Wetlands

1. Description: Wetlands are semi-terrestrial areas with a high degree of humidity and profuse vegetation that have certain biological, physical and chemical characteristics that give them a high potential for self-cleaning. Natural wetlands can achieve great complexity, with a mosaic of sheets of water, submerged vegetation, floating vegetation, emergent vegetation and areas that are close to the water surface. Wetlands fill the areas between the humid areas and those that are generally dry. They possess characteristics of both so they cannot be categorically classified as aquatic or terrestrial.

Between the characteristic of wetlands are the presence of water over large periods of time that alter the soil,  its micro-organisms and flora and fauna communities are so many  that soil no longer act  as either aquatic or terrestrial ecosystem. Typical depths of these lands are less than 0.60 m where emerging plants such as reeds, typha, and duckweed growth contribute to the pollutants reduction through aerobic degradation processes.

An artificial wetland is a wastewater treatment system that uses a shallow man-made pond, in which aquatic plants have been placed so as to make use of natural processes to treat swegage. Man-made wetlands have advantages over alternative treatment systems because they require little or no power to operate. If there is enough cheap land available close to the installation of the wetlands for aquatic cultivation, it can be a cost effective alternative. The wetlands provide a habitat for wildlife and are aesthetically pleasing to the eye.

2. Important factors to be considered in the design:

     a. Calculation of the required area.

     b. Depth of the wetland.

     c. Slope.

     d. Substrate.

     e. Length and width.

3. Applications: Unloading for municipalities and occasionally in industrial plants.

4. Benefits:

     a. Primary and secondary flows can be treated.

     b. Can operate with high and low organic loading rates.

     c. Greater or smaller-sized surfaces can be used for the required area.

     d. The cost may vary depending on the granular material to be used.

     e. Operation is simple.