# The Influence of Waste Composition on Landfill Gas Generation in a Pilot-Scale Lysimeter
## 3 Results
### Results of Elemental Analysis  
Results of elemental analysis are shown in Table 4. The chemical composition of the samples was investigated. The chemical composition of nitrogen, carbon, hydrogen, sulphur, and oxygen was analyzed. The percentage of sulphur (S) that contains SO\({}_{4}\)\({}^{2-}\) generating H\({}_{2}\)S and carbon (C), which is an energy source of microorganisms, was identified through elemental analysis. The sample that contained the most carbon was domestic waste at 57.17%. However, the carbon content in brick construction waste and earth and sand construction waste, which are non-flammable, was 3.24% and 7.23%, respectively.  
Earth and sand construction waste that contained fine particle such as gypsum showed the highest sulphur contents. Fine particles of C&D debris waste generated in Florida had sulphur. It has been reported that gypsum remaining in C&D debris waste is the main source of sulphate [29; 30]. Earth and sand construction waste shows a high percentage of sulphur. The reason C&D debris waste + solidified sludge shows a higher sulphur contents than C&D debris waste + sewage sludge seems to be the influence of a firming agent (cement). It seems that the creation of SO\({}_{4}\)\({}^{2-}\) generating H\({}_{2}\)S and the  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Waste Type** & **C** & **H** & **O** & **N** & **S** \\ \hline \multirow{4}{*}{C\&D debris waste} & Brick construction waste & 3.24 & 0.45 & 36.01 & 0.20 & 0.00 \\ \cline{2-7}  & Earth and sand construction waste & 7.23 & 1.42 & 42.42 & 0.67 & 5.15 \\ \cline{2-7}  & Combustibles & 47.27 & 5.53 & 38.97 & 2.88 & 0.25 \\ \cline{2-7}  & C\&D debris waste & 26.77 & 3.36 & 39.93 & 1.72 & 2.08 \\ \hline \multirow{2}{*}{Sludge} & Sewage sludge & 32.25 & 4.67 & 23.32 & 5.15 & 0.41 \\ \cline{2-7}  & Solidified sludge & 23.93 & 2.27 & 13.59 & 2.35 & 1.41 \\ \hline \multicolumn{7}{c}{Domestic waste} & 57.17 & 8.42 & 21.78 & 0.41 & 0.00 \\ \hline \multicolumn{7}{c}{C\&D debris waste + sewage sludge} & 28.31 & 3.73 & 35.28 & 2.68 & 1.62 \\ \hline \multicolumn{7}{c}{C\&D debris waste + solidified sludge} & 26.17 & 3.13 & 34.40 & 1.85 & 1.94 \\ \hline \multicolumn{7}{c}{Mixed waste} & 35.22 & 4.85 & 32.09 & 2.12 & 1.23 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Chemical composition of seven wastes from the Sudokwon landfill site (%, on a dry basis, Average of two analyses).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Waste Type**} & \multirow{2}{*}{**Solidified Substances (\%)**} & \multicolumn{3}{c}{**Three Components**} \\ \cline{3-5}  & & & **Moisture (\%)** & **Combustibles (\%)** & **Ash (\%)** \\ \hline C\&D debris waste & 91.05 & 8.95 & 43.65 & 47.4 \\ C\&D debris waste + sewage sludge & 69.57 & 30.43 & 35.52 & 34.05 \\ C\&D debris waste + solidified sludge & 76.15 & 23.85 & 37.25 & 38.90 \\ Domestic waste & 73.14 & 26.86 & 64.25 & 8.89 \\ Mixed waste & 71.52 & 28.48 & 37.25 & 34.27 \\ Brick construction waste & 99.99 & 0.01 & 3.59 & 96.41 \\ Earth and sand construction waste & 84.12 & 15.88 & 13.25 & 70.87 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Three component analyses of seven wastes from the Sudokwon landfill site (Average of two analyses).  
increased carbon, an energy source of microorganisms, facilitates SRB microorganism proliferation increasing H\({}_{2}\)S production.