PRD Brochure

Biotrickling Filter Odor and VOCControl Systems for:• Wastewater treatment and sludge- composting operations• Retrofit conversion of chemical wetscrubbers• Lift stations• Industrial odors and VOC emissionsInnovative Biotrickling FilterTechnology Featuring:•Long-life synthetic media – 10 yearwarranty• Minimal equipment size – ultra-compactspace saving footprint • Energy efficient operation – low pressuredrop & low powerconsumption • Fully automatic control Advanced Odor Control TechnologyFor the control of odors and volatile organiccompounds (VOC’s), PRD Tech biofiltrationsystems provide an economical and environ-mentally friendly method of treatment for a widerange of organic and inorganic air emissions.PRD Tech biotrickling filters are fully automatedand custom engineered to meet or exceed theperformance requirements for virtually any odoror VOC control application.What is biofiltration?Biofiltration is a biological process that usesmicro-organisms to convert odor causing com-pounds into harmless by-products, i.e., carbondioxide, water and biomass.Since the introduction of the technology inthe 1960's, most biofilters have used naturallybioactive media such as peat, compost, soil orwood chips to biologically degrade odors andVOC’s.Recognizing the limitations associated withthese organic media systems and other conven-tional odor control technologies, PRD Techdeveloped an innovative biotrickling processthat achieves an entirely new level of perform-ance for biological air treatment systems.What is PRD Tech syntheticmedia?PRD Tech biotrickling filters offer importantstate-of-the-art improvements in biofilterdesign that translate into tangible perform-ance and economic benefits. Foremostamong these improvements are the uniquesynthetic medias developed by PRD Techspecifically for use in biotrickling filters.Depending on the application, the mediamay be either randomly packed hollow poly-meric spheres (1", 2", 3" or 3" in size) orstructured packings made of PVC orpolypropylene. One or both types of mediamay be used in a single PRD Tech biotricklingfilter depending on the flow rate, gas BOD,types of contaminants and operating condi-tions. Regardless of which PRD Tech media isbest suited for any given application, itsdesign will have the following attributes formaximum performance.What are PRD Tech biotricklingfilters?Biotrickling filters utilize synthetic media onwhich contaminant degrading bacteria areimmobilized as biofilms on the surface of themedia. As air flows through the biofilter media bed,the contaminants come in contact with theactive biofilms that degrade the odorous com-pounds. At the same time, a continuous streamof water trickles down through the media tokeep the biofilms moist and biologically active.PRD Tech achieves maximum treatment effi-ciency by also adding a nutrient biocatalyst tothe water that circulates through the biotricklingfilter so that the airborne contaminants areabsorbed into the water where they are biode-graded by the suspended culture. Thus, with thePRD Tech system, contaminant compounds inthe air are biodegraded by the active cultures inthe liquid phase as well as by the active biofilmson the surface of the synthetic media.High void fraction (percentage ofopen space)– PRD Tech’s open structure medias allow ampleroom for biofilms togrow without causing the media to clog dueto excessive biomass growth.High surface area – The media pro-vides a high degree of biologically activesurface area per unit volume (30 – 110 ft/ft)so as to achieve highmass transfer ratesof odors and organic compounds into thebiofilms.Low pressure drop– The high voidfraction of PRD Tech’s synthetic mediaresults in a very low pressure drop acrossthe biofilter bed (<0.3" to 1" water column).Hydrophilic surface– Since biofilmsmust be kept moist for the micro-organismsto remain biologically active, the surface ofthe media must be readily wettable (i.e.hydrophilic) and capable of retainingmoisture. PRD Tech synthetic medias aresurface modified to achieve the hydrophilicproperties needed to retain water andsupport the attachment and growth ofbiofilms on the media surface.Low bulk density- The total weight ofthe biofilter and the cost of the structure tosupport the mediabed(s) are minimizeddue to the light weight of thelow densitysynthetic media (2.5 – 7.0 lb./ft).PRD Tech synthetic mediafeatures2PumpInlet air with odors(organics, H2S, NH3,Mercaptans, Disulfides,etc)Synthetic media withlive bugsTreated airNutrientsPRD Tech biotrickling filters offer manypractical advantages over other biofil-tertration technologies due to the uniqueattributes of their synthetic media.Superior performance– The highsurface area and high void fraction of PRDTech’s synthetic media results in:• Higher gas velocity • Minimal gas residence time• Uniform distribution of gases andwater within the media bed• Rapid response to sharp fluctuationsin contaminant loadings• Ability to treat higher concentrationsof H2S and other odorous compounds Compact in size– Due to the highvelocity at which gas flows through thesynthetic media, the cross sectional areaof the media bed(s) is minimized and theoverall size and footprint of the equipmentis ultra compact.Energy efficient– As a result of thelow pressure drop of the synthetic media,energy costs to operate a PRD Techbiotrickling filter are minimal since the fansize and power consumption are directlyproportional to the pressure drop.No clogging of the media– Thepressure