Effect of carbon source on pollutant removal and microbial community dynamics in treatment of swine wastewater containing antibiotics by aerobic granular sludge.

Aerobic granular sludge sequencing batch reactor (AGSBR) is a promising approach for wastewater treatment. In the paper, the effects of methanol, starch and sucrose as carbon sources on the treatment of swine wastewater (SW) containing antibiotics by aerobic granular sludge (AGS) were studied. The results revealed that the carbon sources could affect the morphology, biomass, and settleability of AGS, and AGS could maintain a better sludge performance when sucrose was used as carbon source. The pollutants (ammonium nitrogen (NH+ 4-N), organic matter and total phosphorus (TP)) in SW also had a good removal effect, and the removal rates reached 81.14%, 96.83% and 97.37% respectively. The removal efficiencies of tetracycline (TC) and oxytetracycline (OTC) from SW were the best when sucrose as co-metabolic matrix by microorganisms. The analysis of miseq pyrosequencing demonstrated that carbon sources with methanol, starch and sucrose improved the diversity of microbial community in AGS, and the dominant bacteria also changed. The dominant groups involved in TC and OTC, removal at different classification levels suggested that the formation of bacterial communities was determined by carbon sources.

Unconventional electro-Fenton process operating at a wide pH range with Ni foam cathode and tripolyphosphate electrolyte.

We propose an unconventional electro-Fenton (EF) system with a nickel-foam (Ni-F) cathode and tripolyphosphate (3-PP) electrolyte at near-neutral pH (EF/Ni-F-3-PP) to overcome pH restrictions in EF while preventing Ni-F corrosion. Response surface modelling was used to optimize the main operating parameters with a model prediction analysis (R2 = 0.99): pH = 5.8, Fe2+ = 3.0 mM and applied current = 349.6 mA. Among the three variables, the pH exerted the highest influence on the process. Under optimal conditions, 100 % of phenol removal was achieved in 25 min with a pseudo-first-order apparent rate constant (kapp) of 0.2 min-1, 3.2-fold higher than the kapp of EF/Ni-F with SO42- electrolyte at pH 3. A mineralization yield of 81.5 % was attained after 2 h; furthermore, it was found that 3-PP enhanced H2O2 accumulation by preventing bulk H2O2 decomposition. Finally, toxicity evaluation revealed the formation of toxic by-products at the early stages of treatment, which were totally depleted after 2 h, demonstrating the detoxifying capacity of the system. In conclusion, this study shows for the first time the potential of Ni-F as a cathode for EF under near-neutral conditions, rendered possible by the 3PP electrolyte. Under these conditions, the Ni-F corrosion issue could be alleviated.

The key role of inoculated sludge in fast start-up of sequencing batch reactor for the domestication of aerobic granular sludge.

Two types of inoculated sludges, granular sludge that had been stored at -20°C and activated sludge, were investigated for the domestication of aerobic granular sludges (AGSs) in sequencing batch reactors (SBRs). The results showed that using the stored granular sludge as inoculation sludge could effectively shorten the domestication time of AGS and yielded mature granular sludge after 22 days of operation. The AGS domesticated by stored granular sludge had better biomass and sedimentation properties; its MLSS and SVI reached 8.55 g/L and 35.27 mL/g, respectively. The removal efficiencies for chemical oxygen demand (COD), ammonium nitrogen (NH4+-N) and total phosphorus (TP) reached 90.76%, 97.39% and 96.40%, respectively. By contrast, 54 days were needed to obtain mature granules using activated sludge. The microbial community structure was probed by using scanning electron microscopy (SEM) and high-throughput sequencing. The results showed that the diversity of the microbial community in mature granules was reduced when stored granular sludge rather than activated sludge was employed as inoculation sludge, and the dominant microbes were changed. The dominant species in mature granules domesticated using stored granular sludge were Zoogloea, Acidovorax and Tolumonas at the genus classification level, while the dominant species were Zoogloea and TM7-genera in granules developed from activated sludge.

Effect of nitrogen/phosphorus concentration on algal organic matter generation of the diatom Nitzschia palea: Total indicators and spectroscopic characterization.

