[Removal Performance of Suspended Solid (SS) and Organic Compounds in the Pre-treatment of Actual Pharmaceutical Wastewater by Microbubble Ozonation].

Actual pharmaceutical wastewater was pretreated with ozone microbubbles and compared with the treatment processes of nitrogen microbubbles, ozone common bubbles, and nitrogen common bubbles. The removal process and performance of suspended solids (SS) and organic compounds were investigated. The results showed that ozone microbubble treatment with strong adsorption-flotation-oxidation effects could enhance SS removal significantly, and the corresponding SS removal efficiency reached 81.67% at 60 min. The SS particle size was reduced, and the negative charge on the SS surface was simultaneously changed into a positive charge. Microbubble ozonation with a strong·OH oxidation effect also significantly enhanced the degradation and removal of organic compounds. The removal efficiency of soluble COD (SCOD) reached 36.60% at 60 min, and the SCOD removal was accelerated after the SS removal. The removal efficiency of UV254 also reached 36.91%. The biodegradability was improved, and the biological toxicity was obviously eliminated. The analysis of three-dimensional fluorescence and GC-MS showed that the macromolecular organic compounds with complex structure could be oxidized and decomposed efficiently with microbubble ozonation, resulting in the aromatic reduction in organic compounds in wastewater. Therefore, microbubble ozonation could be considered as an efficient and feasible pretreatment method for high concentration and refractory pharmaceutical wastewater.

Enhanced atrial internal-external neural remodeling facilitates atrial fibrillation in the chronic obstructive sleep apnea model.

OBJECTIVE: Autonomic imbalance plays a crucial role in obstructive sleep apnea (OSA) associated atrial fibrillation (AF). Here, we investigated the potential neural mechanism of AF induced by OSA. METHODS: Ten dogs were divided into control group (n = 5) and OSA group (n = 5). The chronic OSA model was established by repeat apnea-ventilation cycles for 4 hours a day for 12 weeks. During the process of model establishment, arterial blood gases, atrial effective refractory period (AERP), AF inducibility, normalized low-frequency power (LFnu), normalized high-frequency power (HFnu), and LFnu/ HFnu were evaluated at baseline, 4th week, 8th week, and 12th week. Nerve activities of left stellate ganglion (LSG) and left vagal nerve(LVN) were recorded. Tyrosine hydroxylase(TH), choline acetyltransferase(CHAT), PGP9.5, nerve growth factor(NGF), and c-Fos were detected in the left atrium, LSG, and LVN by immunohistochemistry and western blot. Moreover, high-frequency stimulations of LSG and LVN were conducted to observe the AF inducibility. RESULTS: Compared with the control group, the OSA group showed significantly enhanced neural activity of the LSG, increased AF inducibility, and shortened AERP. LFnu and LFnu/HFnu were markedly increased in the OSA group, while no significant difference in HFnu was observed. TH-positive and PGP9.5-positive nerve densities were significantly increased in the LSG and left atrium. Additionally, the protein levels of NGF, c-Fos, and PGP9.5 were upregulated both in the LSG and left atrium. AF inducibility was markedly increased under LSG stimulation without a stimulus threshold change in the OSA group. CONCLUSIONS: OSA significantly enhanced LSG and left atrial neural remodeling, and hyperactivity of LSG may accelerate left atrial neural remodeling to increase AF inducibility.

[Combination of Microbubble Catalytic Ozonation and Biological Process for Advanced Treatment of Biotreated Coal Chemical Wastewater].

