BAOWen-ting,ZHUYang,DONGWen-ming,et al.Aerobic Granulation and Ecological Succession in a Periodically Stirred SBR with Low Height to Diameter Ratio[J].China Water & Wastewater,2024,40(15):83-92.
Aerobic Granulation and Ecological Succession in a Periodically Stirred SBR with Low Height to Diameter Ratio
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第40卷
Number:
第15期
Page:
83-92
Column:
Date of publication:
2024-08-01
- Keywords:
- mixing mode; SBR with low height to diameter ratio; tomato sauce wastewater; aerobic granular sludge; high-throughput sequencing
- Abstract:
- The culture mode, substrate composition and reactor design for aerobic granulation have an impact on the physical and biological characteristics as well as mass transfer efficiency of the granules, consequently influencing the decontamination efficiency. Utilizing tomato sauce wastewater as the substrate, in conjunction with biophase diagnosis and high-throughput sequencing technology, the development of aerobic granular sludge under continuous and intermittent stirring modes at low superficial gas velocity was investigated in an aerobic blast aeration SBR with H/D ratios of 2.5 (P reactor) and 4.4 (S reactor), respectively. The rotational shear stress induced by the mixer was quantitatively calculated to determine the most suitable stirring speed. The two types of reactors with low height to diameter ratio were successfully consecutively granulated under horizontal stirring. However, the mean particle size of mature granules in the continuous stirring SBR (H2 /D2 of 4.4) was 714 μm, which was less than 1.25 mm in the intermittent stirring SBR (H1 /D1 of 2.5), and the granules formed in the former were predominantly reddish brown. When the shear stress of P and S reactors was within the ranges of 0.159-0.186 N/m2 and 0.188-0.247 N/m2, respectively, the granules tended to become more rounded and denser as the shear strength increased. Beyond this range, excessive shear stress caused large granules to disintegrate into sheets. After achieving stable operation, the presence of dominant microorganisms such as Epistylis, Vorticella and rotifer was observed, indicating favorable effluent quality. High-throughput sequencing revealed an increase in microbial diversity under both continuous and intermittent stirring conditions. The Shannon index of P and S reactors increased from 3.90 to 5.08 and 4.70, respectively. However, the denitrification and phosphorus removal bacteria were more dominant in the intermittent stirring condition. The granular sludge with good performance could be achieved in the reactor with a low height to diameter ratio through a specific combination of blast aeration.
Last Update:
2024-08-01