Phenol-containing Wastewater Research Articles

Treatment of phenol-containing wastewater by photoelectro-Fenton method using supported nanoscale zero-valent iron

This study presents the degradation of phenol by the photoelectro-Fenton method using nano zero-valent iron (nZVI) immobilized in polyvinyl alcohol-alginate beads. The effect of nZVI loading, H(2)O(2) concentration, pH, and initial phenol concentration on phenol degradation and chemical oxygen demand reduction was studied. The scanning electron microscope images of the nZVI beads were used to analyze their morphology, and their diameters were in the range of 500-600 μm. The concentration of nZVI in the beads was varied from 0.1 to 0.6 g/L. Fe(2+) leakage of 1 and 3 % was observed with 0.5 and 0.6 g/L of nZVI, respectively, and the observed beads' fracture frequency was 2 %, which confirmed the stability of the beads. The optimum operating conditions that arrived for better degradation were 0.5 g/L of nZVI, pH 6.2, and 400 mg H(2)O(2)/L. The treatment of effluent by this method increased the biodegradability index of the effluent, and the degradation data were found to follow pseudo first-order kinetics.

Simultaneous thermophilic hydrogen production and phenol removal from palm oil mill effluent by Thermoanaerobacterium-rich sludge

Thermoanaerobacterium-rich sludge was used for hydrogen production and phenol removal from palm oil mill effluent (POME) in the presence of phenol concentration of 100–1000 mg/L. Thermoanaerobacterium-rich sludge yielded the most hydrogen of 4.2 L H2/L-POME with 65% phenol removal efficiency at 400 mg/L phenol. Butyric acid and acetic acid were the main metabolites. The effects of oil palm ash, NH4NO3 and iron concentration (Fe2+) on hydrogen production and phenol removal efficiency from POME by Thermoanaerobacterium-rich sludge was investigated using response surface methodology (RSM). The RSM results indicated that the presence of 0.2 g Fe2+/L, 0.3 g/L NH4NO3 and 20 g/L oil palm ash in POME could improved phenol removal efficiency, with predicted hydrogen production and phenol removal efficiency of 3.45 L H2/L-POME and 93%, respectively. In a confirmation experiment under optimized conditions highly reproducible results were obtained, with hydrogen production and phenol removal efficiency of 3.43 ± 0.12 L H2/L-POME and 92 ± 1.5%, respectively. Simultaneous hydrogen production and phenol removal efficiency in continuous stirred tank reactor at hydraulic retention time (HRT) of 1 and 2 days were 4.0 L H2/L-POME with 85% and 4.2 L H2/L-POME with 92%, respectively. Phenol degrading Thermoanaerobacterium-rich sludge comprised of Thermoanaerobacterium thermosaccharolyticum, Thermoanaerobacterium aciditolerans, Desulfotomaculum sp., Bacillus coagulans and Clostridium uzonii. Phenol degrading Thermoanaerobacterium-rich sludge has great potential to harvest hydrogen from phenol-containing wastewater.

Isolation and characterization of a Rhodococcus strain with phenol-degrading ability and its potential use for tannery effluent biotreatment

Wastewater derived from leather production may contain phenols, which are highly toxic, and their degradation could be possible through bioremediation technologies. In the present work, microbial degradation of phenol was studied using a tolerant bacterial strain, named CS1, isolated from tannery sediments. This strain was able to survive in the presence of phenol at concentrations of up to 1,000 mg/L. On the basis of morphological and biochemical properties, 16S rRNA gene sequencing, and phylogenetic analysis, the isolated strain was identified as Rhodococcus sp. Phenol removal was evaluated at a lab-scale in Erlenmeyer flasks and at a bioreactor scale in a stirred tank reactor. Rhodococcus sp. CS1 was able to completely remove phenol in a range of 200 to 1,000 mg/L in mineral medium at 30 ± 2 °C and pH 7 as optimal conditions. In the stirred tank bioreactor, we studied the effect of some parameters, such as agitation (200-600 rpm) and aeration (1-3 vvm), on growth and phenol removal efficiency. Faster phenol biodegradation was obtained in the bioreactor than in Erlenmeyer flasks, and maximum phenol removal was achieved at 400 rpm and 1 vvm in only 12 h. Furthermore, Rhodococcus sp. CS1 strain was able to grow and completely degrade phenols from tannery effluents after 9 h of incubation. Based on these results, Rhodococcus sp. CS1 could be an appropriate microorganism for bioremediation of tannery effluents or other phenol-containing wastewaters.

