An environmental impact study compares waste decomposition in an open landfill with a controlled closed bioreactor system.
The table below shows the mass of organic municipal waste at the start and after 60 days60\text{ days}60 days of treatment.
MeasurementOpen landfillClosed bioreactorMass at start (tonnes)12001200Mass after 60 days (tonnes)540985\begin{array}{|l|c|c|} \hline \textbf{Measurement} & \textbf{Open landfill} & \textbf{Closed bioreactor} \\ \hline \text{Mass at start (tonnes)} & 1200 & 1200 \\ \hline \text{Mass after 60 days (tonnes)} & 540 & 985 \\ \hline \end{array}MeasurementMass at start (tonnes)Mass after 60 days (tonnes)Open landfill1200540Closed bioreactor1200985
The mass of the waste in the open landfill decreased by approximately 11 tonnes11\text{ tonnes}11 tonnes per day. Calculate the average decrease in mass of the waste in the closed bioreactor per day. Give your answer to 1 decimal place.
Carbon dioxide and methane, which are greenhouse gases, are released during decomposition and are responsible for most of this mass loss. Use your answer from part (a) to explain why the closed bioreactor method might be better for the environment.