# Report on the Substitution of Wood

from Construction & Demolition
Debris for Conventional Fuels in

Biomass Boilers

Maine Department of Environmental Protection
17 State House Station Augusta, Maine 04333-0017

April 2007

Contact: Paula Clark, Director Division of Solid Waste Management

207-287-7718TABLE OF CONTENTS

Report to the Legislature on the

Substitution of Wood from Construction & Demolition Debr is

For Conventional Fuels in Biomass Boilers Submitted Pursuant to PL 2006 Chapter 617

I. INTRODUCTION ................................

................................................... ...........................1

II. BACKGROUND - HISTORY .........................

................................................... ................1 A. Biomass Energy in Maine .........................

................................................... ...................1

B. The Use of Wood from CDD in Biomass Boilers ....

................................................... .....2 C. Regulation of the Use of CDD Wood Fuel ............

................................................... .......3 III GENERATION, HANDLING AND PROCESSING OF CDD ... ......................................4 A. Municipal Collection of CDD ......................

................................................... ................4 B. Processing of CDD.................................

................................................... ......................5

1. Methods ..........................................

................................................... ..........................5

2. Contaminant Identification and Removal .............

................................................... .....6 3. Products and Recyclables.............................

................................................... .............9 4. Maine Processing Facilities........................

................................................... ...............9 5. New England Processing Facilities Review ............

................................................... ...9 C. Material Recovery and Source Separation at the Point of Generation or Collection ....... 10 1. Source Separation during Construction and Demolition . .............................................. 11 2. Economic Feasibility of Building Deconstruction ..

................................................... ... 12

IV. USE OF CDD WOOD FUEL IN BOILERS

...... ............................................... 13 A. CDD Wood Fuel Supply and Use ........................

................................................... ....... 13 B. CDD Wood Fuel Quality ..............................

................................................... .............. 14 C. CDD Wood Fuel Use – Impacts .......................

................................................... .......... 18

1. Ash Generation ....................................

................................................... ................... 18 2. Landfill Capacity .................................

................................................... ................... 19

V. BEST AVAILABLE CONTROL TECHNOLOGY FOR BURNING C DD WOOD

FUEL

............................................................... ........................................... 20 A. Best Available Control Technology ................

................................................... ............ 20 B. Maximum Achievable Control Technology (MACT) ....... ............................................. 21 C. Air Toxic Regulation in Maine .....................

................................................... .............. 22

D. BACT for CDD in Maine ...........................

................................................... ................ 23 E. Fate of Dioxin and Arsenic from CDD Burning...........

.................................................. 23 F. Ongoing Air Toxics Investigation into CDD Wood Fuel ... ............................................ 24

G. Conclusion: What is BACT for CDD? ...............

................................................... ......... 251

I. INTRODUCTION

This report is submitted pursuant to PL 2006 Chapter 617 (attach ed as Appendix A ) which was passed as emergency legislation during the last legis lative session. In part, the legislation directed the Department to:

 Evaluate the feasibility of requiring source separation a nd state-of-the-art processing that will achieve, to the greatest extent practicable, the removal of all toxic materials from construction and demolition debris prior to combusti on in a boiler;
 Evaluate the economic and technological feasibility of requiring all boilers that burn

construction and demolition debris to use the best availa ble control technology in order to minimize toxic air emissions; and,
 Evaluate the effects of allowing the substitution of wood f rom construction and

demolition debris for conventional fuels used in a boile r to exceed 50% of total fuel by weight combusted on an annual average basis if the f ollowing conditions are met: 1. the boiler is designed and constructed for the primary purpose of power generation and not waste disposal; 2. the boiler employs the best a vailable control technology as determined by the department; and 3. all other applicable regul atory standards are met with regard to the facility.

II. BACKGROUND - HISTORY

A. Biomass Energy in Maine

Maine has numerous forest product manufacturing plants tha t burn wood to generate steam, heat and or electricity for internal use. Additionally, ten “stand-alone” biomass facilities have been built in Maine to generate electri cal power from the combustion of wood and wood by-products. The construction of these facilit ies was due in part to public policy that encouraged construction of renewable ener gy facilities. Specifically, state and federal law directed utilities to provide long-te rm purchase contracts for electricity from renewable energy facilities at rate s that were projected to be the future cost for replacement power.