Degradation of Phenol-containing Wastewater Using an Improved Electro-Fenton Process

Degradation of Phenol-containing Wastewater Using an Improved Electro-Fenton Process

Bioaugmentation with a novel alkali-tolerant Pseudomonas strain for alkaline phenol wastewater treatment in sequencing batch reactor

A novel alkali-tolerant strain JY-2, which could utilize phenol as sole source of carbon and energy, was isolated from activated sludge. It was identified as Pseudomonas sp. by 16S rDNA sequencing analysis. The appropriate conditions for strain growth and phenol biodegradation were as follows: pH 8.0–10.0 and temperature 23–30°C. With initial phenol concentrations of 225, 400, 550 and 750 mg/l, the degradation efficiencies were 94.9, 93.3, 89.3 and 48.2% within 40 h at pH 10.0 and 30°C, respectively. The alkaline phenol-containing wastewater treatment augmented with strain JY-2 in sequencing batch reactor (SBR) system was investigated, which suggested that the bioaugmented (BA) system exhibited the better performance for adjusting high pH to neutral value than the non-bioaugmented (non-BA) one. Also, the BA system showed strong abilities for phenol degradation and maintaining good sedimentation coefficient (SV30). The microbial community dynamics of both sequencing batch reactor (SBR) systems were analyzed by Denaturing Gradient Gel Electrophoresis (DGGE) technique, which showed substantial changes between the two systems. This study suggests that it is feasible to treat alkaline phenol-containing wastewater augmented with strain JY-2.

Biohydrogen production from cellobiose in phenol and cresol-containing medium using Clostridium sp. R1

Cellobiose fermentation in batch test using an isolated strain, Clostridium sp. R1, was investigated. The Clostridium sp. R1 achieved a maximum hydrogen yield of 3.5 mol H 2 mol −1 cellobiose at pH 6 and 30 °C, higher than most yields reported in literature. This strain can generate hydrogen from a number of carbohydrates, including galactose, glucose, mannose, maltose, sucrose, and starch. This strain can also convert cellobiose to hydrogen in the presence of toxic phenol or cresol. The inhibition effects of phenolic compounds on strain R1 activity followed phenol > p-cresol > o-cresol > m-cresol. Co-culturing with another strain, Clostridium butyricum, can co-degrade some of the phenol as substrates. The new isolated strain can yield hydrogen from phenol-containing wastewaters.

Biodegradation of phenol at high concentration by a novel fungal strain Paecilomyces variotii JH6

A novel phenol-degrading filamentous fungus, strain JH6, was isolated from activated sludge and identified as a member of Paecilomyces variotii based on standard morphological and phylogenetic analysis. The degradation assays suggested that the strain was able to utilize phenol as the sole source of carbon and energy at concentrations up to 1800 mg/l. The strain exhibited optimum phenol degradation performance with the addition of 100 mg/l glucose at pH 5, 37 °C. Haldane's model could be fitted to the growth kinetics data well over a wide range of initial phenol concentrations (100–1800 mg/l), with kinetic values μ max = 0.312 h −1, K s = 130.4 mg/l, and K i = 200 mg/l. The decay coefficient was found to be 0.0073 h −1. Complete phenol degradation by strain JH6 could be achieved in the presence of other toxicants, such as m-cresol and quinoline, which were often found in the real phenol-containing wastewater.

Biological hydrogen production from phenol-containing wastewater using Clostridium butyricum

Toxicity renders certain industrial effluents unfit for recovering its bioenergy content. An enriched single strain, Clostridium butyricum, was herein applied to fermentatively produce hydrogen from glucose in the presence of 200–1500 mg L −1 of phenol. The enriched C. butyricum yielded hydrogen at approximately 1.4 mol H 2 mol −1 glucose in the presence of 200–400 mg L −1 phenol. Significant inhibition of cell metabolism was noted at phenol concentration >1000 mg L −1. During glucose fermentation, phenol dosed at 200–400 mg L −1 was partly co-degraded. Ethanol and acetate were the primary metabolites, whose yields increased with increasing phenol concentration. The present results revealed the potential to harvest hydrogen from a toxic (phenol-containing) wastewater.

