Pol I ut ion Prevent ion Opportunities for Concrete Batch Plants

Size: px

Start display at page:

Download "Pol I ut ion Prevent ion Opportunities for Concrete Batch Plants"

Griffin Conley
5 years ago
Views:

1 Pol I ut ion Prevent ion Opportunities for Concrete Btch Plnts L This checklist is guide for concrete btch plnt owners nd opertors to ssist in estblishing wste reduction opportunities. Concrete btch plnts, s defined for this checklist, include plnts tht store, mesure nd trnsfer concrete constituents into trucks for trnsport to job site, plnts tht use centrl mix drum to mnufcture concrete on-site for trnsfer to trnsport trucks, nd plnts tht pre-cst products on-site such s concrete bricks. Rw mterils include snd, ggregte, cement nd wter for concrete btching. Prticulte mtter nd stormwter runoff re primry pollutnts of concern. Point sources emissions re result of the trnsfer of mteril to silos. Fugitive sources include the trnsfer of snd nd ggregte, truck loding, mixer loding, vehicle trffic, nd wind erosion from snd nd ggregte storge piles. Potentil btching plnt wstewter nd stormwter pollutnts include cement, snd, ggregtes, chemicl dditive mixtures, fuels nd lubricnts. Dust prevention equipment my include wter sprys, enclosures, hoods, curtins, shrouds, movble nd telescoping chutes, fbric filters, etc. Some of the pollution prevention opportunities presented in this checklist my not be prcticl for ll concrete btch plnts. Plnt owners nd opertors re encourged to evlute wste reduction opportunities bsed upon their fcility's individul opertions. The sme wste reduction ide tht works for one plnt my not necessrily work for ll. Additionl opportunities my exist beyond those identified in this checklist. As owners nd opertors, you hve the expertise to identify those opportunities pplicble to your opertions. ACKNOWLEDGEMENT Informtion support for this document provided by the Florid Deprtment of Environmentl Protection's Pollution Prevention Progrm nd the Ntionl Redy Mixed Concrete Assocition (NRMC)'s publiction, Environmentl Mngement Prctices (Pub # 191).

2 . EMPLOYEE EDUCATION Your Pollution Prevention efforts cn only be successful if ll employees re committed to minimizing their wstes. 1) Are employees trined to: ) recognize nd minimize environmentl hzrds? yes - no - b) hndlehrnsfer rw mterils (snd, snd, ggregte, cement, wter) in mnner to reduce prticulte emissions nd wstewter runoff? yes - no - c) clen equipmenthehicle in mnner to reduce irborne prticles/wstewter runoff? yes - no - d) clen vehicles before trnsporting mterils off-site? yes - no - e) use dry clen-up whenever possible? yes - no - f) dispose of/recycle leftover cement properly? yes - no - 2) Hve you clerly outlined nd explined to your stff nd employees wht pollution prevention nd wste minimiztion re nd encourged their input in identifying site pollution prevention ctivities? yes - no - 3) Do you provide incentives or wrds for those who prctice proper or new pollution prevention techniques? yes - no - 4) Do you hold regulr employee meetings to discuss chnges or ongoing equipment prctices nd procedures? yes - no - Generl Site OpertiondMintennce Locte/operte sttionry CBP equipment, stockpiles nd plnt vehicles t lest 25 feet from ny property line Mintin ll equipment, including dust/prticulte collection equipment, ccording to mnufcturer s recommendtions to prevent leks. Identify buffer zone surrounding your opertions in which you pln to contin primry dust generting ctivities Mintin stockpiles inside this buffer zone within three-wlled bunkers which extend t lest two feet bove the top of the unlod line Use totlly enclosed system for the loding, unloding, hndling, trnsfer or storge of cement, pulverized fuel sh nd/or other dusty rw mterils Keep routine mintennce log on-site of ll equipmenvfilter systems on-site, recording dte nd time of ll corrective ctions Provide integrted qulity, sfety nd environmentl mngement systems for the site, opertion of the plnt, nd delivery process