The electrical rates awarded in the 1980’s to most of bioma ss facilities, turned out to be significantly above the actual electrical market rates that exist now. In turn, most of these contracts have now expired or been terminated, forcing these facilities to sell electricity into the region’s market at rates significantly below their original projections. This drop in electrical price has jeopardized the financial viability of biomass facilities. An analysis of electricity prices in New Hampshire forecast that e lectricity prices there will not reach a level at which existing biomass facilities can be prof itable without external support

until 2014. Maine’s stand-alone biomass facilities have a lso been adversely affected by these lower prices; as many as six of the facilities have been idled for periods of time in recent years. Strategies that these facilities have used to remain financially viable include: timing operation to coincide with high electricity price period, participating in2

“green power” markets, and diversifying their fuel to include wood from non-forest

sources. These sources include wood fuel made from construc tion and demolition debris (“CDD”). CDD derived wood fuel is purchased by biomass plants at a significantly lower price than wood chips made directly from standing for est trees. 1

B. The Use of Wood from CDD in Biomass Boilers

Throughout the 1980’s and 1990’s, Maine’s stand-alone biomass fac ilities burned only wood chips from trees and wood by-products from forest based i ndustries. In 2000, Boralex Athens Energy, Inc., located in Athens, Maine submitted the first application to the Maine Department of Environmental Protection (DEP) to utilize wood from CDD as part of its biomass fuel mix. This application was submitt ed under DEP’s Chapter 418 rules, Beneficial Use of Solid Wastes , which, in part, regulate the use of waste or waste

derived materials as fuel substitutes in industrial boile rs. Prior fuel substitution applications received by the DEP were made primarily by pape r mills for combustion of high fuel value mill wastes in the facility’s own bioma ss boiler(s). Such proposals involved substituting a waste material that did not differ greatly from their current fuels and which constituted a relatively small portion of tha t boiler’s fuel mix.

The Boralex Athens Energy application presented new iss ues and questions involving fuel quality and handling. At this time, the Department al so considered the question of when a boiler is most appropriately licensed under the so lid waste incinerator standards

or under the standards for fuel substitution – beneficial use. As a matter of policy, the Department determined that licensing under the fuel substitut ion standards was appropriate when 50% or less of the total fuel supply was waste or waste derived. Volumes greater than 50% would categorize the boiler as a solid waste incinerator. The significance of this determination, in part, is that unde r Maine law, new commercial solid waste disposal facilities (landfills and incinerators) ar e prohibited. In January 2001, DEP issued the Boralex Athens Energy facility a license to substitute CDD derived wood fuel for up to 50% of its biomass fuel. The existing air emiss ion license was also modified to accommodate differences in the type of fuel.

In 2002, a fire occurred in the biomass fuel stockpile at the Boralex Athens plant. As a result of questions concerning the composition of the fuel and subsequent uncontrolled emissions from the stockpile fire, the Department initi ated an investigation of the quality of the CDD wood fuel then being used. This work, conducted by University of Maine Professor of Civil Engineering Dr. Dana Humphrey, ana lyzed the biomass fuel stockpile for the physical characteristics of its wood and non-woo d components. The Department concluded that the quantity of metal, plastic and treated wood present was sufficient to

raise concerns if the fuel burned in an uncontrolled manne r, such as in the stockpile fire.

It was further concluded that more studies were needed to bet ter define the relationships between contaminants in the fuel and both fugitive and st ack air emissions. The Department determined that it was appropriate and necessa ry to revise the beneficial use-

1 Innovative Natural Resource Solutions LLC, Current Conditions and Factors Influencing the Future of Maine's Forest Products Industry, prepared for Department of Conservation - Maine Forest Service and Maine Technology Institute, March 2005, pages 150-152.3

fuel substitution rules to more fully address the emergi ng issues associated with the processing, storage and use of CDD at biomass boilers.

By the end of 2005, the Department had approved the use of CDD wood fuel at six other power generation facilities: Boralex (Stratton), Bora lex (Livermore Falls), Greenville Steam, Georgia-Pacific (Old Town; now owned by Red Shield) , Lincoln Pulp and Paper (Lincoln), and Wheelabrator (Sherman).

At the present time only three biomass power plants are burning CDD wood fuel. The Boralex plant in Athens was shut down and sold to Georgia- Pacific for its Old Town paper mill. The plant is now owned and operated by Red Shie ld. The other biomass plants presently using CDD wood fuel are the Boralex plan ts in Livermore Falls and Stratton. An application for the use of CDD fuel at S.D.Warren in Westbrook is currently pending. Although an application has not yet been submitted , GenPower has indicated its interest in building a facility with “best available co ntrol technology” (BACT) to control air pollutants, that would be specifically designed to bu rn fuel that consists of 100% CDD derived wood fuel. Although Greenville Steam, Lincoln Pulp and Paper, and Wheelabrator-Sherman are licensed to burn CDD wood fuel, they have either never burned CDD wood fuel or have ceased using this fuel.

C. Regulation of the Use of CDD Wood Fuel

The use of CDD wood fuel is licensed by the Department as a fuel substitution activity under Chapter 418 (Beneficial Use of Solid Waste) of the S olid Waste Management Rules. Such use also requires an air emission license f rom the Department’s Bureau of Air Quality.

Following the fuel fire in Athens, the Department determi ned that further research and evaluation concerning CDD fuel quality was necessary to for m the technical foundation for rulemaking. Revisions to the rules were determined to be appropriate and necessary to strengthen and clarify the standards for use of CDD woo d as fuel. A study was designed and implemented through the cooperative efforts o f the Department (Solid Waste and Air Quality programs), the University of Maine, and Boralex Energy. The work was funded through a “supplemental environmental project (or “SEP”) as part of an enforcement action against Boralex associated with viola tions at Boralex facilities in Maine. The project resulted in a May 2005 report entitled: “Fate of Dioxin and Arsenic

from the Combustion of Construction and Demolition De bris and Treated Wood”.

