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Denitrifying anaerobic methane oxidation (DAMO) process uses methane as electron donor to reduce nitrate/nitrite to dinitrogen, which is a potentially efficient, low-cost and clean biological nitrogen removal technology. However, slow microbial growth rate severely limits the application of this promising process. In this study, a series hollow-fiber membrane biofilm reactor (HfMBR) was operated for 90 days to achieve rapid enrichment of these denitrifying methanotrophs. Finally, the highest relative abundance of denitrifying methanotrophic archaea and bacteria (DAMO archaea and bacteria) reached 47.5% and 11.3%, respectively. And the average abundance of DAMO archaea and bacteria increased 92.9 and 136.6 times respectively during the 90-day enrichment. High growth rate of DAMO archaea with a doubling time of 11.6 days was achieved in the second HfMBR according to quantitative PCR results. The results implied that dissolved oxygen would inhibit the growth of DAMO archaea, but the series HfMBR could effectively counteract this unfavorable factor. This work provided theoretical guidance for the rapid enrichment of denitrifying methanotrophs and contributed to the application of methane-dependent denitrification process., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Soluble microbial products (SMPs), as secondary pollutants, comprise a dominant percentage of residual COD in effluents from biological wastewater treatment processes. They can also be regarded as substitute electron sources if the in-situ utilization of SMPs could be achieved. In this study, the fate of SMPs in a sequencing batch reactor (SBR) treating artificial municipal sewage was investigated. Based on the regular SBR operation mode, a 3 h extension of anoxic phase was provided to promote SMP degradation. Meanwhile, the denitrification efficiencies achieved by adopting SMPs and influent organic substrates (IOSs) were compared to reveal the significant contribution of the in-situ utilization of SMP for nitrogen removal. Approximately 21.1 mg N/L of total nitrogen (TN) was removed over a single cyclic reaction, in which only 13.2 mg N/L was removed via IOS-dependent denitrification. The remaining 7.9 mg N/L of TN was realized via SMP-dependent denitrification, including 3.9 mg N/L by utilization-associated products and 4.0 mg N/L by biomass-associated products, which significantly contributed 37.4% of TN removal. The aromatic proteins, tryptophan-like proteins, polysaccharides and fulvic acids contained in SMP were the potential precursors of electron donors to support SMP-dependent denitrification process., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Aerobic granular sludge (AGS) is promising in wastewater treatment. However, the formation and existence of AGS under low organic loading rate (OLR) is still not fully understood due to a knowledge gap in the variations and correlations of N-acyl-homoserine lactones (AHLs), the microbial community, extracellular polymeric substances (EPS) and other physiochemical granule properties. This study comprehensively investigated the AHL-mediated quorum sensing (QS) and microbial community characters in the AGS fed with ammonium-rich wastewater under a low OLR of 0.15 kg COD (m 3 d) -1 . The results showed that the AGS appeared within 90 days, and the size of mature granules was over 700 μm with strong settleability and ammonium removal performance. More tightly-bound extracellular polysaccharide and tightly-bound extracelluar protein were produced in the larger AGS. C10-HSL and C12-HSL gradually became dominant in sludge, and short-chain AHLs dominated in water. EPS producers and autotrophic nitrifiers were successfully retained in the AGS under low OLR. AHL-mediated QS utilized C10-HSL, C12-HSL and 3OC6-HSL as the critical AHLs to regulate the TB-EPS in aerobic granulation, and autotrophic nitrifiers may perform interspecific communication with C10-HSL. The correlations of bacterial genera with AGS properties and AHLs were complex due to the dynamic fluctuations of microbial composition and other variable factors in the mixed-culture system. These findings confirmed the participation of AHL-mediated QS in the regulation of microbial community characters and AGS properties under low OLR, which may provide guidance for the operation of AGS systems under low OLR from a microbiological viewpoint., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Improvement of the acidification phase is an attractive alternative to break through the rate-limiting step in the two-phase anaerobic digestion of complex organic wastes. An additive named iron oxide-zeolite was introduced into the acidification phase at mesophilic and room temperature. By virtue of the additive supplemented, significantly improved hydrolysis/fermentation in regard to higher soluble chemical oxygen demand (sCOD) concentration (21.53-27.30%) and better lignocellulosic degradation at both temperatures has been obtained. Furthermore, an optimized volatile fatty acid formation type (more favorable acetate and less undesired propionate) has been achieved. The favorable environment of the acidogenic effluent facilitated the subsequent methanogenesis. The increased microbial community abundances of some hydrolytic, acetogenic and cellulolytic bacteria may provide the explanation on the promoted hydrolysis/acidogenesis. The results in this study suggested that supplementation of the iron oxide-zeolite into the acidification phase is a valuable alternative to improve hydrolysis/acidogenesis of the complex substrates., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Tourmaline is a ring borosilicate with unique pyro-electricity and piezoelectricity values. Non-gem tourmaline is usually used as an environmental material. The short-term effects of ultrafine tourmaline particles on nitrogen removal performs microbial population dynamics. Key functional species in a sequencing batch reactor were investigated at 9 ± 1 °C. The investigation results showed that 1 g·L −1 ultrafine tourmaline particles could resist the effect of temperature shock on the metabolism of NH₄⁺-N and were beneficial to the restoration of the metabolism capacity of NH₄⁺-N. 1 g·L −1 ultrafine tourmaline particles, which increased the oxidation rate of NH₄⁺-N in the aerobic phase, the formation rate of NO₃ − -N in the aerobic phase, and the denitrification rate in the hypoxia phase at low temperatures. However, the community richness or diversities were not changed after short-term exposure to 1 g·L −1 ultrafine tourmaline particles at low temperatures and 1 g·L −1 ultrafine tourmaline particles could not change the relative abundances of functional microbes except nitrite oxidizing bacteria.

