Reed bed treatment systemsThe reed bed treatment system combines aerobic and anaerobic decomposition processes in a soil or substratum layer. The system can be used as the main treating layer or as a downstream layer. The polyethylene lined and refilled basins are planted with helophytes like Phragmites communis, Typha latifolia, Typha angustifolia or other aquatic macrophytes.
The wastewater percolates the filter substrate vertically to the bottom drains. Besides the microbial and fungal decomposition of organic matter and pollutants in the rooted soil or substrate matrix, chemical and physical precipitation, adsorption and filter processes occur due to soil constituents like clay minerals and humus particles. This is most important for phosphate and ammonia binding. Some of the wastewater nitrogen is released out of the artificial ecosystem to the atmosphere as nitrogenous gases (denitrification).
Through intermittent loading of the reed beds a radical change of oxygen regime is achieved. After water saturation by feeding with the distribution system a drainage network at the base collects the purified water. The pore space of the substrate is refilled with air thus enabling aerobic decomposition processes.
Some realized constructed wetland projects in the Middle East (U.A.E., Oman, Iran, Jordan, Qatar) are presented here.