The study, done under the oversight of Dr. Dana Humphre y from the University of Maine, included combustion studies of multiple test fuel bl ends and the simultaneous monitoring of boiler operations, stack emissions and emiss ions controls, fuel quality, and ash quality. At the conclusion of the study the University of Maine issued the report

which included a risk evaluation of the air emissions for dioxin and arsenic resulting from these different fuel blends. The study found that the w orst case ambient air impact results were well below the Maximum Ambient Air Guidelines, l eading the DEP to conclude that the levels of dioxin and arsenic emitted by biomass b oilers burning CDD wood fuel4

at any of these levels would not pose significant public health impacts from an ambient air quality standpoint. (Also see Section V(E) of this report.)

Based upon the results of this study and knowledge and experi ence gained over several years, the Department proposed revisions to the fuel sub stitution provisions of the rules. It was concluded by the Department that the most effecti ve way to ensure environmental protection when CDD wood fuel is used, is through the applic ation of specific fuel quality and fuel handling standards. The proposed revisions addressed the potential contaminants in CDD wood fuel itself, the allowable li mits for these contaminants, fuel handling, fuel sampling and testing, and sampling and testing o f the resultant ash. Fuel quality characteristics addressed in the rule included the amount of: pressure treated wood, plastics, non-combustible materials (such as metal ), asbestos, and “fines”. The rule also imposed specific chemical limits for arsenic, lead and PCBs. Revisions to the rule were adopted by the Board of Environmental Protection and became effective on June 16, 2006. The Department’s rule concerning beneficial use of solid waste, specifically, the use of waste including CDD wood as a f uel substitute (CMR 06-096 Chapter 418 Section 6) is attached as Appendix B.

As a matter of practice and policy, prior to the adoption o f the revised fuel substitution rules in 2006, the Department, through its licenses, did not allow the substitution of more than 50% CDD fuel (on an average annual basis) for convent ional fuels at biomass boilers. This limitation was not imposed in response to a specific technical or scientific concern, but to address the policy need to distinguish, fro m a regulatory perspective, between a beneficial use activity (fuel substitution) a nd a solid waste disposal facility (incinerator). This distinction is important since ther e are certain statutory restrictions and standards that apply solely to “solid waste disposal f acilities” (landfills and incinerators). Among these is a ban on the establishment of any new commercial solid waste incinerator. PL 2006 Chapter 617 provided specifically t hat the Department’s rule: “may not allow the substitution of wood from constructi on and demolition debris for

conventional fuels used in a boiler to exceed 50% of total fuel by weight combusted on an average annual basis”.

III. GENERATION, HANDLING AND PROCESSING OF CDD

A. Municipal Collection of CDD

Maine towns manage CDD through their local solid waste facilities, including 239 transfer stations, 9 municipal solid waste landfills, 18 municipal CDD landfills, and 2 commercial landfills. The State Planning Office estimat es that in 2005, Maine generated 301,549 tons of CDD.

Much of Maine’s municipal solid waste is delivered to smal l transfer stations. These

facilities are of a size and have a customer base tha t allow for significant control of how the waste is delivered. They have the ability to direct de livery of relatively pure components of the construction and demolition debris was te stream pre-separated for5

reuse, recycling or processing. At these local faciliti es, residents can be required to separate yard waste for chipping and composting, asphalt shin gles to be recycled into road patching material, tree limbs and trunks into firewood , and “clean” CDD wood (without plastics, pressure-treated wood, wall-board, glas s and siding) for citizen reuse and/or processing into biomass fuel. Transfer stations which manage CDD waste wood for the fuel market by requiring source separation can typi cally receive a waste stream

that is at least 95% wood.

In 2005, 571,834 tons of CDD waste (both in-state and out-of-s tate generated) was landfilled in Maine’s three largest landfills having capac ity available for municipal waste (Pine Tree in Hampden, Juniper Ridge in Old Town, and Waste M anagement in Norridgewock). Data from the Maine State Planning Office s how that in 2004, 12,730 tons of CDD waste from municipalities was recycled. M ost CDD in Maine is landfilled without processing. Additionally, at some small transfer stations, the wood portion of CDD waste suitable for fuel is not recycled; it is open -burned, without air pollution controls or energy recovery.

B. Processing of CDD

1. Methods
Mixed CDD is processed for reuse using a variety of methods at several different types of facilities. CDD processors can produce a fuel t hat meets the new standards of the solid waste rules by employing strategies to control the quality of CDD received for processing and by utilizing various processi ng technologies.

Mechanical processing, in combination with other methods, is used by the established CDD processing facilities to which CDD wastes are transported for processing into fuel and other products and recyclables. Pro cessing facilities known as “positive pick” operations are designed to remove materials from the process conveyor line that are suitable to be processed into recycled materials

such as CDD wood fuel.

