Economical Treatment of Dredged Material to Facilitate Beneficial Use

Abstract

Growing constraints on conventional dredged material disposal are motivating movement toward more sustainable alternatives. Given the lack of universal beneficial use criteria, even the low levels of contaminants typically found in navigation channel sediments may limit or preclude their beneficial use. Intensive treatment to remove or destroy contaminants in such sediments is typically too costly to be a viable alternative within the context of navigation dredging; economical, lowtech sediment and water treatment processes are needed. Recent developments in the area of sediment treatment were assessed through an extensive literature search, and promising technologies were identified. Potentially high value research areas were also identified, to inform subsequent bench and pilot testing. Geochemical contaminant controls and modeling, passive water treatment methods for colloid and ammonia removal, H2S controls, in-CDF biodegradation, aerobic/anaerobic composting, phase-specific physical separation, low temperature thermal treatment, reactive geobags, and coupled geochemical/stabilization process modeling were areas identified as deserving of additional research investment. DISCLAIMER: The contents of this report are not to be used for advertising, publication, or promotional purposes. Citation of trade names does not constitute an official endorsement or approval of the use of such commercial products. All product names and trademarks cited are the property of their respective owners. The findings of this report are not to be construed as an official Department of the Army position unless so designated by other authorized documents.

Lightweight Aggregate Made from Dredged Material in Green Roof Construction for Stormwater Management

“…Raw dredge is sediment in its original unaltered form, and sintered dredge is the manufacturing and processing of the sediment into an industrial “baked” commercial product. The application of raw dredge is most common and occurs within several categories of beneficial use, including (1) habitat; (2) beach nourishment; (3) parks and recreation; (4) agriculture forestry, horticulture and aquaculture; (5) strip-mine reclamation/solid waste management; and (6) construction/industrial development [ 1 , 2 , 3 , 4 , 5 , 6 , 7 ]. The beneficial use of raw dredge material stems from the growing demand for construction materials and dwindling inland sources.…”

Environmental evaluation and management of dredged material for beneficial use : a regional beneficial use testing manual for the Great Lakes

“…One of the early demonstrations of soil washing was conducted under the ARCS program with a barge-mounted pilot scale plant, nominal capacity 5 tons/hr. "Approximately 800 yd3 of partially dewatered mechanically dredged material was barged to the site and used as plant feed" (Estes and McGrath 2014). The plant operations included the following:…”

“…Other amendments have also been considered that are potentially effective for stabilization of both organic and metal compounds, including organoclay, apatite, biochar, coke, zeolites, and zero valent iron, among others. Calcium nitrate has been field demonstrated for reduction of H2S in highly polluted waterways, a problem at some CDFs and beneficial use placement sites (Estes and McGrath 2014), although the potential water quality impacts of this technology do not appear to have been studied.…”

“…Natural organic matter, carbonates, humic acids, by-products of oxidation and the reagents themselves (in peroxide overdosing) can all act as scavengers resulting in higher required reagent dosages. Carbonates may also provide significant buffering, limiting the effectiveness of pH dependent processes (Estes and McGrath 2014).…”

“…Destruction of the natural organics may be necessary to access the associated contaminants rather than being a secondary and undesirable reaction. Separation of the organic fractions prior to reagent addition has the potential to improve effectiveness in treating the larger non-organic sediment fraction but generates a separate (though typically much smaller) waste stream requiring disposal and requires an additional treatment process (separation) (Estes and McGrath 2014). In practice, chemical oxidation has not yet been shown to be an effective and economical means of treating/destroying particulate associated contaminants ex situ.…”