The low-strength domestic wastewater (LSDW) treatment with low chemical oxygen demand (COD) has drawn extensive attention for the poor total nitrogen (TN) removal performance. In the present study, an enhanced multistage anoxic/oxic (A/O) biofilm reactor was designed to improve the TN removal performance of the LSDW treatment. Efficient nitrifying and denitrifying biofilm carriers were cultivated and then filled into the enhanced biofilm reactor as the sole microbial source. Step-feed strategy and internal recycle were adopted to optimize the substrate distribution and the organics utilization. Key operational parameters were optimized to obtain the best nitrogen and organics removal efficiencies. A hydraulic retention time of 8 h, an influent distribution ratio of 2:1 and an internal recycle ratio of 200% were tested as the optimum parameters. The ammonium, TN and COD removal efficiencies under the optimal operational parameters separately achieved 99.75 ± 0.21, 59.51 ± 1.95 and 85.06 ± 0.79% with an organic loading rate at around 0.36 kg COD/m 3  d. The high-throughput sequencing technology confirmed that nitrifying and denitrifying biofilm could maintain functional bacteria in the system during long-period operation. Proteobacteria and Bacteroidetes were the dominant phyla in all the nitrifying and denitrifying biofilm samples. Nitrosomonadaceae_uncultured and Nitrospira sp. stably existed in nitrifying biofilm as the main nitrifiers, while several heterotrophic genera, such as Thauera sp. and Flavobacterium sp., acted as potential genera responsible for TN removal in denitrifying biofilm. These findings suggested that the enhanced biofilm reactor could be a promising route for the treatment of LSDW with a low COD level.

Bioaugmentation is substantially determined by pre-attached communities in biological stuffing systems. However, the inevitable changes of microbial community shift occurred between pre-attached microorganisms on stuffing material and other existing communities in wastewater. Targeting at nitrogen removal in aerobic denitrification reactors, biological augmentation was built by polyurethane supporting material and aerobic denitrification bacteria of Pseudomonas stutzeri strains were primarily colonized. The total nitrogen removal reached a high efficiency of 77 ± 6%, resulting from a relative high nitrate removal (90%) and a low nitrite production of 24 mg l -1 . The nitrate removal was kept 10% higher using preattached strains than that using wastewater communities. During the bioaugmentation process, abundant bacteria related to nitrogen removal were evolutively enriched to compete with preattached Pseudomonas stutzeri. The most abundant bacteria growing up in the biofilm belonged to various Classes of Proteobacteria Phylum. A noticeable nitrite production with a relative low TN removal efficiency occurred when Brucella sp. and Brevundimonas sp. were simultaneously enriched in place of Pseudomonas, because Brevundimonas also accumulated nitrite during denitrification under an aerobic condition. The results indicated that pre-attached denitrifiers in comprehensive communities on stuffing material can be established for the efficient nitrogen and COD removal in aerobic denitrification reactors.

