scholarly journals Kinetic modelling for removal of m-cresol from wastewater using mixed microbial culture in batch reactor

2012 ◽  
Vol 2 (3) ◽  
pp. 149-156 ◽  
Author(s):  
Sudipta Dey ◽  
Somnath Mukherjee

An indigenous mixed microbial culture isolated from an effluent treatment section of a coke oven plant has been studied for its m-cresol biodegradation capacity under aerobic batch reactor operation. The culture, after acclimatization could biodegrade up to 700 mg/L of m-cresol. The m-cresol concentration in the present study was at 50 mg/L and then ranged from 100 to 700 mg/L with step up concentration of 100 mg/L. Both biodegradation kinetics and microorganism growth kinetics were studied and kinetic parameters were estimated. The result showed that m-cresol was an inhibitory-type substrate and the inhibition effect became predominant after 200 mg/L of initial m-cresol. The specific growth rate of microorganisms increased up to 200 mg/L of m-cresol as sole carbon source, and then started decreasing. The kinetic data obtained in this study have been fitted to different substrate inhibition models (Haldane, Han-Levenspiel, Edward, Luong, Aiba, Teissier, Yano-Koga). Among all models, Han-Levenspiel and Luong were best fitted for this study (root mean square error = 0.001349). In addition, the variation of observed yield coefficient Yx/s with initial m-cresol concentration was investigated. The values of kinetic constants estimated by the models proved that the mixed culture used in the study had good potential for m-cresol degradation.

2017 ◽  
Vol 77 (4) ◽  
pp. 1079-1088 ◽  
Author(s):  
Mohit Prakash Mohanty ◽  
Bharati Brahmacharimayum ◽  
Pranab Kumar Ghosh

Abstract Mixed microbial culture collected from the wastewater treatment plant of Indian Institute of Technology Guwahati (IITG) was further grown in anaerobic condition in presence of sulfate where lactate was added as a carbon source. Sulfate addition was increased stepwise up to 1,000 mg l−1 before phenol was added at increasing concentrations from 10 mg l−1 to 300 mg l−1. Kinetics of sulfate, phenol and chemical oxygen demand reduction were studied and experimental findings were analyzed using various bio-models to estimate the bio-kinetic coefficients. This is the first detailed report on kinetics and bio-kinetic studies of sulfate reduction in presence of phenol. Experimental results showed that there was no inhibition of sulfate reduction and microbial growth up to 100 mg l−1 phenol addition. However, inhibition to different degrees was observed at higher phenol addition. The experimental data of microbial growth and substrate consumption in presence of phenol fitted well to the Edward model (R2 = 0.85, root mean square error = 0.001011) with maximum specific growth rate = 0.052 h−1, substrate inhibition constant = 88.05 mg l−1 and half saturation constant = 58.22 mg l−1. The characteristics of the cultured microbes were determined through a series of analysis and microbial tests.


2014 ◽  
Vol 70 (6) ◽  
pp. 1122-1128 ◽  
Author(s):  
Gang Chen ◽  
Maneesha P. Ginige ◽  
Anna H. Kaksonen ◽  
Ka Yu Cheng

Sulfanilic acid (SA) is a toxic sulfonated aromatic amine commonly found in anaerobically treated azo dye contaminated effluents. Aerobic acclimatization of SA-degrading mixed microbial culture could lead to co-enrichment of ammonium-oxidizing bacteria (AOB) because of the concomitant release of ammonium from SA oxidation. To what extent the co-enriched AOB would affect SA oxidation at various ammonium concentrations was unclear. Here, a series of batch kinetic experiments were conducted to evaluate the effect of AOB on aerobic SA degradation in an acclimatized activated sludge culture capable of oxidizing SA and ammonium simultaneously. To account for the effect of AOB on SA degradation, allylthiourea was used to inhibit AOB activity in the culture. The results indicated that specific SA degradation rate of the mixed culture was negatively correlated with the initial ammonium concentration (0–93 mM, R2 = 0.99). The presence of AOB accelerated SA degradation by reducing the inhibitory effect of ammonium (≥10 mM). The Haldane substrate inhibition model was used to correlate substrate concentration (SA and ammonium) and oxygen uptake rate. This study revealed, for the first time, that AOB could facilitate SA degradation at high concentration of ammonium (≥10 mM) in an enriched activated sludge culture.


