Performance Study of Chromium (VI) Removal in Presence of Phenol in a Continuous Packed Bed Reactor byEscherichia coliIsolated from East Calcutta Wetlands

Abstract

Organic pollutants, like phenol, along with heavy metals, like chromium, are present in various industrial effluents that pose serious health hazard to humans. The present study looked at removal of chromium (VI) in presence of phenol in a counter-current continuous packed bed reactor packed with E. coli cells immobilized on clay chips. The cells removed 85% of 500 mg/L of chromium (VI) from MS media containing glucose. Glucose was then replaced by 500 mg/L phenol. Temperature and pH of the MS media prior to addition of phenol were 30°C and 7, respectively. Hydraulic retention times of phenol- and chromium (VI)-containing synthetic media and air flow rates were varied to study the removal efficiency of the reactor system. Then temperature conditions of the reactor system were varied from 10°C to 50°C, the optimum being 30°C. The pH of the media was varied from pH 1 to pH 12, and the optimum pH was found to be 7. The maximum removal efficiency of 77.7% was achieved for synthetic media containing phenol and chromium (VI) in the continuous reactor system at optimized conditions, namely, hydraulic retention time at 4.44 hr, air flow rate at 2.5 lpm, temperature at 30°C, and pH at 7.

Biochemical degradation of Methylene Blue using a continuous reactor packed with solid waste byE. coliandBacillus subtilisisolated from wetland soil

“…The rate of transfer of substrate through the diffusion was inversely proportional to the thickness of this layer. On the other hand, the thickness of this layer was inversely proportional to the substrate flow rate through the reactor [20][21][22]. The hydraulic retention time of the substrate in the reactor was inversely proportional to substrate flow rate.…”

Improvement of simultaneous Cr(VI) and phenol removal by an immobilised bacterial consortium and characterisation of biodegradation products

“…Despite the decreased removal efficiency over time, the successful use of beads in up to 4-5 cycles is important since it could significantly reduce operational costs in industrial applications. Nevertheless, although the possibility of reusing immobilised cells makes them more efficient than free cells, use of immobilised bacteria for co-remediation of organic and inorganic compounds has not yet been intensively explored [2,39].…”

“…Cr(VI) and phenol are toxic chemicals released into the environment through wastewaters from a large number of industries, including tanning, oil refineries, paint manufacturing and chemical plants [1,2].…”

Artificial Neural Networks (ANNs) and Response Surface Methodology (RSM) Approach for Modelling the Optimization of Chromium (VI) Reduction by Newly IsolatedAcinetobacter radioresistensStrain NS-MIE from Agricultural Soil

“…It was first described as a shiny grey metal that is unscented, hard crystalline, tasteless, and lustrous. Chromium is one of the elements in the transition group VIB besides tungsten and molybdenum in the twenty-fourth position of the periodic table [3]. Nearly 0.037% of the earth's crust is comprised of chromium making it as the seventh most abundant element in the earth.…”