61    APPLICATION OF ULTRAFILTRATION FOR THE
TREATMENT OF LANDFILL LEACHATE
Donald A. Isaacs, Chemical Engineer
Alan Li, Senior Project Manager
Chemical Waste Management, Inc.
Research and Development
Geneva, Illinois 60134
Kevin O'Leary, Project Manager
Waste Management of North America
Corporate Engineering
Oak Brook, Illinois 60521
INTRODUCTION
Waste Management of North America (WMNA) operates a solid waste landfill in central Illinois
that requires treatment of approximately 30,000 gallons per day of leachate. The facility includes a 48-
acre landfill which received non-hazardous liquid waste and municipal solid waste until its closing in
early 1989.
The initial sampling and characterization of leachate were conducted from 23 gas recovery wells in
1989. Leachate collected from the wells consisted of two layers; an aqueous and a light organic phase.
The organic layer was primarily non-PCB containing oil (< 50 mg/L) which could be reclaimed or
disposed of off-site. The aqueous leachate phase has an oil content between 200 and 2000 mg/L and a
suspended solids concentration between 400-900 mg/L. The average COD concentration for the
aqueous leachate was over 6000 mg/L. The characterization data for the leachate is summarized in
Table I.
The site has negotiated with the local POTW (Publicly Owned Treatment Works) for a discharge
permit. The site will be required to reduce the oil content of the discharged leachate to less than 100
mg/L and reduce suspended solids to some unspecified concentration, probably also less than 100
mg/L. These restrictions will require pretreatment of the leachate prior to discharge.
Chemical Waste Management (CWM) R&D conducted a leachate treatability study for WMNA at
the Riverdale Technical Center Facility in May of 1989. The primary objective of the study was to
develop design data for the pretreatment facility. This paper documents the results of the study.
LEACHATE TREATABILITY STUDY
The entire treatability study consisted of two phases. During Phase 1 of the study, treatability
studies followed the two proposed treatment schemes illustrated in Figure 1. In Treatment Scheme I,
the leachate would be segregated into oil and aqueous fractions in a gravity separator such as an API
separator. The aqueous fraction would then be treated with chemicals such as polyelectrolytes or alum
to beak the residual oil/water emulsion, so that the residual oil could be separated and removed in a
subsequent separator. The sludge from the secondary separator would be concentrated in a filter press
prior to final land disposal. The second treatment scheme involved free oil removal followed by
membrane ultrafiltration.
Thus, the bench-scale tests in Phase I involved the following tasks:
• Gravity separation of free oil
• Aqueous layer characterization after free oil removal
• Chemical breaking of the residual oil/water emulsion
• Clarification and/or filtration of the emulsion, and
• Bench-scale ultrafiltration testing of raw and pretreated leachates
46th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Printed in U.S.A.
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