인산염은유기물의성장에필요한중요한영양물질이나아주미량이필요하여폐수중의인산염은오염물질로작용하며수생생태계에영향을미친다. 따라서고농도의인산염에대하여칼슘을이용한침전법을사용하여인산염의제거에관한연구를수행하였으며폐수의재이용방안에대해고찰하였다. 인산염의침전제거시 pH 조건은 pH 6 에서 pH 12 로고려하였는데, pH 12 에서가장좋은효율을나타내었다. 또한인산염은침전반응에의하여칼슘을침전반응당량비의 0.5 배투입한경우까지제거율이급격히증가하는경향을나타내었으며인산염의잔존량을 0.0027 mM 까지낮추는효과를가져왔다. 불소가오염물로존재하는상황에서인산염을제거하기위한실험은 pH 및농도비에따라진행되었으며 pH가증가할수록인산염의제거율은증가하였다. 또한인산염: 불소의농도비가증가하여도인산염의제거율은크게영향을받지않는것이관찰되었다.

Phosphate is an essential material for the growth of organisms. However, since relatively small amount is required, a largeamount of phosphate is abandoned in wastes and wastewater, which contaminate the ecological environment including aquaticsystem. Purpose of this study is to treat especially high concentrated phosphate wastewater by use of calcium precipitationmethod. The pH range considered was from 6 to 12 and the maximum removal of phosphate was attained at pH 12. The con-centration of phosphate was observed to decrease rapidly until a half amount of calcium ion to its equivalent for the formationof calcium phosphate precipitate was added, which resulted in the decrease of the remaining concentration of phosphate downto 0.0027 mM. The effect of fluoride ion was examined and the concentration ratio betwen the phosphate and fluoride ion didnot have any significant influence on the removal efficiency of phosphate. The effect of pH was also investigated. With theincreasing of the pH in solution, the removal rate of phosphate was increased. Also it was investigated that the effect of fluor i d eon the phosphate removal was not significant.