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Hughes JM, Eberl HJ, Sonner S. A mathematical model of discrete attachment to a cellulolytic biofilm using random DEs. MATHEMATICAL BIOSCIENCES AND ENGINEERING : MBE 2022; 19:6582-6619. [PMID: 35730273 DOI: 10.3934/mbe.2022310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
We propose a new mathematical framework for the addition of stochastic attachment to biofilm models, via the use of random ordinary differential equations. We focus our approach on a spatially explicit model of cellulolytic biofilm growth and formation that comprises a PDE-ODE coupled system to describe the biomass and carbon respectively. The model equations are discretized in space using a standard finite volume method. We introduce discrete attachment events into the discretized model via an impulse function with a standard stochastic process as input. We solve our model with an implicit ODE solver. We provide basic simulations to investigate the qualitative features of our model. We then perform a grid refinement study to investigate the spatial convergence of our model. We investigate model behaviour while varying key attachment parameters. Lastly, we use our attachment model to provide evidence for a stable travelling wave solution to the original PDE-ODE coupled system.
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Affiliation(s)
- Jack M Hughes
- Department of Mathematics, University of British Columbia, 1984 Mathematics Rd., Vancouver, BC V6T 1Z2, Canada
| | - Hermann J Eberl
- Department of Mathematics and Statistics, University of Guelph, 50 Stone Rd E., Guelph, ON N1G 2W1, Canada
| | - Stefanie Sonner
- Radboud University, IMAPP - Mathematics, Postbus 9010, 6500 GL Nijmegen, The Netherlands
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An X, Cheng Y, Huang M, Sun Y, Wang H, Chen X, Wang J, Li D, Li C. Treating organic cyanide-containing groundwater by immobilization of a nitrile-degrading bacterium with a biofilm-forming bacterium using fluidized bed reactors. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 237:908-916. [PMID: 29551479 DOI: 10.1016/j.envpol.2018.01.087] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 01/13/2018] [Accepted: 01/26/2018] [Indexed: 06/08/2023]
Abstract
Organic cyanide are widely used as an ingredient in the production of plastics, synthetic rubbers, polymers, pharmaceuticals and pesticides or used in laboratories and industries as solvents. Although nitrile-containing wastewater is subjected to primary and secondary treatments, residual nitriles may slowly seep and further migrate through groundwater, resulting in the micropollution of groundwater by organic pollutants. In this study, water samples were collected from different study areas in North China during a period of 3y (from 2013 to 2015) and analyzed to evaluate organic cyanide (CN-) contamination in groundwater. Three parallel lab-scale fluidized bed reactors (FBRs) were tested for their ability to remove organic cyanide from groundwater. The organic cyanide concentration in groundwater increased significantly (P < 0.05) from 2013 to 2015. With an optimal hydraulic residence time (HRT) of 54 min, reactor R3 (inoculated with a nitrile-degrading bacterium, BX2, and a biofilm-forming bacterium, M1) effectively removed 99.8% of CN- under steady operation, which was better than that of other reactors. Short-term shutdowns of FBRs had no serious effects on the efficiency of treating organic cyanide. This work demonstrated that the biofilm-forming bacterium could facilitate the fixation of nitrile-degrading bacterium and enhance the efficiency of removing organic cyanide from groundwater.
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Affiliation(s)
- Xuejiao An
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Yi Cheng
- College of Science, China Agricultural University, Beijing 100083, PR China
| | - Mingyan Huang
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Yueling Sun
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Hailan Wang
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Xi Chen
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Jinming Wang
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Dapeng Li
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China
| | - Chunyan Li
- College of Resources and Environment, Northeast Agricultural University, Harbin 150030, Heilongjiang, PR China.
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