enables comparisons among different landfill designs based on their performances (i.e. leachate head stability, and groundwater contamination), constructional stability and costs. The developed DSS was applied to a real site, and the results demonstrated the strengths of the developed system on designing environmentally sound and feasible landfills.