An aerobic denitrification system, initially bioaugmented with Pseudomonas strain T13, was established to treat coal-based ethylene glycol industry wastewater, which contained 3219 ± 86 mg/L total nitrogen (TN) and 1978 ± 14 mg/L NO 3 - -N. In the current study, a stable denitrification efficiency of 53.7 ± 4.7% and nitrite removal efficiency of 40.1 ± 2.7% were achieved at different diluted influent concentrations. Toxicity evaluation showed that a lower toxicity of effluent was achieved when industry wastewater was treated by stuffing biofilm communities compared to suspended communities. Relatively high TN removal (~50%) and chemical oxygen demand removal percentages (>65%) were obtained when the influent concentration was controlled at below 50% of the raw industry wastewater. However, a further increased concentration led to a 20-30% decrease in nitrate and nitrite removal. Microbial network evaluation showed that a reduction in Pseudomonas abundance was induced during the succession of the microbial community. The napA gene analysis indicated that the decrease in nitrate and nitrite removal happened when abundance of Pseudomonas was reduced to less than 10% of the overall stuffing biofilm communities. Meanwhile, other denitrifying bacteria, such as Paracoccus, Brevundimonas, and Brucella, were subsequently enriched through symbiosis in the whole microbial network.

Sulfur/dolomite and pyrite/dolomite autotrophic denitrification reactors were applied to treat the secondary effluent of wastewater treatment plant to explore the removal effect, the changes of microbial community, and recovery time of reactors after starvation period. It was shown in the results that after 30 d non-water starvation endurance, the effluent concentrations of NO 3 - -N in sulfur/dolomite and pyrite/dolomite reactors increased from 1.78 mg·L -1 , 11.32 mg·L -1 to 27.87 mg·L -1 , 26.56 mg·L -1 respectively at the low temperature of 12-14℃. In addition, sulfur/dolomite and pyrite/dolomite reactors recovered within 5 d and 11 d since restarted and could maintain a good effect of nitrogen removal at low temperature. MiSeq high throughput sequencing results showed that the abundance and diversity of the bacterial communities in starvation period in both reactors were lower than those in recovery period. The dominating phylum was Proteobacteria in both reactors while the dominating class was β -Proteobacteria. Thiobacillus was identified as the main genus for denitrification in sulfur/dolomite reactor.

Aquabacterium parvum strain B6 exhibited efficient nitrate-dependent Fe(II) oxidation ability using nitrate as an electron acceptor. A continuous up-flow bioreactor that included an aerobic and an anoxic section was constructed, and strain B6 was added to the bioreactor as inocula to explore the application of microbial nitrate-dependent Fe(II) oxidizing (NDFO) efficiency in wastewater treatment. The maximum NRE (anoxic section) and TNRE of 46.9% and 79.7%, respectively, could be obtained at a C/N ratio of 5.3:1 in the influent with HRT of 17. Meanwhile, the taxonomy composition of the reactor was assessed, as well. The NDFO metabolism of strain B6 could be expected because of its relatively dominant position in the anoxic section, whereas potential heterotrophic nitrification and aerobic denitrification developed into the prevailing status in the aerobic section after 50days of continuous operation., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this study, Mn(II) as electron donor was tested for the effects on denitrification in the MBBR under the conditions of initial nitrate concentration (10mgL(-1), 30mgL(-1), 50mgL(-1)), pH (5, 6, 7) and hydraulic retention time (HRT) (4h, 8h, 12h) which conducted by response surface methodology (RSM), the results demonstrated that the highest nitrate removal efficiency was occurred under the conditions of initial nitrate concentration of 47.64mgL(-1), HRT of 11.96h and pH 5.21. Analysis of SEM and flow cytometry suggested that microorganisms were immobilized on the Yu Long plastic carrier media successfully before the reactor began to operate. Furthermore, high-throughput sequencing was employed to characterize and compare the community compositions and structures of MBBR under the optimum conditions, the results showed that Pseudomonas sp. SZF15 was the dominant contributor for effective removal of nitrate in the MBBR., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Escherichia coli cells expressing phenol hydroxylase (designated as PHIND) were used to biosynthesize 1,2-dihydroxydibenzofuran (1,2-dihydroxyDBF) from dibenzofuran (DBF). The pathway of DBF biotransformation by strain PHIND was proposed, in which DBF was initially monohydroxylated at C-1 and C-4 positions to produce 1- and 4-hydroxyDBF, then underwent successive hydroxylation to yield 1,2- and 3,4-dihydroxyDBF, of which 1,2-dihydroxyDBF was identified for the first time. Magnetically immobilized cells of strain PHIND in biphasic systems with dodecane as the solvent presented highest biosynthesis activity for 1,2-dihydroxyDBF, which was a 6.5-fold improvement compared to biosynthesis in aqueous system. The recycling experiments demonstrated that magnetically immobilized cells exhibited higher biosynthesis activity for 1,2-dihydroxyDBF than that by nonmagnetically immobilized cells during five cycles in biphasic systems. These works support the development of an efficient biosynthesis process using magnetically immobilized cells in biphasic systems and provide a promising technique for improving the productivity in 1,2-dihydroxyDBF biosynthesis., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

