Sultana Nilufa, Roddick Felicity, Pramanik Biplob Kumar
School of Engineering, RMIT University, Melbourne, VIC, 3001, Australia.
School of Engineering, RMIT University, Melbourne, VIC, 3001, Australia.
Chemosphere. 2025 Feb;370:143987. doi: 10.1016/j.chemosphere.2024.143987. Epub 2024 Dec 20.
Commercial grease interceptors (GIs), commonly used in food service establishments, are primarily designed to treat fat, oil and grease (FOG) from handwash sink (HS) wastewater. They are generally less effective for removing highly concentrated FOG from dishwasher (DW) effluents which contain highly emulsified FOG with complex long-chain fatty acids (LCFAs). Furthermore, standard testing of GIs uses diesel fuel to simulate FOG separation; however, the flow properties of typical cooking oils and animal fats differ significantly from diesel. We developed a novel GI (bench-scale with 72 L capacity) and examined the impact of various baffle configurations on FOG removal efficiency using samples containing representative FOG components of cooked oil, fat and food solids. The results demonstrated that the installation of two short baffles projecting from the top along with one short baffle projecting from the bottom in the first chamber, and another short baffle projecting from the top in the second chamber, led to FOG removal efficiencies of up to 88% and 40% for HS and DW effluents, respectively, at a hydraulic retention time (HRT) of 44 min. The short baffles acted as barriers, thus enhancing the loss of kinetic energy, subsequently ensuring a quiescent flow condition, resulting in an increased HRT for effective FOG separation. The addition of alum as coagulant at 200 mg/L (18.2 mg of Al/L) significantly enhanced the removal of FOG from treated DW effluents (up to 87%), effectively reducing the concentrations of various extra-LCFAs, such as paullinic (C20:1), arachidic (C20:0), eicosadienoic acid (C20:2), mead (C20:3), eicosapentaenoic (C20:5), erucic (C22:1), cervonic (C22:6), tricosanoic acid (C23:0), lignoceric (C24:0) and nervonic (C24:1) acid by up to 99%. These findings provide significant insights into the advanced GI design, offering a proactive solution to prevent fatberg formation while promoting a more sustainable and economically viable approach to sewer management.
商业油脂拦截器（GIs）常用于食品服务场所，主要用于处理洗手池（HS）废水中的脂肪、油和油脂（FOG）。它们对于去除洗碗机（DW）废水中高度浓缩的FOG效果通常较差，这些废水中含有高度乳化的FOG以及复杂的长链脂肪酸（LCFAs）。此外，GIs的标准测试使用柴油来模拟FOG分离；然而，典型的食用油和动物脂肪的流动特性与柴油有显著差异。我们开发了一种新型的GI（容量为72升的实验室规模），并使用含有食用油、脂肪和食物固体代表性FOG成分的样品，研究了各种挡板配置对FOG去除效率的影响。结果表明，在第一个腔室中安装两个从顶部伸出的短挡板以及一个从底部伸出的短挡板，在第二个腔室中安装另一个从顶部伸出的短挡板，在水力停留时间（HRT）为44分钟时，HS和DW废水的FOG去除效率分别高达88%和40%。短挡板起到了屏障的作用，从而增加了动能损失，随后确保了水流静止的状态，从而延长了有效分离FOG所需的HRT。添加200毫克/升（18.2毫克铝/升）的明矾作为凝聚剂，显著提高了处理后DW废水中FOG的去除率（高达87%），有效降低了各种超长链脂肪酸（extra-LCFAs）的浓度，如棕榈油酸（C20:1）、花生酸（C20:0）、二十碳二烯酸（C20:2）、甲基二十碳三烯酸（C20:3）、二十碳五烯酸（C20:5）、芥酸（C22:1）、二十二碳六烯酸（C22:6）、二十三烷酸（C23:0）、木蜡酸（C24:0）和神经酸（C24:1），降低幅度高达99%。这些发现为先进的GI设计提供了重要见解，为防止油脂块形成提供了积极的解决方案，同时促进了一种更可持续、更经济可行的下水道管理方法。
