Biodegradation of wastewater in alternating aerobic-anoxic lab scale pilot plant by Alcaligenes sp. S3 isolated from agricultural field.

The isolated microbial Alcaligenes sp. S3 from the agricultural field was used for the biodegradation of synthetic wastewater containing atrazine. This study was conducted in an alternating aerobic-anoxic lab scale pilot plant. The performance of continuously operated pilot plant was evaluated in three different phases with varying atrazine concentration. The best performance of plant was observed in phase-II. The atrazine (200 mg/L) having COD value 1356 mg/L was used with varying flow rate and 90.56% COD removal was obtained at a flow rate of 300 mL/h on 122th day of operation. The effect of process parameter like pH and DO on the performance of the reactor was studied. The GC-MS analysis was investigated, and urea was found the intermediate/metabolites of atrazine biodegradation. The kinetic parameters such as half saturation rate constant (Ks) 106.80 mg/L; maximum specific growth rate (µmax) 0.208 per day and inhibition constant (Ki) 374.91 mg/L were evaluated by Andrew-Haldane model.

Effect of mixing intensity on biodegradation of phenol in a moving bed biofilm reactor: Process optimization and external mass transfer study.

In this work, an effort has been made to design the process variables and to analyse the impact of mixing intensity on mass transfer diffusion in a moving bed biofilm reactor (MBBR). A lab-scale MBBR, filled with Bacillus cereus GS2 IIT (BHU) immobilized-polyethylene biocarriers, was employed to optimize the process variables, including mixing intensity (60-140 rpm), phenol concentration (50-200 mg/L), and hydraulic retention time (HRT) (4-24 h) using response surface methodology. The optimum phenol removal of 87.64 % was found at 100 rpm of mixing intensity, 200 mg/L of phenol concentration, and 24 h of HRT. The higher mixing intensity improved the substrate diffusion between the liquid phase and the surface of the biofilm. The external mass transfer coefficients were found in the range of 1.431 × 10-5-1.845 × 10-5 m/s. Moreover, the detection of catechol and 2-hydroxymuconic semialdehyde revealed that the Bacillus sp. followed the meta-cleavage pathway during the biodegradation of phenol.

Collective removal of phenol and ammonia in a moving bed biofilm reactor using modified bio-carriers: Process optimization and kinetic study.

The performance of a moving bed biofilm reactor (MBBR) with bio-carriers made of polypropylene-polyurethane foam (PP-PUF) was evaluated for the collective removal of phenol and ammonia. Three independent variables, including pH (5.0-8.0), retention time (2.0-12.0 h), and airflow rate (0.8-3.5 L/min) were optimized using central composite design (CCD) of response surface methodology (RSM). The maximum removal of phenol and ammonia was obtained to be 92.6, and 91.8%, respectively, in addition to the removal of 72.3% in the chemical oxygen demand (COD) level at optimum conditions. First-order and second-order kinetic models were analyzed to evaluate the pollutants removal kinetics in a MBBR. Finally, a second-order model was found to be appropriate for predicting reaction kinetics. The values of second-order rate constants were obtained to be 2.35, 0.25, and 1.85 L2/gVSS gCOD h for phenol, COD, and ammonia removal, respectively.

Novel investigation of the performance of continuous packed bed bioreactor (CPBBR) by isolated Bacillus sp. M4 and proteomic study.

The present study reveals the benzene degrading potential of bacterial species isolated from petroleum contaminated soil. Genomic analysis suggests that Bacillus sp. M4 was found to be dominating species. The process parameters were optimized and found to be pH 7.0 ±â€¯0.2, temperature 32 ±â€¯5 °C, immobilization time (20 days) and benzene concentration 400 mg/L. The maximum removal efficiency of benzene was calculated and found to be 93.13% at elimination capacity156 (mg/L/day) and inlet loading rate 192 (mg/L/day) achieved in 54th days of operation. In the study, the residual metabolites were analyzed by GC/MS analysis and identified as benzene-1,2-diol. In order to identify the responsible protein involved in the process of benzene biodegradation The proteomic study was performed and proteins were identified by MALDI-TOF analysis. The molecular docking was confirmed by the benzene biodegradation.

