This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Diese Arbeit beschreibt ein Verfahren zur Optimierung eines großtechnisch realisierten Biofilters... more Diese Arbeit beschreibt ein Verfahren zur Optimierung eines großtechnisch realisierten Biofilters als biologische Abluftreinigungsanlage zur Behandlung von VOC-Emissionen aus der Tauchschleuderlackierung von Metallwerkstücken. Die Abluft besteht dabei zu nahezu gleichen Teilen aus hydrophilem Methoxypropylacetat sowie lipophilen Xylol-Isomeren. Nachdem im Technikumsmaßstab ein Biofilter als einstufiges Verfahren sich als ineffizient erwies (Wirkungsgrad unter 20 %), besteht die vorgeschlagene Lösung aus einer Kombination von Biowäscher und nachgeschaltetem Biotricklingfilter. Das System war wenig störanfällig und über lange Laufzeiten betriebsstabil bei einem Minderungsgrad von ca. 75 % im Dauerbetrieb.
Applied Microbiology and Biotechnology, May 3, 2015
Acidovorax sp. CHX100 has a remarkable ability for growth on short cycloalkanes (C5-C8) as a sole... more Acidovorax sp. CHX100 has a remarkable ability for growth on short cycloalkanes (C5-C8) as a sole source of carbon and energy under aerobic conditions via an uncharacterized mechanism. Transposon mutagenesis of Acidovorax sp. CHX100 revealed a novel cytochrome P450 monooxygenase (CYP450chx) which catalyzed the transformation of cyclohexane to cyclohexanol. Primer walking methods categorized CYP450chx as cytochrome P450 class I taking into account its operon structure: monooxygenase, FAD oxidoreductase, and ferredoxin. CYP450chx was successfully cloned and expressed in Escherichia coli JM109. The activity of CYP450chx was demonstrated by means of the indole co-oxidation. Biotransformation capability of CYP450chx was confirmed through the catalysis of cycloalkanes (C5-C8) to their respective cyclic alcohols.
Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in concentration... more Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in concentrations up to 30 w% of the total mass of the products. Worldwide consumption of technically relevant PBDE mixtures was about 7500 tons (penta-BDEs), 3790 tons (octa-BDEs) and 56,100 tons (deca-BDE) in 2001 and about 50-60% of this total volume was discharged into environment only by agricultural use of sewage sludges. The use of PBDEs was strictly regulated from 2004 onwards due to their high emission load and their effect as endocrine disrupters, neurotoxins, and fertility reducing agents. Nevertheless, soils worldwide are contaminated by gaseous and particle-bound transport of PBDEs. Therefore, the uptake of PBDEs from contaminated agricultural land via crops and the food chain is a major human exposure pathway. However, uptake and intrinsic transport behavior strongly depend on crop specifics and various soil parameters. The relevant exposure and transformation pathways, transport-relevant soil and plant characteristics and both root concentration factor (RCF) and transfer factor (TF) as derivable parameters are addressed and quantified in this chapter. Finally, based on available crop specific data a general statement about the transport behavior of PBDEs in twelve different crops according to relevant PBDE congeners is given.
A total of 11 bacterial strains capable of completely degrading 2-butoxyethanol (2-BE) were isola... more A total of 11 bacterial strains capable of completely degrading 2-butoxyethanol (2-BE) were isolated from forest soil, a biotrickling filter, a bioscrubber, and activated sludge, and identified by 16S rRNA gene sequence analysis. Eight of these strains belong to the genus Pseudomonas; the remaining three strains are Hydrogenophaga pseudoflava BOE3, Gordonia terrae BOE5, and Cupriavidus oxalaticus BOE300. In addition to 2-BE, all isolated strains were able to grow on 2-ethoxyethanol and 2-propoxyethanol, ethanol, n-hexanol, ethyl acetate, 2-butoxyacetic acid (2-BAA), glyoxylic acid, and nbutanol. Apart from the only gram-positive strain isolated, BOE5, none of the strains were able to grow on the nonpolar ethers diethyl ether, din -butyl ether, n-butyl vinyl ether, and dibenzyl ether, as well as on 1-butoxy-2-propanol. Strains H. pseudoflava BOE3 and two of the isolated pseudomonads, Pseudomonas putida BOE100 and P. vancouverensis BOE200, were studied in more detail. The maximum growth rates of strains BOE3, BOE100, and BOE200 at 30°C were 0.204 h-1 at 4 mM, 0.645 h-1 at 5 mM, and 0.395 h-1 at 6 mM 2-BE, respectively. 2-BAA, nbutanol, and butanoic acid were detected as potential metabolites during the degradation of 2-BE. These findings indicate that the degradation of 2-BE by the isolated gram-negative strains proceeds via oxidation to 2-BAA with subsequent cleavage of the ether bond yielding glyoxylate and n-butanol. Since Gordonia terrae BOE5 was the only strain able to degrade nonpolar ethers like diethyl ether, the degradation pathway of 2-BE may be different for this strain.
