$(15$ points$)$ Mark as True $($T$)$ or False $($F$)$

a$.$ It is impossible to determine a value of sludge age for a trickling filter; however, we do know that attached growth systems can have an effective sludge age sufficient for achieving a high level of nitrification. $(T$ or F$?)$

b$.$ Grit chambers are sized using average daily flow rates rather than peak hourly flow rates. $(T$ or F$?)$

c$.$ Denitrification results in a decrease in alkalinity.

$($ Tor F$?)$

d$.$ Alkalinity and volatile acids concentration are two important parameters for monitoring and controlling anaerobic digesters.

$(T$ or $F?)$

e$.$ Dissolved oxygen saturation increases as temperature decreases.

$($T or F$?)$