생물학적 질산화를 이용한 제올라이트의 재생

Abstract

Zeolite is well known material for its ability to preferentially remove ammonium ions from wastewater. However, its usage has been limited by high cost for chemical regeneration on this purpose. As an alternative, biological regeneration of zeolite has been suggested by some researchers. In this study, the characteristics of biological regeneration of zeolite was studied at various conditions, i.e. changes in microorganism and Na+ concentration.In the first test, the percentage of bio-regeneration via nitrification in the columns (MLVSS 2,250 mg/ℓ and 4,500 mg/ℓ) was 2.6 times higher than the column with NaHCO3 (2,980 mg/ℓ) addition only. In the second test, MLVSS were changed (400, 800 and 3,200 mg/ℓ) but, for alkalinity supply, NaHCO3 concentration was fixed at 745 mg/ℓ. The regeneration rates were proportional to the MLVSS concentration, but the same amounts of total regenerated nitrogen were achieved in all columns tested. In the third test, the regeneration tests were performed to evaluate effects of Na+ concentration on regeneration were tested. The regeneration efficiency was enhanced about 5% when Na+ concentration increased from 342 to 734 mg/ℓ. There was no difference in regeneration rate by nitrification. Therefore the higher regeneration efficiency of zeolite could be obtained by nitrification than by chemical methods. The regeneration rates with the fixed Na+ concentration were proportional to nitrification rate, and the regeneration efficiencies with the fixed microorganism concentration were highly dependant on cation concentrations such as Na+.