A desalination plant uses RO modules to desalt brackish water. To minimize the

environmental impact of the discharge stream, the plant was designed in two parallel

stages. The first stage was arranged in forth series modules, and the second stage has

one module.

a$)$ Draw the sketch of this plant.

b$)$ Determine the desired global recovery ratio $($RR$),$ if the $RR$ of the $1^{st}$ stage

was $70\%$ and RR for the $2^{nd}$ stage was $50\%$

c$)$ For a capacity of $2400\frac{m^3}{d},$ determine the $1^{st}$ stage area of the membrane.

d$)$ If the same flux RO modules will be given by $1^{st}$ and $2^{nd}$ stages, determine the

required pressure for the $2^{nd}$ stage.

e$)$ Assume the pressure drop in the $1^{st}$ stage was estimated to $2$ bars, give the

power required by the booster pump.

Take: