The Removal of Nh₃-N From Primary Treated Wastewater in Subsurface Reed Beds Using Different Substrates

Subsurface flow experimental reed beds, were designed and built based on a combination of two design methodologies, that of the WRc and Severn Trent Water plc [3] WRc. 1996. Severn Trent Water Reed Beds & Constructed Wetlands for Wastewater Treatment Swindon, , UK [Google Scholar] and that of the USA, EPA [17] EPA. Constructed Wetlands and Aquatic Plant Systems for Municipal Wastewater Treatment, Design Manual, EPA/625/1–88/022/. USA, 1998 [Google Scholar]. Four different growing media were used with a combination of top soil, gravel, river sand and mature sewage sludge compost, aiming to determine the best substrate for ammonia removal. Eight units were constructed, two for each material. One bed for each pair was planted with Typha latifolia plants commonly known as cattails. Primary treated domestic wastewater, was continuously fed in to the bed for more than six months. The best results were achieved by the gravel reed beds with an almost constant removal rate of NH3-N above 80%. There was no significance difference on the performance of planted and unplanted reed beds.