The use of the fermented total mixed ration (FTMR) is a promising approach for the preservation of homogeneous feed, but changes during fermentation and links with the bacterial community of FTMR are not fully understood. This study investigated the effects of adding oat silage (OS) to the fermented total mixed ration (FTMR) in terms of fermentation, chemical composition, and the bacterial community. The fermentation quality of FTMR with 22% OS was greatly improved, as demonstrated by decreases in the butyric acid concentration, a lower lactic acid/acetic acid ratio, a larger population of lactic acid bacteria (LAB), and quicker spoilage yeast death. Further examination of the effects of various ensiling days on nutritive values showed stable crude protein and nonprotein nitrogen (NPN) contents. The concentrations of acetic acid, propionic acid, and ammonia–nitrogen (NH₃–N) were increased following all FTMR treatments after 15 d, while the concentration of water-soluble carbohydrates (WSC) was decreased. More heterofermentative LAB, such as Lentilactobacillus buchneri, Lentilactobacillus brevis, and Companilactobacillus versmoldensis were found after adding 11% and 22% OS. Moreover, the addition of 22% OS caused a marked increase in both bacterial richness and diversity, dominated by the Lactobacillus genus complex. Among species of the Lactobacillus genus complex, the occurrence of Loigolactobacillus coryniformis was positively correlated with lactic acid, NPN, and NH₃–N concentrations, suggesting its potential role in altering the fermentation profiles.

Ubiquitous nitrate (NO₃⁻) in groundwater sources is considered a hazard compound for human health. Photo-catalytic reduction by Ag-TiO₂/formic acid/visible light represents an emerging method for NO₃⁻ removal without secondary pollution. In this contribution, the removal of NO₃⁻ by photo-catalytic reduction and the selectivity of N₂ were systematically investigated under varied conditions, including concentrations of Ag-TiO₂, NO₃⁻, and formic acid (HCOOH). The removal efficiency of NO₃⁻ reached 84.47%, 82.68% of which was converted to N₂ under the optimal conditions: NO₃⁻ at 50 mg-N/L, Ag-TiO₂ at 1.0 g/L, HCOOH at 20.05 mmol/L, and reaction time at 120 min. The removal of NO₃⁻ was enhanced mainly by CO₂⁻ rather than by photo-generated electrons or HCOO⁻. The results of this study indicated that the production of ·CO₂⁻ by Ag-TiO₂ and HCOOH under visible light catalysis can achieve efficient NO₃⁻ removal.

This study extends the previous research focused on enhancing the sustainable flux of a high-solid anaerobic membrane bioreactor (AnMBR) for the food waste (FW) and sewage sludge (SeS) co-digestion. A control strategy was implemented by adjusting instantaneous flux and filtration-to-relaxation (F/R) ratio under different total solid (TS) concentrations. The maximum sustainable fluxes of 8.7 ± 0.1, 13.3 ± 0.2, 20.3 ± 0.2, and 20.3 ± 0.6 LMH were achieved at the TS concentrations of 30, 25, 20, and 15 g/L, respectively, with corresponding optimal F/R ratios of 3:1, 5:1, 9:1, and 9:1, respectively. These sustainable fluxes were significantly improved, 4.24, 3.33, 2.18, and 2.01 times of those observed in the mono FW digestion at the same TS concentrations. Furthermore, a mathematical simulation in the form of an exponential function was developed to forecast the optimal sustainable flux at other TS levels. The improved sustainable flux of FW and SeS co-digestion than mono FW digestion might due to (1) the lower apparent viscosity, (2) the larger particle size, and (3) the synergistic effect existed in this co-digestion system. Based on the control strategy of membrane filtration, a TS concentration of 20 g/L is recommended for the AnMBR in the anaerobic co-digestion of FW and SeS. This research provides a valuable guidance for optimizing working mode of high-solid AnMBRs.