Evaluation of Trickle-Bed Air Biofilter Performance under Periodic Stressed Operating Conditions as a Function of Styrene Loading

Abstract

Trickle-bed air biofilters (TBABs) are suitable for treating volatile organic compounds (VOCs) at a significantly high practical loading because of their controlled environmental conditions. The application of TBAB for treating styrene-contaminated air under periodic backwashing and cyclical nonuse periods at a styrene loading of 0.64 -3.17 kg chemical oxygen demand (COD)/m 3 ⅐day was the main focus of this study. Consistent long-term efficient performance of TBAB strongly depended on biomass control. A periodic in situ upflow with nutrient solution under media fluidization, that is, backwashing, was approached in this study. Two different nonuse periods were employed to simulate a shutdown for equipment repair or during weekends and holidays. The first is a starvation period without styrene loading, and the second is a stagnant period, which reflects no flow passing through the biofilter.For styrene loadings up to 1.9 kg COD/m 3 ⅐day, removal efficiencies consistently above 99% were achieved by conducting a coordinated biomass control strategy, that is, backwashing for 1 hr once per week. Under cyclical nonuse periods for styrene loadings up to 1.27 kg COD/m 3 ⅐day, stable long-term performance of the biofilter was maintained at more than 99% removal without employing backwashing. No substantial impact of nonuse periods on the biofilter performance was revealed. However, a coordinated biomass control by backwashing subsequently was unavoidable for attaining consistently high removal efficiency at a styrene loading of 3.17 kg COD/m 3 ⅐day.As styrene loading was increased, reacclimation of the biofilter to reach the 99% removal efficiency following backwashing or the nonuse periods was delayed. After the nonuse periods, the response of the biofilter was a strong function of the biomass in the bed. No significant difference between the effects of the two different nonuse periods on TBAB performance was observed during the study period.

Interactions of hydrophobic and hydrophilic solvent component degradation in an air‐phase biotrickling filter reactor

“…Recent studies [24,25] have demonstrated that when the loading rate of a mixture of hydrophobic and hydrophilic compounds is below a saturation of the catabolic capacity of the mixed culture, both types of the components can reach a RE above 98%. The variations of the RE that manifested themselves at the high loading rates (Figures 3c and 5b-5d) agree with those of Kim et al [5] for toluene, styrene, and MIBK high loadings.…”

“…Paint solvents are particularly prevalent air pollutants and consist of a mixture of VOCs containing both hydrophobic and hydrophilic components. Their removal from waste air has recently been studied using biotrickling filters [2][3][4][5] and biofilters [6,7]. These studies have demonstrated the general efficacy of biological systems in treating paint solvent emissions.…”

Treatment of hydrophobic VOCs in trickling bed air biofilter: Emphasis on long-term effect of initial alternate use of hydrophilic VOCs and microbial species evolution

“…Liquid n-hexane was injected via a syringe pump and vaporized into the air stream. Buffered nutrient solution was supplied at a rate of 2.0 L day À1 ; the composition of the nutrient solution is similar to that reported by Kim et al (2005c). The experimental runs for the four biofilters were conducted in four phases (I-IV).…”

“…The detection limit was 0.001% v CO 2 . A detailed description of the analytical method was provided previously by Cai et al (2005) and Kim et al (2005c).…”

Effects of nitrogen source and empty bed residence time on the removal of styrene gaseous emissions by biotrickling filtration

“…The number of studies simulating industrial emissions has increased, aimed at proving the viability or adjusting the operating conditions of the technologies at an industrial scale. These experiments have involved treating mixtures of compounds [11], applying starving periods [12,13] or using transient conditions with or without activated carbon prefilters coupled to the bioreactor in order to operate the system under more stable conditions [14,15]. However, the technology must progress further before its use at an industrial scale, with few studies in the literature on pilot or industrial prototypes [16][17][18][19], and to facilitate this scale-up it is necessary to keep studying the process at the laboratory scale.…”