Insights into function of hydrocyclone separator and modified volcanic rock coagulant on formation of aerobic granular sludge

Hydrocyclone separator and novel coagulants were adopted to separately enhance the granulating process of aerobic granular sludge. For hydrocyclone separator, although there was no obvious large particle, it was feasible to improve the sludge sedimentation capacity, indicated by the sludge volume index. Moreover, the nitrogen removal performance was promoted by the separator with a nitrogen removal rate of 8.2 mg/(L center dot h), nearly two times of system without a separator. Meanwhile, nitrogen-related microbial communities were stimulated, for example, Thauera and Nitrosomonas. Another method of coagulation by the modified volcanic rock promoted the sludge settling performance. The optimum coagulating conditions were the coagulant size of 100 mu m with dosage of 6 g/L. The addition of polyacrylamide played a weak role in granulation. Overall, the role of hydrocyclone separator and modified volcanic rock coagulant belonged to the improvement of the settleability of sludge and the aggregation of sludge, respectively.

Automated summary

Hydrocyclone separator and modified volcanic rock coagulant were used to enhance the granulation process of aerobic granular sludge separately. The separator improved the sedimentation capacity of sludge and promoted nitrogen removal performance, while stimulating nitrogen-related microbial communities. The modified volcanic rock coagulant enhanced the settling performance of sludge. The addition of polyacrylamide had a weak effect on granulation.