$15-3$ The sidestream described in Problem $15-2$ is discharged to the inlet of the primary clarifiers in the mainstream process. Ferric chloride is applied to the primary clarifiers at an average

$F\frac{e}{P}$ mass ratio of $2k\frac{g}{k}g$ to reduce the orthophosphate concentration in the primary tank effluent. Using the given data,

a$.$ Estimate the volume of concentrated ferric chloride solution required to precipitate the orthophosphate$-$P contributed by sidestream to the primary tank influent. The physical property data for the ferric chloride solution is shown below:

b$.$ The implementation of a struvite crystallization process for sidestream pretreatment is being considered. Assuming negligible loss of phosphate during to precipitation in the equalization tank, a target soluble orthophosphate$-$P concentration of $15m\frac{g}{L}$ in the crystallizer effluent and $100$ percent recovery of the crystallized product, estimate the average daily mass of struvite that can be potentially harvested from this process. An air$-$dried product in the form of a hexahydrate salt should be assumed in the calculation.