Aysun Özkan

Life cycle assessment of solid waste management options for Eskisehir, Turkey

Life cycle assessment (LCA) methodology was used to determine the optimum municipal solid waste (MSW) management strategy for Eskisehir city. Eskisehir is one of the developing cities of Turkey where a total of approximately 750tons/day of waste is generated. An effective MSW management system is needed in this city since the generated MSW is dumped in an unregulated dumping site that has no liner, no biogas capture, etc. Therefore, five different scenarios were developed as alternatives to the current waste management system. Collection and transportation of waste, a material recovery facility (MRF), recycling, composting, incineration and landfilling processes were considered in these scenarios. SimaPro7 libraries were used to obtain background data for the life cycle inventory. One ton of municipal solid waste of Eskisehir was selected as the functional unit. The alternative scenarios were compared through the CML 2000 method and these comparisons were carried out from the abiotic depletion, global warming, human toxicity, acidification, eutrophication and photochemical ozone depletion points of view. According to the comparisons and sensitivity analysis, composting scenario, S3, is the more environmentally preferable alternative. In this study waste management alternatives were investigated only on an environmental point of view. For that reason, it might be supported with other decision-making tools that consider the economic and social effects of solid waste management.

Evaluation of healthcare waste treatment/disposal alternatives by using multi-criteria decision-making techniques

Healthcare waste should be managed carefully because of infected, pathological, etc. content especially in developing countries. Applied management systems must be the most appropriate solution from a technical, environmental, economic and social point of view. The main objective of this study was to analyse the current status of healthcare waste management in Turkey, and to investigate the most appropriate treatment/disposal option by using different decision-making techniques. For this purpose, five different healthcare waste treatment/disposal alternatives including incineration, microwaving, on-site sterilization, off-site sterilization and landfill were evaluated according to two multi-criteria decision-making techniques: analytic network process (ANP) and ELECTRE. In this context, benefits, costs and risks for the alternatives were taken into consideration. Furthermore, the prioritization and ranking of the alternatives were determined and compared for both methods. According to the comparisons, the off-site sterilization technique was found to be the most appropriate solution in both cases.

Utilization of Waste Clay from Boron Production in Bituminous Geosynthetic Barrier (GBR-B) Production as Landfill Liner

Bituminous geomembranes, one type of geosynthetics, include a hot bituminous mixture with mineral filler and reinforcement. In this study, boron production waste clay (CW) was used as filler to produce a geosynthetic barrier with bentonite, waste tire, and bitumen. Bentonite and waste tires were used as auxiliary fillers and bitumen as the binder. CW/bitumen, CW/bentonite/bitumen, and CW/waste tire/bitumen mixtures were prepared by using a laboratory mixer at 100°C. Hot mixtures were extruded into strips by using a lab-scale corotating twin screw extruder (L/D: 40) followed by die casting (2 mm × 100 mm). Glass fleece or nonwoven polyester was used as reinforcement material and while die casting, both sides of the reinforcement materials were covered with bituminous mixture. Thickness, mass per unit area, tensile strength, elongation at yield, and hydraulic conductivity were used to characterize the geomembranes. Among all geomembranes, nonwoven polyester covered with 30% bitumen-70% boron waste clay mixture (PK-BTM30CW70) was found to be the most promising in terms of structure and mechanical behaviour. After that, consequences of its exposure to distilled water (DW), municipal solid waste landfill leachate (L-MSW), and hazardous waste landfill leachate (L-HW) were examined to use for an innovative impermeable liner on solid waste landfills.

