Modelling the Simultaneous Adsorption and Biodegradation of Aromatic Hydrocarbons onto Non-Carbonized Biological Adsorbent in Batch System

In this study, a modified two-site sorption kinetic numerical model that differentiates between the adsorption and biodegradation quantities of a non-carbonized biological activated adsorbent (NCBAA) was developed and validated. Also, the effects of initial naphthalene and phenol concentrations on the simultaneous adsorption-biodegradation performances of orange and pineapple peel immobilized Pseudomonas aeruginosa NCIB 950 in naphthalene and phenol removal was respectively evaluated. Adsorption-biodegradation model was developed from the modification of a two-site kinetic numerical model by combining the elements of adsorption and biodegradation models and validation of the model carried out through the application of batch adsorption-biodegradation equilibrium and kinetic experimental data. Results showed that the model predictions of the naphthalene and phenol concentrations are in good agreement with the experimental data. For simultaneous adsorption-biodegradation of naphthalene by orange peel immobilized Pseudomonas aeruginosa, adsorption rate coefficient increased with initial naphthalene concentration and biodegradation rate coefficient decreased with increased initial concentration; and for phenol simultaneous adsorption-biodegradation by pineapple peel immobilized Pseudomonas aeruginosa, adsorption rate coefficient decreased with increased initial phenol concentration and biodegradation rate coefficient increased with increased initial phenol concentration. Thus, the adsorption-biodegradation model is a reasonable tool for simulating the adsorption-biodegradation behaviors of aromatic hydrocarbons in NCBAA. Keywords: Bacteria; Simultaneous adsorption-biodegradation; Phenol; Naphthalene; Non-carbonized biological activated adsorbent; Numerical model.

Biological removal of phenol from wastewaters: a mini review

Phenol and its derivatives are common water pollutants and include wide variety of organic chemicals. Phenol poisoning can occur by skin absorption, inhalation, ingestion and various other methods which can result in health effects. High exposures to phenol may be fatal to human beings. Accumulation of phenol creates toxicity both for flora and fauna. Therefore, removal of phenol is crucial to perpetuate the environment and individual. Among various treatment methods available for removal of phenols, biodegradation is environmental friendly. Biological methods are gaining importance as they convert the wastes into harmless end products. The present work focuses on assessment of biological removal (biodegradation) of phenol. Various factors influence the efficiency of biodegradation of phenol such as ability of the microorganism, enzymes involved, the mechanism of degradation and influencing factors. This study describes about the sources of phenol, adverse effects on the environment, microorganisms involved in the biodegradation (aerobic and anaerobic) and enzymes that polymerize phenol

Enhanced biodegradation of phenolic wastewaters with acclimatized activated sludge – a kinetic study

This work reports the biodegradation of phenol with enhanced efficiency in a sequencing batch reactor (SBR) after an acclimatization procedure with mixed culture activated sludge. The effects of temperature, initial phenol concentration and acclimatization procedure on phenol biodegradation were investigated. Acclimatization greatly favoured biodegradation rate of the phenol, while temperature showed no significant effect. After 60 days of acclimatization, the Haldane kinetic inhibition model indicated that activated sludge could degrade phenol at the maximum rate of 0.117 (g phenol/g VSS/h) at pH ~6 and phenol concentration of 400 mg/L at room temperature (T = 15–18 °C). Kinetic parameters including maximum phenol degradation rate (qmáx) of 0.521 (g phenol/g VSS/h), half-saturation constant (KS) of 692 mg/L and an inhibition constant KI of 231 mg/L were computed. The results of this study represent the highest phenol biodegradation efficiency in terms of the parameters such as time and phenol concentration, suggesting that acclimatized activated sludge exhibited a high resistant ability to phenol. In addition, inhibitory effects were identified at phenol concentrations higher than 400 mg/L. The system also showed high degree of stability and resistance to a load shock by increasing the initial concentration of phenol from 500 to 1000 mg/L.publishe

Biodegradation of Phenol in Petroleum Industry Produced Water by Estuary Mikroorganisms

The study was undertaken to calculated the biodegradation kinetic parameters of phenol in water and sediment estuary. Biodegradation of phenol compound in brackish water have special characteristic due to the effect of high salinity and the activities of special groups of microorganisms. The biodegradation of this compound is provided from laboratory experiments in batch reactor system. The culture for the biodegradation assay is taken from the sediment in the estuary of Mahakam River. The growth medium is made of seawater, with phenol as the substrate. The biodegradation is observed for 40 days. The initial phenol concentration in Reactor was 450.65 to 469.57 mg/l. The kinetic study showed that specific growth rate microorganism (µ) in sea water was 0.092 to 0.1356 day-1, the decay specific rate was 0.473 to 0.494 day-1, with the degradation rate was 11.19 to 11.73 mg/l.day-1.The dominant bacteria in the culture are Pseudomonas putida, Pseudomonas diminuta, Bacillus sphaericus, Enterobacter sp and pseudomonas sp. Key words: phenol, biodegradation, seawater, sediment, estuary, microorganis

