scholarly journals Effects of illumination time on biological community of algal-bacterial granules and lipid content

2021 ◽  
Vol 27 (6) ◽  
pp. 210334-0
Author(s):  
Limeng Xi ◽  
Wenli Huang ◽  
Binbin Sun ◽  
Fansheng Meng ◽  
Shiguo Gu
Keyword(s):  
Lipid Content ◽  
Unsaturated Fatty Acids ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Short Photoperiod ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Illumination Time ◽  
Long Photoperiod ◽  
Better Than

Synthetic wastewater was used to culture granular sludge for 21 weeks at three sequencing batch reactor activated sludge process (SBR) under different photoperiods. The growth of algae changed granular oxygen distribution, which affected the composition of microbial communities. Different photoperiods were able to alter the formation of granular sludge and the microbial community granules. In short photoperiod (12 h/d) sludge could generate symbiotic algae-bacteria granules in the SBR. By contrast, the long photoperiod (24 h/d) promotes the growth of algae and Ascomycota early, and then inhibits algae, especially chlorophyta (only 1.18%). In the end, algae-bacteria-fungi granules were formed in long photoperiod (LP). By GC-MS and model calculation, the lipid content of algae-bacteria granules was 33.71% more than that of pure aerobic granular sludge. However, the proportion of unsaturated fatty acids in algae-bacteria granules was as high as 43%, resulting in the quality of biodiesel prepared from algae-bacteria granule being slightly worse than that prepared from pure aerobic granular sludge. But both of them were better than biodiesel prepared from pure algae. The biodiesel content of algae-bacteria granule in short photoperiod (SP) and LP were 68.79 and 70.66 mg/g, respectively, which was better than that of pure aerobic particles (52.30 mg/g). Therefore, the formation of algae-bacteria granules is an effective way to remove nutrients and reduce harvesting costs.

Generation and properties of aerobic granular sludge

2001 ◽  
Vol 43 (3) ◽  
pp. 19-26 ◽  
Author(s):  
T. Etterer ◽  
P. A. Wilderer
Keyword(s):  
Batch Reactor ◽  
Granular Sludge ◽  
Experimental Period ◽  
Average Diameter ◽  
Average Density ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Aerobic Conditions ◽  
Heterotrophic Microorganisms ◽  
Average Porosity

A sequencing batch reactor (SBR) was used to investigate the generation of different granules cultured under aerobic and alternating anaerobic/aerobic conditions. The reactor was fed with synthetic wastewater. A substrate loading rate of 3.6 kg COD/ (m3 day) was applied. Granules of heterotrophic microorganisms were formed. After the first experimental period of 8 weeks the average granule diameter was 3.2 mm. In the second period, alternating anaerobic/aerobic conditions were applied to form granular sludge with an average diameter of 3.0 mm. An isopycnic centrifugation procedure was used to determine the characteristic density of the aerobic granular sludge. The average density of the granular sludge was 1.044 g/ml and 1.048 g/ml, respectively. In free-settling tests the final settling velocity of single aggregates was examined to estimate porosity. Settling velocities up to 2.0 cm/s could be measured. Calculations based on the experimental results showed an average granula porosity of 72% for the first run and 65% average porosity for the second run. This paper indicates the validity of general assumptions in free-settling tests.

Cultivation of polyhydroxybutyrate-rich aerobic granular sludge in a sequencing batch reactor

2006 ◽  
Vol 6 (6) ◽  
pp. 81-87 ◽  
Author(s):  
J. Wang ◽  
H.Q. Yu
Keyword(s):  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Volume Index ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Second Step ◽  
Sludge Volume Index ◽  
Flat Shape ◽  
Sludge Granulation

In this study a two-step strategy was adopted to cultivate Polyhydroxybutyrate (PHB)-rich aerobic granular sludge in a sequencing batch reactor (SBR) fed with a synthetic wastewater. In the first step both oxygen and ammonia were initially limited, in order to enhance the PHB-storage ability of sludge. In the second step granular sludge was cultivated to get a high PHB volumetric productivity. The PHB content of sludge increased to 43.1±2.0% in the first step. During the sludge granulation, the PHB content was constant at 40±4.6%. With the granulation, the settling ability of the PHB-rich sludge continuously improved, as evidenced by a decreased sludge volume index. The matured PHB-rich granular sludge presented a buff color and regular morphology with elliptical and flat shape.

