Remediation of Contaminated Sediments with Ultrasound and Ozone Nano-bubbles

新泽西州的帕塞伊克河是美国污染第二严重的河流，也是被宣布为超级基金的地点，有100多个工业设施排放许多污染物。2016年3月3日，美国环保局公布了决定记录(Rod)，在六年内从一岸到另一岸从这条河疏浚350万立方码的受污染沉积物，耗资13.6亿美元。修复计划不仅代价高昂，而且有可能在六年的疏浚过程中对该地区的经济和社会增长造成重大破坏，方法是通过驳船将疏浚的沉积物转移到新泽西州纽瓦克附近的一个大型脱水设施，然后通过铁路将脱水后的沉积物运出新泽西州。这项研究将以帕塞伊克河为测试案例，研究一种清洁受污染沉积物的创新替代方法。将使用三项创新技术，即超声波、臭氧和纳米气泡，以提供具有成本效益和环境可持续的现场处理技术，预计在较短的时间内总成本较低。预计这一替代方法对该区域的环境和社会经济健康的不利影响也将微乎其微。超声波能量提供搅拌和土壤净化。臭氧与解吸的污染物发生反应，有助于将它们从河流中去除。纳米气泡有助于臭氧气体在水中的溶解。一旦处理完成，任何剩余的溶解臭氧都会分解成氧气，这将有助于振兴微生物和生态系统。除了社会效益外，该项目还将为几名代表性不足的研究生和本科生提供持续培训的机会，以获得对多学科研究的深刻欣赏，并扩大NSF资助的研究的参与度和多样性。这项研究将评估在臭氧纳米气泡存在的情况下，利用超声波能量进行原位沉积物净化程序的可行性。这项研究结合了三种新兴技术，即超声波、臭氧处理和纳米气泡，以解决一个主要问题，即沉积物的原位去污。超声波能量的目的是提供搅拌，使沉积物保持悬浮状态，将污染物从沉积物表面分离出来，并将它们释放到大块溶液中。超声波能量还将产生整体运动，以加强臭氧对所有受污染颗粒的均匀应用，并促进沉积物中污染物的解吸。臭氧的作用是将沉积物中解吸的有机污染物降解为可溶于水相的中间产物，并将沉积物中解吸的重金属氧化为可溶离子，以便通过过滤强化去除。臭氧气体将以纳米气泡的形式输送，以增加臭氧气体在水中的溶解，并增强臭氧气体在液体中的稳定性。为了验证和优化技术，将进行台架试验，然后进行统计分析。将在小试试验中确定影响去除效率的关键因素，并进行完全析因设计，以生成用于统计分析的去除效率数据。此外，还将研究纳米气泡的稳定性，以延长纳米气泡在水中的停留时间，作为处理受污染土壤和地下水的可能新技术。并利用冲击波理论对超声波的清洗机理进行了研究。总体而言，这项研究将提供一种更便宜、更有效的方式来清理被危险沉积物污染的河流。

The Passaic River, New Jersey, is the second most polluted river in the USA and a declared Superfund site with over one hundred industrial facilities discharging a number of contaminants. On March 3, 2016, the USEPA announced the record of decision (ROD) to dredge 3.5 million cubic yards of the contaminated sediments from the river, bank-to-bank at a cost $1.36 billion over six years. The remediation plan not only has a high price tag, but also has the potential to cause significant disruptions to the economic and social growth of the region over the six years of dredging by transferring the dredged sediments via barges to a large dewatering facility close to Newark, New Jersey, and then transporting dewatered sediments via rail out of New Jersey. This research will investigate an innovative alternative approach to clean contaminated sediments, using the Passaic River as a test case. Three innovative technologies will be used, namely, ultrasound, ozone and nano bubbles, to provide a cost effective and environmentally sustainable on-site treatment technology, with expected lower total cost over shorter time span. This alternative methodology is also expected to have minimal adverse impact on the environment, and the socio-economic health of the region. The ultrasound energy provides agitation and soil decontamination. The ozone reacts with desorbed contaminants to help removal of them from the river. The nano bubbles help dissolution of ozone gas in water. Once the treatment is completed, any remaining dissolved ozone will break into oxygen, and will help to revitalize microbes and the eco-system. In addition to the societal benefits, the project will accord the opportunity for the continuous training of several underrepresented graduate and undergraduate students to acquire deep appreciation for multidisciplinary research and to broaden participation and enhance diversity of NSF funded research.This research will evaluate the feasibility of the in-situ sediment decontamination procedure with ultrasound energy in the presence of ozone nano-bubbles. Three emerging technologies, namely ultrasound, ozone treatment and nano bubbles are combined in this research to address a major problem, in-situ decontamination of sediments. The purpose of the ultrasound energy is to provide agitation that will maintain the sediments in a suspended state, detach contaminants form the surface of sediments and release them to the bulk solution. The ultrasound energy will also generate bulk motion to enhance uniform application of the ozone to all contaminated particles and to facilitate desorption of contaminants from sediments. The role of ozone is to degrade desorbed organic contaminants in the sediment into intermediate products that are soluble in the aqueous phase and also to oxidize the desorbed heavy metals from sediments into soluble ions for enhanced removal by filtration. The ozone gas is to be delivered as nano bubbles to increase the ozone gas dissolution in water and to enhance the ozone gas stability in the liquid phase. In order to validate and to optimize the technology bench scale tests will be performed followed by statistical analysis. The key factors that contribute to the removal efficiency will be identified in bench scale tests and full factorial design will be performed to generate removal efficiency data for statistical analysis. In addition, stability of nano bubbles will be investigated to prolong the residence time in water as possible new technology to treat contaminated soils and ground water. Also the cleaning mechanism of ultrasound will be investigated using the theory of shock wave. Overall this research will provide a cheaper and efficient way to clean rivers contaminated with hazardous sediments.