Bioremediation of Congo red dye in immobilized batch and continuous packed bed bioreactor by Brevibacillus parabrevis using coconut shell bio-char.

In the present study, bacterial species capable of degrading colour waste were isolated from the water bodies located near the carpet cluster in the Bhadohi district of U.P., India. Among the isolated species best one was selected on the basis of its capability to degrade Congo red in batch experiments using NaCl-Yeast as the nutrient media and further it was identified as Brevibacillus parabrevis using 16S rDNA sequencing. The process parameters were optimized for maximum degradation in batch experiments and found out to be: Inoculum size: 3 ml, Temperature: 30 °C, Time: 6 days leading to a removal of 95.71% of dye sample. The experiment showed that bacteria immobilized with coconut shell biochar in continuous mode showed much better degradation than batch study without immobilization. The kinetics parameters µmax, Ks, and µmaxKs were found to be 0.461 per day, 39.44 mg/day, and 0.0117 L/mg/day using Monod model.

Assessment of pesticides removal using two-stage Integrated Aerobic Treatment Plant (IATP) by Bacillus sp. isolated from agricultural field.

The biodegradation of synthetic wastewater containing Atrazine, Malathion and Parathion was studied in two stage Integrated Aerobic Treatment Plant using Bacillus sp. (consortia) isolated from agricultural field. The influent stream containing these pesticides with initial COD of 1232mg/L were fed to first reactor and treated effluent of first reactor was fed to second reactor. The maximum removal of pesticides in IATP was found to be greater than 90%. The various process parameters such as pH, DO, Redox potential and BOD5/COD were monitored during the treatment. The degradation of pesticides and its metabolites in the treated effluent were confirmed by GC-MS. Kinetic parameters such as first order rate constant (Kobs), cell yield (YX/C) and decay coefficients (Kdp) were evaluated and found to be 0.00425 per hr, 0.696mg of COD/mg MLSS and 0.0010 per hr respectively. This integrated process was found more effective than physico-chemical treatment of pesticides.

Biodegradation and kinetic study of benzene in bioreactor packed with PUF and alginate beads and immobilized with Bacillus sp. M3.

Benzene removal in free and immobilized cells on polyurethane foam (PUF) and polyvinyl alcohol (PVA)-alginate beads was studied using an indigenous soil bacterium Bacillus sp. M3 isolated from petroleum-contaminated soil. The important process parameters (pH, temperature and inoculums size) were optimized and found to be 7, 37°C and 6.0×108CFU/mL, respectively. Benzene removals were observed to be 70, 84 and 90% within 9days in a free cell, immobilized PVA-alginate beads and PUF, respectively under optimum operating conditions. FT-IR and GC-MS analysis confirm the presence of phenol, 1,2-benzenediol, hydroquinone and benzoate as metabolites. The important kinetic parameter ratios (µmax/Ks; L/mg·day) calculated using Monod model was found to be 0.00123 for free cell, 0.00159 for immobilized alginate beads and 0.002016 for immobilized PUF. Similarly inhibition constants (Ki; mg/L) calculated using Andrew-Haldane model was found to be 435.84 for free cell, 664.25 for immobilized alginate beads and 724.93 for immobilized PUF.

Performance evaluation of Malathion biodegradation in batch and continuous packed bed bioreactor (PBBR).

The aim of this work was to study the biodegradation of Malathion in batch and continuous packed bed (Polyurethane foam; PUF) bioreactor (PBBR). After 10days, 89% Malathion removal was observed in batch PBBR. Continuous PBBR was operated at various flow rates (5-30mL/h) under optimum condition over a period of 75days. Inlet loading rates and elimination capacities were observed in the range of 36-216 and 7.20-145.4mg/L/day with an average removal efficiency of more than 90% under steady state conditions. GC/MS analysis confirms phosphorodithionicacid,O,O,S-trimethylester and diethylmercaptosuccinate as metabolites. Biodegradation of Malathion under inhibitory and non-inhibitory conditions was studied using Monod and Andrew-Haldane models and the kinetic constants were calculated and found to be µmax: 0.271 per day; Ks: 126.3mg/L using Monod and µmax: 0.315 per day; Ks: 151.32mg/L; Ki: 594.75mg/L using Andrew-Haldane models.

