3) Manufacturing of electronic chips or wafers requires ultrapure water (UPW) in substantial quantities; the primary...

 

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3) Manufacturing of electronic chips or wafers requires ultrapure water (UPW) in substantial quantities; the primary use of this water is to clean the wafers after various manufacturing steps. As a result, wafer fabrication plants have a UPW production plant to supply this water to the manufacturing plant. Typically, the UPW plant takes municipal tap water and treats it further to remove a substantial fraction of the solutes. The UPW then flows into the manufacturing plant, where it is contaminated as it is used to clean the wafers. It is very expensive to make UPW, and the contamination levels in the manufacturing process are quite low. Therefore, it makes sense to consider recycling some of the wastewater back to the start of the UPW production plant as shown in the figure below. Q-Q Cmani Q C₁n UPW Q-Q₂ Cr (a) Unfortunately, some contaminants that are added to the water in the chip manufacturing process are not removed at all in the UPW production plant. As a result, they accumulate in the system with recycle until a steady-state condition is achieved. If the particular chemical that is added at the rate X is not removed at all in the UPW treatment, and if it is also not present at all in the influent (municipal water), what is the steady-state concentration in the effluent (Cout) in terms of X and the flow rates indicated? (Note: We are not concerned in 3) Manufacturing of electronic chips or wafers requires ultrapure water (UPW) in substantial quantities; the primary use of this water is to clean the wafers after various manufacturing steps. As a result, wafer fabrication plants have a UPW production plant to supply this water to the manufacturing plant. Typically, the UPW plant takes municipal tap water and treats it further to remove a substantial fraction of the solutes. The UPW then flows into the manufacturing plant, where it is contaminated as it is used to clean the wafers. It is very expensive to make UPW, and the contamination levels in the manufacturing process are quite low. Therefore, it makes sense to consider recycling some of the wastewater back to the start of the UPW production plant as shown in the figure below. Q-Q Cmani Q C₁n UPW Q-Q₂ Cr (a) Unfortunately, some contaminants that are added to the water in the chip manufacturing process are not removed at all in the UPW production plant. As a result, they accumulate in the system with recycle until a steady-state condition is achieved. If the particular chemical that is added at the rate X is not removed at all in the UPW treatment, and if it is also not present at all in the influent (municipal water), what is the steady-state concentration in the effluent (Cout) in terms of X and the flow rates indicated? (Note: We are not concerned in

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a The rate at which the pollutant accumulates in the system must be zero in steadystate conditions The rate of contaminant buildup in the system with ... View the full answer