Levent Altaş - Academia.edu (original) (raw)

Papers by Levent Altaş

Journal of Hazardous Materials, Mar 1, 2009

Biotechnology & Biotechnological Equipment, 2010

Wastewater management, as water pollution control and resources management, is one of the priorit... more Wastewater management, as water pollution control and resources management, is one of the prioritized problems of Turkey including in Aksaray. The domestic wastewater of Aksaray City was classified as polluted domestic wastewater when COD was considered. Treatability of wastewater was investigated in this study by using upflow anaerobic sludge bed (UASB) reactor and aerobic completely mixed activated sludge reactor (CMASR), with ambient temperatures for duration of approximately five months. The removal of organic matter differed in direct relation with the water's pollutant degree but was not significantly affected by the temperatures. A total of 58% and 63% of the organic matter was removed in the first and second phases, respectively. COD removal efficiency of the system with HRT of 12.7 hours and organic loading rate of 1.47 COD/m 3 .day was obtained as 78%. This study states that domestic wastewater in UASB/CMASR could be digested efficiently in Aksaray City.

Journal of Industrial and Engineering Chemistry, Nov 1, 2012

Ã is constant with pH (Eq. (1)), while C T changes with the pH. For example, as the pH increases,... more Ã is constant with pH (Eq. (1)), while C T changes with the pH. For example, as the pH increases, ½HCO 3 À and

Journal of Hazardous Materials, Oct 1, 2010

The present paper reports on results obtained from experiments carried out in a laboratory-scale ... more The present paper reports on results obtained from experiments carried out in a laboratory-scale anaerobic packed bed biofilm reactor (APBR), with recirculation of the liquid phase, for continuously biohydrogen production via dark fermentation. The reactor was filled with Kaldnes ® biofilm carrier and inoculated with an anaerobic mesophilic sludge from a urban wastewater treatment plant (WWTP). The APBR was operated at a temperature of 37 C, without pH buffering. The effect of theoretical hydraulic retention time (HRT) from 1 to 5 h on hydrogen yield (HY), hydrogen production rate (HPR), substrate conversion and metabolic pathways was investigated. This study indicates the possibility of enhancing hydrogen production by using APBR with recirculation flow. Among respondents values of HRT the highest average values of HY (2.35 mol H 2 /mol substrate) and HPR (0.085 L h À1 L À1) have been obtained at HRT equal to 2 h.

Chemical Engineering Research & Design, Oct 1, 2017

The purpose of this research was to comprehensively evaluate the characterization and the optimiz... more The purpose of this research was to comprehensively evaluate the characterization and the optimization of electrocoagulation for sanitary landfill leachate treatment in Aksaray/Turkey. This is the first study conducted with regard to both the characterization and the electrochemical treatment of leachate in Aksaray province. For this purpose, leachate samples 4 were collected in situ at a monthly interval for a period of 13 months and physicochemical parameters and heavy metals were monitored. Meteorological data were also recorded for the same sampling period to calculate the leachate production amount (LPA) and to correlate between the physicochemical parameters. The results were statistically analyzed by using Pearson Correlations Analysis, SPSS software. In the next step, the leachate was treated by the electrocoagulation (EC) method with aluminum and iron plate electrodes together in a laboratory-scale batch process. The effects of process variables such as current densities, time, and pH were investigated for chemical oxygen demand (COD) removal. Stepwise regression analysis was done for determining which variable, acting independently, best explains or predicts the variation in the removal efficiency of COD. As a result of this study, a feasible model containing variables of the electrocoagulation process on COD removal was derived using stepwise regression analysis.

Environmental Science and Pollution Research, Feb 20, 2013

Journal of Chemical Technology & Biotechnology, Feb 1, 2009

BACKGROUND: Ureolytic microbial carbonate precipitation (MCP) is a novel process for removing exc... more BACKGROUND: Ureolytic microbial carbonate precipitation (MCP) is a novel process for removing excess calcium from industrial effluents. This process is based on the hydrolization of urea to provide a suitable medium for the precipitation of Ca as CaCO 3. RESULT: A toxicity identification evaluation was conducted on synthetic wastewater simulating wastewater from paper recycling to determine the inhibition or toxicity of chromium(VI) ions on the activities of a ureolytic mixed culture (UMC) with respect to the removal rate of COD and removal of Ca 2+ in batch reactors. The 50% inhibiting concentration (IC 50) and the 25% inhibiting concentration (IC 25) values of Cr(VI) on UMC were determined as 40 and 18 mg L −1 , respectively, for an exposure time of 1 day. The inhibitory effects of Cr(VI) were lower on UMC after longer exposure times of 3, 4 and 5 days. COD removal rate, ammonium production and Ca removal of samples with 512 mg Cr(VI) L −1 were significantly inhibited. CONCLUSION: The present study has shown that the effects of different metallic species, organic toxicants and other environmental factors should be taken into account when removing problematic Ca and other possible elements from the environment using UMC.

Process Safety and Environmental Protection

DESALINATION AND WATER TREATMENT

Fresenius Environmental Bulletin, 2011

Journal of Animal and Veterinary Advances, 2013

Turkish Journal of Fisheries and Aquatic Sciences, 2010

In this study, hematological and biochemical investigations were carried out on Cyprinus carpio, ... more In this study, hematological and biochemical investigations were carried out on Cyprinus carpio, Leuciscus cephalus, Capoeta trutta ve Capoeta capoeta umbla fish species living in Sultansuyu Dam Lake (Malatya). The physical, chemical and microbiological features of the reservoir were specified and heavy metal analyses were also conducted. As a result of hematological investigation, a statistical increase of P<0.05 in total leukocyte count, and a decrease of P<0.05 in erytrocyte, hemoglobin and hematocrit values were observed. With respect to microbiological analysis, the presence of Enterococcus shows the drainage of domestic wastes into the reservoir. With water analyses, it was found out that the water quality was second rate and the sulphur content in the water was above standard levels. The existence of large amount of sulphur was presumed to be the result of apricot processing. Significant heavy metal pollution was not observed.