Critical algal blooms in great lakes increase the level of algal organic matters (AOMs), significantly altering the composition of natural organic matters (NOMs) in freshwater of lake. This study examined the AOM's characteristics of Nitzschia palea (N. palea), one kind of the predominant diatom and an important biomarker of water quality in the great lakes of China, to investigate the effect of AOMs on the variation of NOMs in lakes and the process of algal energy. Excitation-emission matrix fluorescence (EEM) spectroscopy, synchronous fluorescence (SF) spectroscopy and deconvolution UV-vis (D-UV) spectroscopy were utilized to characterize AOMs to study the effects of nutrient loading on the composition change of AOMs. From results, it was revealed that the phosphorus is the limiting factor for N. palea's growth and the generation of both total organic carbon and amino acids but the nitrogen is more important for the generation of carbohydrates and proteins. EEM spectra revealed differences in the composition of extracellular organic matter and intracellular organic matter. Regardless of the nitrogen and phosphorus concentrations, aromatic proteins and soluble microbial products were the main components, but the nitrogen concentration had a significant impact on their composition. The SF spectra were used to study the AOMs for the first time and identified that the protein-like substances were the major component of AOMs, creating as a result of aromatic group condensation. The D-UV spectra showed carboxylic acid and esters were the main functional groups in the EOMs, with -OCH3, -SO2NH2, -CN, -NH2, -O- and -COCH3 functional groups substituting into benzene rings.

Sensitized chemiluminescence of 2-phenyl-4,5-di(2-furyl)-1H-imidazole/K3Fe(CN)6/propyl gallate system combining with solid-phase extraction for the determination of propyl gallate in edible oil.

In this paper, a novel chemiluminescence (CL) method has been developed for the determination of propyl gallate (PG). The proposed method was based on the enhancing effect of PG on the CL signal of 2-phenyl-4,5-di(2-furyl)-1H-imidazole (PDFI) and K3Fe(CN)6 reaction in an alkaline solution. Under the optimum conditions, the enhanced CL intensity was linearly related to the concentration of PG. The linear range of the calibration curve was 0.05-8 µg/mL, and the corresponding detection limit (3σ) was 0.036 µg/mL. The relative standard deviation for determining 1.0 µg/mL PG was 2.8% (n=11). The proposed method has been successfully applied to the determination of PG in edible oil. The edible oil samples were prepared by the solid-phase extraction (SPE) with a C18 column served as the stationary phase. Furthermore, the possible CL mechanism was also discussed briefly based on the photoluminescence (PL) and CL spectra.

Performance of aerobic granular sludge in different bioreactors.

Inoculated sludge from the Brewery wastewater treatment plant was cultured in a sequencing batch reactor (SBR). The granular sludge was then used to process the artificial simulation wastewater to compare the performance and efficiency of the granular sludge in organic matter removal by using SBR and granular membrane bioreactor (GMBR). Results showed that the granular sludge in the SBR exhibited desirable characteristics and good removal efficiency. The mixed liquor suspended solids (MLSS) and the sludge volume index (SVI) were approximately 2.56 g/L and 78.13 mL/g, respectively, and it exhibited a satisfactory settling ability. The removal efficiency of the resulting chemical oxygen demand (COD), NH3-N and total phosphorus (TP) reached 89.35%, 96.49% and 83.76%, respectively. The removal efficiency of both nitrate nitrogen and total nitrogen (TN) reached 90%. The performance of the granular sludge as well as the removal efficiency of the organic matter in the GMBR was subsequently observed. Results showed that the process influenced the characteristics and microbial biomass of the granular sludge. The SVI and the MLSS were about 175.82 mL/g and 1.14 g/L, respectively. The removal efficiency of COD and TP increased to 93.17% and 90.42%, respectively. The removal efficiency of NH3-N was slightly affected, whereas that of both nitrate nitrogen and TN increased to 95%. In this study, the physical properties and the removal efficiency of granular sludge in different bioreactors were compared. The comparison demonstrated that granulation membrane bioreactors perform more efficiently compared with SBR in wastewater treatment for organic matter removal.

Adsorption kinetics of benzotriazole and its derivatives by nano Zn-Al-O.