“Negative pick” operations are designed to remove materia ls from the process conveyor line that are not suitable for such recycling ( such as metal, plastics, treated wood, shingles, aggregates, etc.). All CDD proce ssing facilities receive materials in a similar manner. Materials are “tipped” from the delivery container or truck onto a floor or pad where the load is inspected by the facility staff. Processing facilities immediately remove oversized mat erials that are clearly not suitable for further processing into a container destined for a disposal. Removal

of oversized material is essential to efficient throu ghput of CDD materials and for protection of the processing equipment. CDD materials a re then put through a vibrating shaker screen to remove dirt and aggregates. The remaining material is placed on a conveyor belt to remove the suitable wood m aterial (in a positive pick process) or to remove the non-wood material (in a negati ve pick process). Nonwood materials are then removed for off-site disposal o r recycling.6 If appropriately sized, positive pick facilities are capabl e of producing a higher quality CDD wood fuel with less effort than negative pic k operations. They tend to require a more “wood rich” feedstock and to recover a lesser percentage of the total wood content due to their inability to remove small pieces of wood (<12 inches) at the picking stations. Positive pick faciliti es generally do not process as much CDD on a daily basis as negative picks, as the proc ess sorting line is more heavily dependent on people than removal machinery. In gen eral, negative pick facilities are able to process larger volumes of CDD on a daily basis and capture a greater percentage of the total wood content. In order to accomplish this however, significant capital and operational expenses ar e incurred for additional processing equipment with which to separate usable from non -usable materials (such as screens, float tanks, etc.) and for employees to hand pick unsuitable materials (such as metal, plastics, treated wood, shingle s, etc.)

2. Contaminant Identification and Removal

The Department’s rules concerning the use of CDD wood fuel focus on fuel quality and the removal of contaminants necessary to ac hieve the fuel quality standards. The rule establishes specific standards for: n on-combustibles, plastics, treated wood, fines, asbestos, arsenic, lead and PCBs.

Plastics in the fuel may be removed by hand at the processing fa cility and by equipment such as screens or “classifiers” that separa te low density plastics from

more dense materials.

Non-combustibles and fines can also be removed by screens or sometimes by flotation units which separate the wood from heavier non-co mbustibles. “Fines” (small sized particles that may contain relatively high concentrations of certain contaminants such as lead), are a fuel contaminant that traditionally may be difficult for the small source separation facilities such as Maine’s municipal transfer stations to minimize, since their fuel wood stockpiles may not be stored on a paved surface and the mobile processors that serve t hem many not employ screens to remove these fines. Negative pick facilitie s tend to generate a significant amount of fines and usually install additional processing equipment to

remove them.

Pressure treated wood

can be controlled by visual inspection and removal. This

can first be carried out at the construction or demolit ion site by the people doing

the construction/demolition work. It can also be carr ied out at the processing facility by people specifically tasked with spotting and re moving any pressure

treated wood that is delivered.

Studies concerning the accuracy and feasibility of using che mical or other

methods to differentiate CCA treated wood from non-treate d wood in construction and demolition debris have been on-going by the University of Miami and the7 University of Florida since 2001. The most recent document c ompleted on this subject was a final draft of a report dated January 3, 2006, en titled titled

“ Augmented Sorting of Recovered Wood Waste Using Stain and X-ray Technologies”, and prepared for the Town of Medley, Florida. The repor t
evaluated the effectiveness of visual identification of treated wood using a chemical indicator stain (“PAN indicator”) and using no stain, and using a hand held X-ray fluorescence (“XRF”) unit. Prior to this study, the performance of portable hand-held x-ray units for sorting wood waste had n ot been documented during either manual sorting or sorting through the traditi onal conveyor belt picking-line process.

The conclusions of this study were the following:
 the facility hosting the study was able to effectively i dentify loads of wood that were relatively uncontaminated by CCA wood by spot-c hecking source separated loads of wood as they entered the facili ty;  visual sorting methods with no augmentation were found to be quick and reliable for relatively uncontaminated loads of constructi on and demolition debris wood;
 visual sorting augmented by PAN Indicator stain was most useful for source-separated loads that were suspected of containing a l arger amount of suspect treated wood;
 visual methods augmented with PAN Indicator stain were found to be more time consuming and not sufficiently reliable with c ommingled construction and demolition debris wood;
 identification in commingled construction and demolition debris wood could be aided with the use of hand-held x-ray fluorescent (XRF) units to spot check suspect wood; and
 sorting times and accuracy depended highly on the individual s orting the wood although improvement was noticed with experience.

XRF units can present a safety issue in that the x-ray s were found to penetrate through wood and therefore the units needed to be handled care fully and appropriately.

The report indicated that the relative costs per metri c ton of the different sorting methods were influenced primarily by labor costs which ran ged from $24 for visual sorting of relatively uncontaminated source-separa ted wood to $114 for XRF sorting of commingled wood. 2

Two existing Maine programs target contaminants that can s ignificantly contaminate CDD wood generated from demolition activity. These programs target the treatment and/or removal of asbestos and lea d containing paint from standing structures and from some buildings scheduled for de molition.