War-related contamination of water and sediment of the Tigris River within the urban area of Mosu... more War-related contamination of water and sediment of the Tigris River within the urban area of Mosul leads to seasonally independent exceedances of the WHO limit values for Cd, Pb, Cr, and Ni up to a factor of 100 in water and sediments. Furthermore, exceedances consistently occur for conductivity, PO 4 3-, and SO 4 2-, as well as sporadically for salinity and COD in water samples, and consistently for salinity in sediment samples, highlighting the direct impact of war (amunition, ignition of sulfur elds) as well as indirect effects (destroyed wastewater infrastructure). Con ict-related emissions from the former con ict zone (S5-S7) are highlighted by the sudden increases in load from S4 to S5, although partially masked by discharge of highly polluted water from the Khosr River (between S3 and S4). Due to sorption to sediments and presumed wind-borne discharge of highly polluted particles into the Tigris River, sediments at S10 on the southern edge of Mosul showed the highest pollutant loads. Signi cant statistical differences were observed by T-test analyses for E.C., TDS, salinity, COD, PO 4 3-, NO 3-, SO 4 2-, Cd, Pb, Zn, Cr, and Ni for water samples as well as salinity, Cd, Pb, Zn, and Cr for the sediment samples for seasonal comparison. Since the percentage difference of water samples at S4-S7 is smaller than upstream and downstream, contaminant input is not limited to rainwater, but also via year-round in ltration of highly polluted wastewater from the surrounding valleys or suburban areas as well as presumably polluted groundwater or windblown particulate input.
Etwa 10 bis 15 % aller industriellen Abluftsituationen sowie alle Emissionssituationen in der lan... more Etwa 10 bis 15 % aller industriellen Abluftsituationen sowie alle Emissionssituationen in der landwirtschaftlichen Tierhaltung können durch biologische Abluftbehandlungsverfahren ökonomisch und ökologisch effizient behandelt werden, tatsächlich kommen sie bis dato erst in ca. 1 % (Industrie) bzw. 0,4 % (Landwirtschaft) der entsprechenden Anlagen zum Einsatz. Begrenzungen in Wirkungsgrad, Rohgaskonzentration, Bioverfügbarkeit, Transformationskinetik, Abbau komplexer Schadstoffgemische, ein hoher Platzbedarf sowie hohe Druckverluste stellen hohe Markteintrittsbarrieren dar. Um diese Restriktionen zu beseitigen, wurden diverse neue, hier vorgestellte Füllkörper für Biotricklingfilter entwickelt, die die Vorteile der Tricklingfilter-Füllkörper mit denen der Biofilterpackungen kombinierten. In Abluftsituationen, die durch lipophile oder xenobiotische Abluftinhaltsstoffe geprägt werden, erweisen sich zunehmend Kombinationen aus nicht-biologischen und biologischen Verfahren oder aus verschiedenen biologischen Verfahren als ökonomisch und ökologisch effizient.
Beim Bedrucken von Folien in einem Druckereibetrieb treten großvolumige Abluftströme auf, die Eth... more Beim Bedrucken von Folien in einem Druckereibetrieb treten großvolumige Abluftströme auf, die Ethanol, Butanol sowie Ethoxy-2-propanol (EP) enthalten. Diese Abluft wird über einen Biowäscher gereinigt. Bei kontinuierlichem Betrieb tritt jedoch eine Akkumulation von Ethoxy-2-propanol im Waschwasser auf. Zusätzlich kommt es in unregelmäßigen Zeitabständen zu einem starken Biomassewachstum auf der Schüttung des Absorbers und somit zu dessen Verstopfung. Beide Probleme sollten einer Lösung zugeführt werden.
