Biogeochemical Evaluation of Mechanisms Controlling CaCO3(s) Precipitation in Landfill Leachate-Collection Systems

Leachate treatment before injection into a bioreactor landfill: Clogging potential reduction and benefits of using methanogenesis

“…3). Rittmann et al (2003) showed that the main mechanism for CaCO 3 precipitation from leachate was acetate fermentation producing methane (CH 4 ) and carbonic acid (H 2 CO 3 ). As the pH in the digester effluent was higher than the influent and acetate was consumed within the reactor, a change on FSS was expected.…”

“…Thus, the long-term efficiency of the leachatecollection and injection system is therefore essential to the management and operation of the landfill. Studies from around the world (Canada, USA, Germany, France, Central America, Europe, Japan) have reported clogging (sometimes called bio-rock) in leachate-collection and injection pipes that convey leachate Lozecznik and VanGulck, 2009;VanGulck and Rowe, 2004a,b;Lozecznik, 2006;Rittmann et al, 2003;Rowe et al, 2004). Clogging results in the eventual failure of these engineered systems to perform as designed.…”

Achieving “Final Storage Quality” of municipal solid waste in pilot scale bioreactor landfills

“…in the drainage layer (Rittmann et al, 2003;VanGulck and Rowe, 2004), since carbonate concentrations in solid, liquid or gas phases are dependant on the chemical equilibrium governed by the pH of the system (Garcia-Heras, 2003). Additionally, carbon could be lost as CH 4 and CO 2 escaping from the liquid phase during sampling and recycling of the leachate manually into the reactor.…”

Laboratory studies of clogging of landfill leachate collection and drainage systems

“…From the interpretation of the dissolution-precipitation equilibrium for calcite in influ- ent and effluent samples from mesocosm studies, it was inferred that the disequilibrium of the system with respect to carbonate could represent a rate-limiting factor with regard to the precipitation of CaCO 3 as calcite. The reason for this phenomenon is hypothesized to be associated with limited mass transfer of carbonate to calcite nucleation sites (i.e., the tendency for off-gassing from the system) as discussed by Rittmann et al (2003). As a result, batch incubation tests were repeated with some important differences as described in this section.…”