Question

In order to safeguard the public health, environment, public beaches, water quality, and economy of south San Diego County, California, and Tijuana, Mexico, federal agencies in the United States and Mexico developed four alternatives for treating wastewater prior to discharge into the ocean. The project will minimize untreated wastewater flows that have caused chronic and substantial pollution in the Tijuana River Valley, the Tijuana River National Estuarine Research Reserve, coastal areas used for agriculture and public recreation, and areas designated as critical habitat for federal- and state-listed endangered species. For the costs and benefits estimated, which alternative should be selected on the basis of a B/C analysis at 6% per year and a 40-year project period?

Pond System Expand Plan Advanced Prima Partial Secondary
Capital cost, $5.8 76 2 48
M&O cost, $/year 5.5 5.3 2.1 4.4
Benefits, $/year 11.1 12.0 2.7 8.3

Answer 1

Answer:

Following are the solution to these question:

Explanation:

Follows are the AW calculation to the total cost and add according to the rank of the increasing costs.  

     

               $= 58 (0.06646) + 5.5\\= \ 9.35$

$AWexpand = 76(\frac{A}{P}, 6\%, 40) + 5.3$

                  $= 2 (0.06646) + 2.1\\\\= \ 2.23$

$AWprimary = 2(\frac{A}{P}, 6\%, 40) + 2.1$

                     $= 2 (0.06646) + 2.1\\\\= \ 2.23$

$AW partial = 48(\frac{A}{P}, 6\%, 40) + 4.4$

                  $= 48 (0.06646) + 4.4\\\\= \ 7.59$

Calculating the benefits of the directly estimate on the DN of the first alternative and rank as follows: DN, Primary, Partial, Pond, Expand

$Primary \ DN: \frac{\Delta B}{с} = \frac{2.7}{2.23}= 1.21 \ eliminate\ DN\\\\Partial \ Primary: \frac{\Delta B}{с} =\frac{(8.3-2.7)}{(7.59-2.23)}= 1.04 \ eliminate \ Primary\\\\Pond \ Partial: \frac{\Delta B}{с} = \frac{(11.1 - 8.3)}{(9.35-7.59)}= 1.59 \ eliminate \ Partial\\\\Expand \ Pond: \frac{\Delta B}{с} = \frac{(12.0 - 11.1)}{(10.35 - 9.35)}= 0.90\ eliminate\ Expand$

select the Pond system