Aerobic granular sludge: a promising technology for decentralised wastewater treatment

2006 ◽  
Vol 53 (9) ◽  
pp. 79-85 ◽  
Author(s):  
Z.H. Li ◽  
T. Kuba ◽  
T. Kusuda
Keyword(s):  
Sequencing Batch Reactor ◽  
Loading Rate ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Volume Index ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Organic Loading ◽  
Fast Settling

In order to evaluate the characteristics of aerobic granular sludge, a sequencing batch reactor, feeding with synthetic wastewater at the organic loading rate of 8 kg COD/m3 d, was employed on the laboratory scale. Granules occurred in the reactor within 1 week after the inoculation from conventional flocculent sludge. Aerobic granular sludge was characterised by the outstanding settling properties and considerable contaminates removal efficiencies. The SVI30 values were in the range of 20 to 40 ml g−1. However, the sludge volume index of short settling time (e.g. SVI10 – 10 min) is suggested to describe the fast settling properties of aerobic granular sludge. The potential application in the decentralised system is evaluated from the point view of footprint and high bioactivity. The occurrence of sloughing, resulting from the outgrowth of filamentous organisms, would be responsible for the instability of aerobic granules. The starvation phase should therefore be carefully controlled for the maintenance and stability of aerobic granular sludge system.

Research on Filamentous Bulking in Aerobic Granular Sludge

2011 ◽  
Vol 356-360 ◽  
pp. 1267-1271
Author(s):  
Feng Jiang ◽  
Yang Li Zhao ◽  
Shuai Fu Chen ◽  
Rui Liang
Keyword(s):  
Removal Rate ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Ammonia Nitrogen ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Feed Water ◽  
Filamentous Bulking ◽  
Hydrodynamic Shear ◽  
Cultivation Process

Aerobic granular sludge (AGS) was cultivated successfully in a sequencing batch reactor (SBR), which has floc sludge as seeding sludge in synthetic wastewater. Removal efficiency in the reactor during the entire working period was investigated. Controlling strategy for filamentous bulking and the effect of a filamentous microorganism on granulation of sludge were discussed. The results showed that whether filamentous bulking occurred or not, there was little impact on the removal rate of phosphorus and ammonia nitrogen, which maintain about 90% and 95%, respectively. Increasing the hydrodynamic shear force has certain effects on the controlling of filamentous bulking. Declining C/N ratio, balancing nutrition in feed water can fundamentally solve the problem of filamentous bulking in the cultivation process of aerobic granular sludge.

Optimization of operation conditions for preventing sludge bulking and enhancing the stability of aerobic granular sludge in sequencing batch reactors

2014 ◽  
Vol 70 (9) ◽  
pp. 1519-1525 ◽  
Author(s):  
Jun Zhou ◽  
Hongyu Wang ◽  
Kai Yang ◽  
Fang Ma ◽  
Bin Lv
Keyword(s):  
Batch Reactor ◽  
Biomass Concentration ◽  
Granular Sludge ◽  
Synthetic Wastewater ◽  
Aerobic Granular Sludge ◽  
Organic Loading Rate ◽  
Filamentous Bacteria ◽  
Operation Conditions ◽  
Sludge Bulking ◽  
The Stability

Sludge bulking caused by loss of stability is a major problem in aerobic granular sludge systems. This study investigated the feasibility of preventing sludge bulking and enhancing the stability of aerobic granular sludge in a sequencing batch reactor by optimizing operation conditions. Five operation parameters have been studied with the aim to understand their impact on sludge bulking. Increasing dissolved oxygen (DO) by raising aeration rates contributed to granule stability due to the competition advantage of non-filamentous bacteria and permeation of oxygen at high DO concentration. The ratio of polysaccharides to proteins was observed to increase as the hydraulic shear force increased. When provided with high/low organic loading rate (OLR) alternately, large and fluffy granules disintegrated, while denser round-shape granules formed. An increase of biomass concentration followed a decrease at the beginning, and stability of granules was improved. This indicated that aerobic granular sludge had the resistance of OLR. Synthetic wastewater combined highly and slowly biodegradable substrates, creating a high gradient, which inhibited the growth of filamentous bacteria and prevented granular sludge bulking. A lower chemical oxygen demand/N favored the hydrophobicity of granular sludge, which promoted with granule stability because of the lower diffusion rate of ammonia. The influence of temperature indicated a relatively low temperature was more suitable.

