scholarly journals Nonlinear Modelling and Qualitative Analysis of a Real Chemostat with Pulse Feeding

2010 ◽  
Vol 2010 ◽  
pp. 1-18 ◽  
Author(s):  
Yuan Tian ◽  
Kaibiao Sun ◽  
Andrzej Kasperski ◽  
Lansun Chen
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Impulsive Control ◽  
Substrate Inhibition ◽  
Stable State ◽  
Oxygen Demand ◽  
Biomass Concentration ◽  
Operating Conditions ◽  
State Feedback Control ◽  
Period 2

The control of substrate concentration in the bioreactor medium should be due to the substrate inhibition phenomenon. Moreover, the oxygen demand in a bioreactor should be lower than the dissolved oxygen content. The biomass concentration is one of the most important factors which affect the oxygen demand. In order to maintain the dissolved oxygen content in an appropriate range, the biomass concentration should not exceed a critical level. Based on the design ideas, a mathematical model of a chemostat with Monod-type kinetics and impulsive state feedback control for microorganisms of any biomass yield is proposed in this paper. By the existence criteria of periodic solution of a general planar impulsive autonomous system, the conditions for the existence of period-1 solution of the system are obtained. The results simplify the choice of suitable operating conditions for continuous culture systems. It also points out that the system is not chaotic according to the analysis on the existence of period-2 solution. The results and numerical simulations show that the chemostat system with state impulsive control tends to a stable state or a period solution.

scholarly journals Energy-Efficient Single-Stage Nitrite Shunt Denitrification with Saline Sewage through Concise Dissolved Oxygen (DO) Supply: Process Performance and Microbial Communities

2020 ◽  
Vol 8 (6) ◽  
pp. 919 ◽  
Author(s):  
Huichuan Zhuang ◽  
Zhuoying Wu ◽  
Linji Xu ◽  
Shao-Yuan Leu ◽  
Po-Heng Lee
Keyword(s):  
Dissolved Oxygen ◽  
Microbial Communities ◽  
Energy Efficient ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Single Stage ◽  
Rrna Gene ◽  
Unexpected Finding ◽  
Sequencing Analysis ◽  
Ratio Requirement

Single-stage nitrite shunt denitrification (through nitrite rather than nitrate) with low dissolved oxygen (DO) supply is a better alternative in terms of energy-efficiency, short-footprint, and low C/N-ratio requirement. This study investigates the optimal DO level with temperature effect, with saline sewage at the fixed hydraulic and solids retention times of 8 h and 8 d, respectively. Moreover, 16S rRNA gene sequencing analysis corresponding with total nitrogen (TN) and chemical oxygen demand (COD) removals in each operating condition were performed. Results showed that DO of 0.3 mg/L at 20 °C achieved over 60.7% and over 97.9% of TN and COD removal, respectively, suggesting that such condition achieved effective nitrite-oxidizing bacteria inhibition and efficient denitrification. An unexpected finding was that sulfur-reducing Haematobacter and nitrogen-fixing Geofilum and Shinella were highly abundant with the copredominance of ammonia-oxidizing Comamonas and Nitrosomonas, nitrite-oxidizing Limnohabitans, and denitrifying Simplicispira, Castellaniella, and Nitratireductor. Further, canonical correspondence analysis (CCA) with respect to the operating conditions associated with phenotype prediction via R-based tool Tax4Fun was performed for a preliminary diagnosis of microbial functionality. The effects of DO, temperature, nitrite, and nitrate in various extents toward each predominant microbe were discussed. Collectively, DO is likely pivotal in single-stage nitrite shunt denitrification, as well as microbial communities, for energy-efficient saline sewage treatment.

STUDY ON THE BIODEGRADATION OF OIL SPILLED ON THE SEA

1997 ◽  
Vol 1997 (1) ◽  
pp. 989-990 ◽  
Author(s):  
Zhao Jianqiang ◽  
Zhu Junhuang
Keyword(s):  
Chemical Composition ◽  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Oxygen Demand ◽  
Nutrient Elements ◽  
Factors Affecting ◽  
Major Factors ◽  
Spilled Oil

ABSTRACT Three major factors affecting the biodegradation of spilled oil (chemical composition of spilled oil, dissolved oxygen content in water, and nutrient elements for microorganisms) were analysed. The sequences of biodegradation rates of some hydrocarbon compounds are summarized. The oxygen demand for biodegradation of 1 g of hydrocarbons was derived as 3 to 4 g. The maximum ratio of carbon (C), nitrogen (N), and phosphorus (P) that microorganisms need was suggested as C:N:P = 100:7:0.14.

Oxygen budget for an urban estuary

1982 ◽  
Vol 33 (4) ◽  
pp. 607
Author(s):  
DW Connell ◽  
HC Morton ◽  
BM Bycroft
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Water Mass ◽  
Oxygen Demand ◽  
Major Influence ◽  
Benthic Respiration ◽  
Oxygen Budget ◽  
Urban Estuary ◽  
Benthic Sediments ◽  
Plant Respiration

Various processes affecting the dissolved oxygen content of waters of the Norman Creek estuary, Brisbane, were measured or estimated and standardized for the mid tide daylight situation. Over a 9-week period, accrual, aeration and photosynthetic processes resulted in the daily addition of 76,225 and 214 kg oxygen, respectively, and export, deaeration, biochemical oxygen demand, plant respiration and benthic respiration in the daily loss of 30, 89, 91, 97 and 335 kg oxygen, respectively. These processes are highly dynamic, with substantial daily turnover in the water mass. Benthic sediments; enriched with organic matter, exercise a major influence on the dissolved oxygen content of the water.

