The treatment of waste air containing phenol vapors in biotrickling filter

This research aimed at investigating the biodegradation of phenol contaminated-air streams in biotrickling filter. The effect of inlet concentration (200-1000 ppmv) and empty bed contact time (EBCT) (15-60 s) were investigated under steady state, transient and shock loading, and shutdown periods. Upon rapid start up operation, inlet phenol concentrations of up to 1000 ppmv did not significantly affect the performance of the biotrickling filter at EBCT of 60 s, so that removal efficiency was well greater than 99%. In addition, the EBCT as low as 30 s did not have detrimental effects on the efficiency of the bioreactor and phenol removal was greater than 99%. Decreasing the EBCT to 15s reduced the removal efficiency to around 92%. The maximum elimination capacity obtained in the biotrickling filter was 642 g(phenol) m(-3) h(-1), where the removal efficiency was only 57%. Results from the transient loading experiments revealed that the biotrickling filter could effectively handle the variations of the inlet loads without the phenol removal capacity being significantly affected.     

以焦炭为填料的生物滴滤塔处理含挥发性脂肪酸臭气

在以焦炭为填料的生物滴滤塔对挥发性脂肪酸臭气的处理研究中考察了空床停留时间、臭气浓度、体积负荷以及进气温度等参数对净化效果的影响。结果表明，空床停留时间较长时对臭气降解有利。在停留时间超过97 s时，能实现完全降解；此外，净化率随臭气浓度和体积负荷的不断增加呈先增加后降低的趋势。当臭气浓度为24.29 mg/m³即臭气的体积负荷为3 g/（m³·h）时，去除率约为96%；当臭气浓度增至1 345.74 mg/m³即体积负荷增至18 g/（m³·h），去除率达100%；然而，当臭气浓度增至4 934.38 mg/m³即体积负荷增至66 g/（m³·h）时，去除率降至73.1%。另外，进气温度对净化率也有一定程度影响。当进气温度较低时，净化效率相对较高。     

Treatment of ethylether in air stream by a biotrickling filter packed with slags.

This paper reports results of studies using a biotrickling filter with blast-furnace slag packings (sizes = 2-4 cm and specific surface area = 120 m2/m3) for treatment of ethylether in air stream. Effects of volumetric loading, superficial gas velocity, empty bed gas retention time, recirculation liquid flow rate, and biofilm renewal on the ethylether removal efficiency and elimination capacity were tested. Results indicate that ethylether removal efficieincies of more than 95% were obtained with an empty bed retention time (EBRT) of 113 sec and loadings of lower than 70 g/m3/hr. At an EBRT of 57 sec, removal efficiencies of more than 90% could only be obtained with loadings of lower than 35 g/m3/hr. The maximum elimination capacities were 71 and 45 g/m3/hr for EBRT = 113 and 57 sec, respectively. The maximum ethylether elimination capacities were 71 and 96 g/m3/hr, respectively, before and after the renewal at EBRT = 113 sec. With an EBRT of 113 sec and a loading of lower than 38 g/m3/hr, the removal efficiency was nearly independent of the superficial liquid recirculation velocity in the range of 3.6 to 9.6 m3/m2/hr. From data regression, simplified masstransfer limited, and reaction- and mass-transfer limited models correlating the contaminant concentration and the packing height were proposed and verified. The former model is applicable for cases of low influent contaminant concentrations or loadings, and the latter is applicable for cases of higher ones. Finally, CO2 conversion efficiencies of approximately 90% for the influent ethylether were obtained. The value is comparable to data reported from other related studies.     

