The placement of remediation amendments into contaminated sediments via waterjet technologies

The use of amendments to perform in situ remediation of contaminated sediments is a technique that is relatively mature. The need exists to develop a method of amendment delivery that will efficiently place the amendments into the contaminated zone at depth with minimal impacts to the benthic communities and contaminant resuspension. Waterjets have been used for hundreds of years as an excavation, cutting, and cleaning tool, but they can also be used to inject remediation amendments into contaminated sediments if setup properly. In order to test this concept, a waterjet amendment injection system and nozzle have been developed and tested. The system functionality was tested by the characterization of the concentration distributions of the injected amendments into a surrogate sediment. The powdered activated carbon characterization was performed through the use of a novel spectroradiometry technique developed in this work, while granular iron characterization was done using visual comparison and a digestion/Inductive Coupled Plasma mass spectrometry analysis. The distribution patterns exhibited by both of the injected amendments were very similar, while the injection depths varied between the two types of amendment. Analysis of these patterns and depths provides insight as to what occurs during an injection and can lead to the more efficient placement of these waterjet injected remediation amendments --Abstract, page iv

Physical Impact of Waterjet-Based Sediment Remediation on Benthic Organisms

Adding Activated Carbon to Sediments Has Been Shown to Be an Effective Means of Reducing the Bioavailability of Certain Contaminants. the Current State of the Practice is to Mechanically Mix Activated Carbon to a Target Concentration of 3 Percent at Depths of Approximately 30 Cm using a Rotovator or Similar Construction Equipment. Waterjets Have Been Used to Cut Hard Material using a Mixture of Water and an Abrasive. If Activated Carbon is Substituted for the Abrasive, Waterjets Have the Potential to Use Surface Injection as a Replacement for Mechanical Mixing during Sediment Remediation. a Perceived Benefit of Waterjet-Based Sediment Remediation is that There May Be a Reduced Potential for Benthic Organism Mortality Related to Amendment Delivery. a Set of Waterjet Parameters Were Identified that Have the Potential to Achieve Amendment Placement Goals, and a Series of Waterjet Tests Were Conducted to Evaluate the Potential Impact on the Benthic Community. the Tests Included Mortality Testing using a Swimming Macroinvertebrate and a Burrowing Invertebrate, Benthic Artifacts Such as Shells, and Craft Foam as a Surrogate for Living Organisms. the Results Indicated that the Immediate Survivability Was Typically Greater Than 50 Percent, and that Empirical Relationships between Two Variables (Waterjet Nozzle Diameter and the Water Column Height between the Nozzle and the Target) and the Depth of Cut in the Foam Could Be Established. Data Are Not Available in the Literature for Direct Comparison of Organism Survivability Immediately after Mechanical Mixing, But the Results of This Study Provide Motivation for the Further Evaluation of Waterjets on the Basis of the Low Observed Mortality Rates. Future Waterjet Work May Address Field-Scale Characterization of Mixing Effectiveness, Resuspension Potential, Technical Feasibility, and Cost. © 2011 Wiley Periodicals, Inc

Development of a Waterjet System for Direct Delivery of Granular Iron and Activated Carbon to Remediate Contaminated Aqueous Sediments

While the Techniques and Technologies Associated with Contaminated Sediment Remediation Are Relatively Mature, There Are Several Issues Associated with These Practices that Make Them Unattractive. the Inability of Currently Used Mechanical Mixing Implements to Place Amendments in Aqueous Environments and their Intrusive Behavior toward Benthic Communities Are Just Two Examples of a Necessity for an Improved Delivery Method. Waterjets May Be a Viable Option for Placement of Particulate Remediation Amendments, Such as Activated Carbon and Granular Iron, at Depth. a Custom Waterjet Nozzle and Injection System Has Been Fabricated by the Authors to Examine This Delivery Concept. the Developed Injection System\u27s Performance Was Tested by Characterizing the Waterjet-Delivered Amendment (Activated Carbon and Granular Iron) Distributions in a Surrogate Sediment. the Delivered Amendment Distributions Followed Similar Patterns for a Range of Injection Times and a Variety of Amendments. the Injection Depths, However, Were Dependent Upon the Type of Amendment Being Injected. These Findings Have Led to a Better Understanding of What Occurs during an Amendment Injection, Which Can Be Used for a More Controlled Placement of Remediation Amendments using This Technique in the Future. the Laboratory Results Indicate that the Subject Waterjet System May Have the Potential for Field-Scale Applications, Especially for Granular Iron Delivery, as the Authors Were Able to Place between 60 and 70 Wt Percent into a Surrogate Sediment Bed Along the Path of Injection. © 2011 Wiley Periodicals, Inc

