BASIC HAZARDOUS WASTE MANAGEMENT - CHAPTER 8 ppt

Pollution Prevention, Waste Minimization, Reuse, and RecyclingOBJECTIVES At completion of this chapter, the student should: • Understand the basic operational approaches to waste minimiz

Pollution Prevention, Waste Minimization, Reuse, and Recycling

OBJECTIVES

At completion of this chapter, the student should:

• Understand the basic operational approaches to waste minimization, i.e.,product changes, source controls, use and reuse, and reclamation

• Be familiar with the principles, process, and practice of waste reductionassessment

• Understand the imperatives of waste minimization, reduction, reuse, andrecycling

• Be familiar with the RCRA regulatory mechanisms and program tives to achieve waste minimization, the national policy aspects, and thelocal impediments

incen-• Be similarly familiar with the objectives of the Pollution Prevention Actand the implementing mechanisms

INTRODUCTION

We now take up the most important issue in the study of hazardous waste ment — the elimination or reduction in the quantity of waste generated Throughoutthe previous chapters, we have emphasized the fact that much of what has passedfor hazardous waste management ultimately came to little more than moving itaround, transferring it from one environmental medium to another, changing itsform, or hiding it

manage-Great strides have been made in the sophistication of regulatory programs,treatment and destruction technology, and secure disposal The thrust of industriesand government, until recently, has been toward ever-tightening pollution controlrather than pollution prevention Politicians (and others) are fond of referring to thistraditional sanitary engineering approach as the “end-of-the-pipe mentality.”The legislate-regulate-treat-dispose approach has three primary roots:

8

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1 As hazardous wastes became a more serious aspect of industrial ment, they were initially handled in a manner similar to the handling ofsewage and refuse There is little that can be done to reduce the amount

manage-of sewage generated, so we taught ourselves to treat it to make it lessthreatening to our health and aesthetic sensibilities and to our environ-ment Refuse management was based upon similar thought processes, butwith somewhat less validity Sanitary engineers did not advocate addinghazardous wastes to our sewerage systems and had little to do with thedumping of hazardous wastes into whatever refuse management systemswere in use The sewers, atmosphere, and dumping grounds were there,and our use of them was dictated by the politics and the economics ofthe free enterprise system

2 During and after the Vietnam War, former President Lyndon Johnson andhis Secretary of Defense Robert McNamara, were criticized for theirfailure to mobilize the nation and vigorously prosecute the war The policywas referred to as “gradualism,” meaning that the resources (men andmaterials) were added in small increments, to which the enemy was able

to accommodate The parallel with the nation’s approach to hazardouswaste management is unmistakable When hazardous wastes began torequire our attention, we did not mobilize to deal with them We did notexamine the sources to determine their necessity; or whether there might

be alternative processes, raw materials, or end products; or even goodoperating practices that might reduce quantities or strengths of wastes.The feeble impact of the resurrected 1899 Rivers and Harbors Act and theearly efforts of environmentalists led us to put in equally feeble “treatment”schemes to transfer pollutants between environmental “media” or to hideour dumping more carefully As regulatory pressures increased, we addednew treatment units, upgraded existing ones, and created the treatment,storage, and disposal industry With the advent of the Hazardous and SolidWaste Amendments (HSWA), we pushed innovative treatment and destruc-tion and tried to reduce our dependence upon disposal Only recently have

we begun to seriously consider new approaches

3 The third of these roots is, of course, economics The economic pressuresupon U.S industry have ranged over the ever-escalating labor-wage demands

of the 1960s and 1970s; the profit greed of the 1970s and 1980s; the overseascompetition of the late 1980s; and the siren calls of minimal or no environ-mental controls and cheap labor in “developing” countries Industry repre-sentatives and lobbyists have been highly effective in softeningenvironmental legislation and regulatory issue Fears of job losses, reces-sions, stockholder demands, and debt have been the dominant themes Indus-trial decision makers tended to opt for the least expensive option of themoment and in hazardous waste management that frequently translated intothe purchase of a treatment unit or a new contract with a disposal facility.Until recently, there have been few, if any, economic incentives to examine majorchanges in products, raw materials, materials handling, or process controls to elim-L1533_frame_C08 Page 198 Tuesday, May 1, 2001 12:40 PM

inate a waste stream or reduce it in volume or strength The economic incentives ofpoor corporate image, Superfund nomination, tort filings, and criminal penaltieshave much to do with the newly found interest in waste minimization Ever-dimin-ishing availability of space for disposal services; public resistance to siting of anykind of hazardous waste management facility; and increasingly stringent regulationadd further pressures to rethink our traditional approaches More pointedly, thePollution Prevention Act of 1990 (PPA) intensifies requirements for reporting ofreleases and analysis of progress in achieving waste minimization goals The newAct and the EPA’s implementation program have stopped just short of mandated

reductions of releases The agency refers to the waste minimization, source reduction,and recycling/reuse program emphasis implemented immediately after enactment ofthe PPA as “Phase I” of the pollution prevention programs

