Environmental Engineering / Çevre Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4321
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Article Citation - WoS: 40Citation - Scopus: 47Boron in Geothermal Energy: Sources, Environmental Impacts, and Management in Geothermal Fluid(Elsevier, 2022) Mott, A.; Baba, Alper; Hadi Mosleh, Mojgan; Ökten, Hatice Eser; Babaei, Masoud; Gören, Ayşegül Yağmur; Feng, C.; Recepoğlu, Yaşar Kemal; Uzelli, Taygun; Uytun, Hüseyin; Morata, Diego; Yüksel Özşen, AslıThe problem of hazardous chemicals in geothermal fluid is a critical environmental concern in geothermal energy developments. Boron is among the hazardous contaminants reported to be present at high concentrations in geothermal fluids in various countries. Poor management and inadequate treatment of geothermal fluids can release excessive boron to the environment that has toxic effects on plants, humans, and animals. Despite the importance of boron management in geothermal fluid, limited and fragmented resources exist that provide a comprehensive understanding of its sources, transport and fate, and the treatment strategies in geothermal energy context. This paper presents the first critical review from a systematic and comprehensive review on different aspects of boron in geothermal fluid including its generation, sources, toxicity, ranges and the management approaches and treatment technologies. Our research highlights the origin of boron in geothermal water to be mainly from historical water-rock interactions and magmatic intrusion. Excessive concentrations of boron in geothermal fluids have been reported (over 500 mg/L in some case studies). Our review indicated that possible boron contamination in geothermal sites are mostly due to flawed construction of production/re-injection wells and uncontrolled discharge of geothermal water to surface water. The dominancy of non-ionic H3BO3 species makes the selection of the suitable treatment method for geothermal waters limited. Combining boron selective resins and membrane technologies, hybrid systems have provided effluents suitable for irrigation. However, their high energy consumption and course structure of boron selective resins encourage further research to develop cost-effective and environmentally friendly alternatives.Article An Experimental Study on Release Mechanism of Iron and Manganese From Sediments To the Water Column in Reservoirs(2021) Vural, Buse; Elçi, Şebnem; Ökten, Hatice EserIron and manganese accumulation in drinking water reservoirs is a challenging issue and should be controlled to prevent their adverse effects on human health. Accumulation of these elements not only clogs pipeline systems but also causes stains on fixtures and laundry. Also, high concentrations of iron and manganese may lead to various health problems when ingested. This study focuses on the release mechanism of iron and manganese from sediments to the water column in reservoirs and investigates methods to prevent this release. Effects of hypoxia, hypolimnetic aeration, alkalinity of water, and thermal stratification on iron and manganese concentrations were investigated through laboratory experiments. Experiments done simulating the water column showed that hypoxia caused more dissolution of ferrous iron when compared with that of manganese. Accordingly, aeration of the water column in hypoxic conditions lead to a significant decrease in ferrous iron concentrations (in our case reaching zero). However, manganese and total iron levels were not affected by the aeration of the water column. Alkalinity level of the water column was observed to have a great effect on the solubility of iron and manganese. Concentrations of total Fe and total Mn measured for acidic (pH = 5) conditions were considerably greater than concentrations measured at neutral conditions. As for alkaline (pH = 11) conditions, the opposite was observed with measured concentrations of total Fe and total Mn being lower than the ones measured for neutral conditions. Thermal stratification had an enhancing effect on the solubility of both