Waste Management Overview and Techniques

Waste Management Overview

• Waste management encompasses collection, transportation, and disposal of various waste products (garbage, sewage).
• It includes compliance with health and environmental regulations.

Liquid Waste Disposal Methods

Screening

• Preliminary treatment for liquid waste.
• Removes large solid particles before discharge into municipal sewage systems.

Lagooning (Biological Disposal)

• Liquid wastes held in open earthen pits.
• Achieves treatment through: biological action (aerobic and anaerobic), sedimentation, soil absorption, evaporation, and dilution.
• Two types:
  • Impounding Lagoons: Suitable for industries with small daily waste volumes (e.g., canning). Volumetric capacity matches waste flow, minimizing evaporation and percolation losses.
  • Flow-through Lagoons: Requires less land and relies primarily on biological action.

Spray Irrigation (Land Disposal)

• Cost-effective and acceptable method if suitable land is available.
• Limited by the spray field's absorption capacity.
• Factors for implementation:
  • Waste volume (hourly, daily, etc.)
  • Land characteristics (soil type, area, topography, groundwater depth, proximity to plants, infiltration rate).
  • Waste properties (chemical composition).
  • Operational climate.

Chemical Treatment

• Partial waste treatment using chemical coagulants (e.g., lime, ferrous sulfate, alum).
• Removes 25-50% of biochemical oxygen demand (BOD).
• Uses analytical measurements like BOD, chemical oxygen demand (COD), and solid determination for control.