scholarly journals Finding optimal algal/bacterial inoculation ratio to improve algal biomass growth with wastewater as nutrient source

Water SA ◽  
2019 ◽  
Vol 45 (4 October) ◽  
Author(s):  
Le Anh Pham ◽  
Julien Laurent ◽  
Paul Bois ◽  
Adrien Wanko
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Algal Biomass ◽  
Algal Growth ◽  
Total Biomass ◽  
Batch Reactors ◽  
Biomass Growth ◽  
Sequencing Batch Reactors ◽  
Solids Retention ◽  
Removal Efficiencies

Algal growth, nutrient removal and settling efficiency were quantified while inoculating sequencing batch reactors with a mixture of microalgae and bacteria (activated sludge). Three algae/bacteria inoculation ratios (5:1, 1:1 and 1:5) as well as pure algal biomass (control) were assessed. Algal biomass production increased with the addition of activated sludge. However, the addition of too much activated sludge can cause disturbance to the Al-Bac biomass growth and algal bacterial processes. All reactors including the control with only algae showed similar settling and nutrient removal efficiencies. Good settling was observed in all reactors with only 5% of total biomass found in supernatant after 1 h of settling. Removal efficiencies of COD, TN and PO4-P in all reactors were 79–82%, 61–65% and 15–37%, respectively, with the lowest phosphorus removal efficiency belonging to 1:5 algae/activated sludge ratio. These results may be due to both long hydraulic (7 days) and solids retention times (up to 30 days). Finally, Al-Bac biomass with 1:1 inoculation ratio showed the best enhancement in terms of biomass growth and algal activities.

Comparison in growth, lipid accumulation, and nutrient removal capacities of Chlorella sp. in secondary effluents under sterile and non-sterile conditions

2013 ◽  
Vol 69 (3) ◽  
pp. 573-579 ◽  
Author(s):  
Qiao Zhang ◽  
Yu Hong
Keyword(s):  
Growth Rates ◽  
Nutrient Removal ◽  
Lipid Accumulation ◽  
Algal Biomass ◽  
Algal Growth ◽  
Chlorella Sp ◽  
Algal Lipid ◽  
Secondary Effluents ◽  
Removal Efficiencies ◽  
Biomass Increase

The growth, lipid accumulation and nutrient removal characteristics of an oleaginous microalga Chlorella sp. HQ in two types of secondary effluents (named as X and Q) before/after sterilization were evaluated. The results show that the algal growth rates under sterilization were higher than those under non-sterilization. However, sterilization caused a significant decrease in algal lipid and triacylglycerol (TAG) contents in both X and Q. And the lipid and TAG yields in non-sterile X were as much as 2.7 and 7.7 times higher than those in sterile X, reaching up to 51.3 and 16.1 mg L−1, respectively. However, the sterilization caused algal biomass increase in sample Q. Sterilization or not had almost no effect on the total phosphorus (TP) removal ability of Chlorella sp. HQ and it was found to have similar abilities to remove almost 100.0% TP from samples X and Q. While the total nitrogen (TN) removal efficiencies were promoted slightly under non-sterilization, increasing from 88.5 to 89.7% in X and from 13.3 to 17.2% in Q. Hence, non-sterile circumstances are basically beneficial for Chlorella sp. HQ to accumulate its lipid (TAGs) and remove nutrients from wastewater.

Control of algal production in a high rate algal pond: investigation through batch and continuous experiments

2014 ◽  
Vol 69 (12) ◽  
pp. 2519-2525 ◽  
Author(s):  
H. Derabe Maobe ◽  
M. Onodera ◽  
M. Takahashi ◽  
H. Satoh ◽  
T. Fukazawa
Keyword(s):  
Retention Time ◽  
Algal Growth ◽  
High Rate ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Flow Reactors ◽  
Solids Concentration ◽  
Solids Retention ◽  
Continuous Flow Reactors ◽  
Algal Productivity