Die seit November 2007 für Altanlagen gültige TA Luft 2002 sieht eine signifikante Verschärfung d... more Die seit November 2007 für Altanlagen gültige TA Luft 2002 sieht eine signifikante Verschärfung der Abluftgrenzwerte vor, die aufgrund der vermeintlichen Nicht-Realisierbarkeit zu einer Substitution biologischer Verfahren führte. Am Beispiel eines bislang nicht konformen Biowäschersystems zur kombinierten biologischen Behandlung von Abwasser und-luft in einem Sonderabfallbehandlungsbetrieb wurde die TA Luft umgesetzt. Der Modernisierungsfortschritt des biologischen Verfahrens wurde analytisch vor Ort begleitet und das schadstoffspezifische Abbaupotenzial der Anlage im Labor verifiziert.
A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow... more A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow was operated for 1220 days for treatment of emissions of styrene and secondary emissions of germs formed in the biological process. The biotrickling filter was operated at variable inlet concentrations, empty bed residence times (EBRT), type and dosage of fertilizers, irrigation densities, and starvation periods, while dielectric barrier discharge and corona discharge were operated at different specific input energy levels to achieve optimal conditions. Under these conditions, efficiencies in the removal of volatile organic compounds (VOCs), germs and styrene of 96-98%, 1-4 log units and 24.7-50.1 g C m −3 h −1 were achieved, respectively. Fluid simulations of the NTP and a germ emission-based clocking of the discharge reveal further energy saving potentials of more than 90%. The aim of an energy-efficient elimination of VOCs through a biotrickling filter and of secondary germ emissions by a NTP stage in a downstream airflow for potential re-use of purified waste gas as process gas for industrial application was successfully accomplished.
Biotrickling filter (BTF) tend to accumulate biomass leading to clogging and a subsequent increas... more Biotrickling filter (BTF) tend to accumulate biomass leading to clogging and a subsequent increase in pressure losses and energy demands at high volatile organic compound (VOC) loadings under long-term conditions. Besides higher pressure losses and energy demands, the treatment performance gradually declines due to inhomogeneous gas distribution within the biofilm. Clogging prevention techniques are highly interesting regarding the design of BTFs, high performance levels, energy efficiency and corresponding costs. Squeezing out and backflushing as clogging prevention techniques with optional addition of auxiliary gas injections and chemicals were tested under various conditions. Five BTFs equipped with 17.6 L of different Poret® PPI10 PU foam structures were used to analyze removal efficiencies of both biomass and 2-butoxyethanol as VOC, testing different clogging prevention techniques in comparison to two reference systems without prevention steps. Up to 109.5 g organic dry matter were removed (270 s of gas injection, 0.2 w% sodium hydroxide).
Journal of environmental chemical engineering, Apr 1, 2018
Highlights Test plant for 600-650 m³•h-1 was installed at two organic waste treatment plants. ... more Highlights Test plant for 600-650 m³•h-1 was installed at two organic waste treatment plants. Combined process of NTP and adsorber showed higher performance than single stages. Odor abatement of 95.9-98.3% at 2.1-2.2 kWh•1000m-3 as SIE value. Removal of 62.9%, 15.9%, and 30.1% of VOCs, NH3, and CH4 at similar SIE values. NH3 and N2O were converted to NO and NO2 by the installed system.
Biogas internal combustion (IC) engines of less than 1 MW are either equipped with an oxidative c... more Biogas internal combustion (IC) engines of less than 1 MW are either equipped with an oxidative catalyst or operate at low-emission operation parameters to meet national emission standards of NO x , CO, VOCs, HCl, H 2 S, SO 2 , and formaldehyde safely. However, expensive oxidative catalysts have a limited lifetime of less than two years, and electrical efficiency at low-emission conditions is lower than that at optimal conditions, characterized by higher emission levels. While NO x levels increased seven times from 282.2 to 1965.7 mg NO x •m À3 by changing the operational parameters of the four-stroke gas engine (P el ¼ 360 kW), emission levels of CO and VOC slightly changed from 540.3 to 452.5 mg CO•m À3 and 509.6 to 329.9 mg C•m À3. Furthermore, NO x emission levels could be reduced by a minor air to gas ratio, but levels of VOC, CO, and HCl increased at these conditions as shown for a four-stroke gas engine (P el ¼ 635 kW). The emissions of the dual-fuel gas compression-ignition engine (P el ¼ 265 kW) were generally characterized by higher emission levels. A chemical scrubber with an optional subsequent biofilter was installed as a low-cost alternative for oxidative catalysts as a waste gas treatment system. Corresponding performance levels of the chemical scrubber were in the range of 28.3e38.6% (NO x), 19.2 e30.8% (CO), 22.6e23.8% (VOCs), and 33.3e70% (odor). Formaldehyde, which occurred at levels of 43.4 e59.6 mg m À3 , was almost completely eliminated by the scrubber after injection of ambient air, but the system failed in tests without air injection. The performance was further enhanced by addition of H 2 O 2. Further approaches in chemical removal of formaldehyde by addition of NH 3 or urea failed. The biofilter showed no treatment performance under thermophilic conditions. The amortization time of the scrubber system was less than three years, caused by economic benefits of higher electrical efficiency and substitution of the catalyst.
