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Öğe Biogas production and utilization potential of wastewater treatment sludge(TAYLOR & FRANCIS INC, 2008) Berktay, A.; Nas, B.Municipal wastewater treatment plants generate sludge as a by-product of the physical, chemical and biological processes used in the treatment of wastewater. Generally, this sludge must be subject to some form of treatment in order to alter its character. By using anaerobic digestion in the treatment of wastewater sludge, methane gas is produced and it is known as biogas. It must not only be seen as a renewable energy source, but even more as one of the promising solutions to the large environmental problem concerning waste handling, water pollution, CO2 emission, etc. This article presents the biogas generation from wastewater treatment sludge, its energy potential and also its usage in some treatment plants operated in Turkey. Although the estimation of recoverable energy from municipal wastes and sewage is difficult to assess, total recoverable bioenergy potential is estimated as being 16,920 ktoe. Of this, 1,300 ktoe of municipal wastes and sewage whereas biogas production potential is 1.5-2 Mtoe in Turkey.Öğe EFFECT OF TEMPERATURE ON FENTON OXIDATION OF YOUNG LANDFILL LEACHATE: KINETIC ASSESSMENT AND SLUDGE PROPERTIES(GLOBAL NETWORK ENVIRONMENTAL SCIENCE & TECHNOLOGY, 2012) Aygun, A.; Yilmaz, T.; Nas, B.; Berktay, A.Treatment of young landfill leachate, collected from municipal solid waste site of city of Konya, was investigated by using the Fenton process. The leachate itself showed the characteristics of pH 7.25, COD 38.2 g L-1 and BOD5 22 g L-1. Ratio of BOD5 to COD with 0.58 indicates that leachate can be defined young. Fenton oxidation of landfill leachate was expressed in two-stage process, where a fast initial reaction (H2O2/Fe2+) was followed by a much slower one (H2O2/Fe3+). Overall kinetics can be described by a second-order rate equation followed by zero-order one. The kinetic studies were undertaken at the different temperatures and reaction rates increcesed by increasing temperature. The apparent kinetic constants at 303 K are k = 3.16 x 10(-3) L g(-1) min(-1) and k(0) = 0,171 g L-1 min(-1), respectively. Fenton reagents effectively degraded the leachate organics and most of the degradation was completed within 30 minutes for all temperatures. The performance of Fenton process was not only presented as a COD removal but also expressed as the amount of generated sludge and its properties. Sludge properties were revealed with Capillary Suction Time (CST) and Sludge Volume Index (SVI). The minimum CST value was obtained at the optimum molar ratio of 4.12 mol/mol and increasing temperature resulted in a positive effect on CST values. All SVI values were significantly low which indicates that sludge itself had good settling properties.Öğe Energy potential of biodiesel generated from waste cooking oil: An environmental approach(TAYLOR & FRANCIS INC, 2007) Nas, B.; Berktay, A.As far as environmental pollution concern, the utilization of all fuels produces air pollutants, causing local and trans-boundary air pollution and acid rain problems. Biodiesel is a clean renewable fuel with its properties similar to diesel but generated from renewable resources such as vegetable oils and animal fats. Although this fuel has been developed some two to three decades ago, it is not commonly used, mainly due to the higher production cost involved. Due to the increasing concern on environmental protection, a lot of researches on the usage of this fuel are carried out in recent years. This paper presents a brief overview of biodiesel generated from waste cooking oil and its potential, including the environmental approach. Annually 733,000 tons of cooking oil is consumed in Turkey. If half of its returns to waste oil, this will be about 350,000 tons in each year. Approximately 350,000 tons of biodiesel, 35,000 tons of glycerin, and 3,500 tons of soap can be produced when the waste oil is recycled or reused properly.Öğe Geostatistical Approach to Assessment of Spatial Distribution of Groundwater Quality(HARD, 2009) Nas, B.A large portion of the water requirements of Konya, Turkey, is supplied by 200 groundwater wells. The quality of this groundwater was determined by taking samples from 156 of the wells within a study area of 427.5 km(2). The locations of the wells were obtained using a hand-held global positioning system (GPS) receiver. The purposes of this investigation were to provide an overview of current groundwater quality and to determine spatial distribution of groundwater quality parameters in the study area. The geostatistical analyst extension module of ArcGIS was used for exploratory data analysis, semivariogram model selection, cross-validation, and development of a distribution pattern of groundwater quality parameters such as pH, electrical conductivity, Cl(-), SO(4)(-2), hardness, and NO(3)(-) concentrations. The ordinary Kriging (OK) method was used to produce the spatial patterns of water quality over the study area. The result of OK interpolation showed that higher chloride, sulfate, conductivity and hardness concentrations are clearly situated in the northeast of the study area. Concentrations of groundwater quality parameters were compared with World Health Organization, U.S. Environment Protection Agency, and Turkish Standards Institute drinking water guidelines.Öğe Influence of salt and Cr(VI) shock loadings on oxygen utilization and COD removal in SBR(MARY ANN LIEBERT INC, 2006) Ertugrul, T.; Berktay, A.; Nas, B.The effects of salt (NaCl) and chromium (VI) shock loadings on oxygen use and chemical oxygen demand (COD) removal efficiency were investigated by using two laboratory-scale sequencing batch reactors (SBR). The feed water used in this investigation was synthetic sewage with a ratio of 100/5.4/1.1 as COD/N/P. Reactors were operated at a 0.34-0.52 F/M ratio, 2000-2500 mgL(-1) mixed liquor suspended solids (MLSS) concentration and 10 days sludge retention times (SRT). All results were compared with those from an identical reactor operating at normal conditions. At concentrations of 20 gL(-1) NaCl, 5 mgL(-1) Cr(VI), and 10 mgL(-1) Cr(VI) shock loadings were applied to the shock-loaded reactor. Temperature, dissolved oxygen (DO), and pH in the reactors were measured at hourly intervals during the cycle period; however, the COD, MLSS, and sludge volume index (SVI) were daily. For the salt shock loading, COD removal efficiency decreased and the system could return to steady-state conditions within 3 days. For 5 mgL(-1) Cr(VI) shock loading, COD removal efficiency was affected and the system tended to recover itself within 3 days. However, for 10 mgL(-1) Cr(VI) shock loading, COD removal efficiency decreased dramatically, and it required more time to return to steady-state conditions, and the system could recover itself within 5 days. Although the differences in MLSS values were about 10% for the Cr(VI) shock loadings, there were no apparent effects observed on the biomass concentration and sludge-settling properties for the salt shock loading.