For decades, arid and semi-arid regions in Africa have faced issues related to water availability for drinking, irrigation and livestock purposes. To tackle these issues, a laboratory scale greywater treatment system based on high rate algal pond (HRAP) technology was investigated in order to guide the operation of the pilot plant implemented in the 2iE campus in Ouagadougou (Burkina Faso). Because of the high suspended solids concentration generally found in effluents of this system, the aim of this study is to improve the performance of HRAPs in term of algal productivity and removal. To determine the selection mechanism of self-flocculated algae, three sets of sequencing batch reactors (SBRs) and three sets of continuous flow reactors (CFRs) were operated. Despite operation with the same solids retention time and the similarity of the algal growth rate found in these reactors, the algal productivity was higher in the SBRs owing to the short hydraulic retention time of 10 days in these reactors. By using a volume of CFR with twice the volume of our experimental CFRs, the algal concentration can be controlled during operation under similar physical conditions in both reactors.

Comparison of Biocenoses from Continuous and Sequencing Batch Reactors

1992 ◽  
Vol 25 (6) ◽  
pp. 239-249 ◽  
Author(s):  
J. Wanner
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Continuous Flow ◽  
Sequencing Batch Reactor ◽  
Flow System ◽  
Batch Reactor ◽  
Continuous Reactor ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Filamentous Microorganisms

Sequencing batch reactors (SBR) are often used for research on nutrient removal systems. A model anaerobic-oxic SBR was compared with a compartmentalized continuous-flow system. The levels of COD, phosphorus, and nitrogen removal in both systems were comparable but the biocenoses differed significantly. The SVI values of activated sludge from the continuous reactor ranged between 100 and 200 ml/g although no significant occurrence of filamentous microorganisms was observed. The sequencing batch reactor produced activated sludge with the SVIs below 100 ml/g and with high settling velocities. Filamentous microorganisms were frequently observed in the biocenosis of the SBR. The differences in settling properties and filamentous growth in both reactors are discussed and explained.

Sequencing Batch Reactors for Nutrient Removal at Small Wastewater Treatment Plants

1993 ◽  
Vol 28 (10) ◽  
pp. 233-242 ◽  
Author(s):  
Bjorn Rusten ◽  
Helge Eliassen
Keyword(s):  
Wastewater Treatment ◽  
Nutrient Removal ◽  
Wastewater Treatment Plants ◽  
Batch Reactor ◽  
Treatment Plant ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Biological Phosphorus Removal ◽  
Solids Retention ◽  
Co Precipitation

In order to optimize the sequencing batch reactor (SBR) process for nutrient removal at small wastewater treatment plants, a two year study was carried out at a treatment plant designed for 300 population equivalents. Different operating cycles, solids retention times (SRTs) and periods with co-precipitation were included in the test program. Based on the results, recommendations for achieving nitrification, denitrification and biological phosphorus removal were given. A suitable coagulant (and the optimum dosage) for co-precipitation was found as well.

scholarly journals Influent with Particulate Substrate, Clean, Innocuous and Sustainable Solution for Bulking Control and Mitigation in Activated Sludge Process

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 984
Author(s):  
Pedro Cisterna-Osorio ◽  
Claudia Calabran-Caceres ◽  
Giannina Tiznado-Bustamante ◽  
Nataly Bastias-Toro
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Nutrient Deficiency ◽  
Microscopic Analysis ◽  
Volume Index ◽  
Favorable Effect ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Active Sludge ◽  
Chemical Reagents