2 Solo-Gabriele, Helena, Gary Jacobi, Eduardo Lam and Ti mothy Townsend, Augmented Sorting of Recovered Wood Waste Using Stain and X-ray Technologies, Department of Civil, Arch., and Environ. Engineering, University of Miami, submitted January 3, 2006 (draft).8 Department of Environmental Protection Regulation Chapter 425 (Asbestos Management Regulations) requires that prior to conducting a renovation or demolition activity that impacts any building material or component likely to

contain asbestos , the owner or operator must have an inspection conducte d to determine if asbestos-containing materials are present or must presume that asbestos –containing materials are present and an asbestos abatement is required. Prior to renovation or demolition, if more than 3 squar e feet or 3 linear feet of asbestos containing material is present, that material must be removed by properly trained and licensed asbestos abatement professionals. A sbestos contained in

materials that are intact and bound with a matrix that will minimize the potential release of asbestos fibers (e.g., floor tile, asphal t shingles) may be left in place when demolition is performed by large equipment and specifi c work practices and worker protection actions are implemented. Single famil y residences, and residences constructed after 1980 that consist of two (2) to four (4) units, are exempt from the inspection provisions stated above. The result of these regulatory requirements is that no building can legally be demolished or renovated in Maine in a manner likely to release asbesto s fibers.

For structures demolished by large equipment with non-friabl e asbestoscontaining flooring or roofing left in place, an additiona l processing step is needed to prevent asbestos contamination of wood fuel deri ved from construction and demolition debris. This additional process step must insure that asbestoscontaining roofing and flooring and the attached substrate mat erials are separated from wood that is going to be shredded or abraded. Subjectin g non-friable asbestos-containing materials (“ACM”) to crushing, shreddin g or abrading will release previously bound asbestos fibers into the environmen t and contaminate

other materials intended for use. State and federal law s require that the separated ACM and attached substrate be disposed of in a landfill licensed to accept

asbestos waste.

The Department believes that lead is potentially present in the environment of almost 80% of the housing in Maine. Buildings built befor e 1950, could have been painted with paints containing up to 50% lead. Buildings built, painted or remodeled before 1978 are also likely to have paint coating th at contain some percentage of lead. In 1997, Maine enacted an “Act to Ensure Safe Abatement of Lead Hazards” which directed the Maine DEP to adopt regulat ions establishing procedures and requirements for the certification and lice nsing of persons engaged in residential lead-based paint activities, work pr actice standards for those activities, and licensing and accreditation of lead abatement training

programs.

The primary risk posed by lead-based paint and lead dust contam ination in a pre1978 house is the likelihood of causing lead poisoning in children a nd adults, with children under 6 (six) years of age being particularly vulner able. Currently, the

Maine Lead Management Regulations apply only to work performed on9 residential buildings and child occupied facilities when t he clear intent of the

work is to abate lead hazards. The Lead Management Regulations do not apply to renovation or remodeling activities or to work on other c ommercial and industrial facilities and consequently do not serve to limit lead le vels in construction or demolition wood that may be used as fuel. The Department has established in rule a specific standard for lead concentrations in blen ded CDD wood fuel (<375 mg/kg).

Neither of these Federal or Maine laws or regulations prevent the potential lead contamination of wood fuel derived from building remodeli ng or demolition activities. Levels of contamination higher than 350 mg/kg a re considered to present a potential lead poisoning hazard to people who come in direct contact

with the wood fuel or dust from the wood fuel that contains that concentration.

3. Products and Recyclables

Most large construction and demolition debris processing fac ilities produce a variety of recycled products in addition to CDD wood fuel. These facilities remove as much salvageable and reusable material from CDD as is practical in

order to recover value from the waste constituents and t o minimize the transportation and disposal costs associated with landf illing construction and demolition debris. Materials recovered by these facilities include aggregate from bricks, concrete, asphalt, rocks, and dirt; ferrous and n on-ferrous metal; asphalt shingles, un-used gypsum board for reuse, and wood for reuse o r for fuel in woodfired biomass boilers. Additionally, other CDD component s not suitable for recycling may be mixed with the recovered aggregate materia ls and marketed to operating landfills as a soil substitute to cover wast e or for shaping and grading material for landfill closure projects. Generally, 3 5-40% of a mixed CDD waste stream can be processed into CDD wood fuel. (See Appendix C: “Components

of Processed Construction and Demolition Debris From 4 New England Processing Facilities”).

4. Maine Processing Facilities

Current in-state processing of CDD wood is performed by mobi le shredders that process stockpiles of pre-separated CDD wood into fuel at mu nicipal collection sites, and by four commercial processing plants – Aggregate R ecycling Corp (ARC) in Eliot, Commercial Paving in Scarborough, KTI B iofuels in Lewiston, and Simpson, Inc. in Sanford. In 2005, these facilities pr ocessed a total of 69,787 tons of mixed CDD, with about 30,000 tons of this brought in from out of state.

