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Morton Rowe postete ein Update vor 1 Jahr
Migration characteristics of the heavy metals Fe, Zn, Mn, and Ni during the preparation of biochar from municipal sludge were studied, and the optimal pyrolysis temperature for the preparation of biochar was determined based on potential environmental risks. Four heavy metals (Fe, Zn, Mn, and Ni) with high total contents in the biochar were selected to determine their species and content changes under different pyrolysis temperatures using the BCR extraction method. An environmental risk assessment for sludge-based biochar was also carried out using the potential ecological risk index (PERI) and risk assessment code (RAC). The results showed that the volatility of the four metals is ranked as followsZn>Mn>Fe>Ni. The distribution and transformation of the four metal species were different, but their migration paths shared similar characteristics. In the pyrolysis stage at low temperatures (500℃) showed lower environmental risks, with the best outcomes at 500℃.At 4℃ and with no substrate, the activity recovery of ANAMMOX granular sludge was examined after 230 days of storage, and the effect of adding two organic carbon sources (glucose and sodium propionate) on the recovery was explored. After 230 days of long-term storage, the activity of ANAMMOX bacteria was 0.013 g·(g·d)-1, which was just 6.02% of the baseline, and the average particle size was 135.05 μm, which was 38.23% lower. The sludge disintegration, black in color. In the activity recovery stage, the R2 and R3 reactors added glucose and sodium propionate as organic carbon sources. The recovery results showed that after 15 days of recovery, the PN content of the R1, R2, and R3 reactors reached 126.30, 188.86, and 168.82 mg·g-1, respectively, and the activity of the ANAMMOX bacteria was improved, reaching 0.145, 0.185, and 0.126 g·(g·d)-1, respectively. The R2 reactor with glucose as the organic carbon source had the highest ANAMMOX bacteria activity, which recovered 85.65% before preservation, and the total nitrogen removal rate reached 81.61%. On the 20th day, the particle sizes of the ANAMMOX granular sludge in the R1, R2, and R3 reactors were 289.81, 359.66, and 314.37 μm, respectively, indicating that the long-term preservation of ANAMMOX granular sludge is not an insurmountable problem. GS-441524 in vitro Furthermore, adding glucose during the recovery phase can not only effectively increase the EPS content and promote particle growth and adhesion, but also enrich the reaction pathways of ANAMMOX, enhancing recovery rates.In this experiment, three replicated SBR reactors were operated using asynchronous acclimation of the phased method (A/O-A/O/A), simultaneous domestication of continuous aeration by A/O/A, and simultaneous domestication of intermittent aeration by A/O/A. Using artificial water distribution as the influent substrate, flocculent sludge was inoculated and granulated by hydraulic selection. The domestication and nitrogen and phosphorus removal characteristics of shortcut nitrification denitrifying phosphorus removal granules under different operation modes were assessed. The results show that simultaneous domestication of intermittent aeration by A/O/A has the most efficient under the combination of short aeration time (140 min) and low aeration strength[3.5 L·(h·L)-1]. The average removal rates of carbon, nitrogen, and phosphorus were 90.74%, 91.15%, and 95.66%, respectively, which could achieve synchronous removal during later stable operation. The particle size was 895 μm, and the particles were small but uniformly dense in microscope observations. The f value (MLVSS/MLSS) was kept stable at 0.8-0.85 and sludge had a high biomass due to the alternate aerobic/anoxic operation with intermittent aeration. This supported anoxic heterotrophic bacteria at the core of the particles, which was conducive to the stability of the granular sludge structure. Batch experiments showed that the specific ammonia-oxidation rate of the simultaneous domestication of intermittent aeration by A/O/A system was 3.38 mg·(g·h)-1, and denitrifying phosphate accumulating organisms (DPAOs) able to utilize nitrite as electron acceptor accounted for 65.46%. This was more conducive to the simultaneous domestication and enrichment of ammonia-oxidizing bacteria (AOB) and NO2–type DPAOs, ensuring a stable treatment effect.Research on the distribution of antibiotic resistance genes (ARGs) in urban sewage treatment systems is extensive, but there is still insufficient research on their abundance in industrial wastewater recycling systems. In this study, a printing and dyeing wastewater (PDWW) recycling system was constructed, and 16S rDNA and high-throughput sequencing technology was used to analyze the microbial communities and ARG abundance during the treatment process. A total of 52 ARGs in nine categories were detected, of which the relative abundance of β-lactam resistance genes was the highest. During the treatment cycle, the concentration of aromatic pollutants increased with an increase in the number of cycles, while the abundance of β-lactam resistance genes increased first, decreased, and then increased (reaching 61.85% on the 100th day). At the same time, the abundance of Firmicutes, Actinobacteria, and Cyanobacteria related ARGs decreased significantly (by 84.66%, 64.38%, and 85.15%, respectively). More than 21 kinds of ARGs were significantly affected by the enrichment by the aromatic pollutants. Among them, 6 kinds of ARGs were significantly positively correlated with changes in the concentrations of the aromatic pollutants (P less then 0.01), while 6 were