Insights into Removal of Phenol from Aqueous Solutions by Low Cost Adsorbents: Clays Versus Algae

Exchanged clays and cross-linked algae were compared based on their properties for the removal of phenol from aqueous solutions. Algae Lessonia nigrescens Bory (A1) and Macrocystis integrifolia Bory (A2) were cross-linked with CaCl2 to enhance their physical and mechanical properties. The natural clays were chemically-exchanged with salts of tetramethyl ammonium (B1), hexadecyltrimethyl ammonium (B2), and bencyltriethyl ammonium (B3) ions to increase their affinity towards organic substrates. The effects of pH and adsorbent dose were evaluated. pH exhibited a strong effect mainly on the phenol aqueous chemistry. Sorption isotherm results were modelled on the Langmuir and Freundlich equations and complemented with EDX analysis, indicating that adsorption of phenol from water was mostly driven by hydrophobic forces, with the exchanged bentonites being the adsorbents that reported the maximum adsorption capacities. Conversely, a polar surface adsorption is suggested for algae mostly by means of hydrogen bonding formation. These results provide further insight into the adsorption mechanism of phenol and analogues and their use as powerful and cheap adsorbent for the treatment of phenol-containing real wastewater.

Biodegradation and detoxication of phenol by using free and immobilized cells of Acinetobacter sp. XA05 and Sphingomonas sp. FG03

Strain XA05 and FG03 with high biodegradation activity of phenol were isolated from the activated sludge and phenol-contaminated soils in Northwest of China, respectively. DNA sequencing and homologous analysis of 16s rRNA gene identified that XA05 belonged to an Acinetobacter sp. and FG03 was closely related to the Sphingomonas sp. Cells of strain XA05 and FG03 were mixed at the ratio of 1:1, and polyvinyl alcohol (PVA) was used as a gel matrix to immobilize mixed cells by repeated freezing and thawing. Biodegradation was evaluated by determining phenol. Detoxication was evaluated by using Daphnia magna toxicity tests. The removal effciency of phenol and factors affecting phenol degradation were investigated, the stability of the immobilized cells was also reported. Experimental values indicated that both free cells and immobilized cells showed high phenol degradation effciencies, higher than 95% within 35 h with an initial concentration of 800 mg/L phenol, and the immobilized cells showed better performance than that of the suspended-culture cells. These results indicate that immobilized Acinetobncter sp. XA05 and Sphingomonas sp. FG03 possesses a good application potential in the treatment of phenol-containing wastewater.

Regeneration methods of decontamination of phenol-containing waste waters

Regeneration methods of phenol extraction from waste waters using evaporation, liquid extraction, adsorption, ion exchange and membrane techniques have been reviewed based on the data found in Khimiya (Russian Journal of Chemistry) issued after 1993.

Estimation of the contribution of immobilized biofilm and suspended biomass to the biodegradation of phenol in membrane contactors

Abstract The biodegradation of phenol by Pseudomonas putida BCRC 14365 at 30 °C and pH 7 was studied in microporous polypropylene (PP) hollow-fiber membrane contactors. The fibers were pre-wetted by ethanol to make them more hydrophilic. The initial cell concentration was fixed at 25 g/m3 (optical density, 0.064). In this system, microbial cells are separated from phenol-containing wastewater to avoid the toxic effect of phenol. Phenol could be completely degraded, even though the initial phenol level was high up to 2150 g/m3, with the help of not only suspended biomass but also membrane-attached biofilm. In order to quantitatively estimate the contribution of biofilm to the overall process, a simplified kinetic model was proposed that combines the steady mass transfer equations and dynamic growth kinetics of suspended cells but assumes the absence of membrane-attached biofilm. Under the phenol levels studied (500–2150 g/m3), it was shown that the amount of phenol removed by the biofilm was less than 50% during the process. Also, the contribution of biofilm remained not more than 35% when the initial phenol level was increased to 2150 g/m3.

