I need help please: Calculate the surface area required for a stabilization pond to serve a domestic population of $1000.$ Assume $80$ gpcd at $210$ mg$/$l of BOD. Use a design loading of $20$ lb of BOD$/$acre$/$day$.$ If the average liquid depth is $4$ ft$,$ calculate the retention time of the wastewater based on influent flow.The effluent is spread on grassland by spray irrigation at a rate of $2\mathrm{.}0$ in$./$week $(54,300$ gal$/$acre$/$wk$).$ Compute the land area required for land disposal. In these computations, assume no evaporation or seepage losses from the ponds.