Nitrogen Removal in Mangroves Constructed Wetland

The potential use of Mangroves Constructed Wetland (MCW) as a low cost, efficient and suitable method for nitrogen removal from sewage in coastal zone of urban cities was examined in Dar es Salaam, Tanzania. In-situ examinations were done in horizontal surface flow Mangrove Constructed Wetland situated at Kunduchi beach area in Dar es Salaam. A wetland of 40 meters by 7 meters was constructed to receive domestic sewage from septic tank of Belinda Beach Hotel and was operated in an intermittent continuous flow mode. The wetland employed the already existing mangrove plants known as Avicennia Marina. The plants had an average breast height of 4 meters during commencement of experiments. The wetland collected the mixture of sewage and seawater at strength of 60% to 40%, respectively. The treatment efficiency of the wetland in nitrogen removal from sewage was determined. The observed removal rates of nitrogen inform of ammonia nitrogen (NH3-N) and nitrate nitrogen (NO3--N) were 85% and 76%, respectively. Mangrove Constructed Wetland has a potential in nitrogen removal from sewages and it is suggested to be used for sewage treatment in coastal areas.