Start-up Stage Research Articles

Hydrocarbons removal and microbial community succession in petroleum-contaminated soil under hydrogen peroxide treatment.

Chemical oxidation as a pretreatment step coupled with bioremediation for petroleum-contaminated soil may pose serious impacts on indigenous microorganisms and the available nutrients. Petroleum-contaminated soil were treated by hydrogen peroxide (H2O2) at initial concentrations of 105mM (HH), 21mM (HL), and 105mM in three equal amounts (HT) without adding any external catalyst. The contents of total petroleum hydrocarbons (TPH) and dissolved nutrients (total organic compounds, nitrogen, and phosphate), and the indigenous bacteria community succession (analyzed by high-throughput sequencing of 16S rDNA) were investigated over 50days. Compared to the control treatment without H2O2 addition, H2O2 treatments for the petroleum-contaminated soil significantly promoted the TPH removal especially in the first 4days and impacted the contents of dissolved nutrients. Both of chemical oxidation and nutrients contributed to microbial community structure changes in alpha diversity. Although the soil microbial community structure had undergone significant changes after different chemical oxidation pretreatments, Firmicutes, Proteobacteria, Gemmatimonadetes, and Actinobacteria were the main bacterial phyla. Compared with adding H2O2 at one time, H2O2 added in stepwise was beneficial to indigenous bacterial diversity recovery and TPH removal. H2O2 oxidation treatments showed a great influence on the microbial community structures in the start-up stage, while recovery time rather than the oxidation treatments presented greater effects on the composition of the microbial community structure with the incubation time extended. Therefore, adding H2O2 as pretreatment for petroleum-contaminated soil showed little effect on the structure of soil indigenous microbial community from a long-term scale, and was conducive to the continuous removal of TPH by indigenous microorganisms.

Application of Minimally Invasive Surgery-Multidisciplinary Team in Advanced and Recurrent Gynecological Cancers: 10-Year Exploration and Practice.

The treatment of advanced and recurrent gynecological cancers (ARGCs) remains more difficult evens. This assay aims to introduce the application of minimally invasive surgery-multidisciplinary team (MIS-MDT) as well as a comprehensive evaluation and treatment program of ARGC. The diagnosis and treatment model of MDT collaboration has become a new model of clinical cancer treatment. In my country, it is in the start-up and trial stage. Our team began to explore surgical treatment of recurrent gynecological cancers in 2011 and has been committed to MDT treatment of ARGC for more than 3 years. So far, 61 patients have completed MDT treatment (28 of them were advanced gynecological cancer patients, 33 of them were recurrent gynecological cancer patients). Among them, MDT involved 43 times in gastrointestinal surgery, 21 times in urology, 5 times in the department of intractable abdominal diseases, and 5 times in other departments. After surgery, 58 patients (95%) restarted adjuvant therapy such as radiotherapy and chemotherapy. In addition, 32 patients (52.5%) underwent genetic and molecular testing, of which 14 patients (23%) accepted targeted and immunotherapy based on the testing results. After MIS-MDT treatment, the median progression-free survival of these patients was >30 months, respectively. These patients have achieved good results after surgery of MDT. With continuous accumulation and summarization, we have systematically reviewed the diagnosis and treatment model of ARGC and guided clinical work as the model of Tongji Tenth Hospital (comprehensive evaluation and treatment).

Low-temperature-resistance granulation of activated sludge and the microbial responses to the granular structural stabilization

