Activity

The main aim of this work was to characterize the microbial community structure and resistance gene (CzcA) shifts in up-flow constructed wetlands-microbial fuel cell (CW-MFC) treating Zn (II) contaminated wastewater. Two CW-MFC devices were operated, i.e. the experimental group (EG) treating Zn (II) wastewater, and the control group (CG) treating Zn (II)-free wastewater. The results showed the CW-MFC combination exhibited good removal efficiency on Zn (II), while the average voltage, the power density and the removal rates (TP, TN, NH4+-N and COD) significantly reduced (p  less then  0.05). The microbial community structure showed that the Zn (II) significantly reduced the abundance of some functional genus (p  less then  0.05), such as Ochrobactrum, Nitrosomonas, Pseudomonas and Dechloromonas. Zn (II) inhibited the microbial richness in the anode, but it played a positive role in the cathode. Anew, the expression of the CzcA in the CW-MFC was promoted by Zn (II), particularly in the cathode. The impact of the addition of salinity on partial nitrification and anammox (PN/A) was investigated in this study. The sludge was immobilized by polyethylene glycol (PEG)-modified polyvinyl alcohol (PVA)-sodium alginate (SA) immobilization technology, and the effective diffusion coefficient (De) of the immobilized particles was measured to be 0.313 × 10-9 m2·s-1, indicating that the system has excellent mass transfer performance. An experiment was carried out by adding NaCl to create a salinity gradient. It was found that the initiation of partial nitrification was achieved at a concentration of 10 g·L-1 NaCl and the nitrite accumulation rate (NAR) reached 81.03%, which could provide sufficient NO2–N for subsequent anammox. Additionally, an anammox reactor operating at the same salinity maintained a stable state after acclimation, and the removal rates of NH4+-N and NO2–N reached 80%. The dominant population in the anammox system was Planctomycetes. Salinity is a feasible factor for controlling the PN/A process. The effects of the initial concentrations of Cr(VI) on chlorophyll-a (Chl-a), soluble protein and ultrastructure were investigated. Results showed that 1.0 mg L-1 Cr(VI) stimulated and inhibited the growth of Isochrysis galbana, respectively. The tolerance mechanisms of I. galbana to Cr(VI) included the following (1) increased activities of superoxide dismutase (SOD) and peroxidase (POX) for peroxidative damage resistance, (2) accumulation of Cr(VI) on the cell surface and inside the cell for detoxification and (3) conversion of intracellular Cr(VI) to less toxic Cr(III) as indicated by X-ray photoelectron spectroscopy (XPS) results. Cr(VI) enrichment by I. galbana may cause damage to marine ecology and human bodies through the food chain. The tolerance mechanisms of I. galbana to Cr(VI) may be potentially used to treat low-concentration Cr(VI) wastewater. Therefore, the responses and tolerance mechanisms of I. galbana to Cr(VI) must be further studied. This study involved a comparison between mesophilic (MAD) and thermophilic anaerobic digestion (TAD) of municipal sludge with high (10%) solids content; the reactor performance and the response of total and active microbial communities to changes in sludge properties were monitored. Both TAD and MAD were stably maintained. TAD performed better than MAD in biogas production and volatile total solids reduction upon feeding sludge 1. TAD was slightly inhibited by ammonia, whereas the performance of MAD was improved when sludge 2 was used as the feedstock. Alpha- and beta-diversity analyses revealed significant differences in the microbial community based on DNA and RNA datasets, indicating that not all microbes function in AD. The active microbial community diversity and composition in MAD and TAD were also driven by sludge properties. Moreover, MAD showed significantly higher richness and diversity of the active microbial community compared with TAD, regardless of changes in sludge properties. This study analyzed the chemical speciation, leaching ability, and environmental risk of heavy metals (Cd, Cr, Cu, Ni, Pb, and Zn) in cow manure biochar (CMBC) pyrolyzed at various temperatures. The total content, chemical speciation, and leaching ability of the heavy metals were determined through microwave digestion, modified BCR three-step sequential extraction procedure, and leaching solution systems (TCLP, distilled water, and SPLP). The risk assessment code, Muller geo-accumulation index, potential ecological risk index, and germination index were used to evaluate the environmental safety and ecotoxicity of heavy metals. Significant differences were observed in the physicochemical properties of CMBCs. The heavy metal contents in CMBCs were higher than those in CM. The bioavailable fraction of heavy metals was transformed into a relatively stable fraction with increasing pyrolysis temperature. Furthermore, the potential risks and ecotoxicity of biochar were reduced, thus improving environmental safety. The study results provide important data for biochar applications. In this work, two plant wastes were reused to fabricate the homogeneous 3D micro-nano porous structured humic acid/cellulose nanocomposite beads (IHA@CB) embedded with insoluble humic acid (IHA) particles. The subtle synthesis method attributed to the homogenous distribution of IHA particles in the cellulose matrix and improved the adsorption performance of IHA@CB for low concentration ciprofloxacin in water. H 89 Physical and chemical properties of the beads were characterized by SEM, EDX, XRD, FTIR, and the adsorption process of ciprofloxacin was studied by isotherm, kinetic and dynamic adsorption experiments. The maximum adsorption capacity of IHA@CB on CPX reached 10.87 mg g-1 under 318 K. The dynamic experiments were conducted by adjusting bed height, flow rate, initial concentration and pH values, and the regeneration experiments proved the adsorbent exhibited good repeatability. The adsorption mechanism was revealed that CPX was adsorbed by IHA@CB mainly through cation exchange. Anaerobic membrane bioreactor (AnMBR) is an advanced technology in treating pharmaceutical wastewater, but the membrane fouling limits its development. In this study, the biochar with adsorption capacity of biopolymers was added in AnMBR to investigate its potential in treating pharmaceutical wastewater and alleviating membrane fouling. In the biochar-amended AnMBR, adsorbable organic halogen (AOX) was removed effectively, and more COD was biotransformed into CH4. Membrane fouling mitigation was achieved in the third stage with a 56% decrease of average transmembrane pressure difference (TMP) rising rate. The predominant culprit, proteins of extracellular polymeric substance (EPS-proteins) in sludge mixture and cake layer, was reduced significantly. Particularly, the proportion of micromolecular (0.1-0.15 kDa) EPS-proteins in cake layer was 1.5-folds that of the control group. The important bio-foulant genus Arcobacter aggregating on the membrane had less and almost half the relative abundance (16.5%) than that of the control group (30.