生物滴滤塔净化苯乙烯废气的实验研究

采用生物滴滤(BTF)系统对含苯乙烯的有机废气进行了生物净化实验并研究该系统VOCs生物降解性能。实验表明,苯乙烯进气浓度低于20 mg/m3时BTF去除效率可达92%以上,出口苯乙烯浓度低于1.6 mg/m3,达到GB14554-1993中规定的排放标准;该BTF装置对苯乙烯的去除负荷在2.0 g/(m3.h)左右;系统稳定运行时循环液COD、浊度和pH等都保持稳定,无脱落生物膜积累现象;生物滴滤塔系统适宜的气液比为300;系统总压降约100 Pa,鲍尔环填料和聚氨酯发泡填料混合装填方式可以降低系统压降并有利于微生物挂膜。     

Carbon disulfide and hydrogen sulfide removal with a peat biofilter

Simultaneous removal of H2S and CS2 was studied with a peat biofilter inoculated with a Thiobacillus strain that oxidizes both compounds in an acidic environment. Both sulfurous gases at concentrations below 600 mg S/m3 were efficiently removed, and the removal efficiencies were similar, 99%, with an empty bed retention time (EBRT) of more than 60 sec. Concentrations greater than 1300-5000 mg S/m3 caused overloading of the filter material, resulting in high H2SO4 production, accumulation of elemental sulfur, and reduced removal efficiency. The highest sulfur removal rate achieved was 4500 g-S/day/m3 filter material. These results indicate that peat is suitable as a biofilter material for the removal of a mixture of H2S and CS2 when concentrations of gases to be purified are low (less than 600 mg/m3), but it is still odorous and toxic to the environment and humans.     

生物滴滤塔净化甲苯启动性能研究

研究以甲苯为驯导物的生物滴滤塔挂膜启动阶段净化性能的变化。实验结果表明,通过控制pH和湿度得到了真菌滴滤系统,启动周期为14 d,比细菌滴滤塔长7 d;在进化性能方面,在入口负荷、浓度为80 g/(m3.h)、3 000 mg/m3的条件下获得了稳定在98%以上的去除效率;对比2种填料对启动阶段的影响,在较低负荷下(≤80 g/(m3.h))对系统的启动时间和去除效率没有显著影响。     

H₂S abatement in a biotrickling filter using iron(III) foam media

Airstreams polluted with H(2)S at inlet loads ranging from 2.4 to 40.9 g H(2)Sm(-3)h(-1) were treated in a biotrickling reactor packed with hematite bearing, open pore foam units, at Empty Bed Residence Times (EBRT) ranging from 20 to 60s over a period of 80 d, with almost complete removal of the pollutant from the startup of the system. The media had been seeded with sludge from a local water works facility, and removal efficiencies in excess of 80% were consistently observed along the operation of the reactor, with an average of 98%. Based on section performance, being a section one third of the bed length, observed elimination capacities (EC) reached up to 88.7 g H(2)Sm(-3)h(-)(1) and 72.0 g H(2)Sm(-3)h(-1) at section EBRT of 10 and 7s, respectively. The observed EC values compared much better than data reported on other packed bed reactors using biological iron oxidization to treat H(2)S airstreams indirectly, and so did it when comparing the EC per unit of specific area in a similar study using polyurethane (PU) foams. Further, and unlike PU packed biofilters, no compaction occurred due to the iron foam rigidity, which translated in much better observed gas phase pressure drop as opposed to other conventional biofilters. Denaturing gel gradient electrophoresis was performed on the biomass collected in the packing after the biofilter service, and it was found that though a multi bacterial colony was seeded in the system via the sludge, the only surviving genus was the iron oxidizing Alicyclobacillus spp.     

Biological sweetening of energy gases mimics in biotrickling filters

Removal of hydrogen sulfide from waste and energy-rich gases is required, not only because of environmental health and safety reasons, but also because of operational reasons if such gases have to be used for energy generation. A biotrickling filter for the removal of ultra-high concentrations of H2S from oxygen-poor gases is proposed and studied in this work. Two laboratory-scale biotrickling filters were used to study the startup period and to determine the long-term performance of the gas sweetening process. The inlet H2S concentration ranged from 900 to 12000ppmv and two different packing materials were investigated. There was no toxicity effect observed even at a the highest H2S concentration, and maximum elimination capacities of 280 and 250g H2Sm(-3)h(-1) were obtained at gas contact times of 167 and 180s, respectively. Elemental sulfur and sulfate were found to be the most abundant end-products of the biological oxidation of sulfide when operated under microaerophilic conditions. The biotrickling filter was able to quickly recover its nominal performance after different load increases and system shutdowns simulating field operation. The results reported here show that biotreatment can be an interesting alternative to conventional gas sweetening systems normally used for such applications.     