Biological Rhythm Research, 2019

Ladik Lake (Samsun, Turkey) is a natural landscape under the threat of pollution because of urban... more Ladik Lake (Samsun, Turkey) is a natural landscape under the threat of pollution because of urban, agricultural and industrial activities. In this study, accumulation of heavy metals (Al, Ba, Cr, Cu, Fe, Mn, Pb and Zn) in the tissues (muscle, liver and gill) of sediment dwelling pike fish and in different substrates of Ladik Lake were investigated. Seasonal haematological, biochemical and histopathological parameters of the carp are also reported. In general, heavy-metal levels in water and sediment samples were found in the highest level in summer and the lowest in autumn. Histopathologic changes in the tissues of the fish (liver and gill) were at the minimum in winter while it was highest in summer. Blood biochemical parameters exhibited higher level in summer in comparison with other seasons. Al, Ba, Cr, Mn and Zn levels in the tissues of the fish were in the order gill>liver>muscle in all seasons. The levels of Cu, Fe and Pb were in the sequence liver>gill>muscle. Cr, Cu, Pb and Zn levels were determined to be in high level in the tissues of the fish with respect to the literature values. The heavy-metal levels in Ladik Lake and the fish health need to be regularly monitored for a sustainable environmental health.

Process Safety and Environmental Protection, 2017

International Journal of Environmental Research, 2017

This study was aimed to compare the Pb(II) adsorption from aqueous solutions between raw phosphog... more This study was aimed to compare the Pb(II) adsorption from aqueous solutions between raw phosphogypsum (UP) and lime-conditioned phosphogypsum (LCP) in batch systems. The Pb(II) adsorption by UP and LCP was investigated depending on the process variables, such as solution pH, contact time, and initial Pb(II) concentration. The adsorption capacity (q m) of UP and LCP as mg/g was found to be 1.85 and 2.90, and the pseudo-secondorder rate constant as g/mg min and the initial adsorption rate were found to be 0.27 and 7.57 for LCP and 0.74 and 7.52 for UP, respectively. Studies on the removal of Pb(II) from wastewater of storage battery industry by LCP and UP showed that these adsorbents can be used efficiently.

Journal of Selcuk University Natural and Applied Science, Oct 26, 2013

In this study, characterization and treatability with electrocoagulation (EC) method of leachate ... more In this study, characterization and treatability with electrocoagulation (EC) method of leachate from landfill of Aksaray Province, Turkey were investigated. Physical and chemical characteristics of leachate samples taken from same location were performed about one year as monthly. As a result of thirteen-month long characterization studies, parallel literature, it was observed that biochemical oxygen demand (BOD 5 )/ chemical oxygen demand (COD) ratio within the range of 0.44-0.8 in fresh landfill. In fresh landfill area, pH, temperature, total organic carbon (TOC), COD, BOD5, alkalinity (TA), total nitrogen (TN), total kjeldahl nitrogen (TKN), total suspended solid (TSS), chloride (Cl-), sulphate (SO4 2- ) and heavy metals such as arsenic (As), boron (B), barium (Ba), calcium (Ca), cadmium (Cd), chromium (Cr), cobalt (Co), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), sodium (Na), nickel (Ni), lead (Pb) and zinc (Zn) were analyzed. After the characterization study, treatment of the leachate by electrocoagulation method with aluminum (Al) and iron (Fe) plate electrodes that was using together was investigated. In addition to leachate characterization and develop current experiences of treatment methods, COD removal from leachate using electrocoagulation method also carried out in the scope of this study. In EC removal of COD, the effects of current intensity and retention time parameters were investigated. In leachate samples where COD concentrations were even higher than 5000 mg/L, a successful removal of COD was accomplished by electrocoagulation, electroflotation and electrooxidation mechanism in completely mixed batch reactor conditions. COD removal efficiency was over 75% with Al and Fe electrodes in the EC reactor which was operated during the retention time of 60 minutes. According to the results, the most acceptable current intensity for COD removal was determined to be 5,08 mA/cm2 and the most acceptable treatment time was determined to be 5 minute. It is observed that EC process may be an acceptable solution for the pre or post treatment of leachate.

![Research paper thumbnail of Tuz Gölü`nün Aksaray İli Yeraltı Sularına Etkisinin Coğrafi Bilgi Sistemi Kullanılarak Değerlendirilmesi](https://attachments.academia-assets.com/114085401/thumbnails/1.jpg)

Environmental Earth Sciences, 2014

The present study describes the removal of arsenite by iron oxide-coated pumice and iron oxide-co... more The present study describes the removal of arsenite by iron oxide-coated pumice and iron oxide-coated sepiolite. Pumice and sepiolite were coated with iron oxide and used as adsorbents for the removal of arsenite from aqueous solution in batch experiments. Arsenite concentration decreased exponentially with time, and equilibrium was attained in 84 h. The kinetics of the adsorption process was tested for the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The adsorption of arsenite onto iron oxide-coated pumice and iron oxide-coated sepiolite followed the pseudo-second-order model. Freundlich, Dubinin–Radushkevitch, and Temkin isotherm models were applied to the experimental equilibrium data. The adsorption of arsenite fit these isotherm models. The results indicated that the iron oxide-coated pumice and iron oxide sepiolite could be alternative adsorbents for arsenite removal. Among the adsorbents, iron oxide-coated pumice was found to be more effective than iron oxide sepiolite in the removal of arsenite.

Journal of Industrial and Engineering Chemistry, 2012