19    BIOPHYSICAL TREATMENT OF LANDFILL LEACHATE
CONTAINING ORGANIC COMPOUNDS
Sheila F. McShane, Senior Engineer
T. E. Pollock, Manager
Industrial Services Department
James M. Montgomery, Consulting Engineers, Inc.
Pasadena, California 91109
Alon Lebel, Project Engineer
BKK Corporation
West Covina, California 91791
Bryan A. Stirrat, Principal
Bryan A. Stirrat and Associates
City of Industry, California 91744
INTRODUCTION
BKK Corporation (BKK) operates the BKK Landfill in West Covina, California, which is located
approximately 20 miles east of central Los Angeles. The total area occupied by the landfill is approximately 580 acres. The landfill operations commenced in 1963 when non-hazardous municipal and
commercial wastes were accepted. In 1972 the landfill began accepting hazardous waste and that
phase of the operation continued until 1984 when it was voluntarily discontinued. BKK has continued
dumping non-hazardous wastes on top of the hazardous waste area to complete the contouring of the
landfill for adequate site draining and landfill gas control. In 1987 the non-hazardous waste disposal
operations will commence in a new canyon on-site away from the previous hazardous waste area. It is
expected that disposal operations will continue until 1995. The landfill is presently accepting 7,500
tons per day of non-hazardous wastes.
To mitigate environmental impacts associated with the landfill, BKK operates an extensive
leachate/gas collection system, as well as an extensive series of monitoring wells. The purpose of the
majority of these facilities is to collect all liquids emanating from the trash disposal area and treat
them onsite. Figure 1 presents the liquid management systems within the landfill. Currently, mildly
contaminated landfill waters are used for dust control onsite, and the more contaminated leachate
wastestreams are subjected to air stripping prior to onsite solidification and redisposal at the landfill.
Due to regulatory restrictions at the landfill and the labor intensive nature of these processes, BKK
wishes to discontinue the solidification of the leachate and redisposal onsite. It is BKK's intent to
implement a program to dewater the landfill. To aid in accomplishing this, a series of horizontal
drains and vertical wells extending into the trash prisms have been installed and more are planned for
installation in the near future. This dewatering activity is part of BKK's plan to close and maintain
that portion of the landfill containing deposits of hazardous waste in accordance with RCRA requirements.
Several disposal options for the leachate were evaluated. The disposal options considered included
discharge to a publicly owned treatment works (POTW), discharge to a surface water body or on-site
use for landscape irrigation and dust control utilizing the POTW for disposal of excess as needed. The
last option is considered the most viable at this time. In order to utilize any of these options, treatment
of the leachate would be required. Biological, physical/chemical, and biophysical processes were
evaluated to determine their potential suitability for treatment of the leachate from the landfill. A
biophysical process which utilizes a suspended growth biological culture supplemented by the addition
of powdered activated carbon (PAC) to the aeration basin was recommended as the basic treatment
system. This is a proprietary system named PACT (Powdered Activated Carbon Treatment) which is
licensed by Zimpro, Inc. of Rothchild, Wisconsin. The biophysical treatment system has been used
successfully for the treatment of hazardous waste and in industrial applications with highly variable
influents [1,2,3]. Since landfill leachate contains a heterogeneous mixture of biodegradable com-
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