Biodegradation of naphthalene using Pseudomonas aeruginosa by up flow anoxic-aerobic continuous flow combined bioreactor.

Behrooz Karimi,Maryam Habibi,Mehry Esvand

doi:10.1186/s40201-015-0175-1

Abstract

BackgroundNaphthalene is a poly aromatic hydrocarbon (PAH) present in many sediment-water systems. The aim of this study was to evaluate the applicability of an anoxic/aerobic system for the biological treatment of water polluted by naphthalene by Pseudomonas aeruginosa PTCC 1707 to utilize naphthalene. The naphthalene elimination from wastewater was determined in anoxic–aerobic continuous flow combined bioreactor under continuously oxic and anoxic conditions. Experiments were conducted in continues mode, and naphthalene was administered in consecutive spike doses. Then Pseudomonas aeruginosa bacteria suspension with a specific turbidity (0.5-10 NTU) was prepared from growing bacteria on R2A medium and injected to reactor.FindingsAt naphthalene concentration = 0.5-20 mg/L, 33–65.5% naphthalene removal efficiencies were observed. Mean COD removal efficiency in solid retention times of 2, 4, 6, and 8 days was 82.7, 92.45, 95.97 and 96.1%, respectively. Naphthalene removal efficiency by bacterium pseudomonas at pH 8 was 96% and at pH 4, 5.5, 7 and 9.5, 68, 80, 90 and 85%, respectively. As the initial concentration of naphthalene increased from 0.5 to 20 mg/L, the remaining concentration of naphthalene decreased from 33.4% to 65.5% after 3 days.ConclusionBased on experimental results, it was determined that this process can effectively reduce naphthalene under optimal conditions and this method can be used for the removal of similar compounds.

Highlights

Remediation of contaminated soil and groundwater is an important issue that is of concern among environmentalists and hydrogeologists [1]
Concentration of the input glucose to the system was gradually reduced, while increasing naphthalene dose. This course continued to the point where the bacterium became perfectly compatible with naphthalene, and in presence of naphthalene, Chemical oxygen demand (COD) concentration was brought within range of 30–40 mg/L
Growth P. aeruginosa on anoxic–aerobic reactor To examine the growth of P. aeruginosa (OD and CFU/ mL) in vertical anoxic–aerobic continuous flow combined bioreactor and tolerance of naphthalene by P. aeruginosa, the cells were cultivated in nutrient broth with concentration of naphthalene

Summary

Introduction

Remediation of contaminated soil and groundwater is an important issue that is of concern among environmentalists and hydrogeologists [1]. PAHs originate from natural and anthropogenic sources. Studies of naphthalene degradation may be significant because naphthalene is a common pollutant that serves as a chemical model for the degradation of PAHs [5]. Naphthalene is a poly aromatic hydrocarbon (PAH) present in many sediment-water systems. The aim of this study was to evaluate the applicability of an anoxic/aerobic system for the biological treatment of water polluted by naphthalene by Pseudomonas aeruginosa PTCC 1707 to utilize naphthalene. Findings: At naphthalene concentration = 0.5-20 mg/L, 33–65.5% naphthalene removal efficiencies were observed. Naphthalene removal efficiency by bacterium pseudomonas at pH 8 was 96% and at pH 4, 5.5, 7 and 9.5, 68, 80, 90 and 85%, respectively. As the initial concentration of naphthalene increased from 0.5 to 20 mg/L, the remaining concentration of naphthalene decreased from 33.4% to 65.5% after 3 days

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