Biofiltration is a cost effective air pollution control technology for volatile organic compounds. Biofiltration of ethanol vapour from air stream was evaluated in this study. Experimental investigations were conducted on a laboratory scale biofilter, containing mixture of compost and polystyrene inert particles as the filter materials. Mixed consortium of activated sludge was used as a inoculum. The continuous performance of biofilter for ethanol removal was monitored for different concentrations and flow rates. The removal efficiencies decreased at higher concentrations and higher gas flow rates. A maximum elimination capacity of 195 g m-3 h-1 was achieved. The response of biofilter to shut down and restart-up operation showed that the biofilm has got a good stability.

Thiyagarajan R. Swaminathan

alcohol

Activated sludge

air pollution

article

Biodegradation

Biofilm

BIOFILTER

Pollution control

priority journal

IIT Madras is a public technical and research university located in Chennai, Tamil Nadu. Founded in 1959, it is recognised as an Institute of National Importance.

IIT Madras has been ranked as the top engineering institute in India for four years in a row by the National Institutional Ranking Framework of the MHRD

It currently offers undergraduate, postgraduate and research degrees across 16 disciplines in Engineering, Sciences, Humanities and Management. About 596 faculty belonging to science and engineering departments and centres of the Institute are engaged in teaching, research and industrial consultancy.

IIT Madras

Biodegradation of ethanol vapour in a biofilter

Bioprocess Engineering

Biofiltration is an aerobic degradation process in which a well-humidified contaminated air stream is passed through a porous packed medium that supports a thriving population of microbes. The removal of benzene vapor was investigated in a laboratory-scale biofilter packed with compost, inoculated with a mixed microbial consortium. This biofilter was operated continuously in six different phases for a period of 8 months at different flow rates, 0.024-0.144 m3 h-1 with benzene concentrations ranging up to 1.7 g m-3. Under steady-state conditions, the removal efficiencies (REs) in the biofilter was consistently greater than 78% when benzene loading was less than 20 g m-3 h-1. The maximum elimination capacity (EC) achieved in this study is 64 g m-3 h-1 at an inlet loading rate of 128 g m-3 h-1. The response of the biofilter to shutdown, restart operations and fluctuations in inlet con-centration, and flow rate was determined by subjecting the biofilter to inlet loads of up to 120 g m-3 h-1. The biofilter responded effectively to these loading conditions and was found to recover rapidly. The results from this study suggest that a compost biofilter is effective in treating benzene vapor under steady- and transient-conditions. © Springer-Verlag 2009.

Clean Technologies and Environmental Policy

Steady- and transient-state effects during the biological oxidation of gas-phase benzene in a continuously operated biofilter

Biological treatment systems such as biofilters offer a potential alternative to the existing physicochemical techniques for the removal of volatile organic compounds from gaseous emissions. In this experimental work, continuous phase biofiltration of xylene vapors were performed in a laboratory scale compost biofilter that was inoculated with a xylene-acclimatized consortium. The performance was assessed by continuously monitoring the removal efficiency (RE) and elimination capacity (EC) of the biofilter at loading rates varying between 2-220 g∈m-3∈h-1. The steady-state removal efficiencies were maintained between 60% and 90% up to a loading rate of 80 g∈m-3∈h-1. The removal efficiency decreased significantly at loading rates higher than 100 g∈m-3∈h-1. The pressure drop values were consistently less and insignificant in affecting the performance of the system. The present study also focuses in evaluating the stability of biofilter during shut down, restart, and shock-loading operations. An immediate restoration of biological activity after few days of starvation indicated their capability to handle discontinuous treatment situations which is more common to industrial biofilters. The sensitiveness of the biofilm to withstand shock loads was tested by abruptly increasing/decreasing the loading rates between 9-55 g∈m -3∈h-1, where, removal efficiencies between 60-90% were achieved. These results prove the resilience of the biomass and the stability of the compost biofilter. Anew, results from kinetic analysis reveal that, steady-state xylene removal in the biofilter can be adequately represented by Michaelis-Menten type kinetics, and the kinetic constants namely, EC max (120.4 g∈m-3∈h-1) and K s (2.21 g∈m-3) were obtained. © 2009 Springer Science+Business Media B.V.

Water, Air, and Soil Pollution

Effect of flow rate, concentration and transient-state operations on the performance of a biofilter treating xylene vapors

Biofiltration is a versatile waste gas and odour treatment technology that has gained much acceptance in recent years to treat Volatile Organic Compounds (VOCs). A compost-based biofilter unit inoculated with a mixed microbial population was examined to treat toluene vapours from a synthetic and real gas stream. This biofilter was operated continuously for a period of 8 months at different flow rates, 0.024-0.144 m3 h-1, with toluene concentrations ranging up to 2.3 g m-3. Removal efficiencies ranging from 40 to 95% and elimination capacities ranging from 3.5 to 128 g m -3 h-1 were observed depending on the initial loading rates. The dynamic behaviour of the biofilter was evident from the changes in the process conditions. The stability of the biomass was evident from the fast response of the biofilter to intermittent shut down and restart operations. The potential of the biofilter to handle industrial gas mixtures was proved with operation using a real sample from a pharmaceutical industry. Removal efficiencies of 60-90% for toluene and 60-80% for benzene from the gas mixture were achieved. © 2005 Elsevier Ltd. All rights reserved.

Process Biochemistry

Performance evaluation of a compost biofilter treating toluene vapours

Environmental Progress

Biofiltration of benzene contaminated air streams using compost-activated carbon filter media

Journal	Data powered by TypesetBioprocess Engineering
Publisher	Data powered by TypesetSpringer Verlag
ISSN	0178515X
Open Access	No