Pomzanın Desalinasyon Ön Arıtımında Granüler Filtre Malzemesi Alternatifi Olarak Karakterizasyonu ve Geri Yıkama Davranışları

Öz

Bu çalışmada, deniz suyu arıtımında membran ön arıtma prosesi olarak kullanılan granüler filtrelerde alternatif filtre malzemesi olarak pomzanın kullanılabilirliği geri yıkama davranışları açısından araştırılmıştır. Silis kumu, aktif karbon ve pomza farklı tane boyutlarında hazırlanarak yoğunluk, eşdeğer çap ve su tutma kapasiteleri ASTM standartlarına uygun yöntemlerle belirlenmiştir. Doğal deniz tuzu kullanılarak hazırlanan sentetik deniz suyu ile gerçekleştirilen akışkanlaşma (geri yıkama) deneyleri sonucunda malzemelerin yatak genişleme davranışları değerlendirilmiştir. Karşılaştırması yapılan pomza ve aktif karbonun düşük yoğunlukları ve gözenekli yapıları nedeniyle temel filtre malzemesi olan kumdan daha düşük geri yıkama hızlarında beklendiği üzere daha yüksek yatak genişlemelerine ulaştığını göstermiştir. Kum ise yoğun ve düşük gözenekli yapısı nedeniyle daha yüksek hızlarda dahi sınırlı genişleme göstermiştir. Bu durum kum ve bir gözenekli malzemenin kullanıldığı çift tabakalı filtrelerde her iki malzemenin de efektif akışkanlaşmasının sağlandığı hızlarda malzeme kaybı riskini de beraberinde getirmektedir. Sonuçlar, çift tabakalı granüler filtrelerde geri yıkama hızlarının seçilen malzemenin yoğunluk ve tane boyutuna göre optimize edilmesi gerektiğini ortaya koymaktadır. Bu çalışmada değerlendirilen özellikleri açısından, Türkiye’de bol miktarda bulunan pomza, düşük maliyeti ve çevresel sürdürülebilirliği ile aktif karbona alternatif bir filtre malzemesi olarak değerlendirilebilir.

Anahtar Kelimeler

• Granüler filtrasyon
• pomza
• aktif karbon
• geri yıkama
• deniz suyu arıtımı

Teşekkür

Bu çalışma, TÜBİTAK 2209-A Üniversite Lisans Öğrencileri Araştırma Projeleri Destek Programı tarafından desteklenmiştir. Yazarlar bu desteği minnetle kabul ederler.

Backwashing Characteristics of Pumice as a Sustainable Alternative Granular Filter Medium for Desalination Pretreatment

Öz

In this study, the potential use of pumice as an alternative filter medium in granular filters employed for seawater pretreatment prior to membrane processes was investigated in terms of backwashing behavior. Silica sand, activated carbon, and pumice were prepared in different particle size fractions, and their density, equivalent diameter, and water absorption capacities were determined according to ASTM standards. Using synthetic seawater prepared with natural sea salt, fluidization (backwashing) experiments were conducted to evaluate the bed expansion behavior of the materials. As expected, pumice and activated carbon achieved higher bed expansions at lower backwash velocities compared to the primary filter material, sand, due to their lower densities and porous structures. Sand, on the other hand, exhibited limited expansion even at higher velocities because of its dense and less porous structure. This indicates that in dual-layer filters combining sand with a porous medium, achieving effective fluidization for both materials may carry a risk of media loss. The results demonstrate that backwash velocities in dual-layer granular filters should be optimized based on the density and particle size of the selected materials. Considering the characteristics evaluated in this study, pumice (abundant in Turkey, low-cost, and environmentally sustainable) can be considered a promising alternative to activated carbon as a filter medium.

Anahtar Kelimeler

• Granular filtration
• pumice
• activated carbon
• backwashing
• seawater desalination

Teşekkür

This study was supported by the TÜBİTAK 2209-A Research Project Support Program for University Undergraduate Students. The authors gratefully acknowledge this support.

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