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A dense-phase latex rubber tube and a polyporous propylene hollow-fiber membrane module (HFMM) were investigated for control
of benzene-contaminated gas streams. The abiotic mass flux observed through the latex tube was 3.9–13 mg/(min·m2) for 150 ppm of benzene at various gas and liquid flow rates, while a 100-fold lower mass flux was observed in the HFMM.
After seeding with an aromatic-degrading culture enriched from activated sludge, the observed removal was 80% of 150 ppm,
corresponding toa mass flux of 45 mg/(min·m2). The observed mass flux through the HFMM during biofiltration also rose, to 0.4 mg/(min·m2). Because the HFMM had a 50-fold higher surface area than the latex tube, the observed ben zene removal was 99.8%. Compared
to conventional biofilters, the two reactors had modest elimination capacities, 2.5–18 g/(m3·h) in the latex tube membrane bioreactor and 4.8–58 g/(m3·h) in the HFMM. Although the HFMM had a higher elimination capacity, the gas-phase pressure drop was much greater. 相似文献
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Rouhana Nathalie Handagama Naresh Bienkowski Paul R. 《Applied biochemistry and biotechnology》1997,(1):809-821
A vapor-phase bioreactor has been developed utilizing porous metal membranes in a cylindrical design employing radial flow
as opposed to traditional axial flow for the vapor stream. The system was evaluated for the biodegradation ofp-xylene (p-xylene) from a water-saturated air stream byPseudomonas putida ATCC 23973 immobilized onto sand. The biocatalyst was placed in the annular space between two cylindrical, porous stainless-steel
membranes. Details of the reactor system are presented along with biological data verifying system performance. The feed flow
rate andp-xylene concentration were varied between 60 and 130 cm3/min and 15–150 ppm, respectively. Continuous reactor operation was maintained for 80–200 h with removal efficiencies (based
onp-xylene disappearance) between 80 and 95%. The effluent concentration histories were compared to determine the operating range
of the bioreactor. 相似文献
3.
Kalyuzhnyi S Gladchenko M Epov A Appanna V 《Applied biochemistry and biotechnology》2003,109(1-3):181-195
As a first step of treatment of landfill leachates (total chemical oxygen demand [COD]: 1.43–3.81 g/L; total nitrogen: 90–162
mg/L), performance of laboratory upflow anaerobic sludge bed reactors was investigated under mesophilic (30°C), submesophilic
(20°C), and psychrophilic (10°C) conditions. Under hydraulic retention times (HRTs) of about 0.3 d, when the average organic
loading rates (OLRs) were about 5 g of COD/(L·d), the total COD removal accounted for 81% (on average) with the effluent concentrations
close to the anaerobic biodegradability limit (0.25 g of COD/L) for mesophilic and submesophilic regimes. The psychrophilic
treatment conducted under an average HRT of 0.34 d and an average OLR of 4.22 g of ducted under an average HRT of 0.34 d and
an average OLR of 4.22 g of COD/(L·d) showed a total COD removal of 47%, giving effluents (0.75 g of COD/L) more suitable
for subsequent biologic nitrogen removal. All three anaerobic regimes used for leachate treatment were quite efficient for
elimination of heavy metals (Fe, Zn, Cu, Pb, Cd) by concomitant precipitation in the form of insoluble sulfides inside the
sludge bed. The application of aerobic/anoxic biofilter as a sole polishing step for psychrophilic anaerobic effluents was
acceptable for elimination of biodegradable COD and nitrogen approaching the current standards for direct discharge of treated
waste-water. 相似文献
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The performance of a trickle-bed air biofilter (TBAB) in the removal of 1,1,1-trichloroethane (TCLE) was evaluated in concentrations
varying from 0.025 to 0.049 g/m3 and at empty-bed residence time (EBRT) varying from 20 to 90 s. Nearly complete TCLE removal could be achieved for influent
carbon loading between 0.98 and 5.88 g/m3 h. The TBAB appeared efficient for controlling TCLE emission under low-carbon-loading conditions. Carbon recoveries higher
than 95% were achieved, demonstrating the accuracy of results. The carbon mass rate of the liquid effluent was approximately
two orders of magnitude less than that of the effluent CO2, indicating that dissolved TCLE and its derivatives in leachate were present in negligible amounts in the TBAB. 相似文献
6.
