Algal-bacterial Granular Sludge Research Articles

Evaluating the role of carbon sources on the development of algal-bacterial granular sludge: From sludge characteristics, extracellular polymer properties, quorum sensing, and microbial communities

This study investigated the effect of dissolved organic matter (DOM) and particulate organic matter (POM) on the formation process of algal-bacterial granular sludge (ABGS). The results showed that compared with DOM, POM accelerated biomass growth and improved the settling performance of the sludge. However, concerning pollutant removal, ABGS cultured with DOM exhibited high TN and TP removal efficiency. The analysis of extracellular polymeric substances (EPS), indicated that the presence of POM primarily facilitated the production of loosely bound EPS (LB-EPS), whereas the presence of DOM promoted the secretion of tightly bound EPS (TB-EPS). Notably, carbon sources influenced the secretion of different signal molecules. ABGS cultured with POM exhibited higher concentrations of 3-oxo-C8-HSL than that cultivated with DOM, while DOM resulted in the production of more C8-HSL and C6-HSL. Microbial communities analysis revealed that the dominant bacteria in the mature ABGS cultured with different carbon sources were Plasticicumulans, while the predominant algal genus displayed notable diversity. Further investigations into functional genes suggested that the nitrification process (hao) and the denitrification process (nir, nar) were greatly enhanced in the presence of DOM. This study reveals the mechanism of carbon source types and ABGS formation, providing valuable guidance for the treatment of municipal wastewater with high POM proportion.

Formation and adaptation of algal–bacterial granular sludge in real Chinese liquor brewing wastewater treatment

The intricate pollutant composition and pronounced water fluctuations of Chinese liquor brewing wastewater (CLBW) pose formidable challenges for effective treatment, thereby raising significant environmental concerns. This study for the first time delves into the exploration of algal–bacterial granular sludge (ABGS) development and its efficacy in the removal of organic matter and nitrogen and phosphorus over a 100–day investigation of real CLBW treatment. Mature ABGS emerged after approximately 40 days of treating wastewater with 20% real CLBW, exhibiting exceptional settling performance and significant removal of COD (86.2%), NH4+–N (98.0%), and TP (51.5%). As the real CLBW proportion increased to 40% or higher, a stable granular structure and excellent settleability persisted, primarily attributed to the consistent content of tightly bound extracellular polymeric substances, the sustained protein–to–polysaccharide ratio, and the proliferation of microalgae within the granules. Microbial community analysis revealed the dominance of microalgal species, including Sphaeropleales, Scenedesmaceae, and Chloromonas. Moreover, the observed decline in nitrification efficiency with increasing CLBW ratio was linked to reductions in Nitrosomonas and Nitrospira populations. Conversely, the recovered TN removal was primarily associated with the accumulation of denitrifiers, including Azoarcus and Thauera, especially when the real CLBW ratio reached 100%. The findings from this study are anticipated to offer a practical reference for optimizing and promoting the treatment of real CLBW.

New Insight into the Performance and Self-Defensive Responses of the Algal–Bacterial Granular Sludge Process under Cr(VI)-Induced Stress

Algal–bacterial granular sludge, a new biological technology, has been widely recognized due to its highly effective pollutant treatment and energy efficiency. This study investigated the effects of environmental concentrations of Cr(VI) (0.5–2.5 mg/L) on the performance of algal–bacterial granular sludge and self-defensive responses after 90 days of cultivation. The results showed that Cr(VI) affected chemical oxygen demand (COD) decrease, ammonia-N and phosphate removal, with different trends being apparent. A linear decline in COD decrease was observed, whereas an initial decrease and then increase in ammonia-N and phosphate removal took place. Algal–bacterial granular sludge effectively removed Cr(VI) from wastewater through biological adsorption and reduction, showing the potential to treat Cr(VI)-contaminated wastewater. Cr(VI) affected the community abundance of the algal–bacterial granular sludge, in which Chlorophyceae and cyanobacteria were vulnerable under Cr(VI)-induced stress. To reduce the toxicity of Cr(VI), over-produced EPS-PN and antioxidant enzymes (MDA, SOD and CAT) acted as self-defensive responses to resist oxidative damage. This study aimed to conduct a comprehensive environmental sustainability assessment of the algal–bacterial granular sludge process in treating municipal wastewater containing Cr(VI). It is hoped that this study can provide useful information for improved engineering feasibility of algal–bacterial granular sludge.

