Organics Treatment

Framework for Dredged Material Management

May 2004

often require major investments in operational control for efficient operation. Natural ion-

exchange media, such as zeolites, may be effective but have not been demonstrated in

this application. Use of man-made wetlands for retention of heavy metals and other

contaminants from effluents could represent a viable option for certain sites and

contaminants (Fennessy and Mitsch 1989). Less likely choices include biological ion

exchange, electrocoagulation, and ultrafiltration. More detailed guidance on metals

treatment processes as applied to CDFs is available (Cullinane et al. 1986; Averett et al.

1990).

5.4.2.3 Organics Treatment

The applicability and effectiveness of options for treatment of dissolved organic

contaminants are mostly dependent on the concentration and flow of the liquid stream.

Mechanical biological wastewater treatment processes are typically not considered

because it is doubtful that sufficient organic matter would be available to support

biological growth and because operation of biological systems under the conditions of

fluctuating flows and temperatures would be difficult. Biological processes such as

nitrification, nutrient catabolism, and photosynthesis are important degradation

mechanisms for nutrients, oxygen-demanding materials, and other organics in CDFs. The

principal process for dissolved refractory organic contaminants that has been applied to

dredged material effluent is carbon adsorption, which was applied to a PCB spill on the

Duwamish Waterway in the 1970s (Blazevich et al. 1977). Air and steam stripping could

be used for volatile contaminants, but these are generally not a problem for contaminants

originating in most dredged sediments. Ultraviolet light (UV) and chemical oxidation

processes offer destruction of organic contaminants and are being extensively

investigated in the field for a wide range of contaminants. Created wetlands also offer

potential for retention and degradation of organics. The more effective organic treatment

process options are:

Carbon adsorption.

Chemical oxidation using ozone.

UV/hydrogen peroxide.

UV/ozone.

Oil separation.

Resin adsorption.

Steam stripping.

Created wetlands.

More detailed guidance on organics treatment processes as applied to CDFs is available

(Cullinane et al. 1986; Averett et al. 1990; USACE 1983 and USACE in preparation).

5.4.3 Site Controls

Site controls (e.g., surface covers and liners) can be effective control measures

applied at a CDF to prevent migration of contaminants from the dredged material

(Cullinane et al. 1986; Averett et al. 1990). The implementability and effectiveness of