Completely loss of granular structural stability and reliable start-up of aerobic granular sludge (AGS) system are considered as the biggest challenges for its engineering application under seasonal temperature variation, especially extremely low temperatures. In this study, two identical sequencing batch reactors (SBR) were successfully start-up at 10 °C (R1) and 25 °C (R2), respectively, and then operated under a strategy of stepwise change of temperatures to investigate the stability of the granular sludge by examining its microbial characteristics, bis (3′-5′)-cyclic dimeric guanosine monophosphate (c-di-GMP), extracellular polymeric substance (EPS) and sludge physiochemical properties. The results showed that AGS formed under the low temperature preferentially secrete EPS and c-di-GMP for stable granulation and improvement of its resistance to temperature changes. Meanwhile, R1 successfully obtained aerobic granulation with high biomass concentration and superior settleability, as well as high pollutant removal performance. In comparison, R2 took a longer time for granulation and was subjected to serious disintegration of AGS. The matrix structure partially formed by filamentous bacteria during the start-up stage in R1 was one of major reasons for its own superiority beyond R2 in granulation. Slow-growing organisms such as autotrophic nitrifying and Anammox bacteria, phosphorus accumulation organisms, EPS-producing genera, and c-di-GMP pathway-dependent genera, were exclusively enriched in the R1 and resulted in higher pollutants removal efficiencies and stable structure, whereas Sphaerotilus dominated in R2 that related closely with its unstable performance. Therefore, the strategy based on the stepwise change of temperatures from extremely low temperatures may be one feasible way for the sustainable application of AGS system, which is of significance to address the challenging problems of AGS applications.

Effect of sulfur particle morphology on the performance of element sulfur-based denitrification packed-bed reactor

The effect of particle morphology on denitrification performance in element sulfur-based denitrification (ESDeN) packed-bed process is a gap. In this study, three different types of commercial sulfur particles were selected to build the ESDeN reactors. The results showed the reactors filled with rougher sulfur particles took shorter time to reach stable denitrification performance in the start-up stage. The reactors filled with cap-shape sulfur particles received the maximum nitrate removal rate of 849.49 ± 79.29 g N m−3 d−1 at empty bed contact time of 0.50 h, which was 2.34 times higher than that with ball-shape sulfur particles in the steady stage. The superior denitrification performance in the cap-shape particles set linked to its larger effective volumetric surface area (ωe, 1.67 times larger) and to the longer actual hydraulic retention time (AHRT, 1.80 times longer). This study extends the knowledge of the dependency of sulfur particle properties on denitrification performance in ESDeN packed-bed reactor.

Comparative Analysis and Optimization of Novel Pulse Injection Sensorless Drive Methods for Fault-Tolerant DC Vernier Reluctance Machine

Multiphase dc-excited Vernier reluctance machine (DC-VRM) exhibits the merits of robust structure, small torque ripple, and good fault-tolerant ability. Developing advanced sensorless drive methods can further promote its application in the safety-critical system. In this article, pulse injection sensorless drive methods are optimized in a six-phase DC-VRM parallel H-bridge drive system to strengthen their acceleration performance and fault-tolerant ability. The acceleration performance studied in this article corresponds to the acceleration speed during the startup stage. By the full-phase alternative pulse injection method (APIM), each phase can be excited independently to avoid mutual-inductance influence on position estimation, but this method suffers from a long communication delay and relatively poor acceleration performance. A reduced-phase APIM can reduce detection time, but the lack of detected phase may influence position estimation accuracy and fault-tolerant ability. To solve these problems, a novel vertical-axis synchronous pulse injection method is proposed and compared with previous methods in this article. The key is to inject detection pulses into vertical-axis phases simultaneously, thus reducing the detection time and improving the torque generation. It is proved that the influence of mutual inductance on position estimation can be ignored, and the detection accuracy and acceleration performance can be improved without deterioration of fault-tolerant ability.

Motion Characteristics of Collapse Body during the Process of Expanding a Rescue Channel

For the rapid construction of a rescue channel in the process of underground emergency rescue, a method for the expanded rescue channel in the collapse body is proposed and verified by a model test and a numerical simulation experiment. The motion characteristics and motion law of the expanded collapse body are analyzed on the basis of the mechanics of granular media, and a comparative simulation study on the main influencing factors of the collapse body motion is carried out. The results show that: (1) When the collapse body is expanded for a rescue channel, it will form three types of six relative slip planes. According to the position of the slip plane and the distribution of displacement, the collapse body can be divided into a direct displacement region, a stable region, and an indirect displacement region. (2) The expansion process can be divided into the initial start-up stage, the uplift stage, and the collapse stage, according to the formation time of the slip plane and the displacement law of the collapse body. (3) The results of the numerical simulation and the theoretical analysis of the granular media show that the dip angle of the slip plane is determined by the internal friction angle of the collapse particles, and the dip angles of the three slip planes are below θ1=90°−φ, θ2=45°+φ/2, and θ3=90°+φ/2. (4) The transverse scope and longitudinal distance is brought by the expansion increase with the increase in the expansion size, and the simulated dip angles of the slip plane are larger than the theoretical values due to the size effect. (5) In the expansion process, the strong force chain in the collapse body is concentrated in the stress arch above the expander device, and the failure and reconstruction laws of the stress arch at each stage are consistent with the formation of the slip plane and the uplift and instability law of the collapse body.

