A biochar-based medium in the biofiltration system: Removal efficiency, microorganism propagation, and the medium penetration modeling

Abstract

Biofiltration is a method of biological treatment belonging to cleaner technologies because it does not produce secondary air pollutants, but helps to integrate natural processes in microorganisms for decomposing volatile air pollutants and solving odor problems. The birch wood biochar has been chosen as a principal material for biofilter bed medium. The experiments were conducted at the temperatures of 24, 28, and 32°C, while the concentration of acetone, xylene, and ammonium reached 300 mg/m 3 and the flow rate was 100 m 3 /hr. Before passing through the stage of the experimental research into the packing material inside biofilters, microorganisms were introduced. Four strains of microorganisms (including micromycetes Aspergillus versicolor BF-4 and Cladosporium herbarum 7KA, as well as yeast Exophiala sp. BF1 and bacterium Bacillus subtilis B20) were selected. At the inlet loading rate of 120 g/m 3 /hr, the highest elimination capacity of xylene in the biochar-based biofilter with the inoculated medium was 103 g/m 3 /hr, whereas that of ammonia was 102 g/m 3 /hr and that of acetone was 97 g/m 3 /hr, respectively. The maximum removal efficiency reached 86%, 85%, and 81%, respectively. The temperature condition (though characterized by some rapid changes) can hardly have a considerable influence on the biological effect (i.e., microbiological activity) of biofiltration; however, it can cause the changes in physical properties (e.g., solubility) of the investigated compounds.Implications: The birch biochar can be successfully used in the biofiltration system for propagation of inoculated microorganisms, biodegrading acetone, xylene, and ammonia. At the inlet loading rate of 120 g/m 3 /hr, the highest elimination capacity of xylene was 103 g/m 3 /hr, that of ammonia was 102 g/m 3 /hr, and that of acetone was 97 g/m 3 /hr, respectively. The morphological structure of biochar can be affected by the aggressive air contaminants, causing the change in the medium specific surface area, which is one of the factors controlling the biofilter performance. Although biological effects in biofiltration are typically considered to be more important than physical effects, the former may be more important for compounds with high Henry's Law coefficient values, and the biofilter design should thus provide conditions for better compound absorption.PAPER HISTORY

Review of organic and inorganic pollutants removal by biochar and biochar-based composites

“…The study confirmed that the application of a biofiltration bed containing BC can serve as a carbon source, which not only enhanced the efficiency of biological treatment systems but also enhanced the removal rate of contaminations. Baltrėnas et al (2016) examined the removal of xylene with birch wood BC-based filtration bed and the maximum removal efficiency reached 86%. BC effectively promoted the growth and reproduction of microorganisms, and the colony-forming units reached 10 7 -10 9 CFU/g for fungi, 10 7 -10 10 CFU/g for yeast, and 10 8 -10 10 CFU/g for bacteria, respectively.…”

Dissolved Organic Carbon Content and Leachability of Biomass Waste Biochar for Trace Metal (Cd, Cu and Pb) Speciation Modelling

“…In order to avoid potential drawbacks in BC water system application (e.g., filtering media) and to ensure the durability of BC in biofiltration systems (Baltrėnas et al 2016) or its application in soil (Baltrėnaitė et al 2016) resulting from leaching of DOC, it is fundamental to determine the rate of carbon content that is prone to leaching as DOC and its effect on trace metal speciation and mobility.…”

Lignoceliuliozinės žematemperatūrės bioanglies hidrofiliškumo didinimo tyrimai ir technologijos kūrimas

“…Per paskutinius kelis dešimtmečius padidėjusios atmosferinių teršalų emisijos tapo viena svarbiausių problemų, su kuria dabartiniame šimtmetyje susiduria pasaulio šalys. Nustatyta, kad oro tarša sukėlė 420 000 priešlaikinių žmonių mirčių Europos Sąjungoje (ES) vien 2010 m. (Baltrėnas et al, 2016). Lakiųjų organinių junginių (LOJ) emisijos sudaro apie 7 % visų atmosferos teršalų, kurių kiekis palaipsniui didėja nuo paskutinio šimtmečio pradžios.…”

“…Morfologinė analizė buvo atlikta naudojantis skenuojančiąja elektronų mikroskopija (SEM) (Baltrėnas et al, 2016). Prieš analizę mėginiai buvo džiovinami 105 °C temperatūroje 24 val., paskui paskirstyti (apytiksliai vienas šaukštas mėginio) ant Petri lėkštelės.…”