The effect of different carbon sources was studied relative to the treatment effect of aerobic denitrifying bacteria during the treatment of nitrate-containing wastewater as well as the influence of co-metabolism flora. Three carbon sources, i.e., glucose, citric acid, and sodium acetate, were selected to study the changes in the pH, nitrate nitrogen, chemical oxygen demand removal, nitrite nitrogen concentration, physical and chemical properties of sludge and volatile fatty acids, and high-throughput sequencing to study any changes in flora. The results showed that the denitrification ability of the system using citric acid as the carbon source was stronger than the denitrification ability of the system using glucose or sodium acetate as the carbon source. The removal of nitrate nitrogen in the system was the result of the co-metabolism of acid producing bacteria and aerobic denitrifying bacteria. Due to the greater number of types and greater amount of dominant bacteria in the sludge domesticated and cultured with citric acid as a carbon source, the co-metabolism flora formed was more stable, so it could better remove nitrate nitrogen.
In this paper, we studied the pH shock resistance mechanism of GO/iron series from the perspectives of the treatment effect, changes in effluent pH and VFA, and microbial co-metabolic stability, providing a reference for the practical application.
Temperature changes are inevitable during the actual operation of anaerobic systems. Adding an Fe0/GO composite is shown to improve microbial activity and alleviate the adverse effects caused by temperature shock.
The pH is one of the key factors affecting microbial activity in anaerobic systems. In this paper, the pH impact tolerance of Fe0/GO (zero-valent iron/graphene oxide) mediated anaerobic treatment system for high concentration organic wastewater was studied. The effects of a Fe0/GO mediated anaerobic system on wastewater treatment, degradation kinetics, and the physicochemical properties of sludge were studied at pHs of 5.5 and 8.5; the separate addition of Fe0 and GO and a blank system were used as the blank control. The results showed that the pH had adverse effects on the treatment of each system and the physicochemical characteristics of sludge. However, the Fe0/GO system under pH shock maintained a relatively high CODCr removal rate and gas production; the effluent volatile fatty acid content was the lowest, the effluent pH value deviation from the normal range was small, the degradation rate constant, and sludge concentration and flocculation performance of the mixed liquid were better than those of other systems. The recovery phase of Fe0/GO returned to normal in a relatively short time. These results showed that adding Fe0/GO to the anaerobic treatment of high concentration organic wastewater system can drastically improve the pH shock resistance of the system.
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