Operation characteristics and performance prediction of a 3 kW organic Rankine cycle (ORC) with automatic control system based on machine learning methodology

Automatic control system enables the laboratory organic Rankine cycle (ORC) to adapt to variable operating conditions of industrial application. In this study, the operation characteristics of a 3 kW ORC with automatic control system applied to a chemical plant, as well as the performance prediction and optimization using machine learning methodology, are addressed. The dynamic behaviors for startup, operating and stop stages are discussed. The BP-ORC neural network model is established based on 3400 sets of experimental data, while the prediction accuracy is analyzed based on the errors of the training and test samples. The effects of six operation parameters on system performance are examined, while the bi-objective optimization for maximum thermal efficiency and maximum net output work is investigated. Results indicate that the component response times for startup stage and stop stage are 90s and 300s, respectively. Increasing the mass flow rate, decreasing the expander outlet temperature and increasing the expander inlet temperature ensure a higher net output work, while increasing the expander inlet temperature, decreasing the expander outlet temperature and increasing pump outlet pressure enable a higher thermal efficiency. The optimum net output work and thermal efficiency from Pareto-optimal solution are 2.87 kW and 8.855%, respectively.

How does the Macro Policy work in Housing Market of China?

China's housing industry is booming, but it is in its start-up stage, which, together with the complexity of the real estate market, has led to various problems in the real estate market, seriously affecting the sustainable, stable and health development of the real estate market. This study starts from defining the connotation of the health of real estate market, using quantitative analysis tools such as ITS regression analysis, referring to existing research results, and taking into account the characteristics of the domestic real estate market, to establish the concept of the health of real estate market, and to study the correlation between the health of real estate market and various macroeconomic influencing factors. The empirical results find that only housing policy and financial policy have substantial effects on housing prices in the short term. In the long run, none of the four major policies in the empirical results has a long-run effect on the selected dependent variable. Finally, policy recommendations are proposed for the government.

Continuous immobilization of lead by biomineralization in a fluidized-bed biofilm reactor

Microbial-induced phosphate precipitation (MIPP) is a promising biomineralization technology to immobilize lead in wastewater. However, more in-depth biological principles and reactor models with more biomass need to be further explored to guide its engineering applications. In this study, a fluidized-bed biofilm reactor with biomineralization capability was proposed for immobilizing lead continuously and circularly. The optimal operating parameters for the reactor stages of start-up, operation and circulation were investigated. Stable biofilms could be formed by circulating Lysinibacillus suspension into the column containing the polypropylene fiber with the addition of montmorillonite. Its lead removal efficiency reached above 80% within 3 h and decreased to 23% after 12 h continuous operation. Besides, the reactor could maintain a high lead removal efficiency after multiple elutions and had a better performance without secondary pollution in treating practical wastewater due to the organic matter contained. The functional bacteria stability of the dominant position and functions was the main reason for keeping high removal efficiency during the process. This research provided an effective method for the engineering application of biomineralization for lead removal.

A novel two-stage process for the effective treatment of swine wastewater using Chlorella sorokiniana AK-1 based algal-bacterial consortium under semi-continuous operation

This study aimed at developing an eco-friendly and effective treatment for swine wastewater (SWW) using a designer microalgae-bacteria consortium. A functional algal bacterial consortium was developed with SWW-derived bacteria and Chlorella sorokiniana AK-1. Light intensity (300 µmol/m2/s) and inoculum size (0.15 and 0.2 g/L for microalgae and bacteria) were optimized. Semi-batch operation treating 50 % SWW resulted in a COD, BOD, TN, and TP removal efficiency of 81.1 ± 0.9 %, 97.0 ± 0.7 %, 90.6 ± 1.6 % and 91.3 ± 1.1 %, respectively. A novel two-stage process with an initial bacterial start-up stage followed by microalgal inoculation was applied for attaining stable organic carbon removal, in addition to satisfactory TN and TP removal. Full strength SWW was treated with this strategy with COD, BOD, TN, and TP removal efficiencies of 72.1 %, 94.9 %, 88 %, and 94.6 %, respectively. The biomass consisted of 36 % carbohydrates, indicating a potential feedstock for biochar production. In addition, the effluent met the standards for effluent discharge in Taiwan.

