Question

Suppose that the company proposes to install an ion exchange unit to recover 98% of the metal ions i) What is the annual value in dollars of metal lost to the sewer? i) If the ion exchange unit cost $12,000 to operate per year and given that there are no additional fees for releasing the remaining metal to the sewer (it is negligible by PRASA standards) what is the annual dollar expenses (annual capital charge) that is the operating costs plus losses to the sewer? ii What is the present worth of proposed project giving that the discount (interest) rate is 10% and expected life of 10 years?

Answer 1

To calculate the annual value of metal lost to the sewer, multiply the loss (2 units) by the value of one unit of metal ($X).

Step-by-step explanation:

To calculate the annual value of metal lost to the sewer, we need to know the total metal input into the ion exchange unit. Let's assume the company processes 100 units of metal in a year. If the ion exchange unit recovers 98% of the metal, then there will be a loss of 2 units of metal to the sewer. To find the annual value of metal lost, we multiply the loss (2 units) by the value of one unit of metal ($X) and we get the annual value in dollars.

To calculate the annual dollar expenses, we need to add the operating cost of $12,000 to the annual value of metal lost.

To find the present worth of the proposed project, we will use the formula for present worth (PW) which is PW = A / (1 + r)^n, where A is the annual dollar expenses, r is the discount rate, and n is the expected life of the project. Using the given values, we can calculate the present worth.