Biotrickling filtration of nitric oxide

A biotrickling filter with blast-furnace slag packings (sizes = 20-40 mm and specific surface area = 120 m2/m3) was utilized to treat NO in an air stream. The operational stability, as well as the effects of gas empty-bed retention time (EBRT) and nutrient addition on the removal ability of NO, were tested. Approximately six weeks were required for the development of a biofilm for NO degradation, and a two-week organic carbon deficiency resulted in the detachment of biofilms from the packing surfaces. A steady removal rate of 80% was attained at specified influent NO concentrations of 892 to 1237 ppm and an EBRT of 118 sec. The effluent NO concentration diminished exponentially with enlarging EBRT, with influent NO concentrations of 203-898 ppm, and EBRTs of 25 to 118 sec. Nutrient addition is essential for efficient removal of the influent NO. Mass ratios of C: P: N = 7: 1: 30 and NaHCO3: NO-N = 6.3 could be used for practical applications.     

生物转鼓过滤器反硝化净化NO的效率研究

采用自行研制的生物转鼓过滤器(RDB)反硝化净化NO。结果表明,在实验温度为25～30℃、pH为7.0～7.5、转鼓转速为1.0r/min、空床停留时间(EBRT)为86.40s、营养液用量为5.0L、营养液更换频率为0.2L/d的条件下,RDB在30d内完成挂膜;RDB稳定运行期间,当NO进气质量浓度为90～433mg/m3时,NO去除率维持在42.9%～85.2%,平均去除负荷为10.40g/(m3.h);转鼓转速决定了生物膜表面的更新速率和液膜厚度,当转速为0.5r/min时,NO去除率达到最大值(75.0%);将营养液用量控制在1.3～3.0L较为合理;EBRT是决定反硝化效率的重要因素,当EBRT为345.60s时,NO去除率不受其进气浓度的影响,且去除率高达95%以上,当EBRT为43.20s、NO进气质量浓度从98mg/m3增加到1095mg/m3时,NO去除率从62.5%下降到30.7%,当进气负荷为50.00g/(m3.h)时,NO去除负荷达到最大值(27.50g/(m3.h))。     

Removal of nitric oxide in a biotrickling filter under thermophilic condition using Chelatococcus daeguensis

The development of a thermophilic biotrickling filter (BTF) system to inoculate a newly isolated strain of Chelatococcus daeguensis TAD1 for the effective treatment of nitric oxide (NO) is described. A bench-scale BTF was run under high concentrations of NO and 8% O2 in thermophilic aerobic environment. A novel aerobic denitrifier Chelatococcus daeguensis TAD1 was isolated from the biofilm of an on-site biotrickling filter and it showed a denitrifying capability of 96.1% nitrate removal rate in a 24 h period in aerobic environment at 50 degrees C, with no nitrite accumulation. The inlet NO concentration fluctuated between approximately 133.9 and 669.6 mg m-3 and kept on a steady NOx removal rate above 80% in an oxygen stream of 8%. The BTF system was able to consistently remove 80-93.7% NO when the inlet NO was 535.7 mg m-3 in an oxygen stream of 2-20%. The biological removal efficiency of NO at 50 degrees C is higher than that at 25 degrees C, suggesting that the aerobic denitrifier TAD1 display well denitrification performance under thermophilic condition. Starvation for 2, 4 and 8 days resulted in the re-acclimation times of Chelatococcus daeguensis TAD1 ranging between 4 and 16 hours. A longer recovery time than that for weekend shutdown will be required when a longer starvation occurs. The results presented here demonstrate the feasibility of biotrickling filter for the thermophilic removal of NOx from gas streams. Implications: A novel denitrifier Chelatococcus daeguensis TAD1 was isolated from an on-site biotrickling filter in aerobic environment at 50 degrees C. To date, C. daeguensis has not been previously reported to be an aerobic denitrifier. In this study, a thermophilic biotrickling filter system inoculated with Chelatococcus daeguensis TADI for treatment of nitric oxide is developed. In coal-fired power plants, influent flue gas stream for nitrogen oxides (NOx) removal typically exhibit temperatures between 50 and 60 degrees C. Traditionally, cooling gases to below 40 degrees C prior to biological treatment is inevitable, which is costly. Therefore, the application ofthermophilic microorganisms for the removal of nitric oxide (NO) at this temperature range would offer great savings and would greatly extend the applicability ofbiofilters and biotrickling filters. Until now there has not been any study published about thermophilic biological treatment of NO under aerobic condition.     