Multi-Flexible Body Dynamics Modeling and Experimental Study of the Patient Rehabilitation Transfer Device.

Objectives The patient rehabilitation transfer device is a typical personnel transfer equipment, which is mainly composed of outriggers, support arm, lifting arms, hooks, handrails, hydraulic cylinders, and other components. The existing research on the device is mainly focused on the configuration design and transfer mode, and the research on its dynamic characteristics during the transfer process has not been thoroughly discussed. Methodology. Based on the existing research, a portable hydraulic rehabilitation patient transfer device has been developed. Then the multi-rigid body dynamic and finite element flexible body models were established. Next, the dynamic characteristic difference between the two models of the device was studied. Results As shown in the results, the finite element multi-flexible body model has obvious flexible vibration in the lifting stage, and the amplitude reaches 16 mm in the motion startup stage due to the influence of rigid-flexible coupling. The tip acceleration of the flexible body model was also influenced by the vibration, and the maximum acceleration value reaches 0.06 m/s2. According to the test results, the maximum acceleration of the terminal reaches 0.05 m/s2, which is close to the finite-element multi-flexible model simulation results. The experimentally measured natural frequency of the device is 3.1 Hz, which is also close to 3.2 Hz calculated by the simulation. Because the flexible component in the flexible model is only the lift arm, the natural frequency is slightly larger than the experimental value. Conclusion According to the stress value of the finite element multi-body model motion process, the maximum stress appears at the moment when the motion reaches the top end, and the instantaneous stress reaches 206 Mpa, which is in line with the allowable stress range of the material design. The data obtained in this study will provide help for the follow-up clinical rehabilitation and intelligent device research.

CBM Desorption Model and Stages Based on a Natural Desorption Experiment.

Coalbed methane (CBM) desorption modeling is critical for understanding CBM desorption mechanisms and objectively analyzing the production characteristics of CBM wells. According to the CBM natural desorption experimental data of 64 coal samples taken from the Qinshui Basin, we established a CBM desorption model, quantitatively identified the CBM desorption stages, and discussed the relationship between CBM desorption characteristics and well productivity. The results indicated a very significant functional relationship between the CBM natural desorption time and cumulative desorption quantity, which could be accurately described by the model V = aLt/(t + bL). On the basis of this model and the numerical description of the desorption data, the CBM natural desorption process was divided into four stages: the desorption startup stage, desorption sensitive stage, desorption steady stage, and desorption decay stage. As indicated by analogical reasoning of the CBM well production process, the desorption startup stage corresponded to the drainage-based pressure drop stage, the desorption sensitive and steady stages corresponded to the steady production stage, and the desorption decay stage corresponded to the production declining stage. The CBM adsorption time exponentially decreased with the increase in the average CBM desorption rate and with the increase in the CBM gas content and vitrinite/inertinite ratio. Furthermore, within a certain range of desorption pressure, a high ratio between the adsorption time and gas content corresponded to the extension of the steady production stage of CBM wells, whereas higher or lower ratios were adverse to steady production.

