Question $5$

$($a$)$ Explain why the combine sewage arrangement of the underground drainage system is NOT suitable for a building site characterized in Table Q$5-1.$ Support your answer with suitable calculations.

$(15$ marks$)$

Table Q$5-1.$ Site condition for underground drainage design

$($b$)$ Discuss how the problems identified in $($a$)$ could be fixed if the combine sewage system arrangement is applied?

$(5$ marks$)$

$($c$)$ Illustrate with calculation why the separate sewage system is associated with less problems to reach the minimum self$-$cleansing velocity.

$(7$ marks$)$

$($d$)$ Explain why the separate sewage system could be a better choice over the combined system for $($a$).$

$(6$ marks$)$