Start-up of an aerobic granular sequencing batch reactor for the treatment of winery wastewater

2009 ◽  
Vol 60 (4) ◽  
pp. 1049-1054 ◽  
Author(s):  
S. López–Palau ◽  
J. Dosta ◽  
J. Mata-Álvarez
Keyword(s):  
Organic Matter ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Particle Diameter ◽  
Granular Sludge ◽  
Average Density ◽  
Aerobic Granular Sludge ◽  
Organic Load ◽  
Winery Wastewater ◽  
Start Up

Aerobic granular sludge was cultivated in a sequencing batch reactor (SBR) in order to remove the organic matter present in winery wastewater. The formation of granules was performed using a synthetic substrate. The selection parameter was the settling time, as well as the alternation of feast-famine periods, the air velocity and the height/diameter ratio of the reactor. After 10 days of operation under these conditions, the first aggregates could be observed. Filamentous bacteria were still present in the reactor but they disappeared progressively. During the start-up, COD loading was increased from 2.7 to 22.5 kg COD/(m3 day) in order to obtain a feast period between 30 and 60 minutes. At this point, granules were quite round, with a particle diameter between 3.0 and 4.0 mm and an average density of 6 g L−1. After 120 days of operation, synthetic media was replaced by real winery wastewater, with a COD loading of 6 kg COD/(m3 day). The decrease of the organic load implied a reduction of the aggregate diameter and a density increase up to 13.2 g L−1. The effluent was free of organic matter and the solids concentration in the reactor reached 6 g VSS L−1.

Adsorption of Cd(ii) from aqueous solution by biogenic selenium nanoparticles

RSC Advances ◽  
2016 ◽  
Vol 6 (18) ◽  
pp. 15201-15209 ◽  
Author(s):  
Fanghui Yuan ◽  
Chao Song ◽  
Xuefei Sun ◽  
Linrui Tan ◽  
Yunkun Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Sequencing Batch Reactor ◽  
High Efficiency ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Selenium Nanoparticles ◽  
Aerobic Granular Sludge ◽  
Biogenic Selenium Nanoparticles

BioSeNPs, which were produced by aerobic granular sludge in a sequencing batch reactor, could be used to remove cadmium from aqueous solution with high efficiency.

The SBR and its biofilm application potentials

2004 ◽  
Vol 50 (10) ◽  
pp. 1-10 ◽  
Author(s):  
P.A. Wilderer ◽  
B.S. McSwain
Keyword(s):  
Activated Sludge ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Aerobic Granular Sludge ◽  
Waste Streams ◽  
Sludge Flocs ◽  
Biofilm Reactors ◽  
Volatile Organic ◽  
High Level ◽  
Slow Growing

Twenty plus years of experience, innovation, and research in the field of biological wastewater treatment and biofilm applications lead to the conclusion that biofilms are in many cases more desirable in reactors than suspended activated sludge. Biofilm reactors can provide very long biomass residence times even when the hydraulic influent loading is low. This makes them particularly suitable when treatment requires slow growing organisms with poor biomass yield or when the wastewater concentration is too low to support growth of activated sludge flocs. Regardless of the settling characteristics of biological aggregates or the hydraulic influent loading the metabolic activity in the reactor can be maintained at a high level. This paper reviews the application of biofilms in sequencing batch reactor (SBR) systems to treat non-readily biodegradable substrates, volatile organic waste constituents, complex waste streams requiring co-metabolism, and particulate wastewaters. Recent research using the SBR to form aerobic granular sludge as a special application of biofilms is also discussed.

Sign in / Sign up

Export Citation Format

Share Document