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.

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.

Dynamic mathematical modelling of sequencing batch reactors with aerated and mixed filling period

1997 ◽  
Vol 35 (1) ◽  
pp. 105-112 ◽  
Author(s):  
L. Novák ◽  
M. C. Goronszy ◽  
J. Wanner
Keyword(s):  
Activated Sludge ◽  
Batch Reactor ◽  
Major Elements ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Nitrogen And Phosphorus ◽  
Sludge Flocs ◽  
Solids Concentration ◽  
A Minor ◽  
Selection Of

Sequencing batch reactors (SBRs) can be successfully operated for both carbon and nutrient removal, including nitrogen and phosphorus. The major elements of design that accomplish population dynamics control to prevent filamentous sludge bulking, cycle time, oxygen supply, biological nitrification, denitrification, phosphorus removal and solids-liquid separation need to be set in such a way that sufficiently optimal conditions are provided to permit the reactions and processes to take place. SBR processing using cyclic activated sludge technology employs biological selectors in the inlet part of the SBR system and a minor sludge recycle stream to ensure influent wastewater is mixed with activated sludge flocs to create favourable conditions for kinetic and metabolic selection of microorganisms producing floccules. Reaction volume, in addition to the designated bottom water level volume, is variable through time fed-batch reactor mode of operation. A mathematical model that describes volume changes and simultaneously the biodegradation kinetics has been developed. The model describes theoretical behaviour of selected parameters of volume, suspended solids concentration, OUR, ammonia and nitrate nitrogen in the selector compartment and the main aerated basin in ideally mixed and filled reactors of the cyclic system during the phase of mixed-fill (selector) and aerated and non-aerated fill (main aeration reactor basin).

An operational protocol for facilitating start-up of single-stage autotrophic nitrogen-removing reactors based on process stoichiometry

2013 ◽  
Vol 68 (3) ◽  
pp. 514-521 ◽  
Author(s):  
A. G. Mutlu ◽  
A. K. Vangsgaard ◽  
G. Sin ◽  
B. F. Smets
Keyword(s):  
Single Stage ◽  
High Rate ◽  
Normal Operation ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Trial And Error ◽  
Reactor Operation ◽  
N Removal ◽  
Start Up ◽  
Decision Making Tool

Start-up and operation of single-stage nitritation–anammox sequencing batch reactors (SBRs) for completely autotrophic nitrogen removal can be challenging and far from trivial. In this study, a step-wise procedure is developed based on stoichiometric analysis of the process performance from nitrogen species measurements to systematically guide start-up and normal operation efforts (instead of trial and error). The procedure is successfully applied to laboratory-scale SBRs for start-up and maintained operation over an 8-month period. This analysis can serve as a strong decision-making tool to take appropriate actions with respect to reactor operation to accelerate start-up or ensure high-rate N removal via the nitritation–anammox pathway.

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