Prediction for the solid waste composition by use of different curve fitting models: A case study

This study presents a methodology for the prediction of solid waste composition in the urban area based on a set of limited samples. The methodology was applied by a case study for Eskişehir city in Turkey. For this purpose, Municipal Solid Waste (MSW) samples were collected for one year according to socioeconomic structure of districts. MSW samples were separated mainly into five groups of: paper-cardboard, metals, glass, plastics and food wastes as manually. The 75% of the values for each group were used as train data sets and the remains were used as test sets considering to income levels and population. It was used different curve fitting models for training of data and obtained different equations (power, exponential and polynomial) from the models. These equations were used for prediction of test sets and real values and test results were compared. Prediction accuracies were determined and interpreted according to different goodness of measurement values. It was seen that the effect of income level and population on waste composition from the degree of accuracy of this model is very important.

Stabilization of metal processing plant sludge via sequential application of phytoremediation and pyrolysis.

The aim of this study is to evaluate the metal removal ability of three different plants from metal processing sludge containing Pb, Cd, and Zn. Therefore, phytoremediation and pyrolysis were sequentially applied. In the phytoremediation applications, sunflower (Helianthus annuus), corn (Zea mays), and rape (Brassica napus) seeds were sown in sludge/soil mixtures at four different levels (25/75, 50/50, 75/25, 100/0). The chelating agent, ethylenediaminetetraacetic acid, was added to the mixtures for plant uptake during phytoremediation. At the phytoremediation stage, it was noted that rape was the most effective plant for the mixture of 75/25 sludge/soil, with metal removal efficiencies ranging between 80%–90%. At the pyrolysis stage, after harvesting, contaminated plants grown in a 75/25 sludge/soil mixture were pyrolyzed at 500 °C, with a heating rate of 35 °C/min. The results show that 60%–90% of the initial metal content was held by the solid product. In addition to this, it can be concluded that pyrolysis stabilizes metals into a solid product and that this solid product can be safely landfilled as inert waste since its toxicity leaching value is lower than the limit values.

PLASTİK ATIKLARDAN KARBON NANOTÜP (CNT) ÜRETİMİ ÜZERİNE BİR DEĞERLENDİRME

Plastikler gunluk yasantida ve endustriyel uretimde her alanda yogun bir sekilde kullanilmaktadir. Ihtiyaclari karsilamak icin kullanilan plastiklerin cogu kisa surede atiga donustugu icin plastik atik miktari da oldukca fazla olmaktadir. Mevcut durumda bir kismi geri donusturulen, yakilan ya da depolanan plastiklerin hem cevresel hem de saglik acisindan yarattigi olumsuzluklari azaltmak adina bu atiklari urune donusturebilecek alternatif yontemler arastirilmali ve uygulanmalidir. Bu noktadan hareketle, bu calismada plastik atiklarin degerli bir malzeme olan karbon nanotup (CNT) uretiminde kullanimi ele alinmistir. Plastik atiklarla ilgili mevcut veriler, uygulama alanlari degerlendirilmis, CNT uretimi ile ilgili kisa bir bilgi verilmis ve bu proseste karbon kaynagi olarak plastik turlerinin kullanimi irdelenmistir.Plastics are heavily used in every field of daily life and industrial production. Most of the plastics used to meet the requirements are converted to waste in a short time, so the amount of plastic waste is considerably high. Alternative methods of converting these waste into product should be investigated and applied in order to reduce the environmental and health hazards of some recycled, burned or stored plastics in the current situation. From this point of view, this study deals with the use of plastic waste in the production of carbon nanotube (CNT), a valuable material. Present data and application areas related to plastic wastes were evaluated, brief information about CNT production was given and the use of plastic types as carbon source in this process was examined.

Utilisation of waste clay from boron production as a landfill liner material

Abstract The objective of this study was to investigate the potential utilisation of waste clay from boron production in sanitary landfills. The waste clay (CW) was mixed with bentonite (B) and waste tyre (TW) at different ratios. Results show that, any of the CW-TW mixtures were not acceptable to use in landfills because of insufficient bearing capacity values. On the other hand, CW and 2B/98CW mixtures have sufficient values from the point of experimental tests. As a conclusion, it has been concluded that CW can be used as a liner material for landfills without an addition.