5. New England Processing Facilities Review

In 2006, DEP staff visited 12 different processing facilities to review their operations and evaluate the quality of the CDD fuels produce d (See Section IV-B for data and discussion regarding fuel quality). These faci lities included the major commercial processors and several municipal source separation operations at which processing occurs through the use of mobile process ing equipment.10 Table 1 presents information concerning the volumes of material handled at these facilities and the processing methods used.

Table 1
Representative New England CDD Processing Facilities/Site s Volumes of Material Received and Produced and Processing Tec hnology - 2006 Facility/Site Mixed CDD or

Source Separated CDD

Wood* Received (tons/yr) CDD Wood Fuel

Produced (tons/yr) Fuel Sorting

Technology

ERRCO (NH) 175,000 87,000 Negative Pick LL&S (NH) 175,000 30,000 Negative Pick KTI (ME) 48,800 18,130 Negative Pick ARC (ME) 14,680 8,100 Negative Pick Pond View (RI) 100,000 35,000 Positive Pick NER (MA) 73,000 20,000 Positive Pick Simpson (ME) 7,700 ** Positive Pick Plan-It (ME) 4,200* 4,000 Source Separation Old Town (ME) 850* 800 Source Separation Crossroads (ME) 2,100* 2,000 Source Separati on Augusta (ME) 2,100* 2,000 Source Separation Boothbay (ME) 5,250* 5,000 Source Separatio n
** Number not available

C. Material Recovery and Source Separation at the Point of Gene ration or Collection

Source separating non-pressure treated CDD wood at the po int of its generation or collection can significantly simplify and facilitate the processing of this material into quality CDD wood fuel. At municipal transfer stations, so urce separation of many different types of materials is commonly required incl uding the separation of newspaper, cardboard, plastics and glass for recycling. Similar requi rements can be extended to individuals and companies that deliver construction and demol ition debris so the wood suitable for processing into CDD wood fuel is pre-separated fro m roofing, siding, plastics or metal and from pressure treated wood.

“Source separation” is the most basic strategy for con trolling the quality of the waste. It entails the sorting of usable elements of CDD at the po int of generation (i.e. a demolition site) or collection (i.e. a municipal transfer station ). At transfer stations, residents bring in a variety of CDD materials and are typically requ ired to sort them by component (wood, metal, etc.). Municipal wood piles are generally c omprised of around 95% wood and are either processed into fuel by mobile processors or are open burned. Wood storage areas are inexpensive to construct and operate, but are heavily dependent on supervision of the customers to ensure adequate separation of potential contaminants such as plastics and pressure-treated wood.11

At a transfer station, sorting and removal is most eff iciently accomplished by having 1) adequate signage to educate the public on what are “suitable ma terials” and 2) by having facility staff inspect materials as they are disposed o f in the smaller CDD “day pile” storage bins. As material is disposed of at the “day pi le” by the public, facility staff are able effectively inspect this pile and remove any unsuitabl e material they encounter. Facility staff should be the only ones able to move the “day pile” to the larger CDD storage piles as they await adequate volume to enable mate rial processing into CDD

wood fuel.

Some facilities require source separated loads from dem olition and building contractors. Typically, the processing facilities offer generators f inancial incentives to send wood rich loads of CDD separately from wood poor loads. This allows the processor to use the wood poor CDD loads to create landfill closure material or to by-pass the CDD directly to landfills for disposal.

1. Source Separation during Construction and Demolition

Separation of potentially suitable wood during building con struction is straightforward and simple. Wood not used in the structure can be easily separated into a number of separate piles at a site. This scrap or leftover wood is often new lumber that can still be used for its origin al purpose. Wood from demolition activity is not nearly as readily separated for reuse. This wood has already been attached to lumber of other types, dimensio ns and grades, or to other non-wood building materials. In order to achieve a simi lar degree of material salvage at a demolition site, a significantly more invol ved process must be used.

Salvaging activities are differentiated by the scope of t he salvaging operations. The removal of windows, doors, kitchen and bathroom fixtur es, moldings, mantles, and other small architectural components is com monly referred to as

“ non-structural salvage ” . In this context, wooden molding is reused as molding, mantelpieces as mantelpieces, cabinets as cabinets and l umber as lumber. The removal of wooden barn boards, flooring, timbers and lum ber; along with the salvaging of bricks or granite is considered to be “ structural salvage ” . Such material salvaging is practical anywhere there is a real market for the items being salvaged, and is done throughout Maine and the U.S. Whether , when and how it is carried out is simply a matter of economics: the value of the salvaged material, the strength of markets for salvaged materials, and the e xpense of salvage operations.

Structural salvaging is also referred to as “deconstruction ”. The term “deconstruction”, as currently used, is often interpreted to mean the complete disassembly of a building or portion of a building into its component parts and materials. In actuality, the complete dismantling and r euse of every component and all materials from a building is almost never carr ied out. Practical, timing and financial considerations often do not make comprehensive dec onstruction and materials sorting operations feasible.12 The bulk of current lumber reuse activities in Maine occ ur through the “Maine Housing & Building Materials Exchange” (located in Gray a nd Sanford, see Appendix C), through private transactions like those facilitated in Uncle Henry’s weekly publication, and through reclamation at public recy cling programs and

transfer stations.

