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.