From 1995 to 1997, the Montgomery County Leachate Pretreatment Facility (MC
LPF) has successfully pretreated in excess of 18,000,000 gallons of leachat
e generated by the county's municipal solid waste landfill. The collection
system directs leachate from the original landfill, the new lined section,
and the ash cell to the leachate pump station. The leachate, prior to being
pumped to the leachate pretreatment system, is equalized in two storage la
goons with a combined capacity of more than 5,000,000 gallons.
The innovative leachate treatment system, incorporating a biological reacto
r system equipped with a submerged fixed-film reactor using a patented Matr
ix Biological Film (MBF) media, continues to provide excellent pretreatment
results for the leachate generated at the Oaks Landfill in Montgomery Coun
ty, Maryland. In 1995 and 1996, the system responded to the substantial cha
llenges imposed by the changing characteristics of the material being landf
illed and by the significant amounts of incinerator ash, received in 1995 f
rom the county's resource recovery facility (RRF), which influenced the inf
luent leachate characteristics. The extremely wet weather caused the collec
tion and equalization system to be overloaded and required the biological r
eactor system to operate at peak flow and loading conditions for extended p
eriods of time. In fact, the facility pretreated in excess of 12,500,000 ga
llons of leachate in 1996 compared to only 5,500,000 gallons for all of 199
5, and continued to meet permit requirements. Although the landfill closed
in 1997, technological challenges to the system will continue. The past per
formance indicates that this system will continue to provide excellent pret
reatment results and, in future years, may provide an effluent suitable for
direct discharge.