Removal efficiency of organic contaminants in landfill leachate contaminated groundwater under oxygen micro–nano bubble aeration

Abstract

In order to study the contaminant removal efficiency of landfill leachate contaminated groundwater under oxygen micro–nano bubble (MNB) aeration, contaminated groundwater was treated once or twice by oxygen MNB aeration. Specifically, comparisons were conducted on contaminant removal and dissolved organic matter (DOM) of groundwater treated once and twice by MNB aeration. The test results showed that the dehydrogenase activity of groundwater was improved by 101% with a volumetric transfer coefficient value in MNBs of 0.264 s⁻¹. Under twice oxygen MNB aeration, the 5 day biochemical oxygen demand, chemical oxygen demand and ammonia nitrogen removal efficiency of groundwater were about 95%, 60% and 60%, respectively. Furthermore, twice MNB aeration was more conducive to improving the DHA of groundwater and the COD or ammonia nitrogen removal efficiency than once MNB aeration. Under oxygen MNB aeration, most of the biodegraded DOM was degraded, and fulvic acid-like as well as humic acid-like substances were degraded to a certain level. Oxygen MNB aeration was an effective method for remediating landfill leachate contaminated groundwater.