Monotonic Behavior of Improved Soft Sediment under Direct Simple Shear Loading

2025-02-27

Dredging operations produce large volumes of sediment annually; a significant portion of which needs to be improved due to its high water content, poor workability, and low strengths. Assessing improvement efficacy and evaluating improved sediment behavior is commonly limited to unconfined compression strength tests; rarely are any other strength tests such as direct simple shear or triaxial performed. This leads to a lack of understanding of the deformation response of improved sediment under confining pressures that would be encountered in the field, limiting the potential beneficial uses of the material. This paper presents an experimental study on the behavior of cement-improved sediment from Wallabout Channel under direct simple shear loading. The stress–strain response and stress paths were evaluated for specimens subjected to different confining pressures and curing times. Also, unconfined compression tests were conducted to compare the DSS tests with techniques widely employed in practice. Results illustrated that both the curing time and vertical confining stress were key factors for the strength and deformation characteristics of the improved sediment. Moreover, it was shown that the impact of the strength gains due to cementation and the pozzolanic reaction is related to the depth of the improvement. The implications of these results on practice and future research needs are discussed.

Active Turbidity Monitoring During Dredged Material Placement at Dredged Hole #86, Atlantic City, New Jersey

SSRN Electronic Journal · 2025-01-01

Active turbidity monitoring during dredged material placement at dredged Hole #86, Atlantic City, New Jersey

Environmental Challenges · 2025-07-26

• Localized Impact Only • No Exceedance of Water Quality Standards • Supports Beneficial Use of Dredged Material • With proper engineering controls, hydraulic placement in dredged holes can restore habitat without degrading surrounding water quality. This study presents findings from turbidity monitoring conducted during the open-water hydraulic placement of dredged material at Dredged Hole #86 (DH86), located in the back-bay waterways adjacent to Atlantic City, New Jersey. Turbidity, depth and current measurements were collected using in-situ and manual sensors. Results indicated that the hydraulic dredged material placement operations did not lead to observable increases in turbidity levels above background levels (prior to fill operations). This study demonstrated that placement of dredged material into a subaqueous pit resulted in elevated turbidity, however, the impact was temporary and localized and therefore does not pose a risk to the water quality in the area surrounding the discharge location. DH86 will continue to be a viable placement site for ongoing navigational channel dredging needs in this area, while at the same time providing needed habitat restoration in the back bays of New Jersey. The larger implication is that the project will increase acceptance of dredged material placement into dredged holes as a financially and environmentally responsible method for placement of dredged sediments to perform habitat restoration. There are over 100 dredged holes in New Jersey that can be a sediment sink for the New Jersey Marine Transportation System’s navigation channels.

Circulation Dynamics and Dilution in Shallow Estuaries Case Study (2): Numerical Modeling of Plume Dynamics

Journal of marine environmental engineering · 2025-01-01

The mechanisms driving the estuarine circulation, which contributes to dilution in Hendrix Creek were examined by utilizing a validated 3D numerical hydrodynamics model (Delft3D FM) to better understand the transport regime of the WRRF discharge as well as the dilution and mixing conditions. This was phase two of an integrated dilution and mixing study aimed at understanding the circulation dynamics which contribute to dilution in shallow estuaries. In addition to the developed model, numerical scenarios were performed during a dye study period to better understand the significance of plant outfall location, bathymetry, and freshwater discharge from CSO on the dilution of treated wastewater. The main mechanisms involved in the estuarine circulation were found to be the mean advection due to the freshwater discharge from the plant and the residual circulation, which both serve in maintaining the salt balance in the creek. An estimated dilution factor of 1.3 was computed in the receiving environment of the plant discharge, which indicates poor dilution. Numerical experiments of alternative outfall configurations confirm that vertical circulation is important for adequate dilution.

Circulation Dynamics and Dilution in Shallow Estuaries Case Study (1): Dilution Factor Calculations

Journal of marine environmental engineering · 2024-01-01 · 2 citations

The ambient conditions of receiving waters such as currents and density stratification influence the dilution of treated wastewater discharged by WWTPs. Hendrix Creek, a semi-enclosed tidal tributary of Jamaica Bay that serves as receiving water of the 26th Ward WRRF, is not well studied. A near-field dilution model was developed and applied to the plant outfall to simulate plume transport and dilution in the initial mixing zone. The long-term ambient field conditions were characterized, and the dilution factor of a tracer was measured to calibrate the model. This was phase one of an integrated dilution and mixing study aimed at understanding the circulation dynamics which contribute to dilution in the creek. Field measurements during the dye release period also aided in the calibration and development of a 3D hydrodynamic model used to accomplish far-field dilution and mixing in phase two of this study. The near-field model results have good agreement with dye survey data and acoustic doppler current profiler (ADCP) measurements in the creek. Under critical conditions, the model predicts a dilution factor of less than 2 in the initial mixing zone, indicating poor dilution. Saline water from Jamaica Bay which served to dilute the treated wastewater appears to be dominated by the high plant discharge resulting in limited dilution in the near-field region of the creek.

