Search Results (3)

Micro-polluted water, which is widespread in rural areas, poses a serious health risk. To address this issue, we propose a three-dimensional biofilm electrode reactor with triple-layer particle electrodes (TL-BERs) for the decentralized and small-scale treatment of micro-polluted water. The first and second layers of the electrode, granular activated carbon (GAC) and biological ceramsite (BC), respectively, are responsible for electric field oxidation and microbial degradation, respectively, while the third, quartz sand (QS), is responsible for further improving turbidity and pollutant removal. Our tests indicated that the TL-BER-treated effluent met the drinking water quality standards of China. At 10 V, the average turbidity, COD_Mn, NH₄⁺-N, and UV₂₅₄ removal rates of the TL-BERs system were 97.66%, 61.11%, 91.67%, and 72.94%, respectively. Furthermore, the intensities of the main fluorescence peaks, A, B, C, and D, of the raw water sample, decreased by 36.67%, 66.22%, 67.08%, and 69.76%, respectively, after treatment, indicating that tryptophan-like proteins, fulvic acid, and humic acid were also effectively removed. High-throughput sequencing analysis showed the enrichment of microorganisms, such as Proteobacteria, Bacteroidota, and Actinobacteriota, which play important roles in the removal of various pollutants. Therefore, the application of this strategy will enable the practical treatment of micro-polluted water. Full article

Three-dimensional biofilm electrode reactors (3D-BERs) exhibit efficacy in the removal of refractory wastewater of pharmaceuticals due to the resistance of pharmaceutical wastewater to biodegradation. In this paper, a new 3D-BER with a polyurethane sponge carrier was applied to the treatment of pharmaceutical wastewater containing tetrahydrofuran (THF) with an objective of exploring the removal efficiency, degradation pathway and main functions of microorganisms of 3D-BERs for wastewater containing THF. The results indicate that when the voltage is 10 V, the highest COD_Cr removal efficiency is (95.9 ± 1.6)%. Compared to the control group, the removal rate was increased by 21.97 ± 4.69%. The main intermediates of THF, γ-butyrolactone and 4-hydroxybutyric acid, were detected, respectively, by Gas Chromatography–Mass Spectrometry (GC–MS), indicating that 3D-BERs contribute to the degradation of THF with electro-oxidation as well as microbial synergism. Microorganisms, such as Proteobacteria with extracellular electron transfer capacity, Bacteroidetes capable of degrading complex carbon sources and parthenogenic anaerobic bacteria Firmicutes, were found to be enriched by high-throughput sequencing analysis in 3D-BERs, which were conducive to the degradation of refractory pollutants. At the genus level, Chryseobacterium, Brevundimonas, Erysipelothrix, and Desulfovibrio were the main functional genera, whose degradation of THF intermediates was found by functional prediction, mainly through chemoheterotrophy, aerobic chemoheterotrophy, etc. It is to be hoped that this study will provide a solution to the practical treatment of pharmaceutical wastewater containing THF via this new 3D-BER system with a polyurethane sponge carrier. Full article

Three-dimensional biofilm electrode reactors (3D-BERs) were constructed to degrade the azo dye Reactive Brilliant Red (RBR) X-3B. The 3D-BERs with different influent concentrations and external voltages were individually studied to investigate their influence on the removal of X-3B. Experimental results showed that 3D-BERs have good X-3B removal efficiency; even when the influent concentration was 800 mg/L, removal efficiency of 73.4% was still achieved. In addition, the X-3B removal efficiency stabilized shortly after the influent concentration increased. In 3D-BERs, the average X-3B removal efficiency increased from 52.8% to 85.4% when the external voltage rose from 0 to 2 V. We further identified the intermediate products via UV-Vis and gas chromatography-mass spectrometry (GC-MS) analyses, and discussed the potential mechanism of degradation. After the conjugate structure of X-3B was destroyed, all of the substances generated mainly consisted of lower-molecular-weight organics. Full article