3 Storge Silos Vent ll cement/fly sh storge silos nd weigh hoppers to fbric, bghouse or crt ridge f ii te r system. CI Identify the cuse of ll visible emissions nd tke corrective ction immeditely Monitor filter systems to identify when clening/replcement is necessry Regulrly check for ters or leks in fbrickrtridge filter systems nd suction shroud Choose filter systems designed to meet t lest.1 gr/dscf outlet CI Check ll filter systems nd mixedtruck loding control devices for visible emissions dily during plnt opertions Provide sufficient lighting ner cement nd/or fly sh silo filter exhusts to observe visible emissions performnce during fills tht occur during non-dylight hours Totlly enclose ll silo conveying systems nd mintin opertions with no ters or leks Monitor storge silo conveying systems for visible emissions nd correct the cuse of visible emissions immeditely Instll udible nd visul high-level lrms on ll storge silos to void overfilling nd possible filter dmge Use silos to store ll mterils cpble of generting dust (cement, pulverized fuel sh (PFA), etc.) Connect the high-level lrm indictor to n utomtic delivery shut down to prevent overfilling Instll test circuits on ll lrms to test prior to ech silo fill Mintin lrms in working order t ll times Fit ll silo nd weighing scle vents with fbric filtering systems to collect dust Check the seting of ll silos pressure relief vlves nd reset if necessry, before ech delivery Enclose ll receiving hoppers nd for unloding mterils on three sides up to 3 meters bove the unloding point CI Avoid using receiving hoppers s mteril storge devices

4 Rw Mterils Substitute t lest 15% nd up to 35% fly sh for cement in concrete mixes. Some pplictions will ccommodte up to 7% Substitute col-fired boiler, cinder nd bottom sh, for ggregte in concrete building block mnufcturing Use sugr or wood-bsed dmixtues tht re sfer nd less toxic thn other chemicl concrete dditives Mixer Feed Opertions Vent the cemenvfly sh weigh hopper inside the btch mixer Use spry device to prevent dusthisible emissions t the mixer feed Use pickup device tht delivers ir to filter to prevent dust emissions t the mixer feed Use n enclosed btch mixer feed to prevent dust nd visible emissions t the mixer feed Conduct the entire mixing opertion inside n enclosed process building to prevent dust nd visible emissions Mteril HndlingEtorge Store ggregtes 5 millimeters or less in size in totlly enclosed structures (e.g. storge bins) Do not hndle ggregtes 5 millimeters or less in open res Use ground stockpiling only if there is sufficient buffer re surrounding the plnt Enclose stockpiles on t lest the top nd 3 sides Instll flexible curtin to cover stockpile entrnce sides Totlly enclose the opening between the storge bin nd mteril weighing scle

5 , f* Y Conveyors Enclose belt conveyors used for hndling mterils on top nd 2 sides with metl bord t the bottom to eliminte ny dust emissions due to wind effects Enclose ll conveyor trnsfer points. Fit conveyor pssge openings with flexible sels to prevent dust genertion Provide scrpers t the turning points of ll conveyors to prevent dust collection on the belt surfce Arrnge conveyors delivering to mteril stockpiles in wy to minimize free fll Enclose ll free flling trnsfer points from conveyors to stockpiles with chute(s) nd pply dust suppression mterils t these points (suppression gents, wter spry) Loding/Mixing Opertions Lod concrete trucks in wy to minimize irborne dust emissions Pre-mix mterils in totlly enclosed concrete mixer before loding the mterils into the concrete truck is recommended Vent ll irborne dust emissions generted by mteril loding/mixing opertions to fbric filtering systems Totlly enclose the loding by during the loding process. Dust trps nd other dust prevention mterils re vilble for pre-existing equipment. Check with your suppliers for currently vilble dust prevention supplies. Provide equipment necessry to clen ll concrete trucks nd other vehicles fter loding (preferbly dry clening methods) nd before exit from the property to wsh off ny dust nd/or mud deposited on the wheels nd/or vehicle body Pln with the concrete truck driver exctly where rinsing cn be done. Avoid loctions where run-off will get into topsoil or flow into surfce wter. Housekeeping Sweep site regulrly to remove dust buildup Cl Clen up ll spillges or deposits of mterils on ground immeditely Use dry clen-up methods whenever prcticl (sweeping, dust collection vcuum, wiping, etc.) Instruct stff nd drivers to never dump ny mterils in open res

