A rotary drum filter is used to filter a slurry. The drum rotates at a rate of $3 \mathrm{~min} / \mathrm{cycle}$, and $40 %$ of the drum surface is submerged beneath the slurry. A constant pressure drop at 3 psi is maintained across the filter. If the drum is $5 \mathrm{ft}$ in diameter and $10 \mathrm{ft}$ long, calculate the total net filtration rate in gpm that is possible for a slurry having properties as determined by a lab test, as follows. A sample of the slurry was pumped at a constant flow rate of $1 \mathrm{gpm}$ through $0.25 \mathrm{ft}^{2}$ of the filter medium. After $10 \mathrm{~min}$, the pressure difference across the filter had risen to $2.5 \mathrm{psi}$. The filter medium resistance may be neglected.