treatment of swine wastewater in aerobic granular reactors： comparison of different seed granules as factors

The granulation process, physic-chemical properties, pollution removal ability and bacterial com- munities of aerobic granules with different feed-waste- water （synthetic wastewater, R1; swine wastewater, R2）, and the change trend of some parameters of two types of granules in long-term operated reactors treating swine wastewater were investigated in this experiment. The result indicated that aerobic granulation with the synthetic wastewater had a faster rate compared with swine waste- water and that full granulation in R 1 and R2 was reached on the 30th day and 39th day, respectively. However, although the feed wastewater also had an obvious effect on the biomass fraction and extracellular polymeric sub- stances of the aerobic granules during the granulation process, these properties remained at a similar level after long-term operation. Moreover, a similar increasing trend could also be observed in terms of the nitrogen removal efficiencies of the aerobic granules in both reactors, and the average specific removal rates of the organics and ammonia nitrogen at the steady-state stage were 35.33mg.g^-1 VSS and 51.46mg.g^-1 VSS for R1, and 35.47mg.g^-1 VSS and 51.72mg.g^-1 VSS for R2, respectively. In addition, a shift in the bacterial diversity occurred in the granulation process, whereas bacterial communities in the aerobic granular reactor were not affected by the seed granules after long-term operation.

Impacts of produced water origin on bacterial community structures of activated sludge

The purpose of this study was to reveal how activated sludge communities respond to influent quality and indigenous communities by treating two produced waters from different origins in a batch reactor in succession. The community shift and compositions were investigated using Polymerase Chain Reaction–denaturing gradient gel electrophoresis（PCR–DGGE） and further16 S ribosomal DNA（r DNA） clone library analysis. The abundance of targeted genes for polycyclic aromatic hydrocarbon（PAH） degradation, nah Ac/phn Ac and C12O/C23 O, was tracked to define the metabolic ability of the in situ microbial community by Most Probable Number（MPN） PCR. The biosystem performed almost the same for treatment of both produced waters in terms of removals of chemical oxygen demand（COD） and PAHs. Sludge communities were closely associated with the respective influent bacterial communities（similarity 〉 60%）, while one sludge clone library was dominated by the Betaproteobacteria（38%） and Bacteriodetes（30%）and the other was dominated by Gammaproteobacteria（52%）. This suggested that different influent and water quality have an effect on sludge community compositions. In addition, the existence of catabolic genes in sludge was consistent with the potential for degradation of PAHs in the treatment of both produced waters.

Preparation and characterization of a novel microorganism embedding material for simultaneous nitrification and denitrification

A novel microorganism embedding material was prepared to enhance the biological nitrogen removal through simultaneous nitrification and denitrification. Polyvinyl alcohol （PVA）, sodium alginate （SA） and cyclodextrin （CD） were used to compose gel bead with embedded activated sludge. The effects of temperature, CD addition and concentrations of PYA and SA on nitrogen removal were evaluated. Results show that the gel bead with CD addition at 30℃contributed to the highest nitrogen removal efficiency and nitrogen removal rate of 85.4% and 2.08 mg·（L·h）^-1, respectively. Meanwhile, negligible NO3^- and NO2^- were observed, proving the occurrence of simultaneous nitrification and denitrification. The High-Throughput Sequencing confirms that the microbial community mainly contained Comamonadaceae in the proportion of 61.3%. Overall, CD increased gel bead＇s porosity and resulted in the high specific endogenous respiration rate and high nitrogen removal efficiency, which is a favorable additional agent to the traditional embedding material.