Environmental Dredging Pilot on the Lower Passaic River

Lisa A. Baron (1), Maheyar R. Bilimoria (2), Scott E. Thompson (3), Peter M. Weppler (4)

(1) NJ Department of Transportation, Office of Maritime Resources, Trenton, NJ, 08625, (609)530-4779,
(609) 530-4860, lisa.baron@dot.state.nj.us

(2) Earth Tech, Inc. 300 Broadacres Drive, Bloomfield, NJ, 07003, (973)338-6680,  (973) 338-1052, maheyar.bilimoria@earthtech.com

(3) Malcolm Pirnie, Inc., 104 Corporate Park Dr., White Plains, NY 10602, (914) 641-2628,  (914) 641-2455, sthompson@pirnie.com

(4) US. Army Corps of Engineers, NY District, 26 Federal Plaza, NY, NY, 10278-0090, (917)790-8634,     (212) 264-0961, peter.m.weppler@usace.army.mil

As part of the Lower Passaic River Restoration Project (LPRRP), an environmental dredging pilot was implemented by NJDOT, USACE, and USEPA to evaluate remedial dredging of contaminated sediments in the Lower Passaic River estuary. The LPPRP is one of the pilots being conducted under the Urban Rivers Restoration Initiative, using joint CERCLA and WRDA authorities, with the objective of developing a comprehensive watershed-based plan for the restoration of this 17-mile long, highly-degraded industrial waterway and the surrounding watershed.

In December 2005, approximately 4,300 cubic yards (cy) of contaminated sediment were dredged from a 1.5 acre area in 10 to 15 feet of water in the Harrison Reach. Sediments were dredged at an average rate of 830 cy per 10-hour workday using an eight (8) cy Cable Arm mechanical clamshell dredge bucket equipped with sensors for bucket positioning and monitoring bucket closure. The dredged material was then transported to a near shore processing facility for treatment by two innovative decontamination technologies (sediment washing process and thermo-chemical destruction processes) to make beneficial use end products. The major objectives of the pilot study included: 1) Evaluation of dredging equipment performance, including productivity, precision (achieving targeted dredging depth and cut lines), turbidity levels, and operational controls; 2) Monitor sediment resuspension to determine how much sediment was released from the dredging operation and where that sediment was transported; and 3) Evaluation of sediment decontamination and treatability to produce valuable products, such as manufactured soil or construction-grade cement at full scale.

The results of this environmental dredging pilot will aid in the site specific evaluation of remedial alternatives for the overall restoration solution for the Lower Passaic River. In addition, the pilot will also provide valuable information for other remedial dredging projects.