Q$)$ A laboratory test evaluated two$-$step batch process to treat creosote

waste: $1)$ suspending creosote waste with surfactants for $7$ days at $205$

solids in roughing vessel and $2)$ transferring the supernatant to the

polishing reactor for $14$ days of additional biological treatment $.$ The

reported reduction in the concentration of selected PAHs is shown in

the table. How many days of a treatment operation would be necessary

to degrade each of constituents to $100ppm$ or less.