Over-Produced Extracellular Polymeric Substances and Activated Antioxidant Enzymes Attribute to Resistance of Pb(II) for Algal–Bacterial Granular Sludge in Municipal Wastewater Treatment

Algal–bacterial granular sludge technology is a new type of wastewater treatment and resource regeneration process, which has received widespread attention due to its excellent nitrogen and phosphorus removal performance, and energy-saving and emission reduction effects. Although algal–bacterial granular sludge technology has achieved an ideal nutrient removal ability, some pol-lutants in wastewater might affect the symbiotic relationship between algae and bacteria. This study investigated the impact of coexisting Pb(II) on the symbiosis of algal–bacterial granular sludge. It was found that 2.5–10.0 mg/L of Pb(II) exposure increased the relative abundance of Pro-teobacteria. In addition, more protein in extracellular polymeric substances (EPS-PN) was secreted at 2.5 mg/L of Pb(II) exposure while EPS-PN content reduced at a rate of 5.0–10.0 mg/L of Pb(II). Under different concentrations of Pb(II), the damage degree of algal–bacterial granular sludge was exacerbated, evidenced by increased malondialdehyde (MDA) content. To cope with these adverse circumstances, the antioxidant enzyme activity of both super-oxide dismutase (SOD) and peroxidase dismutase (CAT) was boosted. With the help of these adaptive strategies, the symbiosis of algal–bacterial granular sludge was stable. Moreover, the performance of algal–bacterial granular sludge in treating COD, ammonia-N and phosphate-P was kept at above 95%. This study approved that a Pb(II) concentration less than 10.0 mg/L had little effect on the performance of algal–bacterial granular sludge in wastewater treatment. It is hoped that this study can provide useful information for an improved engineering feasibility of algal–bacterial granular sludge process.

Algal-bacterial granular sludge for simultaneous denitrification and yttrium removal

This study investigated the performance and stability of algal-bacterial granular sludge (ABGS) for the treatment of inorganic wastewater containing ammonia and Y(III), which aimed to shed light on efficient treatment of yttrium-rich rare earth mine wastewater. By seeding heterotrophic granules and dosing exogenous algae, cationic polyacrylamide and sodium acetate in a photo-sequencing batch reactor, the algal and granular symbiosis system was successfully established on Day 50, and mature ABGS was harvested on Day 165. When the concentration of Y(III) was no more than 4 mg/L, the system showed good performance for simultaneous removal of nitrogen and Y(III). However, further increasing the Y(III) concentration to 30 mg/L in Days 144–210 gradually inhibited the bacterial activity and killed most of the functional algae, resulting in significant decrease of the activity of bacteria and chlorophyll a content after Days 135 and 180, as well as the oxygen yield rate of the algae and ammonia oxidation rate after Days 140 and 95. The removal efficiency of total inorganic nitrogen maintained mostly above 90% in Days 46–153, and gradually decreased to approximately 50% in Days 154–210. The Y(III) removal efficiency remained above 98% in Days 96–125, and gradually decreased to approximately 60% in Days 126–210. Most of the algal genera disappeared on Day 210. Conversely, the increase of the relative abundance of Nitrosomonas and Thauera was observed. The nitrogen removal pathways included denitrification and algal assimilation. However, the contribution rate of algae gradually decreased from 22% to 4% due to the accumulation of Y.

Effect of different inocula on the granulation process, reactor performance and biodiesel production of algal-bacterial granular sludge (ABGS) under low aeration conditions

The algal-bacterial granular sludge (ABGS) system is a prospective wastewater treatment technology, but few studies focused on the effects of different inoculum types on the establishment of the ABGS system under low aeration conditions (step-decrease superficial gas velocity from 1.4 to 0.5 cm/s). Results from this study indicated that compared with other inocula, the ABGS formed by co-inoculating aerobic granular sludge (AGS) and targeted algae (Chlorella) exhibited a shorter granulation period (shortened by 15 days), higher total nitrogen (89.4%) and PO43--P (95.0%) removal efficiencies, and a greater yield of fatty acid methyl esters (FAMEs) (9.04 mg/g MLSS). This was possibly attributed to that the functional bacteria (e.g. Thauera, Gemmobacter and Rhodobacter) in the inoculated AGS facilitated the ABGS granulation. The inoculated algae promoted their effective enrichment under illumination conditions and enhanced the production of extracellular polymeric substances, thus improving the stability of ABGS. The enriched algae were attached to the outer layer of the granules, which could provide sufficient oxygen for bacterial metabolism, revealing the inherent mechanisms for the good stability of ABGS under low aeration intensity. Overall, the rapid granulation of ABGS can be achieved by inoculating optimal inocula under low aeration conditions, which is convenient and economically feasible, and motivates the application of algal-bacterial consortia.

