Question: you need to consider the feasibility of using a bypass...
You need to consider the feasibility of using a bypass line to reduce the flow of water being treated for water softening (hardness removal). The water coming in has a hardness of 250 mg/l, and the total flow is 15 MGD. Since the softening process is based upon equilibrium, the treated water always leaves with 25 mg/l of hardness - higher effluent criteria is not feasible using this chemical process based upon equilibrium.
However, a hardness of 90 mg/l is more than low enough to meet all treatment needs.
1. If the target outflow concentration is set at 90 mg/l, what flow will need to be treated (Y) and what flow can be bypassed (X)?
Assume a steady-state flow, no leakage in the system, and negligible changes in temperature and pressure throughout the process.