抄録
Phosphorus and nitrogen removals from river water were studied at artificial reed-wetland (9.2m×90m) in Koaidame pond (Mizumoto park, Tokyo) from April to December on 1993.
About 30% of total phosphorus (TP, 0.25-0.48mg·l-1) and 20% of total nitrogen (TN, 1.2-11mg·l-1) of influent were removed. BOD (5.5-22.2mg·l-1) and COD (7.8-20.9mg·l-1) removal rates were low (below 10%) in this wetland.
After pass the wetland, particulate phosphorus and particulate nitrogen of the influent decreased largely, and NO2-N and NO3-N appeared in place of NH4-N depression during the summer (April-September), so that precipitation of particulate in the water and nitrification were considered main causes of TP and TN removal.
The average removed load of TP, TN, BOD and COD during investigation period were calculated at 5.5 mg·m-2·d-1, 67.8mg·m-2·d-1, 82.8mg·m-2·d-1, 79.1 mg·m-2·d-1, respectively.