Settling velocity of algal-bacterial granular sludge studied in the sequence batch reactor

Granule settling velocity is critical to biosolids-liquid separation. The settling velocity of algal-bacterial granules versus the diameter of granules was examined as a function of granule diameter in the sequence batch reactor in eleven days of cultivation. Despite granules having an apparently compact and rounded shape and considerable scatter of the data, the results never showed granules are homogeneously dense packed structures in the range of 10 μm to 1.0 mm in diameter. The settling velocity increases with granule size. The estimated fractal dimension was always less than two. The result was interpreted as forming heterogeneous compact layered structures in the shell from the early stage of cultivation rather than rearrangement from a bulk floc into a dense structure. Additional analysis for the cultivation of 150 days confirmed the considerable growth of size and fluffy hair. However, the settleability of small fragments remained relatively the same as heterogeneous compact structures.

Nitrogen reclamation from aquaculture wastewater as potential fish feed additives via bacterial and algal-bacterial granular sludge systems

In this study, the potentials of aerobic granular sludge (AGS) and algal-bacterial granular sludge (ABGS) systems for the recovery of nitrogen from aquaculture wastewater as protein-rich fish feed additive were assessed. During 88 days' cultivation, the average chemical oxygen demand (COD), total phosphorus (TP) and total inorganic nitrogen (TIN) removal efficiencies were determined to be 96.7 %, 75.7 %, and 73.2 % in the AGS system, 96.8 %, 82.5 %, and 76.6 % in the ABGS system, respectively. The net biomass yield of ABGS was 24.0 % higher than that of AGS. About 11.3 % and 14.1 % of the TIN in wastewater were recovered as organic nitrogen in AGS and ABGS, respectively. The two granules had a similarly high content of total proteins (52 %, dry matter based), both containing 9 essential amino acids for fish and 7 non-essential amino acids, these features enabled them to serve as a low-cost substitute for conventional protein-rich additives in the fish diets.

A novel membrane bioreactor inoculated with algal-bacterial granular sludge for sewage reuse and membrane fouling mitigation: Performance and mechanism

In this study, a novel membrane bioreactor (MBR) inoculated with algal-bacterial granular sludge (ABGMBR) was established to improve pollutant removal and alleviate membrane fouling. The ABGMBR system showed higher pollutant removal rate and longer operation time (152 day) compared to the control MBR (AGMBR). Moreover, the contents of the pollutants such as granular sludges, extracellular polymeric substances (EPS), and soluble microbial products on the membrane were remarkably reduced, leading to the formation of a porous and loose cake layer on the membrane and a slow increase in transmembrane pressure. Standard blocking was the main mechanism of membrane fouling; however, the membrane pore blockage was significantly reduced in ABGMBR. The extended Derjaguin-Landau-Verwey-Overbeek (XDLVO) theory suggested that the aggregation and adhesion of foulants on the membrane were greatly inhibited in ABGMBR. Furthermore, correlation analysis showed significant differences in membrane fouling characteristics between AGMBR and ABGMBR. The ABGMBR system effectively retarded sludge disintegration and increased the repulsion between the sludge and membrane owing to the favorable mixed liquor characteristics. This study showcases the superior operational efficiency and anti-fouling performance of ABGMBR, offering a novel perspective on sewage reuse and membrane fouling mitigation.

Analysing the influence of operating conditions on the performance of algal–bacterial granular sludge processes for wastewater treatment: A review

AbstractThis article discussed the effect of the main operating parameter involved in the operation of algal–bacterial granular sludge (ABGS) systems as promising biological processes for wastewater treatment. The focus was on the operational ranges reported in the literature capable of achieving better granule properties, good stability and high removal capacities. This review identified that hydraulic retention time (HRT), light intensity (LI) and light/dark periods were the most influential operating factors on the formation, stability, settleability and organic pollutant removal efficiency of ABGS. The discussion argued that ABGS systems enhance industrial and domestic wastewater treatment due to additional advantages that provide the symbiotic interactions to process performance, maintaining lesser operating costs concerning aerobic granular sludges (AGS) and microalgae consortia. This review will improve the understanding of the operation of ABGS systems and thus further expand possible operating combinations that help to enhance microbial interactions, microalgae growth and external aeration self‐sufficiency in further research with a focus on its scaling up.