2. Economic Feasibility of Building Deconstruction

A defining characteristic of non-structural salvage is th at it does not affect the structural integrity of the building. For example, the r emoval of fixtures, windows, doors, moldings and most cabinet will not normally w eaken the construction integrity of the remaining structure. People can routinely still safely work inside the structure. Examples of this reuse or t he marketing of salvaged items for reuse can be found each week in Uncle Henry’s “Building Materials” section where typically many individuals and small compa nies will advertise the sale of salvaged fixtures and building items. Other examp les include the monthly State Surplus Sales conducted by the Maine Bureau of General Services where unique windows, hardware and other building materials are avail able for purchaseafter major building renovation projects. Anot her notable example is the “Maine Housing & Building Materials Exchange” (BME) with locations in Gray and Sanford, Maine (See Appendix C ).

The economic feasibility of structural salvage in a part icular municipality, region or state is dependent upon a number of specific factors . Factors that can favorably influence the feasibility of structural salv age or sorting by component

include:

• the building contains particularly valuable or unique raw m aterials such as unique timbers and lumber or other valuable building ma terial;

• the project is not under tight time constraints and rebu ilding pressure;

• there is sufficient space on or adjacent to the demoliti on site to allow for convenient material separation, sorting and organizi ng;

• contaminants have been removed from the building(s) pri or to the start

of demolition..

A number of factors can hamper the degree to which materi als in a structure may be economically salvaged or sorted by component. These f actors include:

• small, disparate projects where economies of scale ar e not possible;

• worker safety or exposure concerns;

• tight project time frame;

• high labor costs; and

• low salvaged material value.

One point of potential relevance to Maine is that often military base salvage projects can be structured to avoid the redevelopment press ures and timelines common among commercial development projects. At the same time, a military base often has a number of buildings consisting of sim ilar building materials so13 economies of scale may be possible. This may provide an o pportunity for base redevelopment authorities to minimize the cost and amount of CDD waste associated with demolition activities on a base undergo ing redevelopment.

IV. USE OF CDD WOOD FUEL IN BOILERS

A. CDD Wood Fuel Supply and Use

As discussed in Section II(B) above, only 3 of the 7 boi lers approved for CDD wood fuel combustion are presently burning it: Boralex- Stratton, B oralex-Livermore, and Red

Shield in Old Town. Table 2 presents data relevant to the use of CDD wood fuel in biomass boilers in Maine in 2005. Using 286,338 tons of fuel in i ts power plant, Boralex-Livermore produced 217,002 megawatts of power, with CDD wood fuel accounting for about 44.2% of the total fuel used in the fa cility. Similarly, using 426,304 tons of fuel in its power plant, Boralex - Stratton pro duced 267,648 megawatts of power with CDD wood fuel accounting for about 25.9% of the total fuel used in the facility.

TABLE 2 2005 CDD Wood Fuel Use by Biomass Boilers in Maine

Roughly 75% of the CDD derived wood fuel for each of the Boral ex plants was fuel that was processed outside of Maine and shipped as fuel to those f acilities.

Red Shield is expected to burn 200,000 tons per year of wood fue l, of which 100,000 tons per year may be CDD wood fuel. The SAPPI biomass f acility has capacity to burn 490,000 tons of wood fuel. This facility has submitted an appl ication to burn up to 50% CDD wood fuel; if approved, this facility may combust up to 245 ,000 tons of CDD wood fuel annually.

As discussed earlier, GenPower has proposed construction of a new boiler designed to burn 100% CDD wood fuel while employing Best Available Control Technology (“BACT”) to meet air emission standards. Its capacity was reported to be planned for 558,000 tons CDD wood fuel per year. DEP estimates that oper ating this facility at full capacity would produce 55,800 tons per year of ash.

At Maine’s current rate of capture and processing of wood w aste from CDD, Maine municipalities supply less than 1% of the maximum annual pro jected demand for CDD Boiler Total annual

wood fuel use Tons CDD

wood fuel % CDD

wood fuel Tons ash

generated % ash per ton

wood fuel

BoralexLivermore 286,338 tons 128,494 45% 28,493

tons 10%

Boralex-Stratton 426,159 tons 110,499 26% 28,156

tons 6.6%14

wood fuel (1.37 million tons – See Table 5 ). Processing of in-state commercial waste currently provides an additional 3%. If all municipal CDD were managed to separate wood waste at the point of collection, and assuming that 25% of the CDD waste stream could be processed into wood fuel, Maine municipalities potent ially could generate 75,500 tons of CDD wood fuel annually. This is an estimated 5% of the maximum CDD wood fuel permitted for use in Maine biomass boilers listed in Table 5 . Managing municipal CDD for maximum CDD wood fuel generation could r educe the amount of Maine landfill capacity currently used for disposal of C DD by 133,200 yds 3 annually.