Effect of temperature on biofiltration of nitric oxide 总被引:2,自引:0,他引:2
Applied Biochemistry and Biotechnology - 相似文献
7.
Chua Hong Li Xiang Z. Yu Peter H. F. Tam Chung Y. Huang Yu L. Yang Shang T. 《Applied biochemistry and biotechnology》2000,84(1-9):469-478
Biological processes have become popular for odor treatment. In this study, a novel fibrous bed bioreactor was applied for
treatment of odorous gas. The column reactor was packed with spirally wound fibrous sheet material on which a consortium of
microorganisms selected from activated sludge was immobilized. The first stage of this work comprised a preliminary study
that aimed at investigating the feasibility of the fibrous bed bioreactor for treatment of odorous volatile fatty acids (VFAs).
In this stage, the performance of a fibrous bed bioreactor at increasing mass loadings ranging from 9.7 to 104.2 g/(m3·h) was studied. VFA removal efficiencies above 90% were achieved at mass loadings up to 50.3 g/(m3·h). At a mass loading of 104.2 g/(m3·h), removal efficiency was found to be 87.7%. In the second stage of the work, the process was scaled up with design and
operational considerations, namely, packing medium, process condition, and configuration selections. A trickling biofilter
with synthetic fibrous packing medium was selected. It was operated under countercurrent flow of gas and liquid streams. The
effects of inlet concentration and empty bed retention time on bioreactor performance were studied. The bioreactor was effective
in treating odorous VFAs at mass loadings up to 32g/(m3·h), at which VFAs started to accumulate in the recirculation liquid, indicating that the biofilm was unable to degradeall
the VFAs introduced. Although VFAs accumulated in the liquid phase, the removal efficency remained above 99%, implying that
the biochemical reaction rate, rather than gas-to-liquid mass transfer rate, was the limiting factor of this process. The
bioreactor was stable for longterm operation; no clogging and degeneration of the packing medium was observed during the 4-mo
operation. 相似文献
8.
The performance of a 20-L anaerobic biofilter treating 2-ethyl-hexanoic acid (2-EHA) operating with the effluent recirculated
was compared with that of the same biofilter operated without any recirculation. The recirculation of effluent was at a rate
of 60 L/h through the biofilter. Tracer experiments were carried out to study the hydrodynamics in the biofilter under different
modes of operation. The dispersion number (D/UL) obtained from these tracer experiments for the biofilter operated with and
without effluent recirculation were 0.65 and 0.06, respectively. These values show that the recirculation was effective in
achieving a mixed-flow pattern in the biofilter, whereas the biofilter operated without recirculation was essentially a plug-flow
column with a moderate level of axial dispersion.
The feed consisted of 2-EHA at a concentration of 8200 mg/L, which is equivalent to a COD of 20,000 mg/L. The optimal performance
of the mixed-flow biofilter was at a hydraulic retention time (HRT) of 1.1 d, with a COD removal efficiency of 92.8% and a
biogas production rate of 6.44 L/L biofilter vol/d. The biofilter failed at 0.83 d HRT, as a result of washout of biomass
at this high hydraulic loading rate. By comparison, the optimal performance achieved for the plug-flow system was at 2 d HRT.
The COD removal efficiency was 74.1%, and biogas production rate was 2.13 L/L biofilter vol/d. When the HRT was lowered to
1.5 d, failure occurred owing to inhibition as indicated by the low methane yield of 0.192 L/g COD removed. The superior performance
of the mixed-flow mode can be attributed to the presence of the recycle stream, which diluted and evenly distributed the feed. 相似文献
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10.
生物过滤技术因其具有有效性、低成本和环境友好等优点引起了人们的广泛关注.该技术主要通过生物过滤器去除含有H2S等废气的有毒有害气体.运用格子Boltzmann方法对三种生物过滤器模型中多孔介质的非均匀性流动进行了数值模拟.数值模拟结果表明,多孔介质的性质和进口流动条件对临界Rayleigh数有显著影响,临界Rayleigh数随着多孔介质的孔隙度和Darcy数的增大而逐渐变小,并随着进口Reynolds数的增大而逐渐变大.所得结果可望为生物过滤器的优化设计提供一个合理的理论依据. 相似文献
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