I am the parent of a student who is using this portal.I am a wastewater treatment engineer with 23 yrs exp.I have to state here that the explanation given by the expert for the use of septic tanks in a community place like cinemas etc is wrong .Septic tanks are used for unsewered houses .iF YOU HAVE COMMUNITY BASED BUILDING AS YOU HAVE STATED  the sewage is conveyed to a sewage treatment plant. Please correct the answers