In this study, zeolite-biological aerated filters (Z-BAFs) bioaugmented by free and magnetically immobilized cells of Arthrobacter sp. W1 were designed to treat coking wastewater containing high concentrations of phenol and naphthalene along with carbazole (CA), dibenzofuran (DBF), and dibenzothiophene (DBT). All treatments were carried out for a period of 100days and the data indicated that bioaugmented Z-BAFs with magnetically immobilized cells was most efficient for treating coking wastewaters. Illumina high-throughput sequencing was used to reveal the microbial community structures of Z-BAFs. Both bioaugmentation treatments could accelerate the shift of the bacterial community structures. The introduced strain W1 remained dominant in the bioaugmented Z-BAFs with magnetically immobilized cells, indicating both strain W1 and the indigenous degrading bacteria played the most significant role in the treatment. Overall, bioaugmented Z-BAF with magnetically immobilized cells can be used to efficiently degrade phenol, naphthalene, CA, DBF, and DBT in coking wastewater., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

The short-cut nitrification and denitrification process of a polyurethane biofilm reactor was studied at four different carbon to nitrogen ratios (C/N ratios) (C/N =15:1, 10:1, 5:1 and 1.8:1) with focus on reactor performance and microbial community composition. Results showed that when the influent carbon/nitrogen ratio decreased from 15 to 10, 5 and 1.8, the nitrite accumulation rate was increased from 56.1% to 62.3%, 72.3% and 83.2% after 100 d operation. System achieved the optimal removal efficiency at an influent carbon/nitrogen ratio of 10 with 99.1% of ammonia removal and 91.0% of total nitrogen removal. Simultaneous nitrification and denitrification occurred in the polyurethane biofilm system at different influent carbon/nitrogen ratio. As the influent carbon/nitrogen ratio decreased from 15 to 10, 5 and 1.8, the efficiency of simultaneous nitrification and denitrification was gradually reduced. The microbial biofilm analysis indicated that the microbial diversity of biofilm with an influent carbon/nitrogen ratio of 15 was significantly higher than that in other conditions. The predominant ammonia oxidizing bacteria and nitrite oxidizing bacteria were Nitrosospira sp. and Nitrospira sp., respectively, and the predominant denitrifying bacteria were Pseudomonas sp.

Sludge bulking caused by loss of stability is a major problem in aerobic granular sludge systems. This study investigated the feasibility of preventing sludge bulking and enhancing the stability of aerobic granular sludge in a sequencing batch reactor by optimizing operation conditions. Five operation parameters have been studied with the aim to understand their impact on sludge bulking. Increasing dissolved oxygen (DO) by raising aeration rates contributed to granule stability due to the competition advantage of non-filamentous bacteria and permeation of oxygen at high DO concentration. The ratio of polysaccharides to proteins was observed to increase as the hydraulic shear force increased. When provided with high/low organic loading rate (OLR) alternately, large and fluffy granules disintegrated, while denser round-shape granules formed. An increase of biomass concentration followed a decrease at the beginning, and stability of granules was improved. This indicated that aerobic granular sludge had the resistance of OLR. Synthetic wastewater combined highly and slowly biodegradable substrates, creating a high gradient, which inhibited the growth of filamentous bacteria and prevented granular sludge bulking. A lower chemical oxygen demand/N favored the hydrophobicity of granular sludge, which promoted with granule stability because of the lower diffusion rate of ammonia. The influence of temperature indicated a relatively low temperature was more suitable.