A combination of microbubble catalytic ozonation and biological process was used for advanced treatment of biotreated coal chemical wastewater (BCCW). The performance of the combination system and the influence of the ratio of ozone dosage to influent COD were investigated. The results indicated that the refractory nitrogen-containing aromatics in the BCCW was degraded efficiently by microbubble catalytic ozonation, which resulted in some COD removal, ammonia nitrogen release, and significant improvement of biodegradability. The ozone utilization efficiency was close to 100% and the off-gas ozone did not need to be treated. Sufficient dissolved oxygen (DO) was provided by the microbubble catalytic ozonation for biological treatment without aeration. COD and ammonia nitrogen were removed further in the biological treatment efficiently. Better performance of the combination system was achieved when the system effluent reflux ratio was 30% and the ratio of ozone dosage to influent COD was 0.44 mg·mg-1. In this case, for microbubble catalytic ozonation, the COD removal efficiency was 42.5%, the ratio of ozone consumed to COD removed was 1.38 mg·mg-1, and the ozone utilization efficiency was 98.0%. For biological treatment, the COD removal efficiency was 42.3%. For the combination system, the total COD removal efficiency was 66.7%, the average final effluent COD concentration was 91.5 mg·L-1, and the estimated total ratio of ozone consumed to COD removed was 0.68 mg·mg-1, indicating better technical and economic performance.

[Characteristics of Perchlorate Reduction and Analysis of Consortium Structure in a Sulfur-Based Reactor at a High Perchlorate Concentration].

The effects of perchlorate concentration and hydraulic retention time (HRT) on perchlorate reduction characteristics were investigated in a sulfur-based perchlorate reduction reactor.The results showed that the perchlorate was completely removed at HRT of 12 h and the influent perchlorate concentration ranged from 50 mg·L-1 to 194 mg·L-1;The perchlorate removal efficiency was 74% at HRT of 4 h and the influent perchlorate concentration was 194 mg·L-1;The yield of sulfate was increased by increasing the influent perchlorate concentration and HRT;The influent pH and alkalinity was approximately 8.0 and 500 mg·L-1 CaCO3,and the effluent pH and alkalinity was approximately 6.7 and 100 mg·L-1 CaCO3,respectively;The oxidation reduction potential (ORP) ranged from -380 mV to -330 mV at the bottom of the reactor,however,ORP ranged from -300 mV to -250 mV at the top of the reactor;The molecular biological analysis showed that the microbial consortium structure was different along the flow path in the reactor,Sulfurovum which is known to oxidize sulfur was decreased from 57.78% to 32.19% and Hydrogenophilaceae which is known to oxidize hydrogen sulfide was increased from 4.35% to 22.24%.

[Effect of Non-dissolved Quinone on Perchlorate Reduction by Strain GWF].

The perchlorate reduction lag phase of the strain GWF (KM062029) was shortened by using non-dissolved quinone. nthraquinone, 1-chloroanthraquinone, 1,5-dichloroanthraquinone, 1,8-dichloroanthraquinone and 1,4,5,8-tetrachloranthtaquinone were the five non-dissolved quinones in this study. The results showed that the accelerating order was 1,5-dichloroanthraquinone > 1,4, 5,8-tetrachloroanthtaquinone > 1,8-dichloroanthraquinone > Anthraquinone > 1-chloroanthraquinone. The optimal concentration of 1,5- dichloroanthraquinone, temperature and pH for perchlorate reduction were 0.036 mmol · L⁻¹, 35 °C and 7.5, respectively. The concomitant anions (nitrate, phosphate, sulfate) were in favor of the perchlorate reduction by strain GWF. After four times of recycling experiments, the accelerating perchlorate reduction rate with the immobilized 1,5-dichloroanthraquinone maintained above 2 times.

[Preparation and Characterization of Quinone Functional Polymer Biocarrier (PET-AQS) for Biodenitrification Catalysis].

Anthraquinone sodium sulfonate (AQS) was immobilized on polyethylene terephthalate (PET) by chemical synthesis, forming quinone functional polymer biocarrier (PET-AQS), and its characteristics in biodenitrification catalysis were analyzed. Quinone group was demonstrated to be successfully immobilized on the surface of the polymer and the concentration of immobilized quinone was 0.140 6 mmol x g(-1) by Attenuated Total Reflectance Spectrometry (ATR-IR) and Energy Dispersive Spectrometry (EDS). The PET-AQS could accelerate biodenitrification. The relationship between the denitrification rate constant (K(x)) and the PET-AQS concentration (C(PET-AQS)) obeyed the pseudo-zero order kinetics. After ten rounds of recycling in the biodenitrification system with approximately 0.056 2 mmol quinone, the denitrification rate was kept at more than 1.2 times of the blank system. This indicated that PET-AQS exhibited a good operational stability and was beneficial to practical application.