PSEUDOMONAS PUTIDA P67.2 AND PSEUDOMONAS FLOURESCENS P75 BASED MICROBIAL SENSORS FOR BIOCHEMICAL OXYGEN DEMAND (BOD) MEASUREMENTS IN PHENOLIC WASTEWATERS OF OIL SHALE INDUSTRY

This study evaluates applicability of microbial sensors based on Pseudomonas putida P67.2 (Ps. p.) and Pseudomonas fluorescens P75 (Ps. fl) for BOD measurements in the phenol-containing wastewaters that mimic the wastewaters from oil shale industry. Sensors are calibrated with OECD synthetic wastewater. Linear range in calibration solution for Ps. p. and Ps. fl. sensors is BOD 0-50 mg/L and 0-65 mg/L, respectively. The steady state response time for both sensors is 15-45 min. Measurements show that although Ps. fl. has better sensitivity to calibration solution, the concurrence between sensor-BOD and BOD7 in phenol-spiked wastewater is better for Ps. p. sensor. In linear range the error is only 1.2–13%. For Ps. fl. the error in linear range is 17–55%. Preconditioning in phenol solution (BOD = 5 mg/L) increases sensor’s sensitivity to phenol considerably (52%). This study demonstrates that preconditioned microbial sensors with specifically selected cultures can give better results for fast BOD determination in specific wastewaters.

Identification of important microbial populations in the mesophilic and thermophilic phenol-degrading methanogenic consortia

Active mesophilic and thermophilic phenol-degrading methanogenic consortia were obtained after an 18-month acclimation and enriching process in the serum bottles, and characterized using the rRNA-based molecular approach. As revealed by cloning, fluorescence in situ hybridization (FISH) and terminal restriction fragment length polymorphism (T-RFLP), these two enrichments differed greatly in the community structures. The results for the first time suggest that group TA in the Deltaproteobacteria (88.0% of EUBmix FISH-detectable bacterial cell area) and Pelotomaculum spp. in the Desulfotomaculum family (81.2%) were the predominant fermentative bacteria under mesophilic (37 °C) and thermophilic (55 °C) conditions, respectively. These populations closely associated with mesophilic and thermophilic members of Methanosaetaceae, Methanobacteriaceae and Methanomicrobiales to mineralize phenol as the sole carbon substrate to carbon dioxide and methane. Moreover, these two enrichments could mineralize terephthalate and benzoate. During benzoate degradation in the mesophilic enrichment, a shift in the predominant bacterial population from Deltaproteobacteria group TA to Syntrophus spp. was observed, suggesting Syntrophus-related spp. could have a higher substrate affinity for benzoate. FISH further revealed that member of the Deltaproteobacteria group TA represented more than 68.3% of EUBmix FISH-detectable bacterial cell area in a full-scale mesophilic bioreactor treating phenol-containing wastewaters.

Preparation of rare-earth metal complex oxide catalysts for catalytic wet air oxidation

Catalytic wet air oxidation (CWAO) is one of the most promising technologies for pollution abatement. Developing catalysts with high activity and stability is crucial for the application of the CWAO process. The Mn/Ce complex oxide catalysts for CWAO of high concentration phenol-containing wastewater were prepared by coprecipitation. The catalyst preparation conditions were optimized by using an orthogonal layout method and single-factor experimental analysis. The Mn/Ce serial catalysts were characterized by Brunauer-Emmett-Teller (BET) analysis and the metal cation leaching was measured by inductively coupled plasma torch-atomic emission spectrometry (ICP-AES). The results show that the catalysts have high catalytic activities even at a low temperature (80°C) and low oxygen partial pressure (0.5 MPa) in a batch reactor. The metallic ion leaching is comparatively low (Mn<6.577 mg/L and Ce<0.6910 mg/L, respectively) in the CWAO process. The phenol, CODCr, and TOC removal efficiencies in the solution exceed 98.5% using the optimal catalyst (named CSP). The new catalyst would have a promising application in CWAO treatment of high concentration organic wastewater.

Biodegradation of phenol by free and immobilized Acinetobacter sp. strain PD12

A new phenol-degrading bacterium with high biodegradation activity and high tolerance of phenol, strain PD12, was isolated from the activated sludge of Tianjin Jizhuangzi Wastewater Treatment Facility in China. This strain was capable of removing 500 mg phenol/L in liquid minimal medium by 99.6% within 9 h and metabolizing phenol at concentrations up to 1100 mg/L. DNA sequencing and homologous analysis of 16S rRNA gene identified PD12 to be an Acinetobacter sp. Polyvinyl alcohol (PVA) was used as a gel matrix to immobilize Acinetobacter sp. strain PD12 by repeated freezing and thawing. The factors affecting phenol degradation of immobilized cells were investigated, and the results showed that the immobilized cells could tolerate a high phenol level and protected the bacteria against changes in temperature and pH. Storage stability and reusability tests revealed that the phenol degradation functions of immobilized cells were stable after reuse for 50 times or storing at 4°C for 50 d. These results indicate that immobilized Acinetobacter sp. strain PD12 possesses a good application potential in the treatment of phenol-containing wastewater.