Eight mixed cultures able to degrade benzoic acid under saline conditions were established and ki... more Eight mixed cultures able to degrade benzoic acid under saline conditions were established and kinetic parameters were determined in batch processes with cultures SBM002 (0.5 g d À1 $g oDM À1), SBM003 (0.7 g d À1 $g oDM À1) and SBM007 (2.2 g d À1 $g oDM À1) showing the highest degradation rates. Treatability of an industrial waste water (12 g L À1 benzoic acid, 82 g L À1 NaCl) by these cultures was proven in a fed-batch system (SBM002 & SBM003) and a continuous flow reactor (SBM007). The performance of the continuous flow reactor was 15-times higher compared to the fed-batch system due to the change of inocula, higher concentration of ammonia as nutrient and less accumulation of possibly toxic catecholic compounds. Average DOC reduction was found to be 98% at 100 g L À1 NaCl and 1.2 g L À1 benzoic acid under these conditions. Pre-treatment of the waste water via chemical precipitation by acidification to pH 3.5 diminished the concentration of benzoic acid to 2.1 g L À1. In a combined chemical-biological process the volume of the bioreactor is reduced to 15% compared to a pure biological process. A comparison of operational costs for these three alternatives is presented.
International contracts to restrict emissions of climate-relevant gases, and thus global warming,... more International contracts to restrict emissions of climate-relevant gases, and thus global warming, also require a critical reconsideration of technologies for treating municipal, commercial, industrial, and agricultural waste gas emissions. A change from energy-and resource-intensive technologies, such as thermal post-combustion and adsorption, as well to low-emission technologies with high energy and resource efficiency, becomes mandatory. Biological processes already meet these requirements, but show restrictions in case of treatment of complex volatile organic compound (VOC) mixtures and space demand. Innovative approaches combining advanced oxidation and biofiltration processes seem to be a solution. In this review, biological processes, both as stand-alone technology and in combination with advanced oxidation processes, were critically evaluated in regard to technical, economical, and climate policy aspects, as well as present limitations and corresponding solutions to overcome these restrictions.
Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and monohalo... more Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and monohalogen benzenes to (3-substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3-methylcatechol, 4-carboxymethyl-2methylbut-2-en-4-olide (2-methyl-2-enelactone, 2-ML) accumulated transiently, being further mineralized only after a lag phase of 2 h in case of cells pre-grown on benzene or mono-halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono-halogen benzenes were unable to metabolize 2-ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2-ML as a substrate. This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate. Thus, 3methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B. fungorum FLU100.
Biodegradability of a VOC mix of 70v %TBA and 30v% acetone in waste air was tested. • Performance... more Biodegradability of a VOC mix of 70v %TBA and 30v% acetone in waste air was tested. • Performance levels of two biotrickling filters and a bioscrubber were compared. • The bioscrubber showed the highest total elimination capacity (80.2 g C m −3 h −1). • BTF I showed the highest specific elimination capacity (2.75 g C g oDM −1 h −1). • Two novel strains TBA100 and TBA200 able to degrade TBA were isolated.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Diese Arbeit beschreibt ein Verfahren zur Optimierung eines großtechnisch realisierten Biofilters... more Diese Arbeit beschreibt ein Verfahren zur Optimierung eines großtechnisch realisierten Biofilters als biologische Abluftreinigungsanlage zur Behandlung von VOC-Emissionen aus der Tauchschleuderlackierung von Metallwerkstücken. Die Abluft besteht dabei zu nahezu gleichen Teilen aus hydrophilem Methoxypropylacetat sowie lipophilen Xylol-Isomeren. Nachdem im Technikumsmaßstab ein Biofilter als einstufiges Verfahren sich als ineffizient erwies (Wirkungsgrad unter 20 %), besteht die vorgeschlagene Lösung aus einer Kombination von Biowäscher und nachgeschaltetem Biotricklingfilter. Das System war wenig störanfällig und über lange Laufzeiten betriebsstabil bei einem Minderungsgrad von ca. 75 % im Dauerbetrieb.