6 it Fbric Filters Service nd mintin fbric filters ccording to mnufcturer s recommendtions Provide dequte ccess to the filters to llow for regulr inspection nd mintennce Record on weekly bsis in mintennce log book: pressure drop visul conditions of exhust mteril incidents of filter medi filure/replcement Rod nd Yrd Dust Minimize dust emissions due to vehicle trvel by: site lyout nd design Q vehicle wheel clening before leving the site (dry clening method or the wheel nd truck wsh fcilities t site exits) Q posted vehicle speed limits Avoid using plnt opertionl vehicles within 25 feet of ny property line, except for entry nd exit to the site Keep ll btch trucks nd mteril delivery trucks on pved surfces for entry, conducting primry opertion nd exit of your property If rodwys re not pved, consider pving ll regulr pths of vehicle trffic (entry, exit, min trffic res of plnt opertions, btch nd mteril truck delivery rods) with hrd surfce tht cn be clened by dry methods to minimize dust nd run-off to nerby properties nd stormwter Where it is not prcticble to pve site (e.g. t short-term loction), number of lterntives exist to reduce dust emissions from yrds nd rodwys: Q ppliction of thin lyer of high qulity pvement over rod surfce Q chemicl suppressnt products (severl options vilble) Q vegettive brriers Use dust-preventtive brriers or vegettive buffers t lest 12 feet high long rods nd other trffidwork res within your specified buffer zone

7 Fugitive Dust Consider previling wind directions in the design nd set-up of bunkers nd conveyors. Bunkers nd conveyors should be set-up so s to minimize wind effects If wter sprys or dust suppression gents must be used to reduce dust, use ppliction equipment nd techniques tht minimize wter nd mteril usge Receive ggregte mteril in dmp condition Provide conveyor brriers on t lest one side Q Equip conveyors with brrier on t lest one side, roof nd spill trys which direct mteril to collection point. Use belt clening devices t the conveyor hed to reduce spillge Conduct ll mteril mixing opertions within n effective enclosure (wlls, screens, dust gurds, trps) Roof nd enclose mixer loding res on two or three sides Instll n effective ir extrction nd filtrtion system to collect dust generted during mixer truck loding Q Enclose weigh bins nd hoppers on three sides nd roof where front-end loder is used Extend roof t lest two meters beyond lod res Use of wter spry system should be your lest desired dust prevention mesure. If you re unble to effectively prevent dust during opertions using the opportunities identified in this checklist. Wter sprys crete stormwter issue for your plnt. Dry method clenup nd wind brrier equipment should be your first choice Clen up ny rw mteril spills by dry sweeping. Wter should not be used in the process of clening up spills except where the re drins to n effective wstewter collection point