INNOVATIVE ENTREPRENEURSHIP AND STARTUP IN THE CREATIVE ECONOMY

The paper examines the theoretical aspects of innovative entrepreneurship and startup in the creative economy. An important task of any economy is to ensure rapid economic growth, which is not possible without the use of entrepreneurial innovations. Various aspects of the concept of “entrepreneurship” were considered, namely global, economic, intellectual and professional. The content of the concepts “creative entrepreneurship” and “creative economy” was analyzed. The specific origin of the creative economy is considered. Three types of creative entrepreneurship are distinguished: cultural, social and hybrid. The types of creative innovations are briefly characterized: creation of new products, improvement of previously existing ones, bringing the existing one to a new level, use of new resources, creation of a new structure. It was established that the concept of “startup” is located next to the concepts of “entrepreneurship” and “innovation”. Peculiarities of a startup in the creative economy have been studied. Currently, it is known that the process of creating and developing conditions for developing and offering new products to the market begins at the startup stage. A startup is a newly created organization that uses different types of innovation. Almost all actions of a startup can be considered as experiments that test the chosen strategies. Various forms of organization of creative and entrepreneurial space in the creative economy have common characteristics.

Rapid start-up and humification of kitchen waste composting by an innovative biodrying-enhanced process

An innovative biodrying-enhanced composting (BEC) system that applies biodrying to composting process as its start-up stage was developed to rapidly process kitchen waste (KW) into highly maturate products. The BEC performance and potential mechanisms of rapid start-up and humification were explored through a continuous pilot experiment. The results showed that the BEC system was designed and operated with 9 d retention time, achieving highly maturate products with a germination index of 91.85%–112.08% and a humification index of 6.21–6.36. The 24 h biodrying stage could markedly accelerate KW dehydration and start-up of the composting process. The stage-enriched Corynebacterium (45.61%–66.91%) and Pichia (76.72%–92.33%) rapidly decomposed macromolecular substances (i.e., methoxylated polysaccharides) and generated humic acid (HA) precursors (especially methoxy groups and residual aromatic-like components). The precursors were utilized to rapidly synthesize HA skeletons and stable HA by thermophilic Firmicutes and Ascomycota in the humification stage. The Maillard reaction and lignin-protein theory contributed greatly to HA elongation, while the “methoxy-aromatic nucleus” pathway might improve HA stabilization during BEC as an alternative to polyphenol humification pathway. BEC technology can be enhanced by reducing the residence time and plant areas required for composting, improving the prospects for recycling organic waste in engineering applications.

Evolutionary Trends in Integrated Care in 2000-2020 in China: A Scientometric Review Using CiteSpace.

Introduction:Owing to an increasing demand for a continuous and coordinated health service, integrated care is being promoted worldwide. Chinese research on integrated care has rapidly increased over the last 20 years. However, popular topics, paths and trends of integrated care research in China have not been systematically summarised. The study aimed to examine the evolution of integrated care research in China and predict future research trends.Methods:We searched for integrated care research in China published 2000–2020 in Chinese (China National Knowledge Infrastructure) and English (Web of Science). Research articles that met the inclusion criteria were selected. CiteSpace 5.7.R3 was used to perform keyword clustering, timeline view and burst detection analyses.Results:We included 786 Chinese articles and 124 English articles. Chinese articles formed 10 clusters with 1814 keywords. English articles formed 5 clusters with 487 keywords. From 2000 to 2020, integrated care research in China comprised three stages: (1) In the start-up stage (2000–2007), keywords mainly focus on medical resource integration and two-way referral; (2) In the emergence stage (2008–2015), keywords primarily include integrated model, benefits of integration, paths to integration and incentive mechanisms; (3) In the maturation stage (2016–2020), the main keywords are patient preferences, shared management mechanisms, symbiosis theory, value-based care, payment methods and people-oriented care.Discussion:With increasing health care system reform, popular integrated care research topics in the next stage will likely focus on people-oriented integrated care, service value and payment method reform. Academic research on integrated care in China will help to shape and lead policymaking.Conclusions:Integrated care research in China has gone through three stages over the last two decades. In the future, integrated care theory in China will be informed by concepts from other fields, such as value co-creation in public management, to address the current problem of lack of synthesis in integrated care in China.

