Question

II. Drinking Water Treatment (30 points) The Belmont Water Treatment plant extracts water from the Schuylkill River. The river often carries 0.010 mm silt particles with an average density of 2.2 g/cm'. The treatment plant uses a circular clarifier in the primary step. The clarifier is 3.5 m deep and 21 m in diameter. After primary and secondary treatment, 2 mg/L free chlorine is added as a disinfectant. Use today's temperature and pH 7 to find: 7. The settling velocity. (5 points) 8. The hydraulic detention time of the clarifier. (5 points) 9. The overflow rate of the clarifier. (5 points) 10. Will the clarifier remove all the silt particles? (5 points) 11. If not, calculate the minimum diameter of the clarifier that allows complete settling. (5 points) 12. Disinfection kinetics constant of Giardia inactivation. (5 points)

Please answer each part with necessary equations and explanations with temperature, T = 64F. Thank you!

Answer 1

ge Belmont water treatment plapate Given Data: Circular clarifice Assume, Flow Q=86 MGD = 325545.4m 3 day caufic dimensions : Diameter (O) = 21m - Depth (H) = 3.5m I sit particle diameter (d) - 0.000mm . Density of silt (Phall = 2.2g/ce T=64 F 17178°C 4 settling relvuty (vod Lo.1 mm = Lominor for I take g = 4181m/ Weg 13-17d? I - Pwater v kinemati histos by = 2.2 = = 9.81 2:2 -1] x 6.01X 10-2) fois Tex10-6 - ko 6.54 xles T-18°c 8 on Hydraulic Detention time rolume = I xd 2x it 3 = I x 21?x3.5 1 = 1212,262 m² Ibt = volume + = 1212.262 3255455.4 DT = 3.7237X10 BT = 5.362 min days