Effect of seed sludge on characteristics and microbial community ofaerobic granular sludge

Aerobic granular sludge was cultivated by using di erent kinds of seed sludge in sequencing batch airlift reactor. The influence ofseed sludge on physical and chemical properties of granular sludge was studied; the microbial community structure was probed by usingscanning electron microscope and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). The results showedthat seed sludge played an important role on the formation of aerobic granules. Seed sludge taken from beer wastewater treatmentplant (inoculum A) was more suitable for cultivating aerobic granules than that of sludge from municipal wastewater treatment plant(inoculum B). Cultivated with inoculum A, large amount of mature granules formed after 35 days operation, its SVI reached 32.75mL/g, and SOUR of granular sludge was beyond 1.10 mg/(g min). By contrast, it needed 56 days obtaining mature granules usinginoculum B. DGGE profiles indicated that the dominant microbial species in mature granules were 18 and 11 OTU when inoculum Aand B were respectively employed as seed sludge. The sequencing results suggested that dominant species in mature granules cultivatedby inoculum A were Paracoccus sp., Devosia hwasunensi, Pseudoxanthomonas sp., while the dominant species were Lactococcusra nolactis and Pseudomonas sp. in granules developed from inoculum B.