Efficiency of Nutrient Adsorption and Nitrification Using Ceramics Combined with Calucium-Carrier.

Effect of ceramics carrier contained calcium on nutrient adsorption and microorganism-affinity in the microbial purification were examined. The carrier confined clay 40% with oyster shell 60%, which was modified with main component of Ca(OH)2 having 100-fold solublity relative to natural oyster, could remove above 95% of PO4-P compared with the oyster shell contained 98% of CaCO3. At the same time the growth rates (μ) of nitrite bacteria and nitrifing bacteria were examined. It was found that the alkalinity of the treated water (90mg·l-1) using ceramics carrier with calcium was 4 times higher than that of the control, followed by the favorable growth (μ=1.31d-1), having effective adsorption of PO4-P and acceleration of nitrification due to the release of OH- from the carrier. Moreover ammonium-nitrogen of about 70% was found to be removed by the replacement reaction of Ca2+ for NH4+ with PO4-P in the hydroxyapatite, even with the use of the lowered carrier with adsorption of PO4-P. Nutrients of NH4-N (107mg·carrier-g-1) and PO4-P (20.4mg·carrier-g-1) were collected as an fertilizer. It was also possible to recover the adsorptive activity.