Abstract:
This paper focuses on providing a decision support tool (DST) to enhance
methane generation at individual landfill sites. To date there is no decision
support tool (DST) available to provide landfill decision makers with clear and
simplified information for decision makers to understand what is happening within
a landfill site, to assess its performance and to be aware of potential remedies to
any issues. The current lack in understanding stems from the complexity of the
landfill waste degradation process. Two scoring sets for landfill gas production
performance are calculated with the tool including (1) methane output score
which measures the deviation of the actual methane output rate at each site
which the prediction generated by the first order decay model LandGEM; and (2)
landfill gas indicators’ score which measures the deviation of the landfill gas
indicators from their individual ideal ranges for optimal methane generation
conditions. Landfill gas indicators selected include moisture content,
temperature, alkalinity, pH, BOD, COD, BOD/COD ratio, ammonia, chloride, iron
and zinc. A total landfill gas indicator score is also provided using multi-criteria
analysis to calculate the sum of weighted scores for each indicator. The weights
for each indicator are calculated using the analytical hierarchical process. The
tool is tested against five scenarios for landfill sites with a range of good, average
and poor landfill methane generation in one year, 2012. An interpretation of the
results is given for each scenario and recommendations are highlighted for
methane output rate enhancement. The scenarios used clearly illustrated how
the tool can be easily used by landfill operators to enhance their understanding
of methane generation at a site-specific level. The tool assists the landfill operator
to track landfill methane generation over time, compare and rank sites and
identify problems areas within a landfill site.
