Bioscrubbing of Gaseous Emissions
Interdisciplinary Bioremediation Working Group
Cook College, Rutgers The State University of New Jersey
BIOSCRUBBING OF GASEOUS EMISSIONS
Wednesday, November 18, 19928:30 a.m. - 2:30 p.m.
A Mini-Symposium Sponsored by NJDEPE and
the AgBiotech Center of Rutgers University
Biofiltration of Industrial Solventsand Solvent Mixtures
Principles of Packed-bed BiofilterModelling and Design
Biological Waste Gas Purification inEurope
Biological Vapor-phase Treatment:Practical Operating Regimes
Cornposting Facility Odor ControlUsing Biofilters
Richard Bartha, Rutgers University, NewBrunswick, NJ
Young-Sook Oh, Richard Bartha, RutgersUniversity, New Brunswick, NJ
Basil Baltzis, Zarook Shareefdeen, New JerseyInstitute of Technology, Newark, NJ
R.M.M. Diks, S.P.P. Ottengraf, TechnischeUniversiteit Eindhoven, The Netherlands
Paul Togna, Envirogen, Lawrenceville, NJ
Frederick C. Miller, Sylvan Foods,Worthington, PA
Richard Bartha, Moderator
Marine & Coastal Sciences Building, Room 102BDudley Road and College Farm Road, Cook College
Rutgers University, New Brunswick, NJ 08903
Richard Bartha, Rutgers University
I wish to welcome all participants to our Mini-Symposium and I am gratified by theunexpectedly high turnout of over 80 persons. This certainly indicates the timeliness of ourSymposium topic. I wish to thank the speakers who agreed to contribute, and I especiallywelcome Dr. Ottengraf and his associate Dr. Diks from the Netherlands. Dr. Ottengraf isregarded as the foremost expert in the biological treatment of air emissions, and his participationlends our Mini-Symposium international stature. I wish to thank the New Jersey Departmentof Environmental Protection and Energy for its financial support of this event and Dr. LauraMeagher and the Agbiotech Institute for all the planning and organizational details.
To comply with the Clean Air Act and its 1990 Amendments without losing competitiveedge constitutes a severe challenge to many U.S. manufacturers. They will need all availabletools to meet this challenge. The biological treatment of volatile organic compound (VOC)emissions is one of the possible air pollution abatement options that, until very recently, hasbeen relatively unknown and certainly underutilized in the USA. In contrast, the biologicaltreatment of air emissions has extensive scientific literature and widespread practical use inEurope. In part to create more awareness for the biological treatment option, and in part toextend biotreatment to various xenobiotic solvents and solvent mixtures, with the sponsorshipof the Hazardous Substances Management Research Center (NJIT, Newark) my laboratory atRutgers University cooperated with Dr. B. Baltzis at NJIT to perform experimental andmodeling work in this area. This program was initiated in 1989 and we will report here ourprogress in this area which was novel to our two laboratories. Dr. Diks and Dr. Ottengraf willreport on the much more extensive utilization of VOC biotreatment in Europe. Dr. P. Tognafrom Envirogen will report on the recent construction and operational experience with a pilot-scale biofilter unit. Dr. F.C. Miller from Sylvan Foods will tell about operational experienceswith a classic industrial biofilter for odor control. We will end our Mini-Symposium with abrief discussion period that will formulate some recommendations designed to promote anawareness and an increased use of the biotreatment option for gaseous emissions. I am lookingforward to a very informative and enjoyable session!
Microbial Scrubbing of BTX Solvent Mixturesand Chlorinated Solvents from Air.
YOUNG-SOOK OH AND RICHARD BARTHA
Depcirtment of Biochemistry and Microbiology, Cook College,Rutgers University, New Brunswick, New Jersey 08903-0231
Microbial enrichments immobilized on perlite/peat-packed columns removed vapors ofseveral industrial solvents from air. The same technique was applied now to scrub commonsolvent mixtures such as benzeneltoluene/p-xylene (BTX) and chlorinated solvents such aschlorobenzene (CB)Io -dichlorobenzene ( D C B ) a n d nitrobenzene(NB). Solvent vaporconcentrations in metered air flow were measured by GC prior to and after passage throughthe column. In long-term experiments, liquid medium was recirculated and replenished asneeded. At air flow rates of 36.7 m3m-2h-1, BTX was removed at up to 16 g rnq3 packing h-l.The column half close to the inlet removed preferential ly toluene and benzene with verylittle xylene degradation. Xylene was removed predominantly in the distant half of thecolumn. CB and DCB scrubbing led to a rapid pH drop and column inactivation, but withrecirculation of l iquid through a neutralizing unit, sustained CB and DCB scrubbing wasachieved at rates up to 300 g me3 packing h-t. NB was removed at 67 gmm3h-. The columnsdid not lose their act iv i ty when solvent loading was interrupted for several days andscrubbing resumed as soon as solvent vapor was reintroduced.
