In this study, experiments were conducted to clarify the characteristics of the ceramics-formed contact carriers made by burning with calcium as its main component, to make clear the adaptability of contact carrier made from oyster shell used anaerobic-aerobic circulation biofilm process, as well as performing the stream purification process for effective biological nitrification and denitrification. Experiments were also carried out to evaluate the reuse of the carrier. The following results were obtained. During the period from the start-up to 200 days, dissolved phosphorus (D-P) removal ratio was about 60%, among which 70% was phosphorate (PO4-P). It was suggested that hydroxyapatite formed by reaction between Ca (OH) 2 and PO4-P, and hydroxyapatite could adsorb Anmonia (NH4-N) dissolved in domestic wastewater. After that, the removal ratio decreased with the time course. However the Ca-carrier could be easyly regenerated through acid washing. And the acid solution used by the regeneration of the lowered-adsorption capacity of Ca-carrier could be also collected as fertilizer components containing NH4-N and PO4-P.
