A hybrid biological process of indoor air treatment for toluene removal

Abstract

Bioprocesses, such as biofiltration, are commonly used to treat industrial effluents containing volatile organic compounds (VOCs) at low concentrations. Nevertheless, the use of biofiltration for indoor air pollution (IAP) treatment requires adjustments depending on specific indoor environments. Therefore, this study focuses on the convenience of a hybrid biological process for IAP treatment. A biofiltration reactor using a green waste compost was combined with an adsorption column filled with activated carbon (AC). This system treated a toluene-micropolluted effluent (concentration between 17 and 52 µg/m 3 ), exhibiting concentration peaks close to 733 µg/m 3 for a few hours per day. High removal efficiency was obtained despite changes in toluene inlet load (from 4.2 × 10 −3 to 0.20 g/m 3 /hr), which proves the hybrid system's effectiveness. In fact, during unexpected concentration changes, the efficiency of the biofilter is greatly decreased, but the adsorption column maintains the high efficiency of the entire process (removal efficiency [RE] close to 100%). Moreover, the adsorption column after biofiltration is able to deal with the problem of the emission of particles and/or microorganisms from the biofilter.Implications: Indoor air pollution is nowadays recognized as a major environmental and health issue. This original study investigates the performance of a hybrid biological process combining a biofilter and an adsorption column for removal of indoor VOCs, specifically toluene.

Bibliometrics and Knowledge Map Analysis of Research Progress on Biological Treatments for Volatile Organic Compounds

“…With toluene as a research object, new technologies are being developed. Hybrid biological treatment technologies, such as biofiltration and adsorption, can be effective in treating VOCs [47]. The biofiltration system of Streptomyces griseus immobilized on activated carbon is feasible for removing toluene and increasing the reuse rate, providing a new solution for industrial applications [48].…”

A comparison of biofiltration performance based on bacteria and fungi for treating toluene vapors from airflow

“…Biological air pollution controls, which are a suitable alternative to conventional physico-chemical technologies, can convert a variety of compounds (such as VOCs) through the microorganisms activities into harmless elements. Thanks to the high efficiency and environmental friendly features, they are widely used by industries (Hort et al 2014;Li et al 2015;Rezaei et al 2014).…”

“…Toluene is a major VOC categorized by the European Commission's INDEX strategy report and it can be found in indoor air at detectable amounts ranging from a few μg/m 3 to 358 μg/m 3 (Baghani et al 2018;Geiss et al 2011;Hort et al 2014;Sarigiannis et al 2011).…”

Toluene Biodegradation using a Lab-Scale Biofilter Inoculated with Pseudomonas Putida PTCC 1694

“…Therefore, these processes overcome many disadvantages of traditional methods (Rojo N et al 2010). Thanks to this mechanism, microorganisms (bacteria, fungi, molds, mite, yeast) are generally the main removal agents (Hort C et al 2014, Schiavon M et al 2016.…”

“…Biological processes are suitable for low-medium concentrations of VOCs and they are considered as durable technologies (Hort C et al 2014). Among the advantages of these technologies are low impact on the environment, small amount of wastes, and negligible environmental consequences.…”