Biodegradation of phenol by bacterial strain isolated from paper sludge

The objective of this project work is to study the degradation of phenol by bacterial strain isolated from paper sludge. Biodegradation is one of the cheapest methods without any production of hazardous by-products. The growth and phenol biodegradation study was carried out in MSM broth with phenol as the sole carbon source and energy. The strains were designated as S1, S2 and S3 and examined for colony morphology, Gram staining and biochemical tests. Phenol degrading performance of all the strains was evaluated initially. One of the strains namely S2 was found to be highly effective for the removal of phenol. The effect of temperature, pH and phenol concentration on the rate of phenol degradation by that particular strain was carried out. Observations revealed that the rate of phenol biodegradation was significantly affected by pH, temperature of incubation and phenol concentration. The optimal conditions for phenol removal were found to be pH of 8, temperature of 30°C and concentration of phenol of 200 ppm

Biodegradation and effect of formaldehyde and phenol on the denitrification process

Formaldehyde and phenol biodegradation during the denitrification process was studied at lab-scale, first in anoxic batch assays and then in a continuous anoxic reactor. The biodegradation of formaldehyde (260 mg l−1) as single carbon source and at phenol concentrations ranging from 30 to 580 mg l−1 was investigated in batch assays, obtaining an initial biodegradation rate around 0.5 g CH2O g VSS−1 d−1. With regard to phenol, its complete biodegradation was only observed at initial concentrations of 30 and 180 mg l−1. The denitrification process was inhibited at phenol concentrations higher than 360 mg l−1. Studies were also done using a continuous anoxic upflow sludge blanket reactor in which formaldehyde removal efficiencies above 99.5% were obtained at all the applied formaldehyde loading rates, between 0.89 and 0.14 g COD (CH2O) l−1 d−1. The phenol loading rate was increased from 0.03 to 1.3 g COD (C6H6O) l−1 d−1. Phenol removal efficiencies above 90.6% were obtained at phenol concentrations in the influent between 27 and 755 mg l−1. However, when the phenol concentration was increased to 1010 mg l−1, its removal efficiency decreased. Denitrification percentages around 98.4% were obtained with phenol concentrations in the influent up to 755 mg l−1. After increasing phenol concentration to 1010 mg l−1, the denitrification percentage decreased because of the inhibition caused by phenol

Treatment of Organic Wastewaters Using Microbial Fuel Cell Technology

The ability of microbial fuel cells (MFCs) to convert chemical or biochemical energy directly into electricity makes them well suited for treatment of wastewaters. Expanding the understanding of the processes and mechanisms that transpire in an MFC was the overall goal of this project with focus placed on the biological aspects of such systems. Biodegradation of model organic compounds of different structures commonly found in wastewaters, specifically lactate, acetate and phenol, and subsequently a representative wastewater was evaluated in H-type MFCs. Biodegradation of evaluated compounds was achieved with concomitant generation of electricity. In MFCs with rod electrodes and suspended microbial cells, substrate biodegradation was accompanied by microbial growth and rise in open circuit potential (OCP). Preferential use of model compounds and effectiveness of biodegradation was observed with lactate being the most favourable substrate followed by acetate and phenol. To promote cell immobilization, granular electrodes were employed which resulted in higher biodegradation rates and electrochemical outputs than those with rod electrodes. Biodegradation performance and associated power and current were improved in continuously operated MFCs. Higher biodegradation rates or removal efficiencies led to higher OCP, power and current indicating a correlation between biodegradation performance and electrochemical output. This correlation was evident in the biodegradation of organics in an internal process stream wastewater whereby the highest electrochemical output was attained when COD removal and coulombic efficiencies were at maximum. Application of neutral red (NR) enhanced the biodegradation of phenol and eliminated inhibition effects in batch MFCs but showed no improvement during continuous operation. Phenol biodegradation was not enhanced when combined with lactate, while the presence of phenol at high concentrations (≥500 mg L-1) negatively impacted the biodegradation of lactate. Co-biodegradation of lactate was more effective than phenol, especially in the continuous systems, and as a result higher power and current output were obtained with lactate. The developed biokinetic model was able to predict microbial growth and biodegradation kinetics in the MFC with high accuracy. The magnitude of biokinetics in MFCs were lower than those reported for conventional bioreactors indicating the need for development of suitable culture along with design of more sophisticated MFC bioreactors

