Rapid cultivation of aerobic granule for the treatment of solvent recovery raffinate in a bench scale sequencing batch reactor

• A novel rapid cultivation of aerobic granule was introduced.
• The feasibility of aerobic granule treating real high C/N ratio chemical wastewater was investigated.
• Mechanism of rapid granulation was explored.

Aerobic granular sludge (AGS) was cultivated in a bench scale sequencing batch reactor within 21 days. Strategy of the rapid startup was inoculated with part of mature AGS during cultivation, while aerobic biological selector was implemented for the inhibiting outgrowth of filamentous bacteria and fast selection of zoogloea bacteria. Then, the cultivated AGS was employed for the treatment of solvent recovery raffinate. Stable AGS was successfully domesticated after 55 days under strategy of gradually increase the proportion of real wastewater in influent. The domesticated AGS was orange, irregular shape, smooth and compact. SVI, SV30/SV5, MLVSS/MLSS, EPS, PN/PS, average particle size, granulation rate, (SOUR)H and (SOUR)N of AGS were 19.06 mL/g, 0.97, 0.55, 30.05 mg/g MLVSS, 1.10, 1.28 mm, 98.87%, 32.47 and 7.97 mg O2/h g VSS respectively. Finally, COD, TIN, NH4+–N and TP of the effluent were lower than 25.9 mg/L, 1.64 mg/L, 1.13 mg/L and 0.21 mg/L, and their removal rate was more than 98.43%, 97.12%, 98.02% and 98.09% respectively. Thus, COD, TP removal, nitrification and denitrification were realized in a single bioreactor. The result indicated that the feasibility of AGS for high C/N ratio industrial wastewater treatment.

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