Ultrasound to Decontaminate Organics in Dredged Sediments
Ultrasound to Decontaminate Organics in Dredged Sediments
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超声波净化疏浚沉积物中的有机物
DOI：
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发表时间：
2002
期刊：
影响因子：
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通讯作者：
Kanya Veerawat
中科院分区：
文献类型：
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作者：
J. Meegoda;Kanya Veerawat
由于过去的处置做法而被有机化合物污染的沉积物威胁环境，需要修复。本研究试图开发一种利用超声波和真空压力相结合的方法来净化疏浚沉积物中的有机物。使用来自纽约/新泽西港的模拟疏浚沉积物进行了一系列实验室规模的实验，这些沉积物是III类沉积物，不符合美国环保局关于毒性或生物积累的要求，需要安全处置。利用超声波能量和真空压力相结合的声空化作用来促进沉积物中对三联苯(选定的有机污染物)的去除。采用两个耦合工艺来分离和处理粗(工艺1)和细(工艺2)的沉积物。用于评估工艺1的选定变量是超声波功率、溶剂与沉淀物的比例、真空压力和超声时间。对工艺2进行了不使用表面活性剂和使用表面活性剂的评估。不加表面活性剂的工艺2有三个变量：功率、剂沉比和超声时间，而加入表面活性剂的工艺2有四个变量对其性能有影响：功率、剂沉比、表面活性剂浓度和超声波时间。根据析因设计，用这些参数的不同组合进行了实验室规模的实验。试验结果表明，在功率为60%(900W)、剂沙比为15：1、真空压力为15 psi、超声时间为9 的条件下，工艺1的污染物去除效率可达99%。同样，不含表面活性剂的工艺2在功率为80%(1200W)、溶剂与沉淀物比为50：1、超声时间为90 的条件下，污染物去除效率为55%。通过添加表面活性剂对工艺2进行改进，在功率80%(1200W)、剂沙比50：1、表面活性剂浓度0.1%、超声作用时间60 的条件下，污染物去除效率达到89%。研究表明，该处理技术对疏浚底泥的处理是有效的。
Sediments contaminated with organics compounds due to past disposal practices threaten the environment and require remediation. This study was an attempt to develop a technology to decontaminate organics in dredged sediments using ultrasound coupled with vacuum pressure. A set of laboratory scale experiments were carried out using simulated dredged sediments from New York/New Jersey harbor, category III sediments that failed to meet USEPA requirements for toxicity or bioaccumulation, and required secure disposal. Acoustic cavitation due to ultrasound energy coupled with vacuum pressure was used to facilitate the removal of p-terphenyl (the selected organic contaminant) from the sediments. Two coupled processes were used to separate and to treat both coarse (Process 1) and fine (Process 2) fractions of sediments. Selected variables for evaluation of Process 1 were ultrasound power, solvent to sediment ratio, vacuum pressure, and sonication time. Process 2 was evaluated without and with surfactants. Process 2 without surfactant had three variables: power, solvent to sediment ratio, and sonication time, while Process 2 with surfactant had four variable contributing to its performance: power, solvent to sediment ratio, surfactant concentration, and sonication time. Laboratory-scale experiments were carried out with various combinations of these parameters according to the factorial design. Experimental test results showed that Process 1 had 99% contaminant removal efficiency at 60% power (900 Watts), 15:1 solvent to sediment ratio, 15 psi vacuum pressure, and 9 min of sonication time. Similarly, Process 2 without the surfactant had 55% contaminant removal efficiency at 80% power (1200 Watts), 50:1 solvent to sediment ratio, and 90 min of sonication time. Modification of Process 2 with the addition of a surfactant produced 89% contaminant removal efficiency at 80% power (1200 Watts), 50:1 solvent to sediment ratio, 0.1% surfactant concentration, and 60 min of sonication time. The study showed that the proposed treatment technique is effective for treating dredged sediments.