高效生物滴滤床净化含二甲苯废气的实验研究

通过摇床实验筛选出一株二甲苯降解菌．将该菌种接种于生物滴滤床中，研究其净化含二甲苯废气的效果。实验结果表明，纯菌种的生物滴滤床的净化效果比混合菌种生物滴滤床有显著提高。当气体停留时间在28．3～84．8s变化时，系统的净化效率变化不大；当气体停留时间缩短到17．0s时，滤床的净化效率随人口浓度有较大变化。在实验范围内，喷淋液的流量对滤床的净化效果几乎没有影响。滤床填料中生物量分布呈递减趋势。     

Effect of Water and Carbon Dioxide in Chemiluminescent Measurement of Oxides of Nitrogen

ABSTRACT

This paper reports results of studies using a biotrickling filter with blast-furnace slag packings (sizes = 2–4 cm and specific surface area = 120 m²/m³) for treatment of ethylether in air stream. Effects of volumetric loading, superficial gas velocity, empty bed gas retention time, recirculation liquid flow rate, and biofilm renewal on the ethylether removal efficiency and elimination capacity were tested. Results indicate that ethylether removal efficiencies of more than 95% were obtained with an empty bed retention time (EBRT) of 113 sec and loadings of lower than 70 g/m³/hr. At an EBRT of 57 sec, removal efficiencies of more than 90% could only be obtained with loadings of lower than 35 g/m³/hr. The maximum elimination capacities were 71 and 45 g/m³/hr for EBRT = 113 and 57 sec, respectively. The maximum ethylether elimination capacities were 71 and 96 g/m³/hr, respectively, before and after the renewal at EBRT = 113 sec. With an EBRT of 113 sec and a loading of lower than 38 g/m³/hr, the removal efficiency was nearly independent of the superficial liquid recirculation velocity in the range of 3.6 to 9.6 m³/m²/hr. From data regression, simplified mass-transfer limited, and reaction- and mass-transfer limited models correlating the contaminant concentration and the packing height were proposed and verified. The former model is applicable for cases of low influent contaminant concentrations or loadings, and the latter is applicable for cases of higher ones. Finally, CO₂ conversion efficiencies of approximately 90% for the influent ethylether were obtained. The value is comparable to data reported from other related studies.     

生物滴滤塔处理有机废气的填料选择研究

以含低浓度乙酸、正己烷和苯乙烯的混合有机气体模拟实际有机废气,采用实验室规模的生物滴滤塔处理有机废气,并比较了海绵、珊瑚石、陶粒和空心塑料小球4种填料的性能。结果表明:(1)生物滴滤塔启动时间最短的为海绵生物滴滤塔(约20d),其次为陶粒生物滴滤塔(约25d),启动时间较长的为珊瑚石生物滴滤塔(约35d)和空心塑料小球生物滴滤塔(约40d)。(2)在稳定运行期,不同填料生物滴滤塔对水溶性和极性较强的乙酸的去除率差异尤为明显,对正己烷和苯乙烯的去除率差异相对较小。(3)4种填料生物滴滤塔中的异养细菌数量依次为海绵>陶粒>珊瑚石>空心塑料小球。运行80d时,海绵、陶粒、珊瑚石和空心塑料小球生物滴滤塔中的异养细菌数量分别达5.9×108、4.8×108、3.6×108、3.0×108 cfu/g(以单位质量干填料计)。(4)在相同的进气流速下,4种填料生物滴滤塔的填料层压力降依次为珊瑚石>陶粒>空心塑料小球>海绵。(5)海绵和陶粒较适宜作为生物滴滤塔的填料。     