The role of light wavelengths in regulating algal-bacterial granules formation, protein and lipid accumulation, and microbial functions

High value-added products recovery from algal-bacterial granular sludge (ABGS) has received great attention recently. This study aimed to explore the role of different light wavelengths in regulating granule formation, protein and lipid production, and microbial functions. Bacterial granular sludge (BGS, R0) was most conducive to forming ABGS under blue (R2) light with the highest chlorophyll a (10.2 mg/g-VSS) and diameter (1800 μm), followed by red (R1) and white (R3) lights. R0-R3 acquired high protein contents (>164.8 mg/g-VSS) with essential amino acids above 44.4%, all of which were suitable for recycling, but R2 was the best. Also, blue light significantly increased total lipid production, while red light promoted the accumulation of some unsaturated fatty acids (C18:2 and C18:3). Some unique algae and dominant bacteria (e.g., Stigeoclonium, Chlamydomonas, and Flavobacteria) enrichment and some key functions (e.g., amino acid, fatty acid, and lipid biosynthesis) up-regulation in R2 might help to improve proteins and lipids quality. Combined, this study provides valuable guidance for protein and lipid recovery from ABGS.

Cultivation of algal-bacterial granular sludge and degradation characteristics of tetracycline.

Due to the increasing use of antibiotics, tetracycline was frequently detected in wastewater. As a novel technology, algal-bacterial granular sludge process is expected to be widely used in wastewater treatment. However, the degradation effect of tetracycline by algal-bacterial granular sludge process and its degradation path is still unknown. In this study, mature and stable algal-bacterial granular sludge was cultured and the degradation of tetracycline by it was investigated. The results showed that the removal amount of 1~25 mg/L tetracycline by algal-bacterial granular sludge was 0.09~1.45 mg/g VSS, in which the adsorption amount was 0.06~0.17 mg/g VSS and the degradation amount was 0.03~1.27 mg/g VSS. Tetracycline biosorption was dominant at its concentration of 1~3 mg/L, while biodegradation was predominant at 5~25 mg/L of tetracycline. At tetracycline concentration of 3~5 mg/L, the contribution of biosorption and biodegradation to tetracycline removal by algal-bacterial granular sludge process was almost equal. Algal-bacterial granular sludge could effectively degrade tetracycline through demethylation, dehydrogenation, deacylation and deamination or their combination. In addition, the degradation products were non-toxic and hardly pose a threat to environmental health. The research results of this paper provide a solid theoretical basis for tetracycline removal by algal-bacterial granular sludge, and a reference for the development of algal-bacterial granular sludge process for wastewater treatment in the presence of tetracycline.

Rapid establishment of algal-bacterial granular sludge system by applying mycelial pellets in a lab-scale photo-reactor under low aeration conditions: Performance and mechanism analysis

Light-driven algal-bacterial granular sludge (ABGS) is an innovative low-carbon technology with significant merits in treating municipal wastewater, but how to shorten the photogranulation process, especially under low aeration conditions, is largely unknown. Herein, two strategies were proposed to accelerate the start-up of the ABGS system in photo-sequencing batch reactors (PSBRs) with a low superficial gas velocity of 0.5 cm/s. Compared to directly dosing mycelial pellets (MPs), applying MPs to flocculate algae and using the formed algal-mycelial pellets (AMPs) as carriers enhanced the establishment of the algal-bacterial symbiosis. The ABGS system developed rapidly within 20 days, with a large particle diameter (mean diameter of 321 μm) and excellent settleability (SVI30 of 55.4 mL/g). More importantly, this system could be stably operated for at least 100 days, mainly attributed to the reinforced secretion of protein with unique secondary structure and elevated hydrophobic functional groups. As for the reactor performance, the average removal efficiencies of the ABGS system were 97.8% for organic matter, 80.0% for total nitrogen, and 84.4% for phosphorus. The enrichment of functional bacteria and algae, and the up-regulation of functional genes and enzymes involved in electron production and transport processes likely drove the transformation of the pollutants, underlining the inherent mechanism for the excellent nutrient removal performance. This study provides a promising approach to solve the problem of a long ABGS start-up period and unstable granular structure under low aeration conditions, which is significant for achieving effective wastewater treatment without energy intensive aeration.