An anaerobic/aerobic/anoxic-type sequencing batch reactor was started up during a summer rainy season to obtain enhanced biological phosphorus removal (EBPR), and its sludge microbial community was also monitored in the hope of observing the microbial community evolution of polyphosphate-accumulating organisms (PAOs). During the start-up process, a total of 17 bands of highest species richness were detected in the sludge microbial community, including Alpha-, Beta-, and Gamma- Proteobacteria, as well as Actinobacteria and Planctomycetes. Major microbial community structural change was observed in Rhodocyclus-related and Acinetobacter-related PAOs, glycogen-accumulating organisms (GAOs), and Actinobacteria. In contrast to the current belief that enrichment of PAOs is essential for the establishment of EBPR, PAOs were not favourably enriched in this study. Instead, Actinobacteria and GAOs overwhelmingly flourished. The overall conclusion of this study challenges the conventional view that EBPR cannot live without traditional PAOs. However, it suggests an non-negligible role of denitrifying phosphorus-accumulating bacteria in EBPR systems, as well as other uncultured bacteria.

In order to strengthen the activity of biofilm on the carrier surface, the tourmpaline on polyurethane (TPU) carrier was prepared using waterborne polyurethane as medium. The physical properties of TPU carrier were characterized by scanning electron microscope(SEM) and water absorbency, and its effect on biofilm biomass and nitrifying ability was studied. The results showed that the tourmaline loading amount of TPU carrier can be affected by waterborne polyurethane. Tourmaline can optimize the number of polar groups of the TPU carrier and the pH of the nitrification condition. The amount of nitrobacteria and nitrate bacteria irreversibly adsorbed on the TPU carrier was increased by 74.82% and 71.89% , respectively. Correspondingly, the removing rate of NH+4 -N and NO-2 -N has risen by 8.12% and 9.08%, respectively, compared to the control without carrier. The TPU carrier was indicated to promote the nitrification.

A sequencing batch biofilm reactor (SBBR) filled with polyurethane (PU) was operated in low dissolved oxygen (DO) (0.1-0.9 mg/L) at three different carbon to nitrogen ratios (C/N ratios) (C/N = 1.8:1, 5.0:1 and 10.5:1) with focus on reactor performance and microbial community composition of nitrifying and denitrifying bacteria. Meanwhile, the ammonium, nitrite, nitrate, pH and dissolved oxygen were analyzed to monitor the process of nitrification-denitrification. The reactor had a steady ammonium removal in spite of a large variation in the initial ammonium loading (the ammonium removal efficiency was 87.2% at C/N 1.8:1, 92.9% at C/N 5.0:1, 88.4% at C/N 10.5:1). However, the total nitrogen (TN) removal was strongly affected by the initial organic loading (the TN removal efficiency was 55.2% at C/N 1.8:1, 74.3% at C/N 5.0:1, 79.0% at C/N 10.5:1). It was indicated that higher organic load promoted denitrification. The real-time quantitative polymerase chain reaction (real-time qPCR) analysis shown that Beta-proteobacteria occupied over 35% numerically. As for the Nitrosomonas sp., Nitrosospira sp. and Nitrospira sp. gene copy numbers, their abundance was generally in the order of magnitude of 10(10). The Nitrosospira sp. fluctuated significantly in the range of 3.1-9.8% at different C/N ratios, while the Nitrosomonas sp. just changed a little.