The control of mercury vapor using biotrickling filters

The feasibility of using biotrickling filters for the removal of mercury vapor from simulated flue gases was evaluated. The experiments were carried out in laboratory-scale biotrickling filters with various mixed cultures naturally attached on a polyurethane foam packing. Sulfur oxidizing bacteria, toluene degraders and denitrifiers were used and compared for their ability to remove Hg 0 vapor. In particular, the biotrickling filters with sulfur oxidizing bacteria were able to remove 100% of mercury vapor, with an inlet concentration of 300-650 microg m(-3), at a gas contact time as low as six seconds. 87-92% of the removed mercury was fixed in or onto the microbial cells while the remaining left the system with the trickling liquid. The removal of mercury vapors in a biotrickling filter with dead cells was almost equivalent to this in biotrickling filters with live cells, indicating that significant abiotic removal mechanisms existed. Sulfur oxidizing bacteria biotrickling filters were the most effective in controlling mercury vapors, suggesting that sulfur played a key role. Identification of the location of metal deposition and of the form of metal was conducted using TEM, energy dispersive X-ray analysis (EDAX) and mercury elution analyses. The results suggested that mercury removal was through a series of complex mechanisms, probably both biotic and abiotic, including sorption in and onto cellular material and possible biotransformations. Overall, the study demonstrates that biotrickling filters appear to be a promising alternative for mercury vapor removal from flue gases.     

Oxidation of gas mixtures containing dimethyl sulfide, hydrogen sulfide, and methanethiol using a two-stage biotrickling filter

A biofiltration technique was developed for removing a mixture of hydrogen sulfide (H2S), methanethiol (MeSH), and dimethyl sulfide (Me2S) from waste gases. Since H2S, especially at high concentrations, disturbs the removal of Me2S, two biotrickling filters with different microbes and operating pH levels were connected in series to create a two-stage system. Different loads of these gases were studied in order to determine their impact on the removal capacity of the system. The microbial consortia for these filters were enriched from the sludge of a Finnish refinery with bubbling H2S or Me2S. Acclimation for Me2S took 2 weeks, though no acclimation time was needed for the other gases. The first filter, at a pH of 2, removed most of the H2S and some of the MeSH and Me2S. The second filter, at a pH of approximately 6.5, removed the rest of the MeSH and most of the Me2S. The total maximum loads of the whole two-stage biotrickling filter were 1150 g/m3/day for H2S-S (suffix S indicates the results are counted as sulfur amounts), 879 g/m3/day for Me2S-S, and 66 g/m3/day for MeSH-S treated in a gas mixture. The average removal efficiencies for all gases tested were 99% or higher.     

Performance of a Pilot-Scale Biotrickling Filter in Controlling the Volatile Organic Compound Emissions in a Furniture Manufacturing Facility

Abstract

A 0.75-m³ pilot-scale biotrickling filter was run for over 1 yr in a Spanish furniture company to evaluate its performance in the removal of volatile organic compounds (VOCs) contained in the emission of two different paint spray booths. The first one was an open front booth used to manually paint furniture, and the second focus was an automatically operated closed booth operated to paint pieces of furniture. In both cases, the VOC emissions were very irregular, with rapid and extreme fluctuations. The pilot plant was operated at an empty bed residence time (EBRT) ranging from 10 to 40 sec, and good removal efficiencies of VOCs were usually obtained. When a buffering activated carbon prefllter was installed, the system performance was improved considerably, so a much better compliance with legal constraints was reached. After different shutdowns in the factory, the period to recover the previous performance of the biotrickling reactor was minimal. A weekend dehydration strategy was developed and implemented to control the pressure drop associated with excessive biomass accumulation.     