Resistance and adaptation of mature algal-bacterial granular sludge under salinity stress

The study investigated the response characteristics of algal-bacterial granular sludge (ABGS) under salinity stress (0 % → 2 %). At 1 % salinity, the sludge performance was inhibited, while recovered rapidly, indicating the ABGS exhibited resistance. However, at 2 % salinity, the suppressed performances did not recover until the stress was eliminated. Under salinity stress, the nutrient removal capacity of the system and the composition and chemical characteristics of extracellular polymers substances also changed. Meanwhile, the ABGS formed adaptation to salinity stress in the early coping process. As a result, the effect of the second 2 % salinity on ABGS was significantly weakened. High-throughput sequencing results showed that the microbial community in ABGS shifted under salinity stress, and the halophilic bacteria genera Arcobacter, Denitromonas, Azoarcus, etc. were enriched, which might be the genetic basis of the adaptation.

Evaluating the role of algae in algal-bacterial granular sludge: Nutrient removal, microbial community and granular characteristics

Algal-bacterial granular sludge (ABGS) and bacterial granular sludge (BGS, control group) were operated over 240 days to investigate the role of algae in treating synthetic municipal wastewater. The results showed that algae significantly improved the removal efficiency of total nitrogen (TN). The nitrogen removal load of ABGS was 2.6 mg-N/g-VSS/day (22.8 %, light) and 1.1 mg-N/g-VSS/day (9.6 %, dark) higher than that of BGS, respectively, which was attributed to algae enhanced NH3-N removal capacity in the anaerobic stage and increased the utilization efficiency of organics in denitrification. Algae increased the relative abundance of denitrifying bacteria, and ABGS (28.83 %) was higher than BGS (14.28 %). Moreover, the dominant phylum of algae was Chlorophyta (98.39 %), the chlorophyll-a was sustained at 1.28 ± 0.26 mg/g-VSS. Algae significantly increased the content of extracellular polymeric substances (EPS), and the increased polysaccharide came from the tightly bound EPS. This study expands the understanding of the role of algae in ABGS.

Deciphering the effect of algae sources on the formation of algal-bacterial granular sludge: Endogenous versus exogenous algae

As a key factor affecting the granulation of symbiotic sludge , the evaluation of the influence of algae sources on the ABGS system is expected to further optimize the cultivation of ABGS. In this study, formation of algal-bacterial granular sludge (ABGS) cultivated with endogenous algae and exogenous algae was comparatively investigated. During ABGS formation, the presence of algae facilitated the settleability improvement and biomass growth. ABGS cultivated with endogenous algae achieved a faster granulation (39 days) than that with exogenous algae (46 days). Inoculating exogenous algae could significantly improve the nutrient removal efficiency at the start-up stage. Tightly-bound extracellular polymeric substances (TB-EPS) were crucial for ABGS formation and maintenance, especially protein (PN) components. More EPS enriched in the mature ABGS enhanced by endogenous algae. The spatial distribution of protein and α-D-glucopyranose was obviously affected by algal sources. During ABGS formation, there was a directional selection in algal species , and the operation condition of the system was the key factor affecting the structure of algae community. The effect of algae sources on the bacterial community structure of ABGS took time to manifest. Correlation analysis showed that endogenous algae contributed more to the metabolism and property improvement of sludge than exogenous algae. • ABGS cultivated by the endogenous algae achieved a faster granulation. • Inoculating EX-A obviously improved the nutrient removal at the initial stage. • Mature ABGS cultivated with endogenous algae could secrete more EPS. • Algae source was not the dominant factor in determining the algal community in ABGS. • The genes related to metabolism were more enriched by endogenous algae in mature ABGS.

Microalgae simultaneously promote antibiotic removal and antibiotic resistance genes/bacteria attenuation in algal-bacterial granular sludge system

