ABSTRACT
Plant based biofilters associated with microorganisms have been gaining popularity in controlling odorous compounds like volatile organic compounds (VOCs) as they are cost effective and an environment friendly alternative to conventional air pollution control techniques. In this context, here, we tried to evaluate the performance of potted plants based Claire’s biofilter for biodegradation of benzene. A sealed perspex chamber with lid and fan was designed to ensure minimum leakage, proper aeration and distribution of benzene inside the chamber. Five different ornamental indoor plants were placed inside the chamber sequentially and exposed to a concentration of 5 ppm benzene for 30 h each. The leakage of benzene was checked beforehand. Epipremnum aureum (Money plant) showed maximum benzene degradation in the aforementioned time period with a removal efficiency of 98%. The µmax and Ks values for 100 ppm concentration of benzene were calculated to be 0.284 h-1 and 0.427 g/m3, respectively.
ABSTRACT
Polycyclic aromatic hydrocarbons (PAHs) are precarious persistent pollutants derived from incomplete combustion of fossil fuel and petroleum products. Due to adverse effects of PAHs on the environment, the wastewater contaminated with PAHs needs to be treated prior to discharge in the water bodies. In the present study, we used immobilized polyurethane foam Pseudomonas pseudoalcaligenes NRSS3 for degradation of fluorene in packed bed bioreactor (PBBR) to stimulate biofilm and possibly enhance removal efficiency. The most affecting process parameters, such as pH, process time and temperature were optimized at batch mode and found to be 7.0, 8.0 days, and 30 °C, respectively. At the optimum condition, the bioreactor was operated in continuous mode up to 45 days and obtained results demonstrate that the maximum removal efficiency (RE) of 91.1% along with 27.3 mg/L day-1 of elimination capacity (EC) were observed. Biodegradation kinetics of fluorene were evaluated by Monod growth and Andrew-Haldane inhibition models and parameters were obtained to be µmax: 0.32 day-1; Ks: 10.8 mg/L by Monod while µmax: 0.47 day-1; Ks: 12.3 mg/L; 27.5 mg/L by Andrews-Haldane.
ABSTRACT
Polycyclic aromatic hydrocarbons (PAHs), often from petroleum oil spill, by-product of petroleum refining, incomplete combustion of fossil fuel, leakage in pipeline and underground storage, apart from the effluents of pesticide, dye, pigment, and drug industries, are considered carcinogenic and mutagenic. As the abundance of PAHs in the environment cause adverse effects on humans and ecosystem, the PAHs contamination needs to be monitored and such polluted sites require remediation. Conventional methods available for remediation of PAHs are adsorption, advance oxidation process, electrochemical remediation, solvent extraction, use of synthetic surfactants and photocatalytic remediation. These methods including the alternative Fenton oxidation technology are not only expensive but also produce secondary pollutants. In this study, we evaluated the performance of UV-Fenton-PBBR (Packed bed bioreactor) hybrid system for the treatment of polycyclic aromatic hydrocarbons (naphthalene and fluorene). Pseudomonas pseudoalcaligenes NRSS3 isolated from petroleum contaminated site and immobilized on Sterculia alata was used as packing media in the PBBR. The naphthalene and fluorene were taken as model polycyclic aromatic hydrocarbon (PAHs) with initial concentration of 400 mg/L. The optimum conditions for UV-Fenton oxidation were (pH: 3, Fe2+: 2.5 g/L, H2O2: 1000 mg/L) for naphthalene and (pH: 3, Fe2+: 3.0 g/L, H2O2: 1200 mg/L) for fluorene. The overall maximum removal efficiency of the combined system was found to be 96 and 94.7% for naphthalene and fluorene, respectively. GC-MS analysis confirmed the formation of catechol, 1-napthol, salicylic acid and phthalic anhydride as metabolites during degradation process. Biodegradation kinetics of naphthalene and fluorene were studied using Monod model and kinetics constants were found to be µmax: 0.3057 per day; Ks: 112.87 mg/L for naphthalene and µmax: 0.2921 per day; Ks: 114.75 mg/L for fluorene