Handbook of Civil Engineering Calculations

xxiv Contents

Design of a Circular Settling Tank ........................................ 8.8

Thickening of a Waste-Activated Sludge Using a

Gravity-Belt Thickener ............................................ 8.10

Design of an Aerobic Digester .............................................. 8.12

Design of an Aerated Grit Chamber ..................................... 8.16

Design of Solid-Bowl Centrifuge for Sludge

Dewatering .............................................................. 8.19

Sizing of a Traveling-Bridge Filter ........................................ 8.23

Design of a Rapid-Mix Basin and Flocculation Basin .......... 8.26

Sizing a Polymer Dilution/Feed System ............................... 8.28

Design of a Trickling Filter Using NRC Equations ............... 8.29

Design of a Plastic Media Trickling Filter ............................. 8.33

Sizing a Rotary-Lobe Sludge Pump ..................................... 8.36

Design of an Anaerobic Digester .......................................... 8.41

Design of a Chlorination System for Wastewater

Disinfection .............................................................. 8.44

Sanitary Sewer System Design ............................................ 8.45

Selection of Sewage-Treatment Method .............................. 8.49

Section 9. Engineering Economics ............................. 9.1

Calculation of Interest, Principal, and Payments .................. 9.4

Determination of Simple Interest .................................. 9.6

Compound Interest; Future Value of Single

Payment ............................................................. 9.6

Present Worth of Single Payment ................................ 9.7

Principal in Sinking Fund .............................................. 9.7

Determination of Sinking-Fund Deposit ........................ 9.7

Present Worth of a Uniform Series ............................... 9.8

Capital-Recovery Determination ................................... 9.8

Effective Interest Rate .................................................. 9.8

Perpetuity Determination .............................................. 9.9