This study investigated the effects of microalgae growth on antibiotic removal and the attenuation of antibiotic resistance genes (ARGs)/ARGs host bacteria in algal-bacterial granular sludge (ABGS) system. In the presence of tetracycline (TC) and sulfadiazine (SDZ) mixture (2–4 mg/L), microalgae could grow on bacterial granular sludge (BGS) to form ABGS, with a chlorophyll-a content of 7.68–8.13 mg/g-VSS being achieved. The removal efficiencies of TC and SDZ by ABGS were as high as 79.0 % and 94.0 %, which were 4.3–5.0 % higher than those by BGS. Metagenomic analysis indicated that the relative abundances of TC/SDZ- related ARGs and mobile genetic elements (MGEs) in BGS were 56.1 % and 22.1 % higher than those in ABGS. A total of 26 ARGs were detected from the granules, and they were identified to associate with 46 host bacteria. 13 out of 26 ARGs and 13 out of 46 hosts were shared ARGs and hosts, respectively. The total relative abundance of host bacteria in BGS was 30.8 % higher than that in ABGS. Scenedesmus and Chlorella were the dominant microalgae that may reduce the diversity of ARGs hosts. Overall, ABGS is a promising biotechnology for antibiotic-containing wastewater treatment.

Light-introduced partial nitrification in an algal-bacterial granular sludge bioreactor: Performance evolution and microbial community shift

This objective of study was to evaluate the influence of light on the achievement of partial nitrification algal-bacterial granular bioreactor and its related nitrite accumulation mechanism. After 150-days operation, partial nitrification algal-bacterial granulation bioreactor was achieved under the 200 μmol/(m2·s) illuminance condition. The effluent NH4+-N, NO2–-N, NO3–-N concentrations were average at 1.1, 61.7 and 8.0 mg/L (n = 21), respectively. The average sphericity of algal-bacterial aerobic granular sludge (AB-AGS) increased from 82.7% to 91.1%, accompanied by the significantly increased diameter. Additionally, extracellular protein increased by 1.5 times and 0.5 times higher in LB-EPS and TB-EPS of AB-AGS, respectively. According to typical cycles, N2O emission amount reactor accounted for 2.4% of the removed nitrogen. Under the combined inhibition of light and free ammonia (FA), Nitrosomonas-related AOB (0.2% to 2.1%) were the predominant functional bacteria, whereas Nitrospira-related NOB (0.07% to below 0.01%) was fully inhibited.

Revealing the influencing mechanisms of polystyrene microplastics (MPs) on the performance and stability of the algal-bacterial granular sludge

Algal-bacterial granular sludge (ABGS) is an energy-saving and environment-friendly wastewater treatment technology; however, the effects of microplastics (MPs) on the performance and stability of the ABGS system remain unknown. Herein, the influencing mechanisms of polystyrene MPs (50 μm) on the ABGS were systematically investigated. The ABGS exhibited a high removal efficiency of MPs (over 96%) at 1 mg/L and 20 mg/L. Although the biomass content, sludge settling and particle size were not obviously affected by MPs, the COD and total phosphorus (TP) removal efficiencies were inhibited by 2.6%-4.1% and 2.9%-5.8%, respectively. Meanwhile, the structural stability of ABGS was damaged by MPs, owing to the excessive oxidative stress, low content of protein-like substance (especially tryptophan and tyrosine), and the large portion of loose protein secondary structure. Microbial community analysis revealed that the relative abundance of some functional bacteria (Candidatus_Competibacter and Rhodobacter) and algal species (Tetradesmus) were decreased under the MPs stress.

A novel strategy for rapid development of a self-sustaining symbiotic algal-bacterial granular sludge: Applying algal-mycelial pellets as nuclei

Algal-bacterial granular sludge (ABGS) is a promising technology for wastewater treatment, benefiting from the synergetic interactions between algae and bacteria. However, the rapid start-up of the ABGS system is not trivial. Herein, a novel strategy was proposed by applying the algal-mycelial pellets (AMPs) as the primary nuclei for accelerating the development of a self-sustaining symbiotic ABGS system. The results indicated that by using this strategy complete granulation was shortened to 12 days, much shorter than the control system without AMPs dosage (28 days). The ABGS had a large particle diameter (3.3 mm), compact granular structure (1.0253 g/mL), and excellent settleability (SVI30 of 53.2 mL/g). Moreover, 98.6% of COD, 80.8% of TN and 80.0% of PO43−-P were removed by the ABGS. The nuclei of targeted algae (Chlorella) and filamentous fungi (Aspergillus niger), the enhanced production of extracellular polymeric substances (especially proteins) and the enrichment of functional bacteria (such as Neomegalonema and Flavobacterium) facilitated the granules development. The low surface free energy (-69.56 mJ/m2) and energy barrier (89.93 KT) were the inherent mechanisms for the strong surface hydrophobicity, the easy bacterial adhesion, and the short granulation period. This study provides an economically feasible approach to accelerate ABGS granulation and sustain system stability.