Compost Piles or Windrows

Piles of organic waste that allow the solids from primary treatment to dry out, heat up and decompose by aerobic means.

Treatment Level:  Secondary
Relative Cost:
Amount of Maintenance Interaction:  medium – high
Beneficial Byproduct:  some – lots (compost)


  • Very little maintenance needed if only used as waste solids treatment.
  • Creates high nutrient compost for re-use or sale.
  • Can also treat kitchen and garden waste.
  • Can be done on a small or large scale, depending on the supply of material to be composted


  • Can take up a lot of space, depending on primary treatment method and other inputs.
  • Must keep piles aerated by either layering with hay, straw, etc or by manual or mechanical turning.
  • Care needed to avoid potential exposure to pathogens during O&M.

Operation & Maintenance

  • Add sludge, kitchen compost, and/or animal waste as often as needed for disposal.
  • Either layer each new input with straw, hay, or dry leaves, or turn pile monthly to add oxygen.
  • Allow compost to age a minimum of 12 months before using for health safety.

Additional Notes:

  • Can be done in long rows or smaller piles, depending on amount of waste to be composted.
  • Try to minimize opportunities for rainwater runoff from compost piles.
  • Consider using in combination with vermiculture (worm composting).

Compost Layers (