Calculation of septic tank capacity The total amount of fecal wastewater generated by this project is 92m3/d, and the formula for calculating the septic tank is as follows: V1=Nqt/(24×1000) where: N-number of users, 3053 people; q-drainage volumeL/ People.d; t-retention time of 36h. V2=0.000336NT Where: N-use of the number of people, 3053 people; T- emptying cycle 180 days.

Substitute the data into the formula to get the effective volume of the project septic tank: V = V1 + V2 = 137.4 + 184.6 = 322.0m3, rounded to 330 m3, so the project set up a septic tank, septic tank is recommended to be not less than the total volume of 330m3 / d to meet the purification requirements. My sewage treatment process on this project is as follows: regulating tank - primary sedimentation tank - biological turntable - secondary sedimentation tank - disinfection tank - external discharge. -Disinfection tank - external discharge.