Enhanced aerobic granulation for treating low-strength wastewater in an anaerobic-aerobic-anoxic sequencing batch reactor by selecting slow-growing organisms and adding carriers

Dongbo Liang; Wei Guo; Dongyue Li; Fan Ding; Peilin Li; Zhaoming Zheng; Jun Li

doi:10.1016/j.envres.2021.112547

Enhanced aerobic granulation for treating low-strength wastewater in an anaerobic-aerobic-anoxic sequencing batch reactor by selecting slow-growing organisms and adding carriers

Environ Res. 2022 Apr 1:205:112547. doi: 10.1016/j.envres.2021.112547. Epub 2021 Dec 10.

Authors

Dongbo Liang¹, Wei Guo¹, Dongyue Li¹, Fan Ding¹, Peilin Li¹, Zhaoming Zheng¹, Jun Li²

Affiliations

¹ Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100124, China.
² Key Laboratory of Beijing for Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing, 100124, China. Electronic address: bjutlijun@126.com.

PMID: 34902378
DOI: 10.1016/j.envres.2021.112547

Abstract

The aerobic granular sludge (AGS) process is a promising technology for wastewater treatment. However, a long start-up period for granulation and instability during long-term operation still hinder the application of AGS technology, especially for low-strength wastewater. To solve these two problems, this study tested a novel strategy involving the selection of slow-growing organisms and the addition of carriers in an anaerobic-aerobic-anoxic sequencing batch reactor (AN/O/AX_SBR). Three identical AN/O/AX_SBRs (R_Ctrl, R_CCM, and R_GAC), fed with low-strength wastewater, were operated for 120 days. R_Ctrl had no carriers, R_CCM contained cell culture microcarriers (CCM), and R_GAC contained granular activated carbon (GAC). Mature AGS was achieved within 80 days in all reactors. The carriers could reduce the maturation period of AGS by approximately 10 days (76, 66, and 69 days in R_Ctrl, R_CCM, and R_GAC, respectively) and improve the physical strength of the AGS. AGS showed a strong structure without excessive proliferation of filamentous bacteria, full-grown size (900-1100 μm), and good settleability (SVI₅ was 15.4-19.4 mL/g). Microbiological analysis showed that AN/O/AX_SBRs can provide a metabolic selective pressure to select slow-growing organisms such as nitrifying bacteria (norank_f__NS9_marine_group, Ellin6067, and Nitrospira), glycogen and phosphorus accumulating organisms (GAOs: Candidatus_Competibacter and Defluviicoccus; PAOs: Candidatus_Accumulibacter and Flavobacterium). All reactors showed good performance for simultaneous nitrification, endogenous denitrification, and phosphorus removal. The removal efficiencies of total nitrogen and total phosphorous were above 70% and 80%, respectively. The cycle test showed intermediate PAO-GAO metabolism prevailed in the system, and endogenous denitrification was primarily carried out by denitrifying GAOs.

Keywords: Aerobic granular sludge; Carriers; Granulation; Low-strength wastewater; Metabolic selective pressure; Stability.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anaerobiosis
Bioreactors / microbiology
Nitrogen / analysis
Phosphorus / metabolism
Sewage / microbiology
Waste Disposal, Fluid*
Wastewater* / chemistry

Substances

Sewage
Waste Water
Phosphorus
Nitrogen