I designed an activated sludge aeration basin. Qmax=3Qavg.
if i don't want to use an equalization tank so the basin volume (V) should be design according Qmax. and for calculating HRT, we have HRT=V/Qavg. HRT &SRT calculated from this method is much more from standards (also SRT may negative).
I Think SRT must be under 30 for activated sludge. Can anyone help?
Qavg= 5000 m3/day
Qmax= 14400 m3/day
BODin=240 BODout=20 ppm
-Calculate V: F/M=(Qmax.BODin)/(V.MLVSS)
v= 5485 m3
-Calculate HRT= V/Qavg=1.09 day
Calculate SRT using Y=0.4 and kd=0.04 1/day: MLSS=SRT×Y×(BODin-BODout)/(HRT×(1+kd×SRT))
SRT=-75 day !!!!!