AREA A/B ENGINEERING REPORT - Waste Management

Geosyntec Consultants
secondary, and tertiary processes. 12 Approaches that are sufficient as primary treatment in one
case may be appropriate as a tertiary stage for “polishing” of pretreated effluent prior to
discharge at another site.
For example, at an older closed landfill, an
engineered wetland or reed bed in which
leachate is physically and biologically treated
may be capable of providing effective
treatment of leachate to achieve surface water
discharge standards. A sustainable LMS
strategy at a newer active landfill might involve
the use of wetlands for effluent polishing;
however, in this application, pre-treatment using
a more active treatment system is typically
required if influent leachate constituent
concentrations are well above surface water
quality standards. As previously discussed,
untreated leachate or treated effluent may be
Constructed vertical wetlands provide a passive
method by which leachate can be treated prior to
discharge. The system design also offers added
value as a potential wildlife habitat.
recirculated back into the landfill depending on the waste degradation strategy or other
potential beneficial use strategy of the landfill (e.g., gas-to-energy plant). Most treated effluent
also has other beneficial uses (e.g., use for dust suppression on access roads within the landfill
footprint or as flush water for toilet facilities).
Because the characteristics of MSW leachate at a landfill are well understood and are
predictable in terms of both their expected quantity and quality over time (see Section 1.4 and
discussion in Appendix A), it is becoming standard practice to design a LMS that considers
changes in long-term leachate management obligations in defining goals for sustainable landfill
operation at the managed modern landfill.
3.4 Landfill Cover Systems
The landfill cover system is designed to promote surface water runoff, minimize erosion, prevent
direct exposure to waste, and control gas emissions and odors. A secondary objective is to
provide an aesthetically pleasing final appearance for the landfill. In this regard, the cover can
be designed to be compatible with the local ecosystem to broaden the potential end uses of the
property. The landfill cover system provides ongoing protection of human health and the
environment, improves the collection efficiency of the gas management system, and serves an
important function in onsite liquids management.
12 A number of technical publications deal extensively with leachate treatment technologies, including USEPA (1995a),
and U.K. Environment Agency (2007), as well as Robinson (1999), Robinson, et al. (2003), and Robinson & Olufsen
(2004).
MD10186.doc 44 29 March 2009