“Phase II” of the PPA implementation has been embodied in a flurry of initiatives,strategies, and policy statements that are designed to persuade, coerce, and/or requireindustries and hazardous waste managers to “virtually eliminate,” reduce generation

of, or find environmentally safe substitutes for hazardous wastes.1 These new thrustsare discussed in a later section of this chapter The new initiatives are well meantand some are, or will be, effective Nevertheless, many of the traditional and moremundane waste minimization, reuse, and recycling measures and technologiesremain valid, useful, and necessary Accordingly, we will attempt to provide thereader/student/practitioner with a balanced overview of the proven waste minimiza-tion, reuse, and recycling techniques and practices, along with the more recentapproaches that the EPA is emphasizing

As noted earlier, the statutory authorities for waste minimization programs and forpollution prevention strategies do not include mandatory controls or mechanisms toregulate waste minimization programs In lieu thereof, the EPA developed a largenumber of good “how-to” publications that deal with program organization andmanagement, as well as technical approaches The “Phase I” pollution preventionprograms were, and continue to be, focused upon extensive reporting requirements,goal setting, and performance evaluation The U.S Congress’ Office of TechnologyAssessment produced an informative critique of the program, entitled “SeriousReduction of Hazardous Waste.” We now borrow from these publications, and others,

to provide some structure to the topic Figure 8.1 diagrams an organized way tothink about the waste minimization techniques We then follow with examples ofeach of the diagrammed techniques

Source Reduction

In the previous chapter, we offered Dr George Combs’ version of the hierarchy ofpreferable waste management options and priorities Following enactment of theHSWA in 1984, the EPA waste minimization program offered a similar hierarchy

1 Particularly for priority persistent, bioaccumulative, and toxic (PBT) pollutants, as will be seen later herein.

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© 2001 by CRC Press LLC

that may be helpful in thinking about approaches to hazardous waste reduction, orminimization:

changes in industrial processes

which they occur

3 Waste Exchange: Transfer wastes through clearinghouses so that they can

be recycled in industrial processes

some other purpose, such as for materials recovery or energy production

5 Incineration/Treatment: Destroy, detoxify, and neutralize wastes into lessharmful substances

encapsulation, leachate containment, monitoring, and controlled air andsurface/subsurface water releases

This hierarchy was the rationale for EPA waste minimization, recycling, and reusepolicies and directives from enactment of HSWA in 1984 until the 1990 PPA was passed

Product Changes

end-products that allow fundamental changes in the manufacturing process or in the use

of raw materials can directly lead to waste reduction Such changes are also themost difficult approach to waste reduction for several reasons, including

• Concerns on the part of the manufacturer regarding customer acceptance,cost of the conversion, cost of the new product, and quality control

• Concerns on the part of the customer regarding acceptability of the uct, quality control, and changes in application made necessary by thesubstitution, general uncertainty, and fear of the unknown

prod-• Concerns on the part of both manufacturer and customer regarding latory and liability impacts

regu-For example, Monsanto (St Louis, MO) reformulated a specialized industrial sive so that hazardous particulates remained in the product, thus eliminating theneed to use and dispose of filters and particulates as waste The company then had

adhe-to convince its cusadhe-tomers that the particulate matter formerly removed by the filterscould remain in the product without affecting its adhesive qualities From the timethe idea of reformulating the product was originated, 2 years of effort by Monsanto’sResearch and Marketing Division was required before the reluctance of the purchaser

to accept a different product was overcome and the change could be made (Office

of Technology Assessment 1986, p 83)

through product conservation is the effective management of inventory having L1533_frame_C08 Page 201 Tuesday, May 1, 2001 12:40 PM

cific shelf-lives Holston Army Ammunition Plant reduced waste pesticide disposalfrom 440 kg to 0 kg in 1 year by better management of stocks (Mills 1988)

it packaged a product and achieved waste reduction in doing so A wettable powderinsecticide, widely used in the landscape maintenance and horticulture business, wasoriginally sold in 2-lb metal cans that had to be decontaminated prior to disposal,thereby creating a hazardous waste Dow now packages the product in 4-oz water-soluble packages which dissolve when the product is mixed with water for use(Office of Technology Assessment 1986, p 83)