Comparison of the purification performance and microbial community functional diversity in flow-directional-switching and unidirectional-flow biotrickling filters

Because of the characteristics of low operating cost and convenient operation, the biotrickling filter is extensively researched and used to treat low concentration waste gas contaminated by volatile organic compounds (VOCs) and other odors. In this paper, two laboratory-scale biotrickling filters were constructed and toluene was selected as the sole carbon source, and the effects of different waste-gas flow configuration patterns on the purification capacity and the microbial community functional diversity of biotrickling filters were evaluated. The results indicated that the flow-directional-switching (FDS) biotrickling filter had better purification performance, and the maximum elimination capacity reached 480 g·m^?3·hr^?1, which was 17.1% higher than conventional unidirectional-flow (UF) biotrickling filter. Comparing the purification capacities of different sections in two biotrickling filters, the maximum toluene elimination capacity of section III in FDS system could reach 542 g·m^?3·hr^?1, which was 2.8 times as great as that in UF system, which resulted from the difference of elimination capacity in two systems. By analyzing the metabolic activity of two systems by community-level physiological profiling (CLPP) with Biolog (Biolog Inc., Hayward, CA) ECO-plate technique, metabolic activity in three sections of FDS system was higher than that of UF system. The metabolic activity was the highest in section III of FDS system and 46.8% higher than that of UF system. Shannon index and McIntosh index of section III in FDS system were 6.2% and 31.5% higher, respectively, than those of UF system.

Implications: The flow-directional-switching (FDS) biotrickling filter had a better purification performance than unidirectional-flow (UF) biotrickling filter at high inlet loadings, because FDS produced a more uniform distribution of biomass and microbial metabolic capacity along the length of the packed bed without diminishing activity and removal capacity in the inlet section.     

Biotrickling Filtration of Nitric Oxide

ABSTRACT

A biotrickling filter with blast-furnace slag packings (sizes = 20-40 mm and specific surface area = 120 m²/m³) was utilized to treat NO in an air stream. The operational stability, as well as the effects of gas empty-bed retention time (EBRT) and nutrient addition on the removal ability of NO, were tested. Approximately six weeks were required for the development of a biofilm for NO degradation, and a two-week organic carbon deficiency resulted in the detachment of biofilms from the packing surfaces. A steady removal rate of 80% was attained at specified influent NO concentrations of 892 to 1237 ppm and an EBRT of 118 sec. The effluent NO concentration diminished exponentially with enlarging EBRT, with influent NO concentrations of 203-898 ppm, and EBRTs of 25 to 118 sec. Nutrient addition is essential for efficient removal of the influent NO. Mass ratios of C: P: N = 7: 1: 30 and NaHCO₃: NO-N = 6.3 could be used for practical applications.     

Treatment of 1,3-Butadiene in an Air Stream by a Biotrickling Filter and a Biofilter

ABSTRACT

This paper presents results obtained from a performance study on the biotreatment of 1,3-butadiene in an air stream using a reactor that consisted of a two-stage, in-series biotrickling filter connected with a three-stage, in-series biofilter. Slags and pig manure-based media were used as packing materials for the biotrickling filter and the biofilter, respectively. Experimental results indicated that, for the biotrickling filter portion, the butadiene elimination capacities were below 5 g/m³/hr for loadings of less than 25 g/m³/hr, and the butadiene removal efficiency was only around 17%. For the biofilter portion, the elimination capacities ranged from 10 to 107 g/m³/hr for loadings of less than 148 g/m³/hr. The average butadiene removal efficiency was 75–84% for superficial gas velocities of 53–142 m/hr and a loading range of 10–120 g/m³/hr. The elimination capacity approached a maximum of 108 g/m³/hr for a loading of 150 g/m³/hr. The elimination rates of butadiene in both the biotrickling filter and biofilter were mass-transfer controlled for influent butadiene concentrations below about 600 ppm for superficial gas velocities of 29–142 m/hr. The elimination capacity was significantly higher in the biofilter than in the biotrickling filter. This discrepancy may be attributed to the higher mass-transfer coefficient and gas-solid interfacial area offered for transferring the gaseous butadiene in the biofilter.