Removal of oil-grease and suspended solid by flotation method-milk and dairy products industry example

Year 2024, Volume: 30 Issue: 2, 263 - 270, 30.04.2024

Yasemin Özdemir Deniz Dölgen , Mehmet Necdet Alpaslan

Abstract

Oil and grease are one of the most important pollutants in dairy industry wastewater. Flotation is a well-known and reliable method used in dairy industry wastewater to remove oil-grease, and it can remove oil & grease as well as suspended solids and organic materials. Dissolved Air Flotation (DAF), is a flotation technique and is classified as (traditional) Classical DAF (CP-DAF) and new generation - microbubble pump DAF (MB-DAF) systems considering the air bubble generation method. The major difference between the two systems is the microbubble size. Generally, the bubble size of 50-120 microns in KP-DAF systems decreases to 20-50 microns in MB-DAF systems. Besides that, the classical DAF system has a more complex structure than the new generation DAF systems. It consists of more equipment, thus maintenance requirement is high and causes troubles more often. This situation requires constant effort and attention during the operation. In this study, oil & grease and suspended solid (SS) removal efficiency was evaluated by using pilot scale experimental DAF system. The impact of inflow rate, pump type, and the pressure was investigated. Pilot-plant was employed in the dairy factory and operated by real wastewater. The results shown that CP-DAF System has yielded lower oil & grease and suspended solid removal efficiency than MB-DAF systems. It has been determined that the optimum working pressure is 4 bar in both systems, and the highest performance was obtained at 1 m3/h. For CP-DAF system, oil & grease and SS removals were obtained as 61% and 54%, respectively. However, 70% and 63% removals for oil & grease and SS were performed for MB-DAF system. Accordingly, it has been obtained that the MB-DAF System operating at 1 m3/h and 4 bar, has approximately 10% higher performance in oil-grease and SS removal than the CP-DAF System.

Keywords

DAF (Dissolved Air Flotation), Industrial wastewater, Removal efficiency, Microbubble pump, Wastewater treatment, Oil & Grease removal, Dairy wastewater

Flotasyon yöntemi ile yağ-gres ve askıda katı madde giderimi-süt ve süt ürünleri endüstrisi örneği

Abstract

Süt endüstrisi atıksularındaki en önemli kirliliklerden biri yağ ve grestir. Flotasyon, yağ-gres gideriminde kullanılan bilinen ve güvenilir bir yöntem olup, yağ-gres ile birlikte askıda katı madde ve organik maddeleri de uzaklaştırabilmektedir. Flotasyon yöntemlerinden biri olan Çözünmüş Hava Flotasyonu (Dissolved Air Flotation, DAF), hava kabarcığı oluşturma yöntemine göre klasik DAF(KP-DAF) ve yeni nesil mikrokabarcık pompalı DAF (MK-DAF) olmak üzere 2 gruba ayrılırlar. İki sistem arasındaki en büyük farklılık mikrokabarcık boyutudur. Genellikle, KP-DAF sistemlerinde 50-120 mikron çapında oluşan kabarcık boyutu, MK-DAF sistemlerinde 20-50 mikron boyutuna inmektedir. Ayrıca, KP DAF sistemi, yeni nesil DAF sistemlerine göre daha karmaşık bir yapıya sahip olup, daha fazla ekipmandan oluştuğu için bakım-onarım ihtiyacı fazladır ve daha sık arıza yapmaktadır. Bu durum işletme açısından sürekli bir efor ve dikkat gerektirmektedir. Bu çalışmada, pilot bir DAF sistemi düzeneği kullanılarak yağ-gres ve askıda katı madde giderimi incelenmiş, giriş debisi, pompa çeşidi, basınç değişimi parametrelerinin verime etkisi araştırılmıştır. Pilot DAF ünitesi, süt ve süt ürünleri üretimi yapan bir işletmede kurulmuş ve gerçek atıksu ile çalışılmıştır. KP-DAF Sisteminin, MK-DAF sistemlerine göre daha düşük yağ-gres ve askıda katı madde (AKM) giderim verimine sahip olduğu tespit edilmiştir. Her iki sistem için optimum çalışma basıncı 4 bar, en iyi verim de 1 m3/h giriş debisinde elde edilmiştir. KP-DAF sistemi ile yağ-gres ve AKM giderimi sırasıyla %61 ve %54, MK-DAF sistemi ile %70 ve %63 mertebesinde gerçekleşmiştir. Bu verilere göre 1 m3/h ve 4 bar işletme koşulunda MK-DAF Sistemi, KP-DAF Sistemine göre, yağ-gres ve AKM gideriminde %10 ve üzeri performans göstermiştir.

Keywords

DAF (Çözünmüş Hava Flotasyonu), Endüstriyel atıksu, Giderim verimi, Mikrokabarcık pompası, Atıksu arıtımı, Yağ-gres giderimi, Süt atıksuyu

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