Startup analyses of a megawatt heat pipe cooled reactor

Heat pipe cooled reactors experience temperature rises of up to 800 K during startup. The in-core heat pipes and the energy conversion system are initially frozen, which leads to a highly coupled heat transfer system that has significant safety challenges. This work modeled the system startup using a two-dimensional heat pipe model and an open-air Brayton cycle model coupled to the Heat Pipe Reactor TRANsient analysis code, HPRTRAN. The heat pipe model was validated with startup experiments showing that the predicted heat pipe wall temperature was within 30 K of the measured temperatures. The Brayton cycle model was validated against experimental data in the literature. The analysis code was then used to analyze a megawatt heat pipe reactor connected to an open-air Brayton cycle, which was used to study the influence of the external reactivity and the inherent feedback on the startup process. The simulations show that the reactor startup process is sensitive to the heat pipe operating state. The startup process can be divided into the subcritical stage, heat pipe startup stage, and increasing power stage. The power peak amplitudes are significantly reduced by slowing the angular speed of the control drum. Reducing the control drum angular speed from 0.1°/min to 0.05°/min reduced the first power peak from 2000 kW to 1000 kW. A modified reactor startup control strategy was then developed that ensures the core safety with the reactivity introduced in steps. Smaller reactivity insertions reduce the power peaks during the initial startup but lead to much longer startup times. A reasonable balance was obtained by repeated insertions of either 30 pcm or 60 pcm for safe startups of the heat pipe cooled reactor.

Experimental study on global visualization of loop heat pipe with a flat disk-shaped evaporator

In this study, a prototype of a flat-disk global visualisation loop heat pipe was constructed, and the two-phase working phenomenon in the system operation was elaborated. This study focuses on a new method for global visualisation of loop heat pipes. The evaporator, condenser, and pipeline are integrated into a single piece of glass. Deionised water was used as the working fluid. Simultaneously, the airtightness of the system was guaranteed. During the experiment, an infrared thermal imager and a high-definition camera were used to collect optical information. The heat and mass transfer phenomena in the system under different working conditions were experimentally studied. The three stages of the loop heat pipe start-up were analysed according to the change in the vapour–liquid state. Through global observation of the heat and mass transfer process, the effects of condenser working efficiency, heat leakage, and non-condensable gas on the thermal performance of the loop heat pipe were studied. During the test, the temperature of the heating surface was lower than 92 °C, and the heat load range of the system was 25–45 W. The condenser was designed as a fan-tube condenser with forced convection heat dissipation. The system achieved self-regulation and stability through the cooperation of various components. The significance of this study is that the global visualisation of the loop heat pipe comprehensively describes the heat and mass transfer process of the system, and the operating characteristics of the loop heat pipe were studied intuitively.

Parameter optimization of control system design for uncertain wireless power transfer systems using modified genetic algorithm

The closed-loop wireless power transfer (WPT) system can realize constant voltage output in the presence of perturbation. However, the parameter design of the controller is a difficult problem. The traditional trial-and-error method is time-consuming and difficult to find optimal parameters. A parameter optimization strategy of control systems for uncertain WPT systems using the modified genetic algorithm (MGA) is proposed. Firstly, because the system has different characteristics at different periods, the simulation process is divided into three stages. The first one is the start-up stage, in which we mainly consider the overshoot and the rate of the voltage rise. The second one is the tracking stage, in which the tracking time and switching loss are mainly considered. The third one is the stabilisation stage, in which the steady-state error and switching loss are mainly considered. Secondly, three cost functions are designed according to the characteristics of the three stages, and then the optimal controller parameters of each stage are obtained by using MGA. Finally, the effectiveness of the proposed method is verified by simulation. The optimization results show that compared with the previous parameter optimization method, the optimal controller parameters obtained by the proposed method make the WPT system achieve better performance.

Effect of rotational speed and flowrate on the startup characteristics of a pumps as turbine

The startup process of pump as turbine (PAT) is actually unavoidable. In order to reveal the transient behavior of a small centrifugal pump reversing as a turbine during an atypical startup, transient experiments are carried out on PAT test rig in the case of two valve openings and four rotational speeds so as to obtain the evolution characteristic of the external performance parameters over time. Meanwhile, three dimensionless parameters are also employed to deeply reveal the transient characteristics. It is found that the shock phenomena in static pressure are prevalent at the outlet of PAT, and that it tends to lag and weaken with increasing stable rotational speed. All three dimensionless factors have maximum values at the initial stage of PAT startup, whereafter they demonstrate the different evolution characteristics.

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.