Benzotriazole and its derivatives are important industrial auxiliaries, which are serious pollution sources in the natural aquatic environment. Benzotriazole and its derivatives adsorption by a novel nano absorbent (nano Zn-Al-O binary metal oxide, named as ZAO) being explored as an effective water treatment method, was carried out in this study. Results showed that benzotriazole and its derivatives were all effectively adsorbed from water by ZAO. Removal efficiencies of benzotriazole, 5-methyl-benzotriazol and 5,6-dimethyl-benzotriazole with 5 g/L adsorbent dosage achieved 89%, 81% and 92%, respectively. The adsorption kinetics and isotherm models were used to express the adsorption process and discuss the adsorption mechanism. The adsorption kinetics well followed pseudo-second-order model, indicating that chemical adsorption dominated the adsorption. Adsorption isotherm was well expressed by Freundlich model. Structure characteristics of benzotriazole and its derivatives had great effect on their adsorption. Hydrogen-bond interaction was considered as the main mechanism for the surface adsorption. However, hydrophobic interactions played an important role in 5,6-dimethyl-benzotriazole adsorption due to its weak polarity.

Ozonation catalyzed by the raw bauxite for the degradation of 2,4,6-trichloroanisole in drinking water.

A kind of inexpensive and environmental friendly mineral, the raw bauxite has been used successfully as a catalyst combined with ozonation in the degradation of 2,4,6-trichloroanisole (TCA). The catalyst was characterized by using various analytical techniques. X-ray powder diffraction (XRD) characterization showed that the raw bauxite containing boehmite (gamma-AlOOH), kaolinite (Al(2)Si(2)O(5)(OH)(4)) and quartz (SiO(2)), and gamma-AlOOH was the major composition. The catalytic ozonation removal effectiveness of TCA was investigated under various physicochemical conditions. Both the adsorption and the single ozonation were not effective for the degradation of TCA, and the presence of the raw bauxite in ozonation enhanced the TCA removal effectiveness. Both the hydroxyl radicals (OH) scavenging experiment and R(ct) characterization confirmed that the generation of OH was accounted for the enhancement of the degradation of TCA. The generation of OH was inhibited faintly by the presence of both natural organic matters (NOMs) and alkalinity in the natural water during catalyzed ozonation with the raw bauxite. The increasing of both the bauxite dosage and the ozone dosage enhanced the removal effectiveness of TCA. The raw bauxite was an efficient green catalyst for TCA degradation in drinking water.

[Mechanism discussion of gamma-alumina catalyzed ozonation for 2-methylisoborneol removal].

The efficiency and mechanism in degradation of 2-methylisoborneol (MIB) as taste and odor compound in drinking water were studied under the condition where gamma-alumina catalyzed ozonation. As a result, gamma-alumina can behave distinct activity in enhancing the efficiency of ozonation MIB. Tert-butyl alcohol had a remarkable restrain effect on removal efficiency of catalytic ozonation MIB by gamma-alumina. The surface charge status and surface hydroxyl groups status of gamma-alumina and pH values of the solution can be linked together. When the pH value of solution was near the pH(zpc) of gamma-Al2O3, there was a most observable activity in catalyzed ozonation process. R(ct), which denoted the relative concentration of hydroxyl radical (*OH), was much higher in catalyzed ozonation process than in ozonation process. This result further illuminated that gamma-Al2O3 can promote ozone decomposition to produce *OH. Finally, it was investigated that the effect of r(P/I) on catalyzed ozone decomposition and ozone decomposition.

[Gamma-Al2O3 catalyzed ozonation for removing taste and odor substance 2-methylisoborneol in drinking water].

gamma-Alumina was used as a catalyst in ozonation, and efficiency and influencing factors in degradation of taste and odor substance 2-methylisoborneol (MIB) in drinking water were studied. The result shown that gamma-alumina was activated in catalytic ozonation for degradation MIB not only in distilled water, but also in tap water. In distilled water condition, catalyzed ozonation could enhance 47% removal efficiency; in tap water condition, catalyzed ozonation could increase 40% removal efficiency. The concentration of ozone, gamma-alumina, MIB can affect the degradation of MIB observably. gamma-Alumina catalyzed ozonation for removing MIB did not depend on rigidity in water, but was affected by inorganic negative ions. By capturing the hydroxyl radicals produced by gamma-alumina catalyzed ozone decomposition, the bicarbonate/carbonate in natural water can restrain the effect of gamma-alumina catalyzed ozonation for degradation of MIB. Lower concentration of humic acid can promote the effect of oxidation of the MIB, but higher concentration of humic acid may reduce the efficiency. As pH values can affect the process of catalyzed ozonation and tert-butyl alcohol can inhibit the efficiency of catalyzed ozonation efficiency of MIB, the mechanism of gamma-alumina enhanced ozone oxidation of MIB can be identified as that gamma-alumina catalyzed ozone to decompose into hydroxyl radicals which further break up the molecule of MIB.