What do know About Sewage treatment and Sewage Reactions ?

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An Overview of Sewage Treatment and Sewage
Reactions
By ABDULRAHMAN AL-BETAR
ECU 2001
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Outline

• Introduction
• Dhahran S.T.P in Saudi Aramco
• Sewage Treatment Processes
• Preliminary
• Primary
• Secondary
• Tertiary

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Introduction

• Definitions
• Sewage
• The content of sewer or drains
• Sewage Treatment
• Removing of impurities so that the remaining
  waste water can be safely returned to the river
  or sea and become part of the natural water cycle
  again.

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Introduction Contd

• Compositions
• Human waste
• paper
• Food
• Grease
• Mineral matter
• and almost any things that can be carried by
  water

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Saudi Aramco
Dhahran S.T.P

• Biggest sewage treatment plant operated by the
  company
• Treat 10 million gallons per day of raw sewage
• Sodium Hypo-chlorite is used in secondary and
  tertiary treatments for disinfections
• Treated water is used for the irrigation purposes

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Sewage Treatment Processes

• Preliminary
• Primary
• Secondary
• Tertiary

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Sewage Treatment Processes Contd
Preliminary Treatment

• Solids like wood paper, rags and plastic are
  removed by screens

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Sewage Treatment Processes Contd
Primary Treatment

• The remaining solids that passed from the
  preliminary treatment are removed
• About 70 of solids settle out at this stage

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Sewage Treatment Processes Contd
Secondary Treatment

• Biological treatment to reduce organic matter in
  the waste stream
• Aerobic bacteria is the main cause for this
  reduction
• The chemical reaction
• Organic matter CO2 H2O

Bacteria
O2
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Sewage Treatment Processes Contd
Secondary Treatment

• This process can be speeded up by blowing air
  into tanks of sewage
• These treatment units are called Aeration
  Tanks.

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Sewage Treatment Processes Contd
Aeration Tank
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Bacteria Found in the Sewage
Sewage Treatment Processes Contd
Secondary Treatment

• Aerobic
• Require dissolved oxygen for their existence
• Ex Earobacter

Facultative Can grow with or without oxygen Ex
Salmonella
Anaerobic Exist in the absence of dissolved
oxygen Ex Sulfate Reducer
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Sewage Treatment Processes Contd
Tertiary Treatment

• Several forms of tertiary treatment are available
  for example
• Passing the effluent over grass plots
• Retaining the effluent in lagoons
• Filtering through sand beds

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Summary of Sewage Treatment Processes
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END OF SEWAGE TREATMENT
Thank You