Waterjet Placement of Remediation Amendments into Contaminated Sediments

The ability to deliver remediation amendments into contaminated sediments without negatively impacting benthic organisms and their environments has proven to be challenging. The use of waterjets to perform this delivery of remediation amendments at depth is a viable alternative. Waterjets are a viable alternative for placement of remediation amendments at depth. An amendment injection system and waterjet nozzle has been developed to test the merit of this concept. The injection system\u27s performance was assessed by characterizing the distribution of delivered amendments throughout a surrogate sediment test bed. A novel spectrometry method was developed for powdered activated carbon characterization, while granular iron was characterized using two different methods, visual comparison and Inductive Coupled Plasma analysis. Distribution of the placed amendments illustrated similar patterns for a range of injection times and amendment types. However, the depth of injection was dependent upon the type of amendment being injected. The findings of this study has lead to a better understanding on what occurs during an amendment injection, which will aide in and allow for more controlled placement of remediation amendments in the future

Waterjet Amendment for Remediation of Contaminated Sediments using Absorptive and Dechlorinating Compounds in Compromised Waterways

Research currently being conducted at Missouri University of Science and Technology involves using a traditionally high pressure water jets in a new and innovative manner to inject adsorptive and dechlorinating amendments at varying depths in contaminated waterways. Previously published works identify Zero Valent Iron (ZVI) and Powdered Activated Carbon (PAC) as effective means of remediating contaminated sediments and groundwater. While the investigations of both amendments are within the breath of this project, this paper will focus primarily on the placement technologies and the analysis of PAC. A laboratory testing platform, novel amendment jetting, and nozzle designs were all developed to inject amendments into sediment beds. Analytical testing was conducted to examine the reliability in detecting amendment concentrations in sediments to evaluate distribution. The results obtained from this portion of testing, while not extensive, have yielded an effective delivery mechanism and reliable data acquisition system. Ultimately, the goal of this project is to remediate sites via targeted amendment delivery, while minimizing re-suspension, and minimizing damage to benthic biotia

Evaluating the Effects of Waterjet Delivered Amendment on Benthic Organism

The remediation of contaminated sediments is regularly performed through the addition of remediation amendments. The delivery of these amendments is typically executed through mechanical mixing methods, which can be devastating to the benthic communities living in these areas. This research combines the efforts of Missouri University of Science and Technology\u27s Environmental, Mining, and Geological Engineering departments, in order to test the effects of a less invasive amendment delivery system on benthic organisms. A custom waterjet nozzle combined with a pressurized amendment vessel and a standard pressure washer are currently being investigated as a means to deliver remediation amendments into contaminated sediments. The functionality of this system and its delivery efficiency are both being assessed in other ongoing research projects. The purpose of this research was to investigate the effects that this waterjet delivery system would have on benthic organisms. The waterjet delivery system was tested on a benthic organism surrogate as a means to evaluate the newly developed delivery systems impacts on these creatures, and Styrofoam coupons were used as the surrogate. The coupons were placed in different environments and the exiting stream from the waterjet delivery system was passed over each. The variables examined in this analysis included water pressure, distance from the jet to the surrogate, depth of surrogate burial in sand and/or water, and different nozzle degree angles. For animals capable of burrowing at least an inch, like mollusks, would be safe from harm unless the waterjet was being operated within two inches of the sediment