72    REVERSE OSMOSIS TREATMENT OF LANDFILL
LEACHATE
Riley N. Kinman, Professor
Civil & Environmental Engineering
University of Cincinnati
Cincinnati, Ohio 45221
David L. Nutini, General Manager
RNK Environmental, Inc.
Covington, Kentucky 41017
INTRODUCTION
The feasibility of using reverse osmosis (RO) technology to treat landfill leachate was studied. The
project was conducted on a pilot-scale in the field. The specific objectives of the study were to: 1)
evaluate the RO treatment processing of landfill leachate; and 2) determine any other requirements
necessary to handle the landfill successfully.
METHODS AND MATERIALS
A pilot-scale reverse osmosis (RO) treatment unit was set-up in the field in July, 1989. The RO was
capable of treating 10,000 gallons of leachate per day. The unit itself consisted of a 5 micron prefilter,
a pump, 4 x 50 square feet of polyamide membranes (total = 200 square feet), pressure valves, flow
meters and an instrument panel, which included a conductivity meter. Operating pressure for the RO
unit was between 200-600 psi. The RO unit is shown in Figure 1.
A flow diagram of the complete treatment system is presented in Figure 2. It consisted of two
20,000 gallon holding tanks. The first tank (Tank #1) was used as a settling tank. The leachate was
pumped from this tank through a 10 micron filter into Tank #2. From Tank #2, it was pumped to a 55
gallon drum and then to the RO unit. The permeate (clean water) from the process was piped to one of
two holding tanks. The concentrate (leachate) was piped back to Tank #1. Therefore, the leachate was
concentrated during processing.
A flow diagram of the treatment process for fresh leachate (treated on October 24, 1989) is
presented in Figure 3. The only change from the above was that a 4000 gallon tanker truck was
hooked up directly to the RO. The concentrate stream was returned directly to the truck. Therefore,
the feed was concentrated during processing.
Several trial runs were made during the study. Samples of the treated leachate (permeate) were
taken during and at the end of each run. Analyses of these samples included the following parameters:
Figure 1.    RO unit.
45th Purdue Industrial Waste Conference Proceedings, © 1991 Lewis Publishers, Inc., Chelsea, Michigan 48118.
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