Which of the following statements is/are TRUE for the aerobic composting of sewage sludge?
Statement (A): A bulking agent is added to increase porosity and improve aeration, not to reduce it. Hence, Statement (A) is False.
Statement (B): During the aerobic composting process, leachate can indeed be generated due to the breakdown of organic matter and moisture content. Hence, Statement (B) is True.
Statement (C): Actinomycetes are microorganisms that play a significant role in the breakdown of tough organic materials like lignin, and they are involved in the composting process. Hence, Statement (C) is True.
Statement (D): In-vessel composting systems can indeed be operated in the plug-flow mode, which is a common setup to optimize the process. Hence, Statement (D) is False.
\[ \boxed{\text{Correct Statements: (B) and (C)}} \]
The wastewater inflow to an activated sludge plant is $0.5\, \text{m}^3/\text{s}$, and the plant is to be operated with a food to microorganism ratio of $0.2\, \text{mg/mg-d}$. The concentration of influent biodegradable organic matter (after primary settling) is $150\, \text{mg/L}$, and the mixed liquor volatile suspended solids (MLVSS) to be maintained is $2000\, \text{mg/L}$. Assuming complete removal of biodegradable organics in the tank, the volume of aeration tank (in m$^3$, integer) required is.