PRDD-Interactive Odor & Particulate Control-Paper

8/6/2019 PRDD-Interactive Odor & Particulate Control-Paper

1/111

INTERACTIVE ODOR & PARTICULATE CONTROL

Robert Richardson Ph.D.

Pacific Rim Design & Development IncPO Box 146 Shingletown, CA 96088

www.prdd.net

ABSTRACTIndoor air quality is an important consideration for Municipal Solid Waste (MSW)facilities that become increasingly enclosed to meet Environmental ProtectionAgency (EPA) mandates for fugitive odors and dust. Enclosure of tipping, sorting andstorage areas effectively resolves fugitive odors, and at the same time increases theneed to improve air quality within the enclosed area to meet OSHA and otherregulatory compliance requirements for personnel.

Odor masking agents that were acceptable in an open area become a problem in anenclosed space because they contribute to the overall organic compound load thatmust be treated within the indoor space to meet air quality requirements.

Particulate matter (dust) is an inherent part of MSW and Green Waste at enclosed

and open facilities. Particulate control is becoming increasingly stringent. Recentlydiesel exhaust particulate has been added to the list of unhealthy particulate matterthat must be monitored and maintained at progressively lower concentrations.

Conventional industrial scale air treatment equipment is NOT a solution for MSWfacilities. Each process is specialized and designed to address specific types ofodors or particulate. Activated carbon is an exception; it can address a wide range ofodors and particulate but is only cost effective in applications where small quantitiesof odor or particulate are present in the air stream. MSW facilities do not fit into thiscategory. MSW facilities in California and elsewhere that have tried filtration andadsorption with carbon and other media find the maintenance cost exorbitant.

There is a solution to MSW fugitive and indoor air quality issues. Pacific Rim Designand Development (Pacific Rim) has effectively integrated three proven and reliableindustrial processes in a way that allows each to contribute its strengths in asynergistic way. This process is known as the Triple Integrated Process TM (TIP). Thetreatment quality and equipment cost of this integrated process are far superior tothe sum of the individual processes.
http://www.prdd.net/http://www.prdd.net/


2/11

2

This process effectively addresses:Treatment of air leaving MSW or Green Waste enclosures meets EPArequirements.

Indoor air quality to meet OSHA requirements.

The treatment addresses:Sulfides and other MSW odors.Turpenes and other Green Waste odors.Particulate is actually utilized by the Pacific Rim process rather than beingfiltered out.

This integrated Pacific Rim process offers the following attributes:Low maintenance costLow operating costCompetitive equipment costsSmall equipment footprintGREEN technology

This Pacific Rim TIP process is the only known wet scrubbing system to effectivelytreat the wide spectrum of odorous and particulate compounds found in MSW andGreen Waste facilities. The TIP process is a combination of biological and chemicalabatement technologies. This integrated process is cost effective to operate becauseit self-cleans thereby eliminating high maintenance costs and high electrical coststhat would otherwise be required to push the foul air through a dirty system. ThisGREEN process also saves operational costs by recycling its biological nutrients andeliminating wastewater pre-treatment. This cost effective process minimizes theburden of maintaining adequate air changes to keep personnel safe within theenclosed areas. These key points are described in greater detail below in theIntroduction.

KEY WORDS / PHRASESMunicipal Solid Waste (MSW) odors & particulate

Green Waste odors & particulate

BioscrubberBiofilter

Mist scrubbing

Sulfides, Turpenes


3/11

3

INTRODUCTIONPacific Rim is recognized for innovative odor and toxic compound abatementprocess development. The firm is proud to introduce a recently created and testedTriple Integrated Process TM (TIP). This process utilizes proven technology in aunique patented configuration that minimizes maintenance and other operating costsrequired in conventional technology. The self cleaning features built into this designnot only eliminate the need for the frequent filter and media changes required inother technologies but also reduce the electrical costs required push air through adirty or clogged scrubbing system.

The Pacific Rim TIP system configuration features allow the three integratedprocesses to actually assist each other. The process features include:

System geometry utilizes gravity and other natural forces to move liquid andair thereby eliminating the need for extra pumps and fans.

Choice of materials and control technology allow the unit to self clean andrecycle the biological mass that is washed out of the beds thereby savingchemical, electrical and maintenance costs.Eliminates the need for waste discharge pre-treatment prior to entering sewersystem. (A common problem with conventional chemical and biological odorcontrol equipment.)

This Pacific Rim TIP process is the only known wet scrubbing system to effectivelytreat turpenes and other higher molecular weight green waste odors. The alternative

to TIP is thermal destruction with its high operating costs (cost of natural gas or otherfuel) and production of environmentally unfriendly NOx compounds. The TIP processconsumes rather than burns the larger organic compounds and does so without thecreation of NOx compounds.

Although the TIP is relatively new, each of the individual components has beenproven for years, and the overall system has been verified in extensive pilottesting.

This paper will describe all three of the abatement technologies that make upthis integrated TIP process and describe how their integration in this processmakes them truly work synergistically the sum is greater than the parts. Asummary of performance test results and more details on pilot testing areavailable upon request.