Evaluation of sequencing batch reactor performance with aerated and unaerated FILL periods in treating phenol-containing wastewater

Performance of the sequencing batch reactor (SBR) treating synthetic phenolic wastewater at influent phenol concentrations from 100 to 1000 mg/L was evaluated. Two identical SBRs were built and operated with FILL, REACT, SETTLE and DRAW periods in the ratio of 4:6:1:1 for a cycle time of 12 h. One of the reactors was operated with aerated FILL (R1) and the other with unaerated FILL (R2). The treated effluent quality and the rate of degradation during REACT were the criteria for evaluating performance of the two reactors. The results showed that the FILL mode had no significant influence on the treatment efficiency of phenol and COD for the entire range of influent phenol concentrations investigated. However, reactor R1 required a relatively shorter REACT time for phenol removal as compared to R2. This meant that R1 had the advantage of providing treatment at a higher organic loading rate.

Effects of Nutrient Addition on Phenol Biodegradation Rate in Biofilm Reactors for Hypersaline Wastewater Treatment

Hypersaline wastewater, generated by many industrial activities, is difficult to treat through conventional biological processes. In this kind of hypersaline environment, complex nutrients are needed for the normal growth of many microorganisms. For this paper, the organisms were taken from a municipal wastewater treatment plant and acclimated to 15% salinity in a biofilm treatment process (Sequencing Batch Biofilm Reactor) during the treatment of phenol-containing synthetic wastewater. They are used to evaluate the effects of nutrient addition on the phenol biodegradation rate. Adding yeast extract, glucose, KCl and four mineral nutrients into the shaking flasks containing wastewater and cultivating organisms, revealed phosphate as the crucial nutrient stimulating phenol biodegradation at 15% salinity. The operation results of the sequencing batch biofilm reactor indicates that phosphate content increased up to five times the original level can increase the phenol removal rate by 150%. A 99% phenol removal efficiency could be achieved by shortening the reaction time in the biofilm reactor from 40h to 16h, compared with basic nutrients added. In this article we applied an applicable and effective shaking-culture method to determine nutrient requirements in biotreatment processes without stopping the running reactors.

Degradation of synthetic phenol-containing wastewaters by MBR

Phenol and their derivatives are widely used as raw material in the petrochemical industry and in oil refineries. The presence of phenols strongly reduces the biological degradation of the other components. This study shows the feasibility of the MBR treatment of a synthetic effluent containing a large amount of phenol. Using a biomass acclimated to phenol degradation, the critical conditions of membrane separation were determined: TMP = 100 kPa (1 bar) and v = 5 m s −1. In these conditions, the permeate flux remained constant and high with a permeability about 10 −3 L h −1 m −2 Pa −1 (100 L h −1 m −2 bar −1). The use of backpulsing enabled the permeate flux to increase by only 10%. On the other hand, backpulsing maintained a high constant permeate flux over several weeks. The membrane bioreactor process was evaluated in terms of membrane performance and biological degradation. The experiment of phenol degradation proved the effectiveness of the step of activated sludge acclimation, since a steady state was reached in a few hours. No phenol was detected in the permeate although a large quantity of phenol (50 g day −1) was degraded. The absence of suspended matter, the removal of a substantial amount of phenol and a good performance on organic substance removal show the excellent performances of MBR.

Anaerobic biological treatment of phenolic wastewater at 15–18 °C

Low-temperature, or psychrophilic (<20 °C) anaerobic digestion has been proven feasible for the mineralisation of simple wastewaters. In this study, hybrid expanded granular sludge bed-anaerobic filter (EGSB-AF) bioreactors were used to evaluate the feasibility of psychrophilic digestion for the treatment of phenol-containing wastewater. Efficient chemical oxygen demand and phenol removal were observed at organic and phenol loading rates of 5 kg COD m −3 d −1 and 0.4–1.2 kg phenol m −3 d −1 (400–1200 mg phenol [l wastewater] −1), respectively. There was no long-term accumulation of volatile fatty acids in the reactor systems. Methanogenic activity was developed under psychrophilic conditions but anaerobic methane-producing populations remained mesophilic throughout the trial of 415 days.