Some of those systems, such as irrigation and constructed wetlands, can be adapted for larger communities. Several systems that can be designed for both cluster and small community systems are listed below. Return to Table of Contents Lagoons Lagoons are essentially artificial ponds, called cells, that are built into or above the ground. The number and size of these cells depend on the needs of the community. Systems that use several smaller cells have proved to be more effective than one large cell for treating wastewater.
Cells are lined with clay or other impervious materials to prevent groundwater contamination.
They vary according to the amount of dissolved oxygen typically present in the water. Their purpose is to retain wastewater for an extended period of time. This acts to stabilize wastewater as heavier particles sink to the bottom and lighter ones rise to the surface. The retention period gives microorganisms time to feed on the nutrients and trace elements in the water. Anaerobic lagoons have steep sides and can be as deep as 20 feet.