Removal of gaseous toluene using immobilized Candida tropicalis in a fluidized bed bioreactor

A pure yeast strain Candida tropicalis was immobilized on the matrix of powdered activated carbon, sodium alginate, and polyethylene glycol (PSP beads). The immobilized beads were used as fluidized material in a bioreactor to remove toluene from gaseous stream. Applied toluene loadings were 15.4 and 29.8 g/m3 h in Step 1 and Step 2, respectively, and toluene removal was found above 95% during the entire operation. A continuous pH decline was observed and pH of the suspension was just above 6 in Step 2 but no adverse effects on treatment efficiency were observed. The CO2 yield values were found to be 0.57 and 0.62 g-\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$C_{{{\text{CO}}_{2} }} /{\text{g-}}C_{\text{toluene}}$$\end{document} in Step 1 and Step 2, respectively. These values indicate that a major portion of toluene-carbon was channeled to yeast respiration even at higher toluene loading. In conclusion, immobilized C. tropicalis can be used as a fluidized material for enhanced degradation of gaseous toluene

Biodegradation of Gas-phase Styrene in a High-performance Biotrickling Filter using Porous Polyurethane Foam as a Packing Medium

A biotrickling filter (BTF) packed with porous polyurethane (PU) foam sheets was developed and operated for removal of gas-phase styrene. The specific surface area and void fraction of the PU foam sheet were determined to be 497 m(2)/m(3) and 0.92, respectively, by using mathematical modeling and experimental measurement. The effects of gas flow direction (co-current and counter-current), styrene loading rate and empty bed residence time on the efficiency of the BTF were analyzed. The BTF achieved a high elimination capacity of 4.0 similar to 5.0 kg styrene/m(3) day due to the high specific surface area of the PU foam. The BTF could be operated repeatedly when excessively-grown biomass was periodically removed, using circulating NaOH solution for 2 h every four day

Research on the aerodynamic resistance of trickle biofilter / Lašelinio biofiltro aerodinaminio pasipriešinimo tyrimai

A four – section trickle biofilter was constructed for experimental research. The filter was filled with the packing material of artificial origin. The material consists of plastic balls having a large surface area. The dependence of biofilter aerodynamic resistance on supply air flow rate and the number of filter sections was determined. The aerodynamic resistance of the biofilter was measured in two cases. In the first case, the packing material of the filter was dry, whereas in the second case it was wet. The experimental research determined that an increase in the air flow rate from 0.043 m/s to 0.076 m/s causes an increase in biofilter aerodynamic resistance from 30.5 to 62.5 Pa after measuring four layers of dry packing material. In case of wet packing material, biofilter aerodynamic resistance after measuring four layers of plastic balls increases from 42.1 to 90.4 Pa. Santrauka Eksperimentiniams tyrimams atlikti sukonstruotas keturių sekcijų lašelinis biofiltras. Filtras užpildytas dirbtinės kilmės įkrova, sudaryta iš didelį paviršiaus plotą turinčių plastikinių rutuliukų. Naudojant įkrovą, skirtą introdukuotų mikroorganizmų asociacijoms kultivuoti, nustatytos biofiltro aerodinaminio pasipriešinimo priklausomybės nuo tiekiamo oro srauto greičio ir sekcijų skaičiaus. Biofiltro aerodinaminis pasipriešinimas matuotas dviem atvejais: esant sausai ir sudrėkintai įkrovai. Nustatyta, kad didinant tiekiamo oro srauto greitį nuo 0,043 iki 0,076 m/s, įrenginio aerodinaminis pasipriešinimas išmatavus keturis įkrovos sluoksnius padidėja nuo 30,5 iki 62,5 Pa tuo atveju, kai įkrova sausa, ir nuo 42,1 iki 90,4 Pa, – kai įkrova sudrėkinta. Raktiniai žodžiai: lašelinis biofiltras; aerodinaminis pasipriešinimas; mikroorganizmai; įkrov