A Cost-Effective Sewage-Treatment Technology for Small, Rural, and Remote Communities

A Cost-Effective Sewage-Treatment Technology for Small, Rural, and Remote Communities

Refer to Chapter 4 of the book
Although ponds generally are a low-cost and environmentally sustainable technology for wastewater treatment in developing countries, they are not commonly used in industrialized countries, except in small rural and remote communities. Researchers have estimated that in the United States there were about 7,000 pond systems in 1975; 868 ponds in Canada in 1981; 1,800 ponds in France in 1987 and 2,500 ponds in 1993 in small, rural communities. In France, researchers estimated that lagoons represented about 26.9% of 976 very small municipal wastewater-treatment plants for communities with fewer than 2,000 population equivalents , or p.e. In Bavaria, Germany, researchers estimated that there are more than 1,500 rural communities, each with fewer than 5,000 people, use ponds for wastewater treatment.

(Photographs by Jo-Shing Yang)

Example of a maturation/polishing pond treating tertiary effluent from a conventional wastewater treatment plant near Los Angeles, California, U.S.A.
(1) This is an unaerated, unplanted pond with algae.
(2) An aerated pond planted with aquatic macrophytes. A solar-powered mechanical aerator has been in stalled in the center of the pond to facilitate oxygen diffusion in the pond.
(3) An unaerated pond planted with aquated macrophytes. This pond is located directly behind a student dormitory.
(4) Another view of #3. The unaerated pond is populated with algae.
(5) A concrete-lined polishing pond with aquatic macrophytes.