Source Control

Input Material Changes

disposable wipes or reusable towels in thousands of industrial facilities using lions of shop towels daily The shop towels come in contact with a variety ofchemicals, some of which are hazardous materials; thus, disposal of the towels maybring the user under RCRA regulation The EPA has deferred making decisions onthe regulatory status of reusable textile wipes to the EPA regional offices and states.Reusable towels are usually rented from industrial towel services (“… a contrac-tual/closed loop cleaning service”) Most of the state agencies have either exempted

mil-or limited the scope of RCRA regulation, where reusable shop towels are inated with listed or characteristically hazardous solvents However, the states andEPA regional offices granting exemptions require that specific reusable shop towelmanagement criteria be followed The criteria vary from state to state, but mostrequire that (1) the laundry be in compliance with its wastewater discharge permitand (2) the towels not contain any free liquids These arrangements reduce thecustomer RCRA liability and the substantially larger volume of hazardous wastecreated by the use of disposable wipes (Smith, 1998, pp 36ff)

gal of waste 1,1,1-trichloroethane (TCA) from vapor degreasing operations ical laboratory personnel discovered that the TCA was being disposed of because itdid not meet an acid acceptance value of 0.10 wt% NaOH Oil contamination levelswere less than 10% at the time of disposal, far less than the expected 30% level Torestore acid acceptance levels, 1,2-butylene oxide was added to the solvent Noadverse reactions or detectable problems were observed when the butylene oxidewas added to the vapor degreasers This example of purification of input material

Chem-is expected to enable reduction of dChem-isposal volumes by 4000 gal (60%) and savings

of $30,000/year (EPA 1989, p 19)

Technology Changes

waste generation, is staged use of solvent An electronics firm switched from usingthree different solvents — mineral spirits for degreasing machine parts; perchloro-ethylene for computer housings; and a fluorocarbon-methanol blend for printedcircuit boards — to a single solvent system Fresh solvent is used for the printedL1533_frame_C08 Page 202 Tuesday, May 1, 2001 12:40 PM

circuit boards, is then reused to degrease the computer housings, and last is reused

to degrease the machine parts This practice not only reduced solvent consumptionand waste, it eliminated potential cross contamination of solvents; generated a singlewaste stream that can be recycled; simplified safety and operating procedures; andincreased purchasing leverage (EPA 1989, p 17)

beneficial in waste reduction programs In an electronic circuit manufacturing plant,flexible electronic circuits are made from copper sheeting which must be cleanedbefore use Cleaning had been accomplished by spraying with ammonium persulfate,phosphoric acid, and sulfuric acid This cleaning operation created a hazardous wastestream that required special handling and disposal Equipment for cleaning bychemical spraying was replaced by a specially designed machine with rotatingbrushes which scrubbed the copper sheet with pumice The resulting pumice slurrywas not hazardous and could be disposed in a sanitary landfill Savings of $15,000

in raw material, disposal, and labor costs were achieved in the first year This processchange also eliminated 40,000 lb of hazardous liquid wastes per year (Dupont et al

2000, p 357)

automatic devices Automation can include the monitoring and subsequent adjusting

of process parameters by computer or mechanical handling of hazardous substances.Minimizing the probability of employee error (which can lead to spills or “off-spec”products) and increasing product yields through the optimum use of raw materialscan reduce waste Bar-coded labels (Figure 8.2) can link containers and materials

to a computer through all stages of a container’s life This improves the accuracy

of material tracking and inventory accounting Bar codes allow material monitoringduring use and can prevent materials from being lost or becoming outdated

Good Operating Practices

requires businesses to maintain files of Material Safety Data Sheets (MSDS) for allhazardous materials The sheets contain the manufacturer’s information regarding:

• Identity of the chemical and the Chemical Abstracts Service (CAS) number

• Physical characteristics

• Physical and health hazards

• Primary routes of entry

• Exposure limits

• Precautions

• Controls

• Emergency and first aid procedures

• Name of the manufacturer or importer

A major industrial facility uses MSDS to screen all material coming into their plant.Before the material is requisitioned, medical and hazardous materials experts mustapprove it This approval ensures that a substance has been researched and evaluatedL1533_frame_C08 Page 203 Tuesday, May 1, 2001 12:40 PM

for its hazardous characteristics prior to its use This potentially reduces generation

of hazardous wastes by eliminating their use.2

the chances of spilling a product The key point is that a hazardous material becomes

a RCRA hazardous waste when it is spilled, and all cleanup material and

cleaned-up material must be managed as hazardous waste A long-term, slow-release spill

is often difficult to find and when found may have caused the creation of a largeamount of hazardous waste A material loss prevention program may include thefollowing procedures:

• Use properly designed tanks and vessels only for their intended purpose

• Pressure-test underground piping

• Install overflow alarms for all tanks and vessels

• Reduce dragout from process/cleaning baths

• Maintain physical integrity of all tanks and vessels

• Set up written procedures for all loading, unloading, and transfer operations

• Install sufficient secondary containment areas

• Forbid operators to bypass interlocks, alarms, or significantly alter points without authorization

2081 Bay Road, Palo Alto, CA 94303.)

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• Install electrolysis (anode and cathode) to recover metallic components

in wastewater

• Isolate equipment or process lines that leak or are not in service

• Have interlock devices to stop flow to leaking sections

• Use seal-less pumps

• Use bellows-seal valves and a good valve layout

• Pressure-test valves and fittings

• Document all spillage

• Perform overall material balances and estimate the quantity and dollarvalue of all losses

• Install leak detection systems for underground storage tanks according toRCRA Subtitle I

• Use floating-roof tanks for VOC control

• Use conservation vents on fixed-roof tanks

• Use vapor recovery systems

exemplified by a large consumer product company which adopted a corporate policy

to minimize the generation of hazardous waste The company mobilized qualitycircles made up of employees representing areas within the plant that generatedhazardous waste The company experienced a 75% reduction in the amount of wastesgenerated by instituting proper maintenance procedures suggested by the qualitycircle teams Since the team members were also line supervisors and operators, theymade sure the procedures were followed (EPA 1988, p 16)

often includes a mixture of two or more different wastes Segregating materials andwastes can decrease the amount of wastes to be disposed Good operating practicesfor successful waste segregation include the following program ingredients:

• Prevent mixing of hazardous wastes with nonhazardous wastes

• Isolate hazardous wastes by contaminant

• Isolate liquid wastes from solid waste

These measures can result in lower volumes of waste haulage and easier disposal

of the hazardous waste Recyclers and waste exchanges are more receptive to wastesnot contaminated with other substances One company altered dust collection equip-ment to collect waste streams from different processes separately Each collectioncan now be recycled back to the process from which it originates The firm haseliminated over $9000/year in disposal costs and recovered useable material worth

$2000/year

organics in wastewater by 93% through 4 separate changes in its handling of phenoland urea resins, as follows:

1 The company altered its method of cleaning the filters which remove largeparticles of resinous material as the resin product is loaded into tank cars.L1533_frame_C08 Page 205 Tuesday, May 1, 2001 12:40 PM

They began collecting the rinse water instead of sending it down the floordrains and into the company’s on-site wastewater treatment plant Thisrinse water can be reused as an input in the next batch of phenolic resin

2 When loading urea resin, they began reversing the loading pump at theend of each load so that resin on the filters would be sucked back intothe storage tank and would not be rinsed out as waste

3 The company revised rinsing procedures for reactor vessels betweenbatches Previously, 11,000- to 15,000-gal chambers had been cleaned byfilling them with water, heating and stirring the water to remove resinresidues, and then draining the rinse water into the plant’s wastewater.The plant now has a two-step process A small, first rinse of 100 gal ofwater removes most of the residue from the containers Then a second,full-volume rinse is used to complete cleaning The first 100 gal of rinsewater is reused as input material for a later batch of resin Water from thesecond rinse is discharged as wastewater, but has a lower phenol concen-tration than the previous volume of wastewater

4 Procedures for transferring phenol from tank cars to storage tanks havebeen altered Formerly, when the hose used to transfer the phenol fromcar to tank was disconnected, a small amount of phenol dripped down thedrain — enough to cause problems given the strict regulatory limitation

of phenol Now, the hose is flushed with a few gallons of water to rinsethe last bit of phenol into the storage tank