[Nitrite denitrification characteristics with redox mediator].

This study optimized the nitrite degradation conditions and explored the characteristics of nitrite degradation with redox mediators and nitrite denitrifying bacteria. The results suggested that the optimal condition of nitrite denitrification was 35 degrees C, pH = 8.0, sodium succinate as the carbon source, the C/N rate of 4 and the initial nitrite concentration of 100 mg x L(-1); the optimal AQS concentration was 0. 16 mmol x L(-1); ORP values stabilized around -400 mV to -500 mV with AQS, which were lower than that of controls during the denitrification process; the pH changed with nitrite removal and stabilized at 9 to 10; through the analysis of denitrifying intermediate metabolites, the impact of AQS on nitrite denitrifying process presumably not only played a coenzyme CoQ role but also accelerated the cytochrome transfer electronic process. This study provides the optimal parameters for practical application of the nitrite biodegradation with redox mediator.

[Biocatalyst of redox mediators on the denitrification by Paracoccus versutus strain GW1].

The quinone respiration process of Paracoccus versutus strain GW1 was characterized and the effects of the four redox mediators on the denitrification process were studied. The experiment results suggested that quinones were utilized by Paracoccus versutus strain GW1 as electron acceptors in the respiratory chain and reduced to hydroquinone. Batch experiments were carried out to investigate the biocatalyst effect of redox mediators as catalyst on the denitrification process at 35 degrees C. All four redox mediators tested were able to enhance the nitrate removal efficiency and the denitrification efficiency by 1.14-1.63 fold and 1.12-2.02 fold, respectively. The accelerating effect from high to low was AQDS > 1,5-AQDS > AQS > alpha-AQS. In the presence of redox mediators, the stabilized ORP values in the nitrate decomposition process were reduced by 33-75 mV. The pH variations in denitrification with redox mediators showed similar tendency to that of the conventional nitrate removal process. In the concentration range of 0-0.32 mmol x L(-1), AQDS had the best accelerating effect and a linear correlation was found for the denitrification rate K and the AQDS concentration cAQDS. This study indicated that the application of redox mediators significantly improved the denitrification process by enhancing the decomposition rate.

[Catalyst effect and the structure-activity characteristics of redox mediators on the reactive brilliant red K-2BP decolorization].

Four selected quinone redox mediators with similar structure were conducted to accelerate reactive brilliant red K-2BP decolorization, and the accelerating structure-activity of redox mediators on the decolorization was also studied. Batch experiments were carried out to determine the catalyst effect on the decolorization of reactive brilliant red K-2BP with temperature of 35 degrees C and under anaerobic conditions. The experiment results suggested that (1) four similar chemical structure redox mediators [1, 4, 5, 8-Tetrachloroanthraquinone (1,4,5,8-AQ), Anthraquinone (AQ), 1,8-Dichloroanthraquinone (1,8-AQ), 1,5-Dichloroanthraquinone (1,5-AQ)], all accelerated the decolorization rate of reactive brilliant red K-2BP and the reaction rate was enhanced 1.4-3 times; (2) the accelerating order was 1,8-AQ >1 ,5-AQ > AQ >1,4,5,8-AQ at the quinone mediator concentration of 4 mmol x L(-1) and reactive brilliant red K-2BP concentration of 300 mg x L(-1); (3) under the reactive brilliant red K-2BP concentration of 300 mg x L(-1), 1,8-AQ had best accelerating effect, and the relationship between decoloring rate constants and 1,8-AQ concentration; (4) and the mediator acclerating effects also related to substituent positioning effects and conjugated effects. The structure-activity mathematical model of redox mediators was put forward, which could improve water-insoluble redox mediators catalytic strengthening theory system.