Which of the following statements is/are TRUE for the aerobic composting of sewage sludge?

A system of seven river segments is shown in the schematic diagram. The R_i’s, Q_i’s, and C_i’s (i = 1 to 7) are the river segments, their corresponding flow rates, and concentrations of a conservative pollutant, respectively. Assume complete mixing at the intersections, no additional water loss or gain in the system, and steady state condition. Given: Q₁ = 5 m³/s ; Q₂ = 15 m³/s ; Q₄ = 3 m³/s ; Q₆ = 8 m³/s ; C₁ = 8 kg/m³; C₂ = 12 kg/m³; C₆ = 10 kg/m³. What is the steady state concentration (in kg/m³, rounded off to two decimal place) of the pollutant in the river segment 7 ? ______

The composition and energy content of a representative solid waste sample are given in the table. If the moisture content of the waste is 26%, the energy content of the solid waste on dry-weight basis is ________ MJ/kg (round off to one decimal place).

$$ \begin{array}{|c|c|c|} \hline \text { Component } & \text { Percent by mass } & \text { Energy content as-discarded basis (MJ/kg) } \\ \hline \text { Food waste } & 20 & 4.5 \\ \hline \text { Paper } & 45 & 16.0 \\ \hline \text { Cardboard } & 5 & 14.0 \\ \hline \text { Plastics } & 10 & 32.0 \\ \hline \text { Others } & 20 & 8.0 \\ \hline \end{array} $$