This research studies the incidence of the type of substrate, soluble or particulate, in the emergence, development, and inhibition of bulking in activated sludge systems. It was evaluated using the sludge volume index (SVI), mixing liquor-suspended solids (MLSS), microscopic analysis of biomass, and effluent suspended solids (ESS). In the first experiment, four sequencing batch reactors (SBRs) were fed with soluble substrate at a fixed mass, while the mass of the particulate substrate varied, as those (saccharose mass/flour mass) ratios were 3:1, 3:2, 3:3 and 3:4., with a deficit ranging from 20 to 30% compared to the ratio recommended. The four SBRs have similar MLSS, IVL, and ESS. From day 30, with a deficit from 80 to 90%, the influents have ratios 1/1 and 1/2 until 48 days. The SBRs present IVL between 600 and 730 mL/g and ESS from 370 to 440 mg/L; unlike influents with ratios 1/3 and 1/4, they present IVL between 170 and 185 mL/g, and ESS from 260 to 270 mg/L. The favorable effect of particulate matter is categorical. In the second set of experiments, two SBRs were studied: SBR 1 fed with saccharose, and SBR 2 with flour; there is a lack of nutrients causing bulking in SBRs. Once the nutrient deficiency condition is changed in day 11 to excess, after 22 days, the SVI was 190 mL/g, ESS was 360 mg/L, and MLSS was 2000 mg/L for influents with saccharose; the influent with flour, with an SVI of 80 mL/g, ESS of 100 mg/L, and MLSS of 4000 mg/L, shows faster and more consistent recovery with the particulate substrate. Therefore, the proposal is to add particulate substrate-like flour to active sludge plants facing bulking. It is a clean, innocuous and sustainable alternative to processes that use chemical reagents.

Wastewater fermentation and nutrient removal in sequencing batch reactors

1998 ◽  
Vol 38 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Germán Cuevas-Rodríguez ◽  
Óscar González-Barceló ◽  
Simón González-Martínez
Keyword(s):  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Organic Load ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Organic Loading ◽  
Nitrogen And Phosphorus ◽  
Loading Rates ◽  
Average Value ◽  
Experimental Runs

This research project was conducted to analyze the performance of a SBR reactor when being fed with anaerobically fermented wastewater. Important was to determine the capacity of the system to remove nitrogen and phosphorus. Two SBR reactors, each one with a volume of 980 liters, were used: one used as fermenter and the other as activated sludge SBR. Using 8-hour cycles, the reactors were operated and studied during 269 days. The fermenter produced an effluent with an average value of 223±24 mg/l of volatile fatty acids. The activated sludge SBR was tested under 3 organic loading rates of 0.13, 0.25, and 0.35 kgCODtotal/kgTSS·d. For the three tested organic loading rates, PO4-P concentrations under 1.1 mg/l and COD between 37 and 38 mg/l were consistently achieved. Exceptionally high NH4-N influent values were measured during the time of the experimentation with the organic load of 0.25 kgCODtotal/kgTSS·d, not reaching in this case full nitrification. Denitrification was observed during the fill phase in every cycle. SVI values between 40 and 70 were determined during the experimental runs.

Study of factors affecting simultaneous nitrification and denitrification (SND)

1999 ◽  
Vol 39 (6) ◽  
pp. 61-68 ◽  
Author(s):  
Klangduen Pochana ◽  
Jürg Keller
Keyword(s):  
Carbon Source ◽  
Activated Sludge ◽  
Physical Phenomenon ◽  
Treatment Plant ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Factors Affecting ◽  
Floc Size ◽  
Sludge Flocs ◽  
Activated Sludge Systems

Experiments have been performed to gain an understanding of the conditions and processes governing the occurrence of SND in activated sludge systems. Sequencing batch reactors (SBRs) have been operated under controlled conditions using the wastewater from the first anaerobic pond in an abattoir wastewater treatment plant. Under specific circumstances, up to 95% of total nitrogen removal through SND has been found in the system. Carbon source and oxygen concentrations were found to be important process parameters. The addition of acetate as an external carbon source resulted in a significant increase of SND activity in the system. Stepwise change of DO concentration has also been observed in this study. Experiments to determine the effect of the floc size on SND have been performed in order to test the hypothesis that SND is a physical phenomenon, governed by the diffusion of oxygen into the activated sludge flocs. Initial results support this hypothesis but further experimental confirmation is still required.

scholarly journals Model evaluation and optimisation of nutrient removal potential for sequencing batch reactors

Water SA ◽  
2002 ◽  
Vol 28 (4) ◽  
Author(s):  
N Artan ◽  
P Wilderer ◽  
D Orhon ◽  
R Tasli ◽  
E Morgenroth
Keyword(s):  
Nutrient Removal ◽  
Model Evaluation ◽  
Batch Reactors ◽  
Sequencing Batch Reactors
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