storm drainage and septic tank

• Storm Drain


  An aspect in plumbing system that conveys rain or storm water to a suitable terminal
• Storm drain is normally discharged into


  Street gutter conveyed by public drain system
• Natural drainage terminals


  • Canals
  • Rivers
  • Lakes
• Size determination of Storm Drain

  1. Gauging rainfall

  2. Varying roof areas

  3. Slope and distance of water

  4. Height of building

  5. Avoiding improper fittings
• Water drains faster on high pitch roof
• Septic tank is a receptacle or vault used to collect organic waste discharged from the house sewer
• Main function of a septic tank

  To liquefy and precipitate solid waste purifying odorous materials
• Sewage discharged into the tank is retained
• About 60-70% of the suspended solid of the sewage is removed largely by sedimentation
• Sludge


  A semi-solid/liquid substance that accumulates at the bottom of the septic tank
• Scum


  Lighter organic materials that rise to the water
• Overall process in septic tank

  1. Sedimentation

  2. Anaerobic decomposition
• Gases produced inside the septic tank

  • Methane gas
  • Carbon Dioxide
  • Carbon Monoxide
  • Hydrogen
  • Hydrogen Sulfide
  • Sulfur Dioxide
• Methane gas (CH4)


  A combination of hydrogen and carbon, a principal component of natural gas
• Carbon Dioxide (CO2)


  A combination of carbon and oxygen, the simplest oxide of carbon
• Carbon Monoxide (CO)


  A by-product of methane, classified as poisonous gas
• Hydrogen (H2)


  Evolves as a moist gas from organic waste
• Hydrogen Sulfide (H2S)


  A colorless gas with offensive odor
• Sulfur Dioxide (SO2)


  A colorless gas having an irritating odor
• These gases are discharged into the atmosphere through the ventilation pipe
• Digestive Chamber


  For the discharge of sewage
• Leaching Chamber


  Disposes of effluent from the septic tanks and distributes this effluent for natural wastewater treatment