The clean Air Act Amendments of 1990 greatly expandthe EPA rule-making authority over toxic or hazardous airpollutants. The law lists 189 chemicals and the toxicchemical regulations have specifically targeted theemissions of organic and halogenated organic compounds.All industries which emit volatile organic compounds willbe subject to new federal and state permits. Among variousemission control measures such as chemical, physical, andbiological treatments, biological systems, known asbiofiltration or bioscrubbing, appear to be the most cost-effective and environmentally sound. Currently,biofiltrations are employed primarily in Europe, however,research on and commercial use of biofilters have been lessextensive in the USA. In response to these problems, weinitiated research on the Microbial Scrubbing of VOCEmissions. Initially, bioscrubbing of nonhalogenatedsingle solvents such as methanol, butanol, acetonitrile, andhexane was performed and by mathematical analysis of thedata a model was developed that describes the removal of asingle solvent. As the next step, solvent mixtures,chlorinated solvents, and nitroaromatic solvents weresubjected to bioscrubbing.
MATERIALS AND METHODS
Isolations of solvent-util izing microorganisms.Microorganisms were enriched under selected solvent
vapors from sludge with pre-exposure history to varioussolvents. Individual microbes were isolated on plates ofmineral agar and consortia were established in a liquidmineral medium.Quantitative tests for solvent uti l izations.
Quantitative tests for solvent utilization were conducted inclosed flasks. Flasks received a liquid mineral medium,isolated microbes, and 20 to 350 ppm(w/v ratio) solvent.Single solvents(B, T, X, CB, DCB, and NB) and solventmixtures(BT, BX, TX, BTX, CB-DCB) were tried in flasktests. The solvent disappearance from the headspace of theflask was monitored by GC. At the same time, increase inbiomass was measured by protein determination(Bradford,1976) and chloride released as the result of CB and DCBdegradation was quantified as described by Bergmann andSanik(1957).Apparatus for scrubbing of solvent vapor.
Figure 1 shows the apparatus used for the measurement ofmicrobial solvent vapor scrubbing.
WATER FLOW N R F L O W
Fig. 1. Flow-through apparatus for measurement ofmicrobial solvent vapor scrubbing. A glass column waspacked with porous support material, 60% perlite and 40%peat moss (v/v ratio). Air samples were taken for GCanalysis by gas-tight syringe prior to, after and at threelevels within the column. For long-term experiments, acontinuous water recycling system and a pH control unitwere added. Removal rates were calculated as g solventremoved per m3 filter bed per hour.
Quantitative tests of solvent utilization.Removal of BTX. Fig. 2 and Fig. 3 show benzene
and xylene removal by a single strain which was identifiedas Pseudmwnas putida and selected as the most effectivestrain in the removal of BTX among the isolated strains.
o! , 1 I I I0 20 40 60 80 loo
Fig. 2. Removal of p-xylene vapor from the headspace offlasks in the presence of benzene. gXylene was removedonly in the presence of benzene or toluene and no biomassformation resulted from xylene degradation. p-Xylenemetabdiim was blocked at dimethylcatechol stage and theaccumnlating intermediate was polymerized.
0 .a.,.$.0 20 40 60 00 loll
Fig. 3. Removal of benzene vapor from the headspace oflasks. Benzene concentration was fixed at 8 ppm(w/v) anttoluene was added in the range of 0 to 173 ppm. Similaexperiments were performed with toluene. Both benzencand toluene appeared to be removed by the same enzymesystems and competitive inhibition between the substratewas apparent.
Removal of chlorobenzene. All flask experimentfor the removal of chlorobenzene were conducted witlmicrobial consortia enriched on chlorobenzene.
Fig. 4. Removal of CB vapor from the headspace of ffasks.Concentration of CB used was 110 ppm. Chloride releaseand biomass formation were measured along with CBremoval, and 30% of the CB added was converted tobiomass. Similar experiments were performed with DCB.