Applied Microbiology and Biotechnology, May 3, 2015
Acidovorax sp. CHX100 has a remarkable ability for growth on short cycloalkanes (C5-C8) as a sole... more Acidovorax sp. CHX100 has a remarkable ability for growth on short cycloalkanes (C5-C8) as a sole source of carbon and energy under aerobic conditions via an uncharacterized mechanism. Transposon mutagenesis of Acidovorax sp. CHX100 revealed a novel cytochrome P450 monooxygenase (CYP450chx) which catalyzed the transformation of cyclohexane to cyclohexanol. Primer walking methods categorized CYP450chx as cytochrome P450 class I taking into account its operon structure: monooxygenase, FAD oxidoreductase, and ferredoxin. CYP450chx was successfully cloned and expressed in Escherichia coli JM109. The activity of CYP450chx was demonstrated by means of the indole co-oxidation. Biotransformation capability of CYP450chx was confirmed through the catalysis of cycloalkanes (C5-C8) to their respective cyclic alcohols.
Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in concentration... more Polybrominated diphenyl ethers (PBDEs) have been widely used as flame retardants in concentrations up to 30 w% of the total mass of the products. Worldwide consumption of technically relevant PBDE mixtures was about 7500 tons (penta-BDEs), 3790 tons (octa-BDEs) and 56,100 tons (deca-BDE) in 2001 and about 50-60% of this total volume was discharged into environment only by agricultural use of sewage sludges. The use of PBDEs was strictly regulated from 2004 onwards due to their high emission load and their effect as endocrine disrupters, neurotoxins, and fertility reducing agents. Nevertheless, soils worldwide are contaminated by gaseous and particle-bound transport of PBDEs. Therefore, the uptake of PBDEs from contaminated agricultural land via crops and the food chain is a major human exposure pathway. However, uptake and intrinsic transport behavior strongly depend on crop specifics and various soil parameters. The relevant exposure and transformation pathways, transport-relevant soil and plant characteristics and both root concentration factor (RCF) and transfer factor (TF) as derivable parameters are addressed and quantified in this chapter. Finally, based on available crop specific data a general statement about the transport behavior of PBDEs in twelve different crops according to relevant PBDE congeners is given.
A total of 11 bacterial strains capable of completely degrading 2-butoxyethanol (2-BE) were isola... more A total of 11 bacterial strains capable of completely degrading 2-butoxyethanol (2-BE) were isolated from forest soil, a biotrickling filter, a bioscrubber, and activated sludge, and identified by 16S rRNA gene sequence analysis. Eight of these strains belong to the genus Pseudomonas; the remaining three strains are Hydrogenophaga pseudoflava BOE3, Gordonia terrae BOE5, and Cupriavidus oxalaticus BOE300. In addition to 2-BE, all isolated strains were able to grow on 2-ethoxyethanol and 2-propoxyethanol, ethanol, n-hexanol, ethyl acetate, 2-butoxyacetic acid (2-BAA), glyoxylic acid, and nbutanol. Apart from the only gram-positive strain isolated, BOE5, none of the strains were able to grow on the nonpolar ethers diethyl ether, din -butyl ether, n-butyl vinyl ether, and dibenzyl ether, as well as on 1-butoxy-2-propanol. Strains H. pseudoflava BOE3 and two of the isolated pseudomonads, Pseudomonas putida BOE100 and P. vancouverensis BOE200, were studied in more detail. The maximum growth rates of strains BOE3, BOE100, and BOE200 at 30°C were 0.204 h-1 at 4 mM, 0.645 h-1 at 5 mM, and 0.395 h-1 at 6 mM 2-BE, respectively. 2-BAA, nbutanol, and butanoic acid were detected as potential metabolites during the degradation of 2-BE. These findings indicate that the degradation of 2-BE by the isolated gram-negative strains proceeds via oxidation to 2-BAA with subsequent cleavage of the ether bond yielding glyoxylate and n-butanol. Since Gordonia terrae BOE5 was the only strain able to degrade nonpolar ethers like diethyl ether, the degradation pathway of 2-BE may be different for this strain.