scholarly journals Ecological characteristic of water in the Eastern Bosporus Strait by oxygen parameters

2015 ◽  
Vol 181 (2) ◽  
pp. 161-168
Author(s):  
Nadezhda K. Khristoforova ◽  
Alexander A. Emelyanov ◽  
Ksenia S. Berdasova ◽  
Yulia E. Degteva
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Peter The Great Bay ◽  
Oxygen Demand ◽  
Japan Sea ◽  
High Water ◽  
Sewage Water ◽  
University Campus ◽  
High Concentration ◽  
Peter The Great

Spatial distribution and seasonal variability of the basic ecological parameters for marine water, as dissolved oxygen content, biochemical oxygen demand, and permanganate oxidizability are considered for the Eastern Bosporus Strait (Peter the Great Bay, Japan Sea) on the data obtained in autumn, spring and summer seasons of 2013-2014, with special attention to the Ajax and Paris Bights of Russky Island on the southern coast of the Strait, changed significantly after construction of new university campus and marine aquarium. Normal oxygen regime is observed over the whole strait in autumn, but cases of low dissolved oxygen content, close to the minimal permissible level, are revealed in spring and summer. This phenomenon is an important feature of environmental conditions in the Strait in the warm period. It is possibly reasoned by general pollution of marine environments by sewage water, high water temperature, and relatively high concentration of suspended matter caused by active water circulation in the narrow strait and heavy rains. However, there is no any specific anthropogenic impact on the oxygen content in the Ajax and Paris Bights.

The Oxygen Supply to Salmon Eggs in Spawning Beds

1954 ◽  
Vol 11 (6) ◽  
pp. 933-953 ◽  
Author(s):  
W. Percy Wickett
Keyword(s):  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Oxygen Demand ◽  
Subsurface Water ◽  
Flow Section ◽  
Apparent Velocity ◽  
Low Oxygen ◽  
Salmon Eggs ◽  
Controlled Flow

By using standpipes set 12 inches into the stream bottom the oxygen content and apparent velocity of the gravel water in the controlled-flow section of Nile Creek were observed. Values of dissolved oxygen content and velocity that just supply the full oxygen demand of salmon eggs were defined. The high mortalities of chum salmon eggs in the pre-eyed stage, that have been found in certain areas, may be explained on the basis that oxygen demands of 0.00013 to 0.0003 mg./egg/hr. at temperatures of 0.1° to 8.2 °C. were not being met, owing to very low oxygen content or very low apparent velocity of the water in the gravel. Values as low as 0.2 p.p.m. and 2 mm./hr. were recorded. A portable gravel-water sampler is described, which can be used (1) to obtain samples of subsurface water for the determination of dissolved oxygen; and (2) to calculate apparent velocity of gravel water from rate of dilution of an added dye.

New Approach to the Nonlinear Analysis of a Chemostat with Impulsive State Feedback Control

2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Kaibiao Sun ◽  
Andrzej Kasperski ◽  
Yuan Tian ◽  
Lansun Chen
Keyword(s):  
Feedback Control ◽  
Substrate Concentration ◽  
State Feedback ◽  
Dynamic Properties ◽  
Substrate Inhibition ◽  
Biomass Concentration ◽  
State Feedback Control ◽  
Objective Functions ◽  
New Approach ◽  
Existence And Stability

Bioreactor control is an important area of research concerning continuous microorganism cultivation. The possible occurrence of the substrate inhibition phenomenon or substrate deficiency engenders the necessity to the control the substrate concentration. Moreover in order to maintain the dissolved oxygen content in an appropriate range, the biomass concentration should not exceed the set out level. To maintain the substrate and biomass concentration in certain desired ranges, a proposal of a new chemostat with pulse state feedback control is presented in the work. Then, a universal mathematical model of the chemostat is formulated, and the dynamic properties of the model including the existence and stability of the periodic solution are discussed. After this, in order to optimize the biomass production, two objective functions are introduced and the optimization is performed. The work shows that the proposed chemostat extends functionality of a chemostat providing in easy way the control of biomass and substrate concentration. The analytical results presented in the work are validated by numerical simulations.

Investigation of the Contribution of Natural Organic Runoff to Dissolved Oxygen Depletion in the Red Deer River

1979 ◽  
Vol 14 (1) ◽  
pp. 71-88
Author(s):  
S.E. Penttinen ◽  
P.H. Bouthillier ◽  
S.E. Hrudey
Keyword(s):  
Dissolved Oxygen ◽  
Red Deer ◽  
Stream Water ◽  
Oxygen Demand ◽  
Oxygen Depletion ◽  
Experimental Program ◽  
Nitrogen Budgets ◽  
Carbon And Nitrogen ◽  
Tributary Stream ◽  
Small Tributary

Abstract Studies on the chronic low dissolved oxygen problems encountered under winter ice in the Red Deer River have generally been unable to account for dissolved oxygen depletion in terms of known manmade inputs. An experimental program was developed to assess the possible nature and approximate bounds of oxygen demand due to natural organic runoff carried to the Red Deer River by a small tributary stream, the Blindman River. The study employed an electrolytic respirometer on stream water samples subjected to prior concentration by vacuum evaporation. Evaluation of carbon and nitrogen budgets in conjunction with the measured oxygen demand indicate that biochemical oxygen demand is originating with natural organic runoff in tributaries of the Red Deer River. The results provide a basis for estimation of the possible contribution to the observed oxygen demand in the Red Deer River originating from natural organic runoff.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

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