Biodegradation of phenol by Pseudomonas pictorum on immobilized with chitin

Biodegradation of phenol using Pseudomonas pictorum (ATCC 23328) a potential biodegradant of phenol was investigated under different operating conditions. Chitin was chosen as a support material and then partially characterized physically and chemically. The pH of the solution was varied over a range of 7 – 9. The maximum adsorption and degradation capacity of bacteria immobilized with chitin at 30oC when the phenol concentration was 0.200 mg/L is at pH 7.0. The results showed that the equilibrium data for all phenol-degradation sorbent systems fitted the Langmuir, Freundlich and Redlich-Peterson model best. Kinetic modeling of phenol degradation was done using the pseudo-first order and pseudo-second order rate expression. The biodegradation data generally fit the intraparticle diffusion rate equation from which biodegradation rate constant, diffusion rate constant were determined

Bioremediation of Phenolic Compounds in Circulating Packed Bed Bioreactor

Wastewaters containing phenolic compounds such as phenol and cresols pose a high risk to human health and natural environment. Compared to physicochemical methods, bioremediation is an attractive alternative for removal of phenolic compounds from contaminated waters. This research aimed to evaluate bioremediation of phenolic compounds in batch systems and in continuously operated circulating packed bed bioreactors (CPBBs). The biodegradation of individual phenol, o-cresol, and p-cresol and mixtures of these compounds (binary and ternary mixtures) were studied. In addition to creating kinetic data on biodegradation of these contaminants, toxicity of the treated effluents generated under various conditions were assessed. Effects of initial concentrations and temperatures were investigated in batch system. Work in continuous flow CPBBs focused on the impact of phenols concentration and loading rate on the removal percentage and removal rate for influents containing individual and mixture of phenols (binary and ternary) for a wide range of conditions. The toxicity of treated effluent samples generated under various conditions was determined and compared with the employed influents to evaluate the potential risk of releasing the effluents into natural water bodies. In batch systems, a linear relationship between biodegradation rate and initial concentration of p-cresol or o-cresol was observed for the range of initial concentrations evaluated. The optimum temperature for biodegradation of p-cresol and o-cresol were 35 and 25 °C, respectively. In a binary mixture, the presence of phenol enhanced p-cresol biodegradation. During both binary- and ternary-biodegradation, p-cresol was the preferred substrate and utilized first, while phenol and o-cresol were used simultaneously (if both were present) upon complete exhaustion of p-cresol. The interaction of phenols in the ternary mixture was more complicated, as a result, polynomial models were used to describe the impact of initial concentration on biodegradation rate. It was shown that increase in p-cresol and o-cresol initial concentrations had positive effects on biodegradation rate of all three phenols, but their interaction appeared to impact the biodegradation rate negatively. In batch system the maximum observed biodegradation rates for phenol, p-cresol, and o-cresol were 17.8, 8.9, and 7.2 mg L-1 h-1, respectively. In continuous flow CPBBs, the maximum removal rates of phenol, p-cresol, and o-cresol were 82.6, 107.2, and 73.8 mg L-1 h-1 at the loading rates of 104.7 (residence time: 4.7 h), 183.9 (residence time: 2.8 h), and 163.9 mg L-1 h-1 (residence time: 1.8 h), respectively under mono-substrate biodegradation. For binary-substrate biodegradation, the presence of o-cresol had a negative impact on phenol removal rate, while p-cresol did not impose the same effect. The maximum removal rates of phenol and p-cresol during binary-substrate biodegradation were 89.2 and 78.4 mg L-1 h-1 at their respective loading rates of 137.9 and 123.9 mg L-1 h-1. The maximum removal rates of phenol and o-cresol during binary-substrate biodegradation were 119.9 and 70.3 mg L-1 h-1 at the respective loading rates of 209.8 and 112.9 mg L-1 h-1. When all three substrates were present in the influent, the maximum removal rates of phenol, p-cresol, and o-cresol were 129.2, 135.3, and 108.0 mg L-1 h-1 at their corresponding loading rates of 179.3, 195.9, and 165.7 mg L-1 h-1. It was also shown that p-cresol was the preferred substrate, followed by phenol and o-cresol. In case of untreated influents, p-cresol presented the most toxicity, followed by o-cresol, with phenol presenting the least toxicity among these three compounds. Toxicity evaluation of effluents obtained under various operating conditions revealed that overall treatment in CPBBs reduced the toxicity of influent containing phenolic compounds, although the decrease in toxicity differed pending on the operating conditions such as nature of phenolic compound, its influent concentration and loading rate

Exploring Kinetics of Phenol Biodegradation by Cupriavidus taiwanesis 187

Phenol biodegradation in batch systems using Cupriavidus taiwanesis 187 has been experimentally studied. To determine the various parameters of a kinetic model, combinations of rearranged equations have been evaluated using inverse polynomial techniques for parameter estimation. The correlations between lag phase and phase concentration suggest that considering phenol inhibition in kinetic analysis is helpful for characterizing phenol degradation. This study proposes a novel method to determine multiplicity of steady states in continuous stirred tank reactors (CSTRs) in order to identify the most appropriate kinetics to characterize the dynamics of phenol biodegradation