War-related contamination of water and sediment of the Tigris River within the urban area of Mosu... more War-related contamination of water and sediment of the Tigris River within the urban area of Mosul leads to seasonally independent exceedances of the WHO limit values for Cd, Pb, Cr, and Ni up to a factor of 100 in water and sediments. Furthermore, exceedances consistently occur for conductivity, PO 4 3-, and SO 4 2-, as well as sporadically for salinity and COD in water samples, and consistently for salinity in sediment samples, highlighting the direct impact of war (amunition, ignition of sulfur elds) as well as indirect effects (destroyed wastewater infrastructure). Con ict-related emissions from the former con ict zone (S5-S7) are highlighted by the sudden increases in load from S4 to S5, although partially masked by discharge of highly polluted water from the Khosr River (between S3 and S4). Due to sorption to sediments and presumed wind-borne discharge of highly polluted particles into the Tigris River, sediments at S10 on the southern edge of Mosul showed the highest pollutant loads. Signi cant statistical differences were observed by T-test analyses for E.C., TDS, salinity, COD, PO 4 3-, NO 3-, SO 4 2-, Cd, Pb, Zn, Cr, and Ni for water samples as well as salinity, Cd, Pb, Zn, and Cr for the sediment samples for seasonal comparison. Since the percentage difference of water samples at S4-S7 is smaller than upstream and downstream, contaminant input is not limited to rainwater, but also via year-round in ltration of highly polluted wastewater from the surrounding valleys or suburban areas as well as presumably polluted groundwater or windblown particulate input.
Etwa 10 bis 15 % aller industriellen Abluftsituationen sowie alle Emissionssituationen in der lan... more Etwa 10 bis 15 % aller industriellen Abluftsituationen sowie alle Emissionssituationen in der landwirtschaftlichen Tierhaltung können durch biologische Abluftbehandlungsverfahren ökonomisch und ökologisch effizient behandelt werden, tatsächlich kommen sie bis dato erst in ca. 1 % (Industrie) bzw. 0,4 % (Landwirtschaft) der entsprechenden Anlagen zum Einsatz. Begrenzungen in Wirkungsgrad, Rohgaskonzentration, Bioverfügbarkeit, Transformationskinetik, Abbau komplexer Schadstoffgemische, ein hoher Platzbedarf sowie hohe Druckverluste stellen hohe Markteintrittsbarrieren dar. Um diese Restriktionen zu beseitigen, wurden diverse neue, hier vorgestellte Füllkörper für Biotricklingfilter entwickelt, die die Vorteile der Tricklingfilter-Füllkörper mit denen der Biofilterpackungen kombinierten. In Abluftsituationen, die durch lipophile oder xenobiotische Abluftinhaltsstoffe geprägt werden, erweisen sich zunehmend Kombinationen aus nicht-biologischen und biologischen Verfahren oder aus verschiedenen biologischen Verfahren als ökonomisch und ökologisch effizient.
Beim Bedrucken von Folien in einem Druckereibetrieb treten großvolumige Abluftströme auf, die Eth... more Beim Bedrucken von Folien in einem Druckereibetrieb treten großvolumige Abluftströme auf, die Ethanol, Butanol sowie Ethoxy-2-propanol (EP) enthalten. Diese Abluft wird über einen Biowäscher gereinigt. Bei kontinuierlichem Betrieb tritt jedoch eine Akkumulation von Ethoxy-2-propanol im Waschwasser auf. Zusätzlich kommt es in unregelmäßigen Zeitabständen zu einem starken Biomassewachstum auf der Schüttung des Absorbers und somit zu dessen Verstopfung. Beide Probleme sollten einer Lösung zugeführt werden.
Die seit November 2007 für Altanlagen gültige TA Luft 2002 sieht eine signifikante Verschärfung d... more Die seit November 2007 für Altanlagen gültige TA Luft 2002 sieht eine signifikante Verschärfung der Abluftgrenzwerte vor, die aufgrund der vermeintlichen Nicht-Realisierbarkeit zu einer Substitution biologischer Verfahren führte. Am Beispiel eines bislang nicht konformen Biowäschersystems zur kombinierten biologischen Behandlung von Abwasser und-luft in einem Sonderabfallbehandlungsbetrieb wurde die TA Luft umgesetzt. Der Modernisierungsfortschritt des biologischen Verfahrens wurde analytisch vor Ort begleitet und das schadstoffspezifische Abbaupotenzial der Anlage im Labor verifiziert.
