Combined dissolved oxygen and pH control strategy to improve the fermentative production of l-isoleucine by Brevibacterium lactofermentum

A rule based control strategy for automatically adjusting phase lengths and aeration intensity for an activated sludge nutrient removal process based on a periodic operation is examined using simulations based on the Activated Sludge Model No. 1. The strategy is based on four criterion functions, two which determine the switching of the roles of two nitrifying/denitrifying reactors and two which adjust the dissolved oxygen setpoint levels in the two reactors as functions of ammonia and nitrate concentrations. Trajectory plots of reactor concentrations in the ammonia-nitrate plane are shown to be a useful means of visualizing process and control performance. Together, the trajectories from a working region in the ammonia-nitrate plane, the size and location of which can to some extent be predetermined by selection of the criterion functions. The presented results include the influence of one of the criterion functions on control strategy performance, how an incompatibility between two criterion functions can lead to unsymmetric reactor loading, and the effect of allowing simultaneous nitrification and denitrification during nitrifying periods by reducing the dissolved oxygen level as ammonia is consumed.

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Research of dissolved oxygen concentration control strategy based on the fuzzy self-tuning PID parameter

2017 29th Chinese Control And Decision Conference (CCDC) ◽

10.1109/ccdc.2017.7978229 ◽

2017 ◽

Cited By ~ 1

Author(s):

Xiaotong Liu ◽

Weibo Yu

Keyword(s):

Dissolved Oxygen ◽

Oxygen Concentration ◽

Control Strategy ◽

Dissolved Oxygen Concentration ◽

Self Tuning

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Coupling the SHARON process with Anammox: Model-based scenario analysis with focus on operating costs

Water Science & Technology ◽

10.2166/wst.2005.0093 ◽

2005 ◽

Vol 52 (4) ◽

pp. 107-115 ◽

Cited By ~ 13

Author(s):

E.I.P. Volcke ◽

S.W.H. Van Hulle ◽

B.M.R. Donckels ◽

M.C.M. van Loosdrecht ◽

P.A. Vanrolleghem

Keyword(s):

Flow Rate ◽

Control Strategy ◽

Air Flow ◽

Operating Cost ◽

Ph Control ◽

Ammonia Concentration ◽

Air Flow Rate ◽

Cost Index ◽

Sludge Digestion ◽

Sharon Process

The combined SHARON-Anammox process for treating wastewater streams with high ammonia concentration is discussed. Partial nitritation in the SHARON reactor should be performed to such an extent that an Anammox-optimal nitrite:ammonium ratio is generated. The SHARON process is typically applied to sludge digestion rejection water in order to relieve the ammonium load recycled to the main plant.A simulation study for realistic influent conditions on a SHARON reactor with a fixed volume and operated with constant air flow rate reveals that the actual nitrite:ammonium ratio might deviate significantly from the ideal ratio and might endanger operation of the subsequent Anammox reactor. It is further examined how the nitrite:ammonium ratio might be optimized. A cascade pH control strategy and a cascade O2 control strategy are tested. Simulation results are presented and the performance of the different strategies is assessed and quantified in an economic way by means of an operating cost index. Best results are obtained by means of cascade feedback control of the SHARON effluent nitrite:ammonium ratio through setting an O2-set-point that is tracked by adjusting the air flow rate.

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Influence of the pH control strategy and reactor volume on batch fermentative hydrogen production from the organic fraction of municipal solid waste

Waste Management & Research ◽

10.1177/0734242x19826371 ◽

2019 ◽

Vol 37 (5) ◽

pp. 478-485 ◽

Cited By ~ 7

Author(s):

Francesco Baldi ◽

Renato Iannelli ◽

Isabella Pecorini ◽

Alessandra Polettini ◽

Raffaella Pomi ◽

...

Keyword(s):

Hydrogen Production ◽

Municipal Solid Waste ◽

Solid Waste ◽

Control Strategy ◽

Ph Control ◽

Organic Fraction ◽

Experimental Conditions ◽

Reactor Volume ◽

Fermentative Hydrogen Production ◽

Fermentative Hydrogen

Three different experimental sets of runs involving batch fermentation assays were performed to evaluate the influence of the experimental conditions on biological hydrogen production from the source-separated organic fraction of municipal solid waste collected through a door-to-door system. The fermentation process was operated with and without automatic pH control, at a pH of 5.5 and 6.5, food-to-microorganism ratios of 1/3 and 1/1 (wet weight basis) and with different working volumes (0.5 and 3 L). The experimental results showed that the pH control strategy and the reactor volume did not affect the final hydrogen production yield but played an important role in determining the time evolution of the process. Indeed, although the different experimental conditions tested yielded comparable hydrogen productions (with maximum average values ranging from 68.5 to 88.5 NLH2 (kgTVSOF)−1), the automatic pH control strategy improved the process from the kinetic viewpoint resulting in a t95 reduction from an average of 34.9 h without automatic pH control to an average of 19.5 h.

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