[Effect of Rate of Salinity Increase on the Performance and Microbial Community Structure of Sequencing Batch Reactors].

In this study, three sequence batch reactors were selected to evaluate the effects of salt-tolerant activated sludge acclimation. The effect of salinity increase rate on pollutant removal, physicochemical characteristics of activated sludge, and microbial community were investigated. The results showed that a rapid salinity increase to 30‰ (within 30 d) reduced removal efficiencies of COD and NH4+-N from 85.5% and 98.5% (18 d) to 72.2% and 81.7% (51 d), respectively. In comparison, a slower salinity increases to 30‰ (within 90 d) had a minor effect on COD and NH4+-N removal. During the rapid salinity increase, a stable shortcut nitrification occurred under 20‰ salinity, in which the effluent NO2--N reached 11.13 mg·L-1 and NO3--N decreased to 0.56 mg·L-1. When salinity increased to 30‰, the nitrite accumulation rate was about 90%, and the removal efficiency of total nitrogen increased to approximately 75%. The contents of polysaccharide and protein in extracellular polymer substances increased as salinity increased, and the polysaccharide content increased significantly when the salinity was higher than 15‰. High-throughput sequencing results illustrated that microbial diversity reduced as salinity increased, following the Shannon index decrease from 8.06 (0‰ salinity) to 4.34 (rapid salinity increase) and 6.17 (slower salinity increase). As salinity increased, Micropruina, Denitromonas, TM7a, and Marinicella exhibited good salt tolerance. The relative abundance of Denitratisoma, Defluviimonas, Arenimonas, and Denitromonas decreased more significantly following the rapid salinity increase compared with that after the slower salinity increase.

[Study on 3-nitrophenol wastewater treatment in UASB].

Characteristics of anaerobic granules before and after acclimation, removal efficiencies of 3-nitrophenol (3-NP) and performance of 3-NP wastewater treatment were investigated in a lab-scale upflow anaerobic sludge bed (UASB). The results showed that granular sludge acclimatized to 3-NP rapidly during acclimation. Using SEM, the filamentous bacteria was the predominant bacteria on the surface of granules. Throughout the study of 3-NP wastewater anaerobic degradation, hydraulic retention time (HRT) and input COD concentration were kept constant as 26 h and 2 500 mg/L, respectively. While 3-NP concentrations increasing from 20 mg/L to 250 mg/L gradually, COD removal decreased from 95.2% to 85.1% and 3-NP removal efficiencies were always more than 99%. 3-AP was found to be the major intermediate during the degradation of 3-NP. Out of the total input of 3-NP concentration, on molar basis, about 58.7% - 111.9% of 3-NP was recovered in the form of 3-AP. With increasing 3-NP concentration, the variations of gas production were minimal. The minimum methane percentage was 65% and the maximum was 74%.

Biological removal of methanol from process condensate for the purpose of reclamation.

The biological removal of methanol from condensate of ammonia manufacturing processes for the purpose of reclamation using contact type reactor was studied. Methanol of 60 mg/L was removed completely under an HRT of 1.12 h. Optimal inorganic nutrient dose was determined on evaluating methanol removal performance and dehydrogenase activities (DHA) under different nutrition doses. The optimal inorganic nutrient dose only gave an increase of conductivity of ca. 10 micros/cm2 in the effluent on treating synthetic condensate containing methanol of 30 mg/L. The results demonstrated that biological removal of methanol was effective for the purpose of recovering the methanol-bearing condensate.

[Activity of nitrifiers and metabolized products in a membrane bioreactor MBR under the condition of non-sludge discharge].

A membrane bioreactor fed with synthetic ammonium bearing inorganic wastewater was operated under the following conditions: HRT, from 30 h to 7 h; influent NH4+ -N, 500 mg/L; non-discharge of sludge. Formation of extra-cellular polymers (ECP) and their influence on the activity of nitrifiers in the membrane bioreactor was investigated. Over the whole experimental period of 200 d, the activity of nitrifiers in terms of overall ammonium-oxidizing rate decreased from 2.1 kg/(L x d) to 1.5 kg/(L x d), and the nitrifier number using INTF absorbency measurement decreased from 0.023 x 10(-3) to 0.01 x 10(-3), although the MLSS increased from 4500 mg/L to 10500 mg/L. The ECP content increased from the initial 300 mg/L to 600 mg/L. Batch tests using the extracted ECP also indicated that the activity of nitrifiers could be inhibited by the existence of ECP.

Identification of ubiquinones and menaquinones in activated sludge by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

A sensitive analytical method has been developed for identification of ubiquinones (UQ-n(Hx)) and menaquinones (MK-n(Hx)) in activated sludge by liquid chromatography-atmospheric pressure chemical ionization mass spectrometry in negative mode (LC-NI-APCI-MS). Extraction and clean-up of samples were carried out on Sep-Pak Plus Silica solid-phase extraction cartridges. Complete separation of quinones was achieved with an ODS analytical column and using isopropyl ether-methanol (17:83, v/v) as the mobile phase. The compositions of ubiquinones and menaquinones were determined directly using combined information on retention time, the molecular ion mass and fragment ion masses. The lowest instrument quantitative detection limits (LODinst) for UQ-6, UQ-10, and Vitamin K1 were estimated to be 0.4, 4 and 0.12 ng (S/N = 10) using LC-NI-APCI-MS in SIM mode, and the lowest method detection limits (LODmeth) achieved by spiking experiment were estimated to be 0.2, 2 and 0.06 microg/g for UQ-6, UQ-10 and Vitamin K1, respectively. On the other hand, the LODinst for UQ-6, UQ-10, and Vitamin K1 were estimated to be 10, 100 and 2 ng (S/N = 10) using LC-NI-APCI-MS in full-scan mode, and the LODmeth were estimated to be 7, 60 and 1.2 microg/g for UQ-6, UQ-10, and Vitamin K1, respectively. Both LC-NI-APCI-MS and LC-UV/DAD were applied in the analysis of an activated sludge extract. UQ-n (n = 6-10), MK-n (n = 6-10), MK-n(H2) (n = 7-10), MK-n(H4) (n = 8-9) and MK-8(H6) were detected by LC-NI-APCI-MS, while UQ-6, UQ-7, MK-7(H), MK-9 and MK-10(H2) were not found by LC-UV/DAD. These results suggest that LC-NI-APCI-MS is more sensitive than LC-UV/DAD for the analysis of quinones in environmental samples such as sediment, activated sludge and bio-film in biological processes and other aquatic environments.