A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow... more A combined system of a biotrickling filter and a non-thermal plasma (NTP) in a downstream airflow was operated for 1220 days for treatment of emissions of styrene and secondary emissions of germs formed in the biological process. The biotrickling filter was operated at variable inlet concentrations, empty bed residence times (EBRT), type and dosage of fertilizers, irrigation densities, and starvation periods, while dielectric barrier discharge and corona discharge were operated at different specific input energy levels to achieve optimal conditions. Under these conditions, efficiencies in the removal of volatile organic compounds (VOCs), germs and styrene of 96-98%, 1-4 log units and 24.7-50.1 g C m −3 h −1 were achieved, respectively. Fluid simulations of the NTP and a germ emission-based clocking of the discharge reveal further energy saving potentials of more than 90%. The aim of an energy-efficient elimination of VOCs through a biotrickling filter and of secondary germ emissions by a NTP stage in a downstream airflow for potential re-use of purified waste gas as process gas for industrial application was successfully accomplished.
Biotrickling filter (BTF) tend to accumulate biomass leading to clogging and a subsequent increas... more Biotrickling filter (BTF) tend to accumulate biomass leading to clogging and a subsequent increase in pressure losses and energy demands at high volatile organic compound (VOC) loadings under long-term conditions. Besides higher pressure losses and energy demands, the treatment performance gradually declines due to inhomogeneous gas distribution within the biofilm. Clogging prevention techniques are highly interesting regarding the design of BTFs, high performance levels, energy efficiency and corresponding costs. Squeezing out and backflushing as clogging prevention techniques with optional addition of auxiliary gas injections and chemicals were tested under various conditions. Five BTFs equipped with 17.6 L of different Poret® PPI10 PU foam structures were used to analyze removal efficiencies of both biomass and 2-butoxyethanol as VOC, testing different clogging prevention techniques in comparison to two reference systems without prevention steps. Up to 109.5 g organic dry matter were removed (270 s of gas injection, 0.2 w% sodium hydroxide).
Journal of environmental chemical engineering, Apr 1, 2018
Highlights Test plant for 600-650 m³•h-1 was installed at two organic waste treatment plants. ... more Highlights Test plant for 600-650 m³•h-1 was installed at two organic waste treatment plants. Combined process of NTP and adsorber showed higher performance than single stages. Odor abatement of 95.9-98.3% at 2.1-2.2 kWh•1000m-3 as SIE value. Removal of 62.9%, 15.9%, and 30.1% of VOCs, NH3, and CH4 at similar SIE values. NH3 and N2O were converted to NO and NO2 by the installed system.
Biogas internal combustion (IC) engines of less than 1 MW are either equipped with an oxidative c... more Biogas internal combustion (IC) engines of less than 1 MW are either equipped with an oxidative catalyst or operate at low-emission operation parameters to meet national emission standards of NO x , CO, VOCs, HCl, H 2 S, SO 2 , and formaldehyde safely. However, expensive oxidative catalysts have a limited lifetime of less than two years, and electrical efficiency at low-emission conditions is lower than that at optimal conditions, characterized by higher emission levels. While NO x levels increased seven times from 282.2 to 1965.7 mg NO x •m À3 by changing the operational parameters of the four-stroke gas engine (P el ¼ 360 kW), emission levels of CO and VOC slightly changed from 540.3 to 452.5 mg CO•m À3 and 509.6 to 329.9 mg C•m À3. Furthermore, NO x emission levels could be reduced by a minor air to gas ratio, but levels of VOC, CO, and HCl increased at these conditions as shown for a four-stroke gas engine (P el ¼ 635 kW). The emissions of the dual-fuel gas compression-ignition engine (P el ¼ 265 kW) were generally characterized by higher emission levels. A chemical scrubber with an optional subsequent biofilter was installed as a low-cost alternative for oxidative catalysts as a waste gas treatment system. Corresponding performance levels of the chemical scrubber were in the range of 28.3e38.6% (NO x), 19.2 e30.8% (CO), 22.6e23.8% (VOCs), and 33.3e70% (odor). Formaldehyde, which occurred at levels of 43.4 e59.6 mg m À3 , was almost completely eliminated by the scrubber after injection of ambient air, but the system failed in tests without air injection. The performance was further enhanced by addition of H 2 O 2. Further approaches in chemical removal of formaldehyde by addition of NH 3 or urea failed. The biofilter showed no treatment performance under thermophilic conditions. The amortization time of the scrubber system was less than three years, caused by economic benefits of higher electrical efficiency and substitution of the catalyst.