Biofiltration of xylene using wood charcoal as the biofilter media under transient and high loading conditions.

The main objective of this study was to evaluate the performance of wood charcoal as biofilter media under transient and high loading condition. Biofiltration of xylene was investigated for 150days in a laboratory scale unit packed with wood charcoal and inoculated with mixed microbial culture at the xylene loading rates ranged from 12 to 553gm-3h-1. The kinetic analysis of the xylene revealed absence of substrate inhibition and possibility of achieving higher elimination under optimum condition. The pH, temperature, pressure drop and CO2 production rate were regularly monitored during the experiments. Throughout experimental period, the removal efficiency (RE) was found to be in the range of 65-98.7% and the maximum elimination capacity (EC) was 405.7gm-3h-1. Molecular characterization results show Bacillus sp. as dominating microbial group in the biofilm.

Performance evaluation of an agro waste based biofilter treating toluene vapours.

Biodegradation of toluene vapour was investigated for 162 days in a laboratory scale biofilter packed with maize waste. Inlet concentration of toluene was varied from 2.86 to 5.79 g m(-3) and the volumetric flow rate of toluene loaded air from 0.09 to 0.3 m3 h(-1). The media bed height used in the study was 0.63 m. Plug flow behaviour of the bed was confirmed by RTD experiments. The steady state was achieved in 18 days. Depending upon initial loading rates, removal efficiency ranging from 54.5 to 85.3% and elimination capacity ranging from 43.47 to 174.6 g h(-1) m(-3) were observed during steady state operation. The dynamic behaviour of the biofilter was evident from response to change in process conditions. The stability of the biomass was evident from the fast response of the biofilter to shutdown and restart operations. High value of carbon recovery confirms the effective biodegradation in the biofilter. In the startup period, the pressure drop in the bed increased for some time after that it tended towards a constant value.

Analysis of Metabolites and Carbon Balance in the Biofilteration of Cumene Using Loofa Sponge as Biofilter Media.

A laboratory-scale biofilter study was performed to treat cumene-inoculated mixed culture of bacterial community and loofa sponge (Luffa cylindrica) as support media for a period of 120 days in five distinct phases. The removal efficiency was obtained in the range of 40-85 % with maximum elimination capacity of 700 g m(-3) h(-1) at the inlet load of 1167 g m(-3) h(-1). The result demonstrated that loofa sponge is good support media for the removal of cumene at higher loading rates. Loofa sponge was characterized via chemical analysis and analytical techniques such as XRD; FTIR; XPS; and CHN, and the result obtained confirms its suitability as biofilter media. The SEM results of loofa with inoculum shows the formation of a biofilm layer on the surface of loofa. The GC-MS analysis of leachate confirms the presence of different organic compounds such as acetaldehyde and 4-hydroxy-2-oxopentanoic acids which are stable metabolites during cumene biodegradation. About 12.69 % of carbon present in inlet cumene was converted to biomass.

Biofiltration of toluene using wood charcoal as the biofilter media.

A laboratory scale biofilter inoculated with Pseudomonas putida (MTCC 102) was used for degradation of toluene present in air. Wood charcoal was used as the filter media and a layer of glass beads (6mm) was used for improved air distribution. The biofilter was operated continuously for a period of 5months at four different flow rates - 0.06, 0.12, 0.18, and 0.24m(3)h(-1), with inlet concentration of toluene ranging from 0.04 to 4.5gm(-3). Air having toluene vapor was fed to the biofilter at various loadings ranging from 30.6 to 1104.5gm(-3)h(-1). The removal efficiency was obtained in the range of 70-99.5%. The maximum elimination capacity of 872.5gm(-3)h(-1) was observed at the inlet load of 1104.5gm(-3)h(-1). Wood charcoal was found to an effective biofilter media for toluene biodegradation.