In years gone by a catchy phrase among waste treatment personnel was, "The solution to pollution is dilution." Of course this is no longer true, to the benefit of us all. Back in those earlier days, though, the $"$It Takes Real Brass Co$."$ metal finishing plant was discharging a wastewater which contained $980ppm$ of chromium. The regulations for wastewater discharge stipulated that it was unlawful to release a stream of water to the environment if it contained more than $26ppm$ chromium. Note that ppm corresponds to parts per million. As we have talked in class, this is mass fraction in liquid phase. For example $998ppm$ corresponds to $0\mathrm{.}098\%$ mass fraction. The plant also had a source of once$-$through cooling water that contained absolutely no chromium, and decided to use it to dilute the $980ppm$ stream. A metering device on the cooling water outlet showed that the flow of this water stream was $1700\frac{m^3}{h}.$ Take density of water to be $1000k\frac{g}{m^3}.$ After mixing with the $980ppm$ stream the chromium level in the outfall was found to be $21ppm.$ The mass flow rate of the $980ppm$ stream is

Hint: First assume a basis for inlet stream.

Perform a chromium balance. Calculate the actual water added by performing overall balance. Scale this back to actual water entering to get your answer.

$50567k\frac{g}{h}r$

$37200k\frac{g}{h}r$

$998k\frac{g}{h}r$

$1700021k\frac{g}{h}r$