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MATHEMATICAL MODEL FOR METHANE PRODUCTION FROM LANDFILL BIOREACTOR - A DISCUSSION PAPER HTTP://OIPS.AIP.ORG/EEO/
Citation:
Chen**, B. Y., V Gallardo*, AND H H. Tabak*. MATHEMATICAL MODEL FOR METHANE PRODUCTION FROM LANDFILL BIOREACTOR - A DISCUSSION PAPER HTTP://OIPS.AIP.ORG/EEO/. JOURNAL OF ENVIRONMENTAL ENGINEERING 126(2):193-194, (2000).
Description:
This discussion explains the experimental results of a landfill bioreactor (LFBR) from a microbiological perspective and provides a feasible strategy to evaluate methane production performance, since suitable models are complicated and not sufficiently reliable for anaerobic-system design, as concluded by the authors. The discussers point out that the LFBR system with a leachate recycle significantly increased the overall residence time of reactants avalable for biodegradation. Thus, a higher conversion of organic carbon resulted compared with the system without leachate recycle (as the authors show in Fig. 6). For the degradation of recalcitrant compounds, it is crucial to acquire relatively longer residence times in order to induce and synthesize essential enzymes in optimum amounts to transform pollutants to CH4. Pirt (1975) mentioned that, as the age of the culture used to inoculate a bioreactor approached the time of late logarithmic phase, the lag time for the bioreactor reached a minimum. This suggests that the degradation rate of the LFBR system can be maximized by using an inoculum of optimum age. This further suggests that biomass age is a critical parameter in the performance of bioreactors. In addition, the discussers propose that certain observations in the authors' paper can be explained in terms of biomass age. The authors' bioreactor with leachate recycle increased the conversion of more complex compounds to more biodegradable ones; this significantly increased the initial gorwth of biomass. This in turn resulted in an increase of the overall age (or residence time) of biomass and thus fostered the adaptation of an efficient mixed consortium to produce a higher level of CH4. Therefore, the LFBR with an optimum leachate recycle can essentially provide a microbial population with an optimum age to maximize CH4 production.