CLEANING OF H2S FROM POLLUTED AIR USING PEAT BIOFILTER

Every year about 64 thousand tons of polluted air is being released to the ambient air. More than 30% of this pollution consists of toxic sulfur compounds. The properties of biological air cleaning technology – biofoltration with peat media – has been discussed in the article. Research was performed by using biofilter from Vilnius Gedimi-nas technical university laboratory. During testing ambient air, polluted with sulfur dioxide, was pulled through the biomedia with division of Thiobacillus microorganisms and calculations of cleaning efficiency were performed. Was determined the efficiency of peat biofilter charge (changing the technical characteristics of the air flow rate, the number of layers, the pollutant concentration value) depending on the nature of the investigated sulfur compounds and their concentrations.

Removal of Herbicides from Landfill Leachate in Biofilters Stimulated by Ammonium Acetate

At a former Danish polluted landfill, a field experiment using biofilters as an ex-situ remediation strategy for leachate water was carried out. The leachate water was polluted with phenoxy acids, mecoprop, dichlorprop, and their impurities originated from previous years of disposal of production wastes. Three individual biofilters were set up and each was filled with different a support material, e.g., sand, stonewool, and peat amended sand. The sand biofilter was spiked with ammonium acetate in pulses lasting a week to stimulate biomass growth and thereby enhance the removal of the phenoxy acids. The effects on removal and enantioselectivity were studied during a 69-day sampling campaign. Results showed that stimulation of the microbial community with ammonium acetate provided a boost, hence removal in the sand biofilter increased after the dosing whereas the stonewool and peat biofilters showed generally low removal. The highest removal was observed after stimulation in the sand biofilter for both herbicides. After a starting period, the removal was compound-specific but ranged from 60–100%. The final concentrations exceeded the drinking water limits slightly (0.25 µg L−1) (mecoprop and 2-(2/4-chlorophenoxy)propanoic acid), while it was considerably below the limit for all other compounds (2-(2-methylphenoxy)propanoic acid and dichlorprop). Enantioselective fractions were already 0.41, and 0.75 for mecoprop and dichlorprop, respectively, in the inlet, probably due to in-situ degradation in the landfill—Mecoprop showed some enrichment of the (R)-enantiomer in the sand biofilter whereas no real trends were seen in the stonewool and peat biofilter. Only minor alterations in enantiomeric fractions were observed for dichlorprop in all three biofilters. This experiment shows that it is feasible to remove micropollutants from landfill leachates and it is possible to stimulate biomass and thereby initiate and obtain increased removal faster.

REMOVAL OF SO2 FROM CONTAMINATED AIR USING A PEAT BIOFILTER / SO2 ŠALINIMAS IŠ UŽTERŠTO ORO NAUDOJANT BIOFILTRĄ SU DURPIŲ ĮKROVA

About 64 thousand tons of contaminated air is annually released into ambient air. More than 30% of such pollution includes toxic sulfur compounds. The article discusses the properties of biofiltration - biological air cleaning technology. Research was performed using a biofilter produced in the laboratory at Vilnius Gediminas Technical University. During testing, ambient air contaminated with sulfur dioxide was pulled through biomedia with a division of Thiobacillus microorganisms, and calculations of cleaning efficiency were performed. Besides, the efficiency of the charged peat biofilter (changing technical characteristics of the air flow rate, number of layers and value of pollutant concentration), depending on the nature of the investigated sulfur compounds and their concentrations, was determined. The biofilter improves the efficiency of air cleaning when the air flow rate reduces from 0,1 to 0,02 m/s (e.g. when sulfur dioxide is used for treating the air flow rate under the initial concentration C = 15 mg/m³, the efficiency of the filter is equal to E = 96,3%). Santrauka Didžiausia šiais laikais išsivysčiusių ir besivystančių šalių problema yra greitai besiplečiančių pramonės ir energetikos sektorių į aplinkos orą išmetami cheminiai junginiai (apie 64 tūkst. tonų per metus), iš kurių apie 30 % – žmogui nuodingi ir aplinkai neigiamą poveikį darantys sieros junginiai. Trumpai aptariama biologinio oro valymo privalumai, pagrindinės pasirinktõs durpių bioįkrovos charakteristikos, pateikiama taikyta metodika bei sieros dioksido valymo iš oro eksperimentų rezultatai, aprašomas biofiltracijos procesas. Biofiltro oro valymo efektyvumas didėja mažinant valomo oro srauto greitį nuo 0,1 iki 0,02 m/s (valant sieros dioksidu užterštą orą, kai pradinė teršalo koncentracija C = 15 mg/m³), filtro efektyvumas yra E = 96,3 %.