4/11

4

THE THREE COMPONENTS THAT FORM THIS PROCESS:

This Triple Integrate Process TM combines the following proven technologies:

First Stage: Fine mist scrubbing with chemical additives to enhance

target compound solubility and scrubbing efficiency.Second Stage: Bioscrubbing increases removal efficiency of sulfides and

volatile organic compounds.

Third Stage: Aerobic digestion Long residence time promotesdestruction of turpenes and other larger organic compounds. Also recycles usedbiological material from biofliter.

Note: A detailed process drawing and description follows the overview of eachprocess.

Fine Mist ScrubbingOne of the secrets to this integrated process is the initial fine mist treatment.Performance test of full scale systems have repeatedly shown 99.9% removalefficiency of hydrogen sulfide. Pilot testing (confirmed with mathematical modeling),demonstrated this first stage treatment removes over 70 percent of the Green Wasteformaldehyde and methanol. The remainder of the formaldehyde and methanol areremoved from the air as it passes through the Second Stage biofilter.

Water in the fine mist is an excellent solvent for the majority of the typical odorsgenerated in MSW like sulfides, acid fumes, ammonia, alcohols and other watersoluble organic compounds. This already good removal efficiency is enhanced bythe addition of chemicals that meet site specific requirements. Pacific Rimprocess chemists evaluate the odor matrix at each site and then formulate sitespecific chemical additives. The addition of biodegradable surfactants improvesorganic compound removal efficiency while the addition of pH adjustingcompounds improves the removal efficiency of inorganic compounds.

BioscrubbingIn this application the biological slime is affixed to plastic media with anoptimized surface to open space geometry that promotes sloughing and allowsdiscarded material to move easily through the packed bed.

Bioscrubbers have demonstrated good removal efficiency for organiccompounds, sulfides and other odorous compounds, so they are qualified tohandle the odors generated in MSW. Although a valuable asset in this integratedprocess, this methodology does not work well by itself in particulate laden foul airlike that found in MSW and Green Waste applications. The particulate clogs thebeds and requires added electrical energy to push the air through up to thepoint where the beds are too clogged to work at all.

In Pacific Rims TIP application, the particulate is removed from the foul air


5/11

5

steam through proprietary vessel geometry that utilizes centripetal force gravityin a dramatically reduced air velocity to separate the particulate from the airbefore it reaches the bioscrubber. The particulate falls into the aerobic digesterwhere it aids in the digestion process. More on the particulates value in theaerobic digester description below.

Nutrient rich recirculated water from the aerobic digester is supplied at twoprocess controlled flow rates. At the lower rate it is used to provide nutrients andmoisture to the bioscrubber organisms. At the higher rate it washes excessbiomass from the bioscrubber and allows it to drop by gravity into the aerobicdigester where it is recycled.

Aerobic DigestionThis third process resides in the scrubber sump and provides many functions. Thelong residence time in this liquid is ideal for the destruction of larger organicmolecules found in Green Waste like turpenes. Organisms in this liquid also digestthe excess biomass dropped from the bioscrubber, thereby returning the nutrients tothe liquid broth for re-use in new organic growth. The particulate dropped into thisliquid agglomerate and act as added surface area for biological growth. The liquidvolume also acts as a thermal shock absorber for the system thereby minimizingthe effects of temporary changes in the foul airstream temperature on the rate of bio-organism metabolism.

PHOTOS OF PROCESS AND PILOT SCALE EQUIPMENT

Photo #1 - Pilot scale unit


6/11

6

Photo #2 Detail of aerobic digester sump

Photo #3 - Full Scale Mist Scrubber


7/11

7

PROCESS DIAGRAM

TABLE FOR PROCESS DIAGRAM ABOVEKEY DESCRIPTION

A Duct routs dirty air from process to Triple Integrated Process vessel for removal oftoxic/odorous compounds and particulate

B Water with optional biodegradable surfactants or other compounds to increase removalefficiency

C Mist nozzles (fine mist)D Dirty air mixes with fine mist coalescing particulates and dissolving soluble

components.E Coalesced droplets (particulate) fall into aerobic digester belowF Air laden with mist turn 180 degrees and moves up through bioscrubber bedG Bioscrubber packing bed proprietary packing allows washing of excess biomass into

aerobic digester belowH Coarse nozzles to wet bioscrubber bed and to aid in bioscrubber bed cleaning

I Blower pulls air through the TIP process whole system in vacuum to insure nountreated air is leaked to atmosphere.

J Liquid recirculation pump(s)K Automated backwash filterL Belt press or similar dewatering device excess solids are typically non-hazardous and

can be burned or disposed of in landfill.M Venturi adds air to liquid (supplies oxygen to aerobic digester)N Aerated liquid to the aerobic digesterO Large diameter jets mix liquid in aerobic digesterP Clumped particulate matter acts as media supporting biological growthQ Optional biodegradable surfactant or other chemicals to aid in scrubber efficiencyR Chemical metering pump


8/11

8

COMPARATIVE PROCESS SUMMARY

FEATURETRIPLE

INTEGRATED

PROCESS TM

OTHER

BIOFILTER /

BIOSCRUBBERTECHNOLOGY

Mist process that provides the following:

Removes the majority of the soluble VOCs from air

Contributes to destruction of particulate material

Introduces biodegradable surfactant to enhance

solubility of other VOCs

YES NO

Avoid particulate clogging by:

Vessel geometry that routes solids to aerobic

digester where it is a benefit to the process.

