Dissolved oxygen (DO) plays an important role in the performance of biological wastewater treatment systems. This study investigated the effect of the DO concentration on nutrient removal performance and microbial community structure in side-stream activated sludge hydrolysis (SSH) and conventional anaerobic/anoxic/aerobic (A2O) processes. The results showed that the change in DO had little effect on the removal performance of chemical oxygen demand (COD), and the removal efficiencies were about 90% for both reactors. Compared with the high DO level (4.1–6.9 mg/L), the A2O and SSH reactors had better nitrogen removal performance at low (0.5–2.2 mg/L) and moderate (2.2–3.9 mg/L) DO levels, with ammonia (NH4+-N) removal efficiencies of 88–89% and 89–91%, respectively, and total nitrogen (TN) removal efficiencies of 74–76% and 75–81%, respectively. Directly reducing the DO concentration from high to low reduced the phosphate removal efficiencies of the A2O and SSH reactors from 80.2% and 86.2% to 63.1% and 70.6%, respectively, while re-elevating the DO concentration to moderate levels significantly improved the phosphate removal efficiencies to 94.6% and 96.0%, respectively. Compared to the A2O reactor, the SSH reactor had more stable and better nutrient removal performance under different DO conditions, partly due to the additional carbon sources produced through the sludge fermentation in the side-stream reactor. The decrease in the DO concentration resulted in a decrease in the relative abundance of Acinetobacter but an increase in the relative abundance of Competibacter, potentially leading to the deterioration in phosphorus removal.
Abstract Purpose: To compare transarterial chemoembolization (TACE) combined with apatinib and PD-1 inhibitor (TACE-AP) with TACE combined with apatinib alone (TACE-A) in the treatment of hepatocellular carcinoma (HCC) with portal tumor thrombus (PVTT) and to explore the prognostic factors affecting the survival of patients. Patients and methods: This retrospective study analyzed data of HCC patients with PVTT who were treated with TACE-AP or TACE-A between January 2018 and June 2021. The primary endpoints of the study were progression-free survival (PFS) and overall survival (OS), and secondary endpoints were objective response rate (ORR) and adverse events (AEs). Propensity score matching (PSM) and inverse probability weighting (IPTW) analysis were used to reduce patient selection bias, and COX regression analysis was used to analyze prognostic factors affecting patient survival. Results: Sixty-nine and 40 patients were included in the TACE-A and TACE-AP group, respectively. After PSM and IPTW analysis, the median PFS and median OS in the TACE-AP group were significantly higher than those in the TACE-A group (PFS: after PSM, 6.9 months vs 4.0 months, P < 0.001, after IPTW, 6.5 months vs 5.1 months, P < 0.001; OS: after PSM,14.6 months vs 8.5 months P < 0.001, after IPTW, 16.1 months vs 10.5 months, P < 0.001). After PSM and IPTW, the tumor ORR in the TACE-AP group was significantly higher than that in the TACE-A group (PSM, 53.6% VS 17.9%, P = 0.005; IPTW, 52.5% vs 28.6%, P = 0.013). All treatment-related adverse reactions (AEs) were observed to be tolerated. Multivariate Cox regression analysis showed that the main prognostic factors affecting the survival of patients were tumor number, PVTT type, AFP, and treatment mode. Conclusion: In the treatment of HCC patients with PVTT, TACE-AP significantly improved PFS, OS and ORR, and the AEs were safe and controllable.
A large number of microplastics (MPs) have been found in various stages of wastewater treatment plants, which may affect the functional microbial activity in activated sludge and lead to unstable pollutant removal performance. In this study, the effects of different concentrations of polylactic acid microplastics (PLA MPs) on system performance, nitrification and phosphorus (P) removal activities, and extracellular polymeric substances (EPS) were evaluated. The results showed that under the same influent conditions, low concentrations (50 particles/(g TS)) of PLA MPs had no significant effect on effluent quality. The average removal efficiencies of chemical oxygen demand, phosphate, and ammonia were all above 80%, and the average removal efficiencies of total nitrogen remained above 70%. High concentrations (200 particles/(g TS)) of PLA MPs inhibited the activities of polyphosphate-accumulating organisms (PAOs) and nitrifying bacteria. The specific anaerobic P release rate decreased from 37.7 to 23.1 mg P/(g VSS·h), and the specific aerobic P uptake rate also significantly decreased. The specific ammonia oxidation rate decreased from 0.67 to 0.34 mg N/(g VSS·h), while the change in the specific nitrite oxidation rate was not significant. The dosing of PLA MPs decreased the total EPS and humic acid content. As the concentration of PLA MPs increased, microbial community diversity increased. The relative abundance of potential PAOs (i.e., Acinetobacter) increased from 0.08 to 12.57%, while the relative abundance of glycogen-accumulating organisms (i.e., Competibacter and Defluviicoccus) showed no significant changes, which would lead to improved P removal performance. The relative abundance of denitrifying bacteria (i.e., Pseudomonas) decreased from 95.43 to 58.98%, potentially contributing to the decline in denitrification performance.
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