Wastewater Composition and Types

Wastewater Composition

• Wastewater primarily consists of water (99.94%)
• Remaining 0.06% includes dissolved and suspended solids.
• Pollutants of concern include pathogens, inorganics, organic matter, oil/grease, and gases.

Types of Wastewater

• Domestic Wastewater:
  • From residences, apartments, motels, etc.
  • Two types:
    • Gray Water: Wastewater from washing processes (bath, shower, sink, laundry).
    • Black Water: Wastewater containing fecal matter and urine (toilets, urinals, bidets).
• Commercial Wastewater:
  • From food service operations and beauty salons.
  • Similar to domestic wastewater but can occasionally have higher concentrations of certain components.
• Industrial Wastewater:
  • From manufacturing, commercial labs, mining operations.
  • Includes runoff from areas exposed to industrial or commercial activities.
  • May contain pollutants from storage, handling, or processing.

On-Site Sewage Treatment (OSST)

• Traditionally called septic systems.
• Components include:
  • Building sewer
  • Septic tank
  • Distribution box
  • Drainage field (or disposal field)
• Treats wastewater from rural/suburban homes, apartments, and businesses without access to central systems.

Primary Wastewater Treatment

• Takes place within the septic tank.
• Heavier solids settle to the bottom.
• Lighter particles (grease, soap) form a scum layer on top.
• Beneficial bacteria in the tank partially treat wastewater.
• Treated wastewater (effluent) leaves the septic tank.

Septic Tank Components & Functions

• Watertight container
• Designed to settle and hold solid wastes
• Bacteria break down waste material.
• Effluent (treated wastewater) leaves the tank.

Other Treatment Components

• Aerobic Tanks: Alternative to septic tanks, comprising different chambers and using active oxygen for treatment.
• Pump Tanks: Temporarily store clarified effluent.
• Sand Filters: Provide additional treatment to effluent, using a bed of granular material.
• Trash/Grease Tanks: Trap materials that treatment microbes can't break down, often used in conjunction with aerobic systems.
• Cesspools: Covered underground containers that receive untreated sewage. Not commonly used today due to health concerns.
• Chamber Systems: A series of connected chambers that further treat wastewater using soil microbes.
• Recirculating Sand Filters: Use sand filters, often placed above or below ground, for additional wastewater treatment.

Additional Wastewater Treatment

• Evapotranspiration Systems: Drainfields lined with watertight material, wastewater evaporates into the air.
• Constructed Wetland Systems: Mimic natural wetlands using a cell with media for treating wastewater via microbes, plants, and other media.
• Cluster/Community Systems: Collects wastewater from multiple dwellings/buildings, and conveying it to a central treatment and dispersal system.

Safety Precautions

• Septic tanks lack oxygen; avoid entering unless well ventilated.
• Gases may be present that could be harmful/flammable.
• Ventilation and proper safety/light equipment (when necessary) should be used when working on or around a septic system.

Explore the essential components of wastewater, which predominantly consists of water while containing crucial pollutants. This quiz covers various types of wastewater, including domestic, commercial, and industrial. Understand the differences and implications of gray and black water, as well as the origin of commercial and industrial waste.