$17\mathrm{.}5$ A single$-$stage super$-$rate trickling filter is to

be designed for a population of $8100$ persons.

Pertinent data are: influent flow $=95ga\frac{l}{c}ap-$day,

influent BOD ${?}_5=210m\frac{g}{l},$ primary clarifier removes

$33\%$ of the influent BOD ${?}_5,$ effluent BOD ${?}_5=20m\frac{g}{l},$

filter depth $=20ft,$ and recycle ratio $\frac{R}{Q}=2.$ Pilot$-$

plant studies have shown that the removal constant

$K=0\mathrm{.}085$ at $20C$ when the depth is in feet, the

hydraulic loading is in gpm $\frac{?}{f{t}^2},$ and the constant $n=$

$0\mathrm{.}5.$ The winter wastewater temperature $=61F$

$(16\mathrm{.}1C).$ The synthetic plastic packing is available

in $2-$ft modules. Two filters in parallel are to be

used. Determine, using USCS units and Eq$.(17\mathrm{.}8)$:

a$.$ The theoretical diameter, $ft.$

b$.$ The design diameter if distributors are available

in $5-ft$ increments in diameter, $ft.$

Skip Part C

d$.$ The hydraulic loading, $8p\frac{m}{f}{t}^2$ and $M\frac{G}{a}c-$day.

e$.$ The organic loading in $l\frac{b}{d}ay-1000f{t}^3$ and $l\frac{b}{d}ay-$

ac$-$ft$.$

Notes for $17\mathrm{.}5$

Use equations on slides $26$ and $27.$

Note that parameters $k{A}_s^{m}C=$ is unique

for a particular media and can be

represented as $K.$

$,$ Correct $K$ for temperature using

$K_T=K_{20}{1\mathrm{.}035}^{T-20}.$

$Q_L=\frac{Q}{?}$ S$.$A$.$

$Q$ is into the trickling filter and includes

$Q_R.$ Conduct a flow balance to calculate.

$2Q,20m\frac{g}{L}$