Water Quality Research Center, Korea Water Resources Corporation, Daejeon 34350, South Korea.
Department of Civil, Environmental, and Construction Engineering, University of Central Florida, Orlando, FL 32816-2450, USA.
Ultrason Sonochem. 2017 Sep;38:326-334. doi: 10.1016/j.ultsonch.2017.03.003. Epub 2017 Mar 6.
Algal blooms are a naturally occurring phenomenon which can occur in both freshwater and saltwater. However, due to excess nutrient loading in water bodies (e.g. agricultural runoff and industrial activities), harmful algal blooms (HABs) have become an increasing issue globally, and can even cause health effects in humans due to the release of cyanotoxins. Among currently available treatment methods, sonication has received increasing attention for algal control because of its low impact on ecosystems and the environment. The effects of ultrasound on algal cells are well understood and operating parameter such as frequency, intensity, and duration of exposure has been well studied. However, most studies have been limited to laboratory data interpretation due to complicated environmental conditions in the field. Only a few field and pilot tests in small reservoirs were reported and the applicability of ultrasound for HABs prevention and control is still under question. There is a lack of information on the upscaling of ultrasonication devices for HAB control on larger water bodies, considering field influencing factors such as rainfall, light intensity/duration, temperature, water flow, nutrients loading, and turbidity. In this review article, we address the challenges and field considerations of ultrasonic applications for controlling algal blooms. An extensive literature survey, from the fundamentals of ultrasound techniques to recent ultrasound laboratory and field studies, has been thoroughly conducted and summarized to identify future technical expectations for field applications. Case studies investigating spatial distribution of frequency and pressure during sonication are highlighted with future implications.
藻华是一种自然发生的现象，可发生在淡水和咸水中。然而，由于水体中过量的营养物质负荷（例如农业径流和工业活动），有害藻华（HABs）已成为一个日益严重的全球性问题，甚至由于释放出的蓝藻毒素而对人类健康产生影响。在现有的处理方法中，由于对生态系统和环境的影响较小，声处理越来越受到关注。超声对藻类细胞的影响已得到充分理解，并且已对诸如频率、强度和暴露时间等操作参数进行了充分研究。但是，由于野外环境条件复杂，大多数研究仅限于对实验室数据的解释。仅报道了一些在小水库中的现场和试点测试，超声处理在控制藻华方面的适用性仍存在疑问。由于缺乏关于在更大水体上控制藻华的超声处理设备放大的信息，因此需要考虑降雨、光强/持续时间、温度、水流、营养负荷和浊度等野外影响因素。在本文中，我们讨论了超声应用于控制藻华的挑战和野外考虑因素。从超声技术的基础到最近的超声实验室和野外研究，我们进行了广泛的文献调查，并对其进行了总结，以确定未来在现场应用中的技术期望。重点介绍了在声处理期间调查频率和压力的空间分布的案例研究及其未来意义。