significantly negatively correlate (P less then 0.01). These results show that the abundance of ARGs was affected by the microbial communities and the aromatic pollutants, which increased at first, decreased, and then increased during the PPDW recycling process. This study reveals the effects of the enrichment of aromatic contaminants and changes in microbial communities on ARGs during PPDW recycling, and provides theoretical guidance for the recycling of PDWW to reduce environmental pollution associated with ARGs.In this study, solid phase extraction (SPE) coupled with high-performance liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-MS/MS) was used to track the contamination of 17 benzodiazepines, 14 acidic pharmaceuticals, and 5 neutral pharmaceuticals in 4 hospital wastewater treatment systems and 3 municipal wastewater treatment plants in Guangzhou, Guangdong Province. The results showed that a total of 10 benzodiazepines, 8 acidic, and 3 neutral pharmaceuticals were detected in the hospital wastewater treatment systems with concentrations in the ranges of 0.41-23376 ng·L-1 and 0.11-22888 ng·L-1 in the influents and effluents, respectively; The 8 benzodiazepines, 8 acidic, and 4 neutral pharmaceuticals were detected in the municipal wastewater treatment plants with concentrations in the ranges of 0.4-1695 ng·L-1 (influents) and 0.1-1526 ng·L-1 (effluents). Among them, high levels of benzodiazepine compounds including lorazepam[(53.1±2.7) ng·L-1, H1], oxazepam[(39.5±4.1) ng·L-1, W2] and clozapeuticals in Guangzhou reached 1456 g·a-1 with concentrations ranging from 3.07 (mefenamic acid) to 378 g·a-1 (oxazepam).The treatment of cadmium-containing wastewater is of great significance for the emission control of the heavy metal cadmium. Here, a superparamagnetic nano-Fe3O4@SiO2 functionalized material (MFS) was prepared via a co-precipitation method, and the adsorption thermodynamic and kinetic characteristics of Cd2+ were studied by isothermal adsorption tests and kinetic experiments. The adsorption process and mechanism of MFS with respect to Cd2+ were also studied using BET, XRD, and SEM. The Langmuir equation well described the isothermal adsorption characteristics of MFS, and the maximum adsorption capacity was 69.49 mg·g-1. The standard free energy (ΔG), enthalpy (ΔH), and entropy changes (ΔS) showed that the adsorption reaction was a spontaneous, endothermic, and entropic process. The optimal initial pH of the adsorption reaction was 7. The four interfering ions (Mg2+, SO42-, Ca2+, and NO3-) in the solution had a certain inhibitory effect on the adsorption reaction. The pseudo-second-order kinetic model showed that the adsorption process of Cd2+ was divided into two stages, namely a rapid external diffusion stage and a slow internal diffusion stage. The removal rate of Cd2+ was still>73% after using the MFS three times. The BET, XRD, FTIR, and VSM analyses showed that SiO2 was successfully modified on the Fe3O4 surface. MFS is mainly spherical in structure with an average particle size of 38.7 nm and has a saturated magnetic intensity of 85.38 emu·g-1. The XRD, EDS, and XPS analyses revealed that Cd2+ was successfully adsorbed by the material, and the main mechanism was the coordination reaction between Cd2+ and -OH on the surface of the material.In this study, the functional material SZVI-SA is successfully prepared to efficiently remove Cr(Ⅵ) from water. This composite, with micron zero-valent iron (ZVI) as its core, is sulfurized and loaded by sodium alginate (SA). Some parameters affecting the Cr(Ⅵ) removal are also tested, including the type and mass fraction of chelating agents as well as S/Fe. SEM-EDS, TEM, XRD, and XPS are used to characterize and analyze the material. The results show that 7% Fe3+ is most suitable as the chelating agent for sodium alginate, and a S/Fe ratio of 3.5 and drying temperature of 70℃ are the ideal formation conditions. The effect of SZVI-SA on the removal of Cr(Ⅵ) is in line with the secondary adsorption rate model, mainly affected by the availability of binding sites. The active ingredient was identified as FeS, and the specific surface area can reach 97.83 m2·g-1. Many pores, especially micropores, are present in this material and in addition to Cr(Ⅵ), SZVI-SA was found to effectively remove Cr(Ⅲ) and Fe(Ⅲ) from the test solution. Overall, the Cr(Ⅵ)-removal efficiency was 92%; the removal mechanism is mainly via redox reactions; and the main reducing active substances are Fe2+, S2-, and S22-. Following the reaction of Fe(Ⅲ) and Cr(Ⅲ), Fe(OH)3 and Cr(OH)3 are formed and Cr2O3 precipitation separation occurs.A pg-C3N4/BiOBr/Ag composite was successfully prepared by simple high-temperature calcination and co-precipitation methods. The composite was characterized by means of XRD, SEM, TEM, XPS, UV-Vis, BET, and photocurrent analyses alongside other detection methods, and the degradation of 10 mg·L-1 sulfamethoxazole was investigated under simulated visible light irradiation. The results showed that the pg-C3N4/BiOBr/Ag composite had the best degradation effect on sulfamethoxazole when the loading ratio of silver was 5%. Compared with pg-C3N4, BiOBr monomer, and pg-C3N4/BiOBr composite, the photocatalytic degradation effect of the pg-C3N4/BiOBr/Ag (5%) was significantly improved, and the degradation rate was almost 100% within 30 min. The reaction rate constant (0.21016 min-1) was 13.15 times that of pg-C3N4/BiOBr. Through radical quenching experiments, it was shown that the main active substances in the photocatalytic degradation were holes (h+), superoxide radicals (·O2-), and singlet oxygen (1O2), among which superoxide radicals (·O2-) contributed the most.