School of Science, RMIT University, Victoria 3083, Australia.
School of Science, RMIT University, Victoria 3083, Australia.
Ultrason Sonochem. 2020 May;63:104944. doi: 10.1016/j.ultsonch.2019.104944. Epub 2019 Dec 30.
Effect of high-frequency ultrasonication was examined on wastewater of a cheese manufacturing plant. Tests were carried out at two frequencies (500 kHz and 1 MHz) and two temperatures (22 and 40 °C). Samples were subjected to different energy densities; 7.5, 30.2, 60.5 and 121.0 J/mL at 500 kHz and 7.9, 31.7, 63.4 and 126.8 J/mL at 1 MHz to observe the creaming and recovery of lipid. These energy densities correspond to 30, 120, 240 and 480 s of sonication. Sonication was performed using a single plate transducer and reflector system at 40 W to create standing wave to coalesce and flocculate lipid globules. Recovery was higher at 40 °C after 480 s of sonication at both frequencies (77% at 500 kHz and 75% at 1 MHz). The lowest recovery of 47% was observed at 500 kHz and 22 °C at all applied energy densities. Changes in particle size and turbidity in the bottom aliquot indicated that high-frequency ultrasound caused coagulation and aggregation and settling of colloidal particles. Increase in particle size was observed to be highest at 1 MHz, 40 °C and 480 s of sonication. These results confirm that high-frequency ultrasound standing wave technology can be used to recover lipid from high-lipid dairy wastewater including that from cheese manufacturing.
研究了高频超声对奶酪制造厂废水的影响。在两种频率（500 kHz 和 1 MHz）和两种温度（22 和 40°C）下进行了测试。样品接受了不同的能量密度；在 500 kHz 下为 7.5、30.2、60.5 和 121.0 J/mL，在 1 MHz 下为 7.9、31.7、63.4 和 126.8 J/mL，以观察脂质的稠化和回收。这些能量密度分别对应于 30、120、240 和 480 s 的超声处理。使用单板式换能器和反射器系统在 40 W 下进行超声处理，以产生驻波使脂质球聚结和絮凝。在两种频率下，480 s 超声处理后，40°C 时的回收率更高（500 kHz 时为 77%，1 MHz 时为 75%）。在所有应用的能量密度下，在 500 kHz 和 22°C 时观察到的回收率最低，为 47%。底部等分试样的粒径和浊度变化表明，高频超声会导致胶体颗粒的凝聚、聚集和沉降。在 1 MHz、40°C 和 480 s 的超声处理下，观察到粒径增加最大。这些结果证实，高频超声驻波技术可用于从包括奶酪制造废水在内的高脂乳制品废水中回收脂质。