In addition to greatly reducing wastewater volumes, these fairly simple changes haveeliminated most of the hazardous solid wastes generated by the resin manufacturingprocesses because the company was able to discontinue use of the on-site evaporationpond to treat these wastewaters (Office of Technology Assessment 1986, p 81)

incorporate good operating practices to improve production scheduling and planning.Improved production techniques may include maximizing batch size, dedicatingequipment to a single product, or altering batch sequencing to reduce cleaningfrequency Production runs of a given formulation should be scheduled together toreduce the need for equipment cleaning between batches Careful examination ofworkload distribution may reveal opportunities for waste reduction Dense loadingmay result in localized instability of the process solution In other situations, max-imizing batch size may minimize waste generated Optimizing production schedulescan greatly reduce waste in a production facility Such options may offer easyimplementation and immediate evidence of results

Hazardous Waste Recycling

In hazardous waste management practice and in the RCRA regulations, “recycling”refers to the effective use or reuse of a waste as a substitute for a commercial product

or use of a waste as an ingredient or feedstock in an industrial process It also refers

to reclaiming useful constituent fractions within a waste material or removing taminants from a waste to allow it to be reused The traditional EPA definition ofL1533_frame_C08 Page 206 Tuesday, May 1, 2001 12:40 PM

recycling implies use, reuse, or reclamation of a waste, either on-site or off-site,3after it is generated by a particular process [40 CFR 261.1(c)]

One of the most basic and frequent applications of hazardous waste recycling

is the distillation of spent solvents Large numbers of companies are engaged in thesolvent reclamation business and much of the solvent in use has been reclaimed.Figure 8.3 diagrams the process Figure 8.4 is of typical distillation columns Figure

also: Allen and Rosselot 1997, Chapter 6)

Use and Reuse

purchased an ink recycling unit to produce black newspaper ink from its variouswaste inks The unit blends the different colors of waste ink together with freshblack ink and black toner to create the black ink This mixture is then filtered toremove flakes of dried ink and is used in lieu of fresh black ink The need forshipment of waste ink to off-site disposal is eliminated The price of the recyclingunit was recovered in 9 months, based upon savings in fresh ink purchases and costs

of disposal of the waste ink (EPA 1988, p 17)

In the microelectronics industry, the high purity requirements for wafer tion make recycling and reuse of the solvents difficult However, waste solvents can

fabrica-be recycled and used for the steps in which ultrahigh purity is not required Examples

now exclude “out-of-process” recycling as a form of pollution prevention.

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of those steps are the wafer-washing step before wafer lapping and the washing stepafter etching and before polishing (Dupont et al 2000, p 356)

reclaiming operation is successfully reclaiming polyurethane paint thinners Theoriginal material contains 40% cellusolve acetate, 12% toluene, 30% methyl ethylketone (MEK), and 10% n-butyl acetate The distillate, which contains only tolueneand MEK, is used for wipedown and cleanup of painting equipment (Harris 1988)

Palo Alto, CA 94303.)

Chem-ical Corporation, 2081 Bay Road, Palo Alto, CA 94303.)

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(For discussion and references on solvent recovery and reuse in laboratories, see:

Reinhardt et al 1996)

Reclamation

process at foundries contains residues of heavy metals such as copper, lead, andzinc If these concentrations exceed Toxicity Characteristic Leaching Procedure(TCLP) standards, the sand is a hazardous waste and must be managed as such.Researchers are investigating various techniques for reclaiming the metal valuesfrom the sand Recent experiments demonstrated that 95% of the copper could beprecipitated and recovered in minutes (McCoy and Associates 1989, pp 1–23) Sandmay also be processed in smelters to recover metal values

A printed wiring board (PWB) operation uses ammoniacal etchants to etch terns on PWBs The spent etchant is sent back to the chemical supplier, where thecopper is extracted with an organic solvent to create a copper-rich organic layer andcopper-lean aqueous solution The aqueous phase is regenerated by the addition ofammonia and other additives to create fresh etchant The organic layer is treated withsulfuric acid to remove the copper from the organic solvent Regenerated solvent isfed back into the process, and the copper in the aqueous stream is recovered as coppersulfate pentahydrate via crystallization or as copper metal via electrowinning Coppersulfate recovered by this process can be used to manufacture other copper-basedchemicals or used directly in applications such as wood preservatives or algicide Asimplified schematic is shown in Figure 8.6 (Milliman and Luyten 1999, pp 32–35)

Henry C Luyten, “Waste Not Want Not,” published in Environmental Protection, May 1999 All rights reserved by Stevens Publishing Corporation Reprinted with permission.) L1533_frame_C08 Page 209 Tuesday, May 1, 2001 12:40 PM