Wastewater Characteristics and Treatment

Wastewater Characteristics and Treatment

Introduction

Wastewater is the polluted form of water generated from rainwater runoff and human activities.

Characteristics of Water and Wastewater

1. Physical Characteristics

  • NTU OR JTU (Turbidity)
  • Colour
  • Odor
  • Suspended solids
  • Temperature

2. Chemical Characteristics

  • Chemical Oxygen Demand (COD)
  • Total Organic Carbon (TOC)
  • pH
  • Chloride
  • Heavy metals

3. Biological Characteristics

  • MPN (Most Probable Number)
  • SPC (Standard Plate Count)
  • Nitrification
  • Microbial population

Types of Treatment

  • Preliminary Treatment
  • Primary Treatment
  • Secondary Treatment
  • Advanced Treatment

1. Preliminary Treatment

Used for the removal of floating material in wastewater.

Units used in preliminary treatment:

  • Screen (to Remove Floating Material)
  • Grit Chamber
  • Oil and Grease Trap

2. Primary Treatment

Used for the removal of suspended solids in wastewater (size range: > 10^3 microns).

Units used in primary treatment:

  • Coagulation (Rapid Mixing)
  • Flocculation (Gentle Mixing)

3. Secondary Treatment

Used for the removal of dissolved solids in wastewater (size range: < 10^3 microns).

Bacteria are used to remove dissolved impurities from the wastewater.

Units used in secondary treatment:

  • Aeration Tank
  • Secondary Sedimentation Tank

4. Advanced Treatment

Units used in advanced treatment:

  • RO (Reverse Osmosis)
  • Filtration
  • UV (Ultraviolet)
  • Osmosis