Transferring and attribution model of phosphorus in the multi-stage eco-ponds/wetlands system sediment

The rule of form distribution and release of phosphorus in the sediments of different units of multi-stage eco-ponds/wetlands treatment system was studied. Affection of season and sediment retention time on form distribution and release of phosphorus were investigated. The proportion of calcium-bound-phosphorus increased gradually and that of aluminum-bound-phosphates and alkali-extractable-organic phosphorus decreased from the front to the latter of this system. The concentrated release period of sedimentary phosphorus was from March to June, the main release unit was hybrid facultative pond and the release forms were aluminum-bound- and alkali-extractable-organic phosphorus, most of these phosphorus would be all released to waters in sediment retention time of 1.3 years. Calcium-bound- and iron-bound-phosphorus were main form of storing phosphorus in this sediment.