Characteristics of the colony structure of A2O processes under different ultraviolet conditions in plateau areas.

Abstract

In this text, a laboratory-scale A2O was performed in Linzhi City at a 3000-m altitude. During the test operation, the UV irradiation was carried out in oxic tank for 0, 5, 10, 30, and 180min. The 16SrRNA gene sequencing was performed on the activated sludge in anaerobic, anoxic, and oxic tanks, and the colony structure characteristics of phyla, genera, and species classification levels in the sludge were analyzed. There were significant differences in the numbers of genera and species (p ≤ 0.05). The community richness, uniformity, diversity, and other indicators differed to some degree compared with those of other regions. The analysis of composition of bacterial colonies revealed different levels. The significance test of the difference between the groups, the significance of the dominant species, and the mechanism of UV was analyzed. A CCA diagram was used to verify that UV is an important factor in the colony structure composition, and the correlation heatmap diagram was used to analyze the microorganisms that are significantly related to UV. A sample hierarchical cluster analysis showed that the time of UV exposure can be divided into two categories, and the effects of UV exposure increase sequentially as the time of exposure increases. A comprehensive analysis found that the enhancing and inhibitory effects of UV affect the composition of the colony structure in the sample, and the time of irradiation will affect the enhancing or inhibitory effect, that is, the colony structure from the samples that were irradiated for different amounts of time differs greatly.