drop between the gas inlet andoutlet of the media bed is continuouslymonitored by differential pressuresensors.If excessive biomass growth causesthe pressure drop to exceed 0.5 inches ofwater column, a supplemental wash isautomatically activated which causesexcess biomass to slough off the mediaand exit the bed, thereby preventing theoccurrence of clogging, gas channeling ordead zones within the media bed.Long media life– With the built-inability to purge the media of excess biomass and prevent clogging, there isno need for periodic replacement orreconditioning of the synthetic media. Inaddition, PRD Tech medias do notdegrade or deteriorate and areguaranteed for 10 years.How do PRD Tech biotrickling filters differfrom otherbiofilters?Fully automated design withflexible system control– PRDTech biotrickling filters require minimaloperator intervention and can functionas stand-alone units or integrated into aplant-wide control system.Biotrickling Filters control odors in waste-water treatment, sludge processing andPRD Tech biotrickling filters are highly effective intreating hydrogen sulfide and other primary sources ofwastewater odors, including ammonia, mercaptans,amines and reduced sulfur compounds. Shown in thephoto below is an installation at a municipal wastewaterplant in northern Kentucky where dual stage biotricklingfilters are treating 15,000 cfm of odorous gases generat-ed from the thermal conditioning of waste activatedsludge. This system eliminates 99.9% of the odors fromthe sludge conditioning process without the use of costlychemicals or adsorptive media.Retrofit conversion of chemical scrubbers tobiotrickling filters offers substantial benefits.The adjacent photo shows achlorine scrubber that was con-verted in-situ to a 30,000 cfmbiotrickling filter and placed backinto operation within a matter of afew weeks A gradual "phase-in"retrofit approach meant virtuallyno downtime for the wastewatertreatment plant. Immediate bene-fits to the district included:• Elimination of chemicalhandling, storage and liabilityissues• Dramatic savings in operatingcosts as a result of reducedelectricity consumption andeliminating the use ofchemical oxidizing agents• Avoidance of the potentialrelease of harmful chemicalby-products (halocarbons)• 99.9% reduction of inlet odorlevels3Biotrickling filters are also effective in treating odorsfrom sludge composting operations that generate a vari-ety of emissions including sulfur compounds, volatilefatty acids, ketones, ammonia and other nitrogen con-taining compounds. While ammonia can be controlled with acid scrubbing,the other primary contaminants are typically treated withchemicals such as hypochlorite and/or hydrogen perox-ide. PRD Tech’s biotrickling process is an economicalalternative that requires no chemical oxidizing agentsand is more energy efficient, more effective in treatingorganics, and produces no potentially harmful by-products.PRD Tech's synthetic media is the key factor to the successfulperformance and ease of conversion when retrofitting conventionalchemical scrubbers. The retrofit investment is quickly offset bysavings in chemical costs and energy consumption.Effective odor control for lift stationsFor reliable treatment of odorousemissions from wastewater lift sta-tions, PRD Tech offers a compact skid-mounted biotrickling filter that is sold orleased as a complete self-containedIt can be quickly and easily installed atany lift or pump station and needs onlyyearly maintenance for the gas blowerand liquid pump. Operation of the unitrequires water and 110 V, 60 Hz powerand the only consumable is a concen-trated biocatalyst solution (PRD-Biospeedup) that is used at a rate ofjust a few gallons per year.PRD Tech biotrickling filter applications include treatment of:•Aromatic hydrocarbons – benzenes,toluenes, xylenes•Organics - aldehydes, amines, ketones,alcohols• Inorganics – hydrogen sulfide, ammonia•Reduced sulfur compounds - mercaptans,disulfides•Unidentifiable odorsThe system includes a biotrickling filterwith PRD Tech synthetic media, a blow-er, pumps, PLC (programable logic con-trols) and the biocatalyst. In comparisonto chemical scrubbing or activated car-bon adsorption, PRD Tech's biofiltrationsystem for wastewater lift stations offersa compact and cost effective alternative.About PRD TechPRD Tech specializes in the design, development and manufacture ofadvanced biological treatment processes for a variety of environmentalapplications. In addition to biotrickling filters for odor and VOC control,other products developed by PRD Tech include:• Biocatalysts to accelerate treatment rates in bioscrubbers,bioreactors, soils, lagoons,composters and digesters.• Zero Emission technology to prevent the release of chromeinto the air during electrplating processesAutomatic system operation is provided by a PLCcontroller which monitors and manages the following:• variable speed drive on blower to maintain a setinlet pressure,• pressure drop measurement across each bed, • automatic start-up and shut-down sequences,• flow switches to turn off addition of biocatalystin the event of pump failure, • alarms, • reminder for biocatalyst drum replacement,• and reporting of system status.Make-up water supply is switched on when thelevel in the sump falls below a minimum set-point.PRD TECH INC.1776 Mentor Avenue; Suite 400-ACincinnati, OH 45212 Tel: (513) 731-1800Fax: (513) 984-5710 www.prdtechinc.comRepresented by:© PRD TECHINC 2003 printed in the USA