Mycelial pellet of Aspergillus niger Y3 was used as a biomass carrier to immobilize the aniline-degrading bacterium, Acinetobacter calcoaceticus JH-9 and the mix culture of the COD rapid degradation bacteria. In order to investigate its removal effect on aniline and COD, the combined mycelial pellets were applied in the SBR. Comparison of the performances was conducted between another SBR inoculated with sole strain JH-9 and the above SBR. The results showed that the stable degradations of aniline and COD were observed in both reactors. In the SBR with combined mycelial pellet, the biological removal efficiency was about 0.9 mg aniline/(L·d). It was much higher than that in the activated sludge reactor. Meanwhile, the performances of the sedimentation velocity, liquid-solid phase separation and the effluent quality were better in the SBR. According to SEM images and PCR-DGGE analysis, the species immobilized on the biomass carrier were more predominant in this system., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

A combined biological (augmented membrane bioreactor (MBR)) and photochemical (photocatalysis and ozonation) treatment has been proposed for bromoamine acid (BAA) removal in dyeing wastewater. It was demonstrated that the color and chemical oxygen demand removal in the sequential augmented MBR was about 90% and 50%, respectively. By ribosomal intergenic spacer analysis, it was found that the introduced strain QYY was maintained as the predominant species and the diversity of the system was relatively low throughout the operation. Photocatalysis and ozonation processes were efficient to treat the effluents from MBR with high color and total organic carbon removal more than 90% within 120 min. Therefore, the hybrid treatment system is a possible way to achieve the complete mineralization of BAA.

Aiming at the complexity and poor biochemical degradability of petrochemical wastewater, the effect of tourmaline on bio-contact oxidation method was investigated. The influent and effluent of petrochemical wastewater were analyzed by GC-MS, and the carrier was observed in reactor by scanning electron microscope (SEM). As the loading rates of influent were COD 0.64-0.72 kg/(m3 x d) and NH4(+) -N 0.058-0.072 kg/(m3 x d), the start up of pilot system supported tourmaline were improved, and the removal rate of COD and NH4(+) -N of effluent was increased 8.7% and 6.4%, respectively. Organic pollutants of 100 kinds were detected in influent, mainly including aromatic hydrocarbon, acids, lipids, phenols, alcohols, and alkanes compounds. The removal efficiency of organic pollutant of reactor 1 with tourmaline was higher than reactor 2 without tourmaline. The number of organic pollutant in effluent from reactor 1 and 2 were 14 and 28, respectively. Zoogloea can be observed on carrier supported tourmaline, and the biomass of bacteria was predominant. The efficiency of bio-contact oxidation method on petrochemical wastewater treatment can be enhanced by tourmaline.

In this study, decolorization of Reactive Brilliant Red X-3B wastewater by the biological process coping with high salinity and metal ions conditions was investigated, and 16S rDNA based fingerprint technique was used to investigate microbial population dynamics. Results of sequencing batch tests showed that the microbial community could keep efficient with high concentration of dye (1100 mg L(-1)), salt (150 g L(-1) NaCl) and some metal ions such as Mg(2+), Ca(2+) (1-10 mmol L(-1)) and Pb(2+) (1 mmol L(-1)). 16S rDNA-based molecular analysis techniques demonstrated that the microbial community shifted during the acclimatization process affected by salt or metal ions. Some stains similar to Bacillus, Sedimentibacter, Pseudomonas, Clostridiales, Streptomyces and some uncultured clones acted for the dynamic succession, supposed as potential decolorization bacteria. This study provided insights on the decolorization capability and the population dynamic shifts during decolorization process of azo dye wastewater coping with salt and metal ions.

In this paper, bioaugmentation was applied to upgrade a full-scale activated sludge system (S2) into a contact oxidation system (S1). Results showed that when chemical oxygen demand (COD) and ammonia nitrogen (NH(4)(+)-N) concentration of the petrochemical wastewater were 320-530 mg/L and 8-25mg/L, respectively, the bioaugmented process (S1) took only 20 days when they were below 80 mg/L and 10mg/L, respectively. However, the unbioaugmented conventional activated sludge process (S2) spent 30 days to reach the similar effluent quality. As the organic loading rate (OLR) increased from 0.6 to 0.9 and finally up to 1.10 kg COD/m(3)d, S1 showed strong resistance to shock loadings and restored after three days compared to the seven days required by S2. Based on the results of this paper, it shows that bioaugementation application is feasible and efficient for the process upgrade due to the availability of the bioaugmented specialized consortia.

