Calculate the clean$-$bed headloss through a deep$-$bed filter with $1\mathrm{.}5$m anthracite coal$($ effective size$=1\mathrm{.}1$mm$)$ over $0\mathrm{.}3$ m sand $($ effective size$=0\mathrm{.}5$mm$)$ at a filtration rate of $15$ m$/$hr and temperature of $15$ degree celcius. pw$=998\mathrm{.}4$ kg$/$m$^3,$ u$=1\mathrm{.}14*10^-3$ kg$/$m$*$s Mid points from table $11-5$ Anthracite coal: kv$=228,$ ki$=4\mathrm{.}4,$ porosity anthracite $=0\mathrm{.}50$ Sand: kv$=112,$ ki$=2\mathrm{.}2,$ porosity sand $=0\mathrm{.}42$ using Ergun equation