8 * 't h Wste Concrete Consider instlling recycling system for residul concrete tht uses crbon dioxide or cid (crbon dioxide is sfer) to lower ph nd filtrtion to remove solids. Vrious types nd sizes re vilble. A recycling system cn reclim ggregte for direct input bck into btching nd cn produce filter ckes tht my be used s limestone substitute (rod bse, prking lots, other pplictions). Consider collecting wste concrete in suitble wshout pit where it becomes grvel, snd nd sludge, which cn subsequently be collected nd reused Offer wste sediment, sludges nd fines s fill mteril, grvel rod stbilizer, or lndfill cover Use wste concrete on site for construction purposes (e.g. bunker blocks, pving unseled res, fill round buildings, prking lot nd drivewy ggregte). Check with your locl permitting gency for rodwy requirements. Use commercilly vilble delyed set d mixtures designed to keep leftover mix truck concrete in liquid form to be dded to the next btch of mix Crush blocks nd bricks tht do not meet stndrds to use for groundcover, wlkwys, trcks, lndfill cover, nd the remnufcture of other types of block wlls, dividers, or curbs Recycle dust into future concrete btches Wheel Wshes Design wheel wshes to ccount for the mximum extended tire length expected Locte wheel wshes in n re tht provides sufficient trck-out distnce before exit from the property Minimize off-property trck-out by providing lrge ggregte or pved rodwy immeditely fter the wheel wsh within property boundries Instll motion sensor on wheel wsh units to provide wter only on-demnd

9 Wste Wter Re-use wstewter, wsh wter nd storm wter for concrete btching. Process wter in the rnge of ph 6-9, nd 5-2 prts-per-million totl suspended solids (TSS) is idel for re-use in btching, wshing nd rinsing. Monitor process wter ph nd TSS to ensure these rnges re met for rinsewter to be re-used for btching. ASTM Specifiction (2-94 permits the use of wsh wter from mixer wshout opertions for mixing fresh concrete, s does Portlnd Cement Assocition (PCA) (1 ) stndrds. Literture indictes tht concrete btched from process wter strength-tests equl to, or greter thn, concrete mde using fresh wter. Re-use either wek wstewterhtorm wter for rinsing truck exteriors, or fresh wter tht is collected seprtely from other process wters Re-use wter for drum nd chute wshing, nd for slumping Re-use wter for plnt nd grounds wsh-down nd dust suppression Consider metering or using timer to dispense wter for mixer flushing An effective lterntive to mixer wsh-out is to use recycling dmixtures to stbilize the concrete residues in the drum. Use only 4-5 gllons of fresh wter nd the suggested dosge or recycling dmixtures to rinse mixer drums nd hold the resulting slurry on the truck nd incorporte into the next btch, or the first btch the following dy. Studies hve shown tht these slurries cn be held for eight hours, or longer. Wherever fesible, divert clen stormwter (e.g. roof run-off) wy from contminted res nd into n pproved stormwter dischrge system Use berms or curbs round truck loding res, ggregte piles, truck wshing sttions, drum nd cute wsh-out res, nd chemicl stging res to cpture contminted stormwter nd process wstewter Use site grding nd porous pving to improve storm wter hndling from the generl plnt site Design wstewter collection nd recycling system to collect contminted wter from: - gittor wshout - truck wshing - yrd wshdown - contminted stormwter - concrete btching re - slump stnd - ny other wstewter from the btching plnt opertion

10 Direct process wstewter nd contminted stormwter from the entire site to n on-site settling pond, or series of ponds. This wter cn be reused in the concrete btching process Protect storm drin inlets from wste concrete/dust runoff c1 Develop routine yrd nd equipment mintennce progrm to considerbly reduce the potentil for dischrge of sediment to your wstewter collection nd recycling system Instll sediment trps within the boundries of the site Regulrly inspect nd provide mintennce of the sediment trps to void dischrges of contminted wter from the site Sel bove-ground fuel nd chemicl dditive storge res with n impervious mteril nd berm to contin spills nd leks Test underground storge tnks nnully for leks or necessry repirs Contct Pinells County's Pollution Prevention nd Resource Recovery (P2R2) Progrm t for Wste Reduction Assistnce

CENTENNIAL MILLS DEMOLITION

CENTENNIAL MILLS DEMOLITION KPFF JOB NO. DEMOLITION PORTLND DEVELOPMENT COMMISSION PROJECT SITE VICINITY MP SHEET INDEX TOPOGRPHY LEGEND: SITE MP CONTCTS DEMOLITION GENERL NOTES: BBREVITIONS Dig Safely. Call the Oregon One-Call Center