2020 ◽  
Vol 12 (24) ◽  
pp. 10386
Author(s):  
Alba Pedrouso ◽  
Andrea Fra-Vazquez ◽  
Angeles Val del Rio ◽  
Anuska Mosquera-Corral

Polyhydroxyalkanoates (PHA) are biodegradable polymers that can be intracellularly produced by microorganisms valorizing organic-rich wastes. In the present study, a PHA production system was fed with mussel cooker wastewater after acidogenic fermentation. Besides low pH (4.0 ± 0.3) and high salt (21.7 ± 2.9 g NaCl/L) concentrations, this wastewater also contained nitrogen concentrations (0.8 ± 0.1 g N/L), which were previously reported to be a challenge to the PHA accumulating bacteria enrichment. Bacteria with a PHA storage capacity were selected in an enrichment sequencing batch reactor (SBR) after 60 days of operation. The enriched mixed microbial culture (MMC) was mainly formed by microorganisms from phylum Bacteroidetes, and genera Azoarcus, Comamonas and Thauera from phylum Proteobacteria. The MMC was able to accumulate up to 25 wt% of PHA that was mainly limited by the wastewater nitrogen content, which promoted biomass growth instead of PHA accumulation. Indeed, when the presence of nutrient was limited, PHA stored in the accumulation reactor increased to up to 40.9 wt%. This work demonstrated the feasibility of the enrichment of a MMC with a PHA storage ability valorizing the fish-canning industrial wastewater at low pH, which is generally difficult to treat in wastewater treatment plants.


2020 ◽  
Vol 10 (3) ◽  
pp. 200-207
Author(s):  
Sabbir Ansari ◽  
Tasneem Fatma

Background: Poly-3-hydroxybutyrate (PHB) has attracted much consideration as biodegradable biocompatible polymer. This thermoplastic polymer has comparable material properties to polypropylene. Materials with more valuable properties may result from blending, a common practice in polymer science. Objective: In this paper, blends of PHB (extracted from cyanobacterium Nostoc muscorum NCCU- 442 with polyethylene glycol (PEG) were investigated for their thermal, tensile, hydrophilic and biodegradation properties. Methods: Blends were prepared in different proportions of PHB/PEG viz. 100/0, 98/2, 95/5, 90/10, 80/20, and 70/30 (wt %) using solvent casting technique. Morphological properties were investigated by using Scanning Electron Microscopy (SEM). Differential scanning calorimetry and thermogravimetric analysis were done for thermal properties determination whereas the mechanical and hydrophilic properties of the blends were studied by means of an automated material testing system and contact angle analyser respectively. Biodegradability potential of the blended films was tested as percent weight loss by mixed microbial culture within 60 days. Results: The blends showed good misciblity between PEG and PHB, however increasing concentrations of plasticizer caused morphological alteration as evidenced by SEM micrographs. PEG addition (10 % and above) showed significant alternations in the thermal properties of the blends. Increase in the PEG content increased the elongation at break ratio i.e enhanced the required plasticity of PHB. Rate of microbial facilitated degradation of the blends was greater with increasing PEG concentrations. Conclusion: Blending with PEG increased the crucial polymeric properties of cyanobacterial PHB.


2008 ◽  
Vol 58 (5) ◽  
pp. 1101-1106
Author(s):  
Pichiah Saravanan ◽  
K. Pakshirajan ◽  
P. K. Saha

An indigenous mixed culture of microorganisms, isolated from a sewage treatment plant, was investigated for its potential to simultaneously degrade phenol and m-cresol during its growth in batch shake flasks. 22 full factorial designs with the two substrates as the factors, at two different levels and two different initial concentration ranges, were employed to carry out the biodegradation experiments. For complete utilisation of phenol and m-cresol, the culture took a minimum duration of 21 hrs at their low concentration of 100 mg/L each, and a maximum duration of 187 hrs at high concentration of 600 mg/L each in the multisubstrate system. The biodegradation results also showed that the presence of phenol in low concentration range (100–300 mg/L did not inhibit m-cresol biodegradation; on the other hand, presence of m-cresol inhibited phenol biodegradation by the culture. Moreover, irrespective of the concentrations used, phenol was degraded preferentially and earlier than m-cresol. During the culture growth, a lag phase was observed above a combined concentration of 500 mg/L i.e., 200 mg/L m-cresol and 300 mg/L of phenol and above). Statistical analysis of the specific growth rate of the culture in the multisubstrate system was also performed in the form of ANOVA and Student ‘t’ test, which gave good interpretation in terms of main and interaction effects of the substrates.


2019 ◽  
Vol 360 ◽  
pp. 1255-1261 ◽  
Author(s):  
Andrea Fra-Vázquez ◽  
Sergio Santorio ◽  
Tania Palmeiro-Sánchez ◽  
Ángeles Val del Río ◽  
Anuska Mosquera-Corral

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