Treatment efficiency and microbial community analysis in the integrated bioremediation system of aquaculture wastewater with the ceramsite and compound bacteria

Abstract

The integrated bioremediation systems (IBSs) are becoming increasingly widespread to treat aquaculture wastewater. However, there is still significant room for the improvement of technological processes of the IBS. In this study, exogenous compound bacteria (ECB) were added to the system and combined with ceramsite to treat wastewater. The changes in bacterial communities within the system were analyzed through high-throughput sequencing and multivariable statistics, and the dynamic changes in bacterial communities within the system was visualized. The results showed that ECB significantly increased the diversity and affected the assembly of the bacterial communities in the water and biofilm, forming three succession stages. The ECB promoted the increase of denitrifying bacteria which play a key role in the ecological function of the system. Sedimentitalea and Paracoccus were the biomarkers of the water and biofilms in the treatment group, and were significantly positively correlated with the denitrification process. The overall nutrients removal efficiency of the treatment group exceeded 80%. And the removal efficiency of TN, NH₄⁺-N, NO₃⁻-N, NO₂⁻-N, and PO₄^3--P in the treatment group were significantly higher than those in the control group, which indicated the ECB led to a significant improvement in purification effectiveness. The significant influence of the ECB on the IBS provided a preliminary theoretical basis for improving the system process, enhancing nutrient removal performance, and exploring system working mechanisms.