Nearshore placement of dredged material for estuarine shoreline restoration in Berkeley Township, New Jersey

Shore & Beach · 2023-03-20 · 1 citations

Nearshore placement of sediments for beach nourishment has become a standard, cost-effective method for shore protection along ocean-facing shorelines but is not a widely adopted practice within tidal estuaries due to environmental concerns such as turbidity, burial of benthic and shore organisms, and pollution. This paper describes the monitoring and evaluation of nearshore placement of dredged materials at Goodluck Point, Berkeley Township, New Jersey. A total of approximately 4,500 cubic meters of dredged material was placed in the nearshore to create a parallel bar along a 0.5 km stretch of existing beach. The narrow beach is the front edge of a marsh system severely impacted by erosion due to lack of sediment supply compounded with local currents and waves that transport sediment out of the beach system offshore and alongshore. This beach erosion is exacerbated during coastal storms events. The Goodluck Point marsh is part of the Edwin B. Forsythe Wildlife Refuge managed by the U.S. Fish and Wildlife Service. Nearshore placement was determined to be part of an experimental project designed to evaluate methods of restoration for the marsh and reduce future impacts. The design for the nearshore placement called for sand to be placed in a temporary parallel bar just offshore of the existing beach, and over time it would weld to the beach. Analysis of pre- and post-placement surveys indicate that much of the dredged material placed in the project area remained there throughout the 18-month monitoring period. However, a combination of storms during and after placement, as well as ongoing longshore transport processes, resulted in the sand being washed south along the beach and accumulating in just the southern 200 meters of the project area. This paper introduces and suggests that the concept of “process-based design” will maximize resiliency benefits through more extensive pre-placement monitoring and modeling to identify optimal placement strategies. Process-based design is a beneficial use strategy that takes advantage of natural sediment transport processes to enhance or re-create nature-based shore protection features.

Detection of Lead and Environmental Parameters with Sulfur Film Modification of Screen Print Electrode

ECS Meeting Abstracts · 2022-10-09

Environmental electrochemical sensors are an exciting field with a high volume of possibilities. Screen print electrodes have a tremendous advantage for environmental applications as they are 1) capable of performing laboratory and field measurements 2) allow a variety of surface science techniques and provide 3) an excellent outreach medium for students to learn about a variety of engineering and scientific disciplines. The use of redox-active (faradaic or “duck curve”) and non-redox (non-faradaic or capacitance) elements were used to detect lead and bicarbonate respectively using cyclic voltammetry. Aims of this project include the performance assessment of a screen print electrode with sulfur films treatments to detect these environmental compounds. This research education and outreach project summarizes efforts made to conduct and disseminate environmental electrochemistry to students in the New Brunswick area and Rutgers University. Remote and in-person learning labs were conducted to teach students fundamentals of electrochemistry and empower an underserved population to pursue science and engineering disciplines.

Evaluation of Long-Term Performance of Stabilized Sediment for Beneficial Use

2020-08-01

Assessment of the suitability of Kuwait oil sands for beneficial reuse

Journal of Engineering Research · 2020 · 3 citations

• Environmental science
• Waste management
• Geotechnical engineering

The purpose of this study was to investigate the potential beneficial use of the oil-contaminated sand of Northern Kuwait as a construction material. Samples with three Portland cement contents (4, 8 and 10% by weight of sand) and three different organic contents (9, 21 and 33%) were cured for seven days and tested for unconfined compressive strength, moisture content, and organic content. The early strength evaluation of stabilized material is an important factor in landfill caps and construction fill beneficial use applications to provide necessary strength for machinery operations. The results of this research show that the Portland cement content has a direct relationship with strength gain in the oil-contaminated sand of Kuwait. These results align with related studies discussing the coating effect of organic matter (such as crude oil) on soil grains, which inhibits the Portland cement hydration reactions and adversely affects the strength gain of stabilized material. Ultimately, the results of this study show that 8% Portland cement, of the total weight of the soil, mixed in the form of a slurry with 1 to 1 or 2.5 to 1 (water: cement) can fulfill the strength requirement to be reused beneficially.

Assessment of the suitability of Kuwait oil-contaminated sands for beneficial reuse

Journal of Engineering Research · 2020-03-01