[Start-up, formation and microbial community analysis of aerobic granules in SABR for treatment of organic wastewater containing aniline and chloroanilines].

The granulation of aerobic sludges for high-rate biodegradation of organic wastewater containing aniline and chloroanilines was investigated in a laboratory-scale sequencing airlift bioreactor ( SABR). Aerobic granules were observed in 15 days after start-up in SABR. After subsequent 83 days, SABR was operated sequentially in superficial air velocity of 2.4cm/s, COD loadings of 1.0-3.6kg/(m3 x d) and (chloro-) anilines loadings increased stepwise to 1kg/(m3 x d), a steady-state performance of aerobic granular SABR was achieved at last, as evidenced by high and stable COD and (chloro-) anilines removal efficiencies of above 90% and 99.9%, respectively. Mature granules with median size of 0.45-2.5mm, minimal settling velocity of 62. 1m/h, and SVI of 56mL/g were developed. Aerobic granular sludge displayed noteworthy SOUR, specific (chloro-) anilines degradation rates, PN content and PN/PS ratio in EPS extracts as 154mgDO/(gVSS x h), 0.18g/(gVSS x d), 28.0 +/- 1.9mg/gVSS and 6.5mg/mg respectively, indicating that they had high activity and ability to withstand high (chloro-) anilines loadings. Phylogenetic analysis of (chloro-) anilines-degrading aerobic granules indicated that beta-, gamma-Proteobacteria and Flavobacteria were dominant classes and the predominance bacteria were closely related to Pseudomonas sp. and Flavo-bacterium sp. Compared to chloroanilines-degrading aerobic granules, the population diversity was higher in the aniline and chloroaniline-degrading aerobic granules.

[Research advance in aerobic sludge granulation for wastewater biological treatment].

The fundamentals and applications of aerobic sludge granulation technology in wastewater biological treatment are reviewed. The aspects discussed include the general characteristics and microbial structure of aerobic granules, major factors influencing granulation, models of sludge granulation, and their applications. This review is hoped to elucidating a unified interpretation of the formation of aerobic granules under various operation conditions. Aerobic granules are self-immobilized aggregates of bacteria and have a regular and smooth round shape, compact microbial structure and good settling ability. Granulation is depending on the composition and loading of the substrate, appropriate hydraulic selection pressure and operation condition.

[Study on the oxygen condition in subsurface flow wetlands in operation].

Horizontal flow wetlands with various kinds of plants grown were studied on their operation characteristics and oxygen condition in treating the sewage out from the primary sedimentary basin. The rules of oxygen condition changed with space and time were studied. Researches showed the oxygen concentration was low in wetlands, and it appeared as a rule that low in both ends, but high in middle of beds. It descended in upright direction. The oxygen concentration changed with seasons as summer > spring > autumn > winter. In one day, the highest oxygen concentration appeared on 14:00, and the concentration was higher in forenoon than afternoon. Reed > canna > camellia > dracaena sanderiana > ipomoea aquatica forsk by comparison of ability of oxygen supply. Experiments demonstrate that the study of oxygen condition in constructed wetlands is propitious to reveal the purifying mechanism of wetlands and improve the purifying efficiency.