10.1 Operational Management Actions

Table 10-1

Applicability of Various Management Actions to CDF Pathways

Applicability to Pathways

Management Actions

Effluent

Runoff

Leachate

Volatiles

Animal

Plant

Operational controls

Selective placement

Surface covers

Lateral barrier systems

Bottom and side liners

Treatment of discharges

Sediment treatment

10.1 Operational Management Actions

If the CDF cannot be sized to provide sufficient clarification of effluent to

meet applicable suspended solids/turbidity standards, control and treatment

measures can be considered. Since a large portion of the total concentration of

contaminants in effluents is associated with the suspended solids, reduction in the

suspended solids also serves to control contaminant releases. Suspended solids

removal therefore offers the greatest benefits in improving effluent quality not

only by reducing turbidity but also by removing particulate-associated

contaminants. Effluent quality may be improved by:

Use of a smaller dredge with reduced inflow rate.

Providing increased ponded area and depth of the CDF.

Relocation of the inflow and effluent discharge points.

Treatment or filtration of effluent to reduce the concentration of

suspended solids and associated contaminants in the effluent.

Treatment of effluent to remove dissolved contaminants.

Simply increasing the ponding depth will increase retention time in the pond

for a given inflow rate. Restricting the inflow rate or consideration of intermittent

pumping will also increase retention time. Relocation of inflow and weir

locations may also increase the hydraulic settling efficiency of the site. Although

these management actions are easy to implement, they will influence the

production rate and may increase costs.

Site operations can also be used to manage CDFs to reduce the exposure of

material through the surface water, volatilization, and leachate pathways.

Management actions may include management of the water ponded in the CDF

during and after disposal operations. Mobilization of contaminants from dredged

material depends on the oxidation state of the solids. Most metals are much less

mobile when maintained in an anaerobic reduced condition. On the other hand,

aerobic sediments generally improve conditions for biodegradation of organic

contaminants. Aerobic sediments generally present the greatest potential for

10-2

Chapter 10

CDF Contaminant Management Actions