Environmental Engineering / Çevre Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/4321
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Article Citation - WoS: 13Citation - Scopus: 14Boron Removal From Geothermal Brine Using Hybrid Reverse Osmosis/Microbial Desalination Cell System(Elsevier, 2023) Jarma, Yakubu A.; Kabay, Nalan; Baba, Alper; Ökten, Hatice Eser; Gören, Ayşegül YağmurAgriculture sector leads worldwide as the most water consuming sector with water demand. Since natural water resources cannot keep up with the demand, a shift from conventional water resources to unconventional ones is needed. While geothermal water was gaining importance for its energy content, small-scale (<10 L/s) energy plants were not required to reinject their spent geothermal brine. As geothermal resources align with agricultural areas in Western Anatolia, discharge of untreated brine might have severe adverse effects on crop yields and soil quality. In this study, we investigated use of spent geothermal brine for irrigation after treatment with Reverse Osmosis/Microbial Desalination Cell (RO/MDC) hybrid process. Treatment efficiencies for B, COD, As, Li, Fe, Cr concentrations and energy production values were determined. Treated water was initially evaluated for irrigation considering three quality categories (I, II, and III) comprised of parameters such as electrical conductivity (EC), total dissolved solids (TDS), and sodium adsorption ratio (SAR), along with sodium, chloride and boron concentrations. Additionally, magnesium adsorption ratio (MAR) and permeability index (PI) were used to evaluate for irrigation suitability. Although B concentrations in MDC-treated permeate (3.29 mg/L) and concentrate (2.99 mg/L) streams were not low enough to meet Quality I criterion (<0.7 mg/L), they can be still utilized in irrigation of moderate-to-high tolerant plants. Furthermore, PI and MAR parameters pointed to suitability for irrigational use. © 2022Article 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 Citation - WoS: 58Citation - Scopus: 59Assessment of Different Nanofiltration and Reverse Osmosis Membranes for Simultaneous Removal of Arsenic and Boron From Spent Geothermal Water(Elsevier, 2021) Jarma, Yakubu A.; Karaoğlu, Aslı; Tekin, Özge; Baba, Alper; Ökten, H.Eser; Tomaszewska, Barbara; Kabay, NalanOne of the factors that determine agricultural crops’ yield is the quality of water used during irrigation. In this study, we assessed the usability of spent geothermal water for agricultural irrigation after membrane treatment. Preliminary membrane tests were conducted on a laboratory-scale set up followed by mini-pilot scale tests in a geothermal heating center. In part I, three commercially available membranes (XLE BWRO, NF90, and Osmonics CK- NF) were tested using a cross-flow flat-sheet membrane testing unit (Sepa CF II, GE-Osmonics) under constant applied pressure of 20 bar. In part II, different spiral wound membranes (TR-NE90-NF, TR-BE-BW, and BW30) other than the ones used in laboratory tests were employed for the mini-pilot scale studies in a continuous mode. Water recovery and applied pressure were maintained constant at 60% and 12 bar, respectively. Performances of the membranes were assessed in terms of the permeate flux, boron and arsenic removals. In laboratory tests, the permeate fluxes were measured as 94.3, 87.9, and 64.3 L m?2 h?1 for XLE BWRO, CK-NF and NF90 membranes, respectively. The arsenic removals were found as 99.0%, 87.5% and 83.6% while the boron removals were 56.8%, 54.2%, and 26.1% for XLE BWRO, NF90 and CK-NF membranes, respectively. In field tests, permeate fluxes were 49.9, 26.8 and 24.0 L m?2 h?1 for TR-NE90-NF, BW30-RO and TR-BE-BW membranes, respectively. Boron removals were calculated as 49.9%, 44.1% and 40.7% for TR-BE-BW, TR-NE90-NF and BW30-RO membranes, respectively. Removal efficiencies of arsenic in mini-pilot scale membrane tests were all over 90%. Quality of the permeate water produced was suitable for irrigation in terms of the electrical conductivity (EC) and the total dissolved solids (TDS) for all tested membranes with respect to guidelines set by the Turkish Ministry of Environment and Urbanisation (TMEU). However, XLE BWRO, CK-NF and NF90 membranes failed to meet the required limits for irrigation in terms of boron and arsenic concentrations in the product water. The permeate streams of TR-BE-BW, TR-NE90-NF and BW30-RO membranes complied with the irrigation water standards in terms of EC, TDS and arsenic concentration while boron concentration remained above the allowable limit. © 2020 Elsevier B.V.