Abstract
The purpose of this reserch was to develop a calcium phosphate crystallization method to remove phosphate from wastewater. The efficiency of phosphorus removal with the contact media prepared from coral reef limestone, phosphate rock or activated alumina was studied by column tests.
A phenomenon was observed that phosphorus removal ability of the coral reef limestone increased as the column test continued. It was found that hydroxyapatite crystals: Ca5(PO4)3 (OH) were formed on the surface of the coral reef limestone and the BET-surface area of the coral reef limestone was increased.
From these results, it was suggested that efficiency of phosphorus removal was affected by the crystallization phenomena on the coral reef limestone. It was shown that phosphate in the feed solution was reduced to a low level by the crystallization method using coral reef limestone as seed materials and the performance of a stability was achieved during 50 days of continuous column test operation.