iron and manganese ions. While aeration of the stratified water column slightly decreased the concentrations of Total Fe and Mn, it had a greater impact on decreasing $Fe^{2+}$ concentrations.Article İzotop Özelliklerinin Kullanılarak Su-kayaç Etkileşiminin İncelenmesi: Alaşehir Alt Havzası Örneği(DSİ, 2019) Tonkul, Serhat; Şimşek, Celalettin; Baba, AlperYeraltı su kaynakları yenilenebilir kaynaklar olmasına karşın, havzalarda aşırı çekim baskısı nedeniyle akiferlerde yeterince depolanamamakta ve depolama rezervi sürekli olarak azalmaktadır. Bu bağlamda son yıllarda yeraltısuyunun sürdürülebilir verimliliğinin arttırılması için kalite ve miktarın belirlenmesine yönelik olarak yüzey ve yeraltısuyu sistemleri arasındaki ilişkinin detaylı olarak çalışılmasına ihtiyaç duyulmuştur. Yüzey ve yeraltısuları arasındaki ilişkinin ortaya konulmasında en çok kullanılan özelliklerden birisi de izotoplardır. İzotoplar yeraltısuları ile kayaçlar arasındaki etkileşimini (su-kayaç ilişkisi) anlamada büyük öneme sahiptir. İzotoplar ile suların izledikleri yollar ve kökenleri hakkında önemli bilgiler alınabilmektedir. Özellikle, jeotermal bir sistemin bulunduğu bölgede, jeotermal rezervuar sıcaklığını tahmin etmede yardımcı olabilen bu izotoplar, aynı zamanda jeotermal bir sistemin evrimini de ortaya çıkarmaktadır. Türkiye’nin batısında yer alan ve ülkenin %2’sini oluşturan Gediz Havzası, önemli bir jeotermal potansiyelin olduğu alan konumundadır. Bu çalışma kapsamında çalışma alanındaki suların fiziksel ve kimyasal özelliklerinin kullanılarak, Alaşehir alt (Manisa) havzasında yüzey ve yeraltısuyu sistemleri arasındaki ilişkinin belirlenmesi amaçlanmıştır. Bu amaçla, Alaşehir alt havzasında 25 farklı noktada araştırma kuyuları açılmış olup, bu kuyulardan yağışlı ve kurak dönemde alınan yeraltısuyu örnekleri ile bu alandaki yağmur suyu örnekleri üzerinde laboratuvar ortamında, 2017 ve 2018 yılına ait numunelerin izotopik özellikleri değerlendirilmiştir. Buna göre, çalışma sahası ve çevresinde yeraltısularının 2017 ve 2018 yıllarına ait yağışlı ve kurak dönem ? 18O, ? 2H ve ? 3H izotop dağılımlarına bakıldığında genel olarak suların önemli bir kısmının meteorik kökenli olduğu anlaşılmaktadır.Conference Object Groundwater Pollution by Nitrate From Agricultural Fertilizers: the Case of Menemen Basin (aegean Region, Turkey)(İZSU, 2017) Gören, Ayşegül Yağmur; Genişoğlu, Mesut; Balcı, Esin; Ökten, Hatice Eser; Baba, AlperGroundwater is an essential drinking water source in Menemen subbasin of İzmir city, Turkey. The aim of this study was to investigate the groundwater contamination by nitrates of agricultural lands. For this purpose, we evaluated variations of groundwater pH, redox potential, electrical conductivity (EC), major anions (NO3, Cl, SO4, HCO3 and CO3) and cations (Na, K, Ca and Mg). A statistical correlation procedure and piper diagram for hydrogeochemistry of groundwater were also applied. Nitrate levels were found to be higher around agricultural areas. Also EC values and Cl were measured to be higher as proximity to coastal areas increased, indicating seawater intrusion. Agricultural activities and excessive freshwater withdrawal were shown to impair groundwater quality and quantity at Menemen subbasin.Article Citation - WoS: 14Citation - Scopus: 22Forecasting Ambient Air So2 Concentrations Using Artificial Neural Networks(Taylor and Francis Ltd., 2006) Sofuoğlu, Sait Cemil; Sofuoğlu, Aysun; Birgili, Savaş; Tayfur, GökmenAn Artificial Neural Networks (ANNs) model is constructed to forecast SO 2 concentrations in Izmir air. The model uses meteorological variables (wind speed and temperature) and measured particulate matter concentrations as input variables. The correlation coefficient between observed and forecasted concentrations is 0.94 for the network that uses all three variables as input parameters. The root mean square error value of the model is 3.60 g/mt 3 . Considering the limited number of available input variables, model performances show that ANNs are a promising method of modeling to forecast ambient air SO 2 concentrations in Izmir.