Vessel geometry that uses gravity and centrifugalforce to separate particulate from air prior to contactwith bioscrubber.

Use polypropylene packing with geometry that

promotes automatic sloughing of excess biomass,

high surface area, high void fraction and large grid

opening all essential for clog free packing

YES NO

Recycles the used biomass to reclaim nutrients, thereby:

Minimizing the need for additional nutrients

Minimizing the load on sewer system (other systems

need to discard liquid that drips through the media

bed)

YES NO

Ability to digest VOCs like turpenes that have limitedsolubility in water and complicated chemical structures because:

Surfactants provide miscible mixture that isaccessible to biological degradation

Long residence time (days) in aerobic digester

YES NO

Extended operational temperature range:

Allows biological treatment of engineered woodeffluent air stream without cooling (saves money)

Avoids propagation of pathogenic (disease causing)bacteria

YES NO


9/11

9

TABLE #1 ABSTRACT OF PILOT SCALE PERFORMANCE TESTING DATA

SCRUBAIR

FLOW(SCFM)

MeOH IN(ppm)

MeOHOUT

(ppm)

%REM.

HCHOIN

(ppm)

HCHOAboveSump(ppm)

HCHOOUT

(ppm)

%REM.

92 34.01 0.35 99.0 12.64 0.14 99.1350 35.04 0.51 99.0 15.66 0.09 99.4690 34.60 2.32 95.5 13.85 0.225 98.4910 35.74 7.03 80.3 11.28 1.02 91.0

530 24.05 0.11 99.6530 6.91 0.42 93.9

920 21.13 1.79 91.6530 24.33 0.86 96.5530 68.95 0.64 99.1

TABLE #2- HENRYS LAW CONSTANTS USED IN THIS MODEL

TABLE #3 - ASSUMPTIONS USED IN THIS MODELING1 Site is very close to sea level therefore one atmosphere is used for ambient

pressure.2 Water recirculated from the sump through fine mist nozzle contained no

formaldehyde.

DETERMINING THE FORMALDEHYDE REMOVAL BY THE MIST AND BIO-SCRUBBER TREATMENT STAGES.Table #1 reports inlet concentrations for the two process comparison tests on 16December. One sample measures the concentration difference across the entire systemand the other the difference across the bio -scrubber alone.

The removal by the mist stage is:

COMPOUND CONSTANTFormaldehyde in water 10log 8.062 2943 / H T Methanol in water 10log 6.391 2047 / H T - Pinene in water 10log 9.875 1792 / H T

24.05 6 .91(1 00 ) 7 1%

24.05


10/11


11/11

11

One mole of formaldehyde weights 30.03 g = 30,030 mg . Substituting this value forformaldehyde into the equation we have:

The mist nozzles sprayed 1.0 gpm of water; this is equal to 3.8 L/min.

If the amount of dissolved formaldehyde in the sprayed water was negligible, themaximum amount of formaldehyde this volume of water could remove from the gasstream is

The number of moles of air in the 560 acfm (530 scfm) pilot scrubber air flow at the timeof testing was:

The untreated inlet air had 24.05 ppm of formaldehyde. To reduce this to 6.9 ppm v, themist scrubbing stage would have to remove formaldehyde at a rate of

min / mol1007.1mol10

mol9.605.24min

mol622HCHO

26

HCHO

This is less than the theoretical maximum removal rate of 2.3210 -2 mol HCHO /min, so the

measured removal efficiency is consistent with the known volatility of formaldehyde overits dilute solutions in water.

MODELING CONCLUSION:The fine mist scrubbing process alone is theoretically capable of removing2.32x10 -2 mol HCHO /min. This exceeds the measured formaldehyde removal rate of1.44x10 -2 mol HCHO /min. Therefore the mist section of this scrubber system is certainly

capable of removing 71% of the formaldehyde that is currently being scrubbed in boththe mist and bio-scrubber.

OVERALL CONCLUSIONThe Triple Integrated Process TM technology provides the best available odor andparticulate control technology for the MSW and Green Waste industries because itprovides benefits not available in any other conventional abatement technology. This TIPprocess also includes lower operating costs that minimize the burden of providingadequate air changes necessary to keep personnel safe in enclosed MSW buildings.

530 / min 454 / # 622 / min387 / #

scf mol mol mol

scf mol

36.11 10 / 30, 030 / 183.5 / 183.5 HCHO HCHO x mol L mg mol mg L ppm

3 23.8 / min 6.11 10 / 2.32 10 / min HCHO HCHO L x mol L X mol

PRDD-Interactive Odor & Particulate Control-Paper

Documents

Transcript of PRDD-Interactive Odor & Particulate Control-Paper