Research was investigated about bioflocculants (BFs) used for turbidity removal from kaolin clay solution and raw water based on jar tests. The results show that the elimination efficiency to turbidity from kaolin clay solution by BFs is 84%, over 5-19 mg/L, which is lower than 93% for Al2(SO4)3 and 94% for Fe2(SO4)3. From the variation of Zeta potential and pH, it was demonstrated that coagulation with BFs was governed by bridging flocculation. It was also observed that the addition of a small amount of inorganic salts (Fe or Al) could substantially enhance the coagulation efficiency. It appeared likely that the combined applications of inorganic salts and BFs resulted in an enhancement of charge neutralization and bridging flocculation. The case study shows that the combination of Fe and BFs can effectively eliminate turbidity from raw water at low dosage and neutral pH (by 94.6%). For biodegradable nature of produced sludge and reducing the health risk related to aluminum accumulation, BFs are considered to be a new type of environmental-friendly flocculants.

In the study on denitrification inhibiting sulfate reducing bacterium, it was discussed for the influence of 16S rDNA target sequence from different primers on DGGE fingerprinting from the anaerobic active sludge diversity in ABR reactor. The sludge DNA in the reactor was isolated, four sets primers 341F/534R, 968F/1401R, 63F/534R, and 341F/926R was used to amplify 16S rDNA, and the resolution of DGGE fingerprinting, community diversity were analyzed. The result indicated that it was beneficial to the DNA extraction from sulfate reducing sludge by PBS washing sludge and sonic oscillation; by analysis of DGGE from different primers, there were obvious differences in community diversity. The target sequences from primers 341F/534R and 968F/1401R were isolated relatively well, that from primers 341F/926R was in common, and that from primers 63F/534R was the worst. The DGGE fingerprinting bands from primers 341F/534R were abundant with the best diversity, while that from 968F/1401R was not as well as the former, that from 341F/926R was in common, and that from 63F/534R was the least with worse diversity than the others. Primers 341F/534R and 968F/1401R are recommended to be used simultaneously to analyze anaerobic active sludge by DGGE.

Biological treatment of nitrate wastewater with aerobic denitrifiers in a bio-ceramic reactor was investigated. And denaturing gradient gel electrophoresis (DGGE) method was used for analyzing the stability of microbial community structure. At the condition of the influent with hydraulic loading 0.75 m/h, gas/water ratio 5:1-10:1, temperature 15-23 degrees C, COD loading rate 1.92-5.98 kg/(m3 x d) and NO3- -N loading rate 0.60-1.34 kg/(m3 x d), high nitrate nitrogen removal of almost 100% and the maximum total nitrogen removal of up to 95.73% were achieved during stable operation stage. In addition, the nitrite concentration of effluent was lower. The PCR-DGGE profiles showed that shift of microbial diversity corresponded to the effect of nitrate removal and the preponderant populations for aerobic denitrification were steady during the test period.

Chinese traditional medicine wastewater, rich in macromolecule and easy to foam in aerobic biodegradation such as Glycosides, was treated by two identical bench-scale aerobic submerged membrane bioreactors (SMBRs) operated in parallel under the same feed, equipped with the same electronic control backwashing device. One was used as the control SMBR (CSMBR) while the other was dosed with powdered activated carbon (PAC) (PAC-amended SMBR, PSMBR). The backwashing interval was 5 min. One suction period was about 90 min by adjusting preestablished backwashing vacuum and pump frequency. The average flux of CSMBR during a steady periodic state of 24 d (576 h) was 5.87 L/h with average hydraulic residence time (HRT) of 5.97 h and that of PSMBR during a steady periodic state of 30 d (720 h) was 5.85 L/h with average HRT of 5.99 h. The average total chemical oxygen demand (COD) removal efficiency of CSMBR was 89.29% with average organic loading rate (OLR) at 4.16 kg COD/(m3 x d) while that of PSMBR was 89.79% with average OLR at 5.50 kg COD/(m3 x d). COD concentration in the effluent of both SMBRs achieved the second level of the general wastewater effluent standard GB8978-1996 for the raw medicine material industry (300 mg/L). Hence, SMBR with electronic control backwashing was a viable process for medium- strength Chinese traditional medicine wastewater treatment. Moreover, the increasing rates of preestablished backwashing vacuum, pump frequency, and vacuum and flux loss caused by mixed liquor in PSMBR all lagged compared to those in CSMBR; thus the actual operating time of the PSMBR system without membrane cleaning was extended by up to 1.25 times in contrast with the CSMBR system, and the average total COD removal efficiency of PSMBR was enhanced with higher average OLR.