Eight mixed cultures able to degrade benzoic acid under saline conditions were established and ki... more Eight mixed cultures able to degrade benzoic acid under saline conditions were established and kinetic parameters were determined in batch processes with cultures SBM002 (0.5 g d À1 $g oDM À1), SBM003 (0.7 g d À1 $g oDM À1) and SBM007 (2.2 g d À1 $g oDM À1) showing the highest degradation rates. Treatability of an industrial waste water (12 g L À1 benzoic acid, 82 g L À1 NaCl) by these cultures was proven in a fed-batch system (SBM002 & SBM003) and a continuous flow reactor (SBM007). The performance of the continuous flow reactor was 15-times higher compared to the fed-batch system due to the change of inocula, higher concentration of ammonia as nutrient and less accumulation of possibly toxic catecholic compounds. Average DOC reduction was found to be 98% at 100 g L À1 NaCl and 1.2 g L À1 benzoic acid under these conditions. Pre-treatment of the waste water via chemical precipitation by acidification to pH 3.5 diminished the concentration of benzoic acid to 2.1 g L À1. In a combined chemical-biological process the volume of the bioreactor is reduced to 15% compared to a pure biological process. A comparison of operational costs for these three alternatives is presented.
International contracts to restrict emissions of climate-relevant gases, and thus global warming,... more International contracts to restrict emissions of climate-relevant gases, and thus global warming, also require a critical reconsideration of technologies for treating municipal, commercial, industrial, and agricultural waste gas emissions. A change from energy-and resource-intensive technologies, such as thermal post-combustion and adsorption, as well to low-emission technologies with high energy and resource efficiency, becomes mandatory. Biological processes already meet these requirements, but show restrictions in case of treatment of complex volatile organic compound (VOC) mixtures and space demand. Innovative approaches combining advanced oxidation and biofiltration processes seem to be a solution. In this review, biological processes, both as stand-alone technology and in combination with advanced oxidation processes, were critically evaluated in regard to technical, economical, and climate policy aspects, as well as present limitations and corresponding solutions to overcome these restrictions.
Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and monohalo... more Burkholderia fungorum FLU100 simultaneously oxidized any mixture of toluene, benzene and monohalogen benzenes to (3-substituted) catechols with a selectivity of nearly 100%. Further metabolism occurred via enzymes of ortho cleavage pathways with complete mineralization. During the transformation of 3-methylcatechol, 4-carboxymethyl-2methylbut-2-en-4-olide (2-methyl-2-enelactone, 2-ML) accumulated transiently, being further mineralized only after a lag phase of 2 h in case of cells pre-grown on benzene or mono-halogen benzenes. No lag phase, however, occurred after growth on toluene. Cultures inhibited by chloramphenicol after growth on benzene or mono-halogen benzenes were unable to metabolize 2-ML supplied externally, even after prolonged incubation. A control culture grown with toluene did not show any lag phase and used 2-ML as a substrate. This means that 2-ML is an intermediate of toluene degradation and converted by specific enzymes. The conversion of 4-methylcatechol as a very minor by-product of toluene degradation in strain FLU100 resulted in the accumulation of 4-carboxymethyl-4-methylbut-2-en-4-olide (4-methyl-2-enelactone, 4-ML) as a dead-end product, excluding its nature as a possible intermediate. Thus, 3methylcyclohexa-3,5-diene-1,2-diol, 3-methylcatechol, 2-methyl muconate and 2-ML were identified as central intermediates of productive ortho cleavage pathways for toluene metabolism in B. fungorum FLU100.
Biodegradability of a VOC mix of 70v %TBA and 30v% acetone in waste air was tested. • Performance... more Biodegradability of a VOC mix of 70v %TBA and 30v% acetone in waste air was tested. • Performance levels of two biotrickling filters and a bioscrubber were compared. • The bioscrubber showed the highest total elimination capacity (80.2 g C m −3 h −1). • BTF I showed the highest specific elimination capacity (2.75 g C g oDM −1 h −1). • Two novel strains TBA100 and TBA200 able to degrade TBA were isolated.
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Papers by Daniel Dobslaw