탈황폐수처리 공정에서 발생되는 스케일의 생성 원인을 규명하고, 스케일 생성 억제제 및 생성 스케일의 용해제를 개발하여 탈황폐수 처리공정에 적용하였다. 탈황폐수 처리공정에서 생성되는 스케일의 주성분은 Si, Al, S성분이며, 그 외 Fe, Mg, Ca성분을 함유하고 있는 것으로 나타났다. 탈황폐수에 포함된 석탄회 성분과 석고, 석회석이 반응하여 스케일의 성장을 촉진시킨다. 탈황폐수 처리공정 제1 반응조의 경우 체류시간이 길어질수록, pH가 높아질수록 황산 제1철과 염소이온이 반응하여 침전물인 Fe₂(SO₄)₃을 발생시켜 스케일의 부착과 성장이 촉진되기 때문에 스케일 생성을 줄이기 위해서는 체류시간을 줄이고, pH를 2로 조절해야 한다. 스케일 생성 억제제 D가 스케일 생성 억제에 가장 효과가 있었으며, 적합한 주입량은 500mg/L로 나타났다. 스케일 용해제의 유효성분(KOH와 Sodium Gluconate) 각 20%에 첨가제 B 2%, 분산 및 침투제 A 0.5% 주입한 경우 스케일의 용해도가 가장 우수하였다. 현장에 스케일 생성 억제제를 주입한 결과 SS 및 COD의 제거효율이 우수하였으며 적합한 주입 농도는 400mg/L로 나타났다.

The aim of this study is to examine closely the cause of scale production that is being created during the FGD(Flue Gas Desulfurization) wastewater treatment process. During the examination, the scale producing inhibitor and scale solvent could be developed and these products were used in FGD wastewater treatment process. The results are as following. The main elements of scale that had been formed in FGD wastewater treatment process, were known as Si, Al, S. Additionally, Fe, Mg, Ca were shown as miner components. The scale production was promoted by the reaction with coal, gypsum and limestone existed in FGD wastewater. With prolonging the water retention time of first reaction pond in FGD wastewater treatment process and increasing pH, the settler as Fe₂(SO₄)₃ that is produced by reaction sulfites and chloride ion, promoted the scale production. Therefore, in order to reduce scale, a management was needed that shorter the water retention time and control the pH to 2. The most effective scale producing inhibitor was determined as D, and its optimal dosage was determined by 500mg/L. The superior scale solvent could be made up by adding admixture B 2%, breakup and permeation matter A 0.5% into effective component(KOH and sodium gluconate) 20%, respectively. From the results of using the scale producing inhibitor on-site, SS and COD removal efficiency was superior and the optimal concentration of inhibitor at that time was shown to be 400mg/L.