Several factors make it highly unlikely that the biomass boilers anticipated to routinely

burn CDD wood fuel will combust their maximum allowed amo unts:

• Currently, of the 5 boilers approved to burned 50% CDD derived wood fuel, 3 are not burning any CDD derived wood fuel, and 2 consistently burn less t han the 50%

allowed.

• There are practical limits to the amount of CDD derive d wood fuel that a boiler burns that are related to operational costs and maintenance.

• There is not sufficient licensed processing capacity in al l of New England to process

the amount of CDD needed to create 1.3 million tons of C DD wood fuel.

• Processing CDD into fuel and other recycled products is a lo w profit undertaking which limits the ease and speed by which processing capacity anywhere could be

increased.

To combust the maximum amount of CDD wood fuel approved for use, biomass boilers would need to rely upon CDD wood fuel that is produced in Maine from out-of-state CDD and/or on CDD wood fuel that originates outside of Maine, since Maine simply does not generated enough CDD to meet this demand. 238,000 tons (190,400 yds 3 ) of

out-of state CDD was sent to Maine’s commercial land fills in 2005. If this amount were separated and processed for CDD wood fuel production rather th an landfilled, it would create an additional 83,300 tons of CDD wood fuel (6% of the projected maximum demand) and reduce the landfill capacity used by at least a n equivalent amount.

The wholesale replacement of out-of-state processing capacity by in-state facilities is unlikely since it is significantly less expensive to proces s locally (nearer the sites of CDD generation) and pay to transport only the portion of CDD th at is processed into wood fuel than to transport mixed CDD into Maine for processing. Th e degree to which out-ofstate CDD processors can increase their operational ca pacity to meet increased fuel demand is also limited. Out-of-state processors are cur rently operating at close to capacity.

B. CDD Wood Fuel Quality

Shortly after the July 2006 implementation of the revise d fuel substitution rules, the Department conducted sampling and analysis of CDD wood fuel from 12 different processing facilities which are representative of the r egional CDD processing industry as a whole. The facilities were representative of diff erent CDD sorting/processing technologies: 4 negative pick processors, 3 positive pic k processors, and 5 source15

separation facilities. Collectively the 12 facilities produce approximately 205,000 tons of CDD wood fuel annually. The CDD wood fuel sampled was tes ted to determine whether the fuel met the regulatory physical standards for plast ics, non-burnable, treated wood, and fines, and the chemical standards for arsenic and lead.

An evaluation was conducted to determine whether there is a correlation between the amount of treated wood and arsenic, and the amount of painte d wood and lead. The relationship between the arsenic and treated wood data doe s not support using the treated wood data to predict arsenic concentration in the CDD woo d fuel. This result supports the conclusion of the university of Maine study that ther e may be sources of arsenic in the

CDD wood fuel other than the treated wood fraction. Sim ilarly, the painted wood data do

not correlate well to lead concentrations in the CDD wood fuel. The percentage of painted wood in the CDD wood fuel has varied without signifi cant corresponding changes in the concentration of lead in the fuel. Th ere has been no correlation between the amount of painted wood in CDD derived wood fuel and lead c oncentration in either the fuel or resulting ash. All future analyses of both will be closely evaluated to

determine if this remains true.

Plastic is readily separated from wood on a pick line in large part because it is often colored and contrasts sharply with wood. When more plas tic than usual is found in the CDD wood fuel the cause is often the presence of a plast ic/wood composite that is designed to resemble wood. This can be addressed by mechanic al separation, as plastics and wood differ significantly in density. Fuels from all facilities reviewed were well within Chapter 418 CDD wood fuel standards for plastic cont ent.

Non-burnable material exclusive of rocks, concrete and bri ck is reported as metal. Magnetic removal of small pieces of ferrous metal gen erally works well with the pick line removing larger pieces of metal. However, small non -ferrous metal, especially if attached to a larger chunk of wood is able to pass through w ith the CDD wood. Technology in the form of an eddy current separator can be used, however this may be cost prohibitive for all but the larger processors. Two of the three facilities that exceeded the non-burnable standard use source separated CDD wood as f eedstock. As has been stated earlier in this report, more diligent supervision of customers as they drop off CDD waste, together with more efficient CDD management an d storage design at Maine’s transfer stations and landfills are most likely to le ad to improvement in CDD wood fuel quality.

CDD wood fuel samples from 2 of 12 facilities failed to mee t the treated wood standard. Treated wood cannot be removed by mechanical means. Only by a trained person picking over the waste wood can the characteristic yel low-green color be seen and removed. Many processors have begun to reach out to thei r commercial customers who generate the CDD waste to encourage them to inspect the ir jobs for treated wood and to organize delivery of their waste by identifying particular lo ads containing the treated wood. Such activity has been shown to lower the quantity of treated wood that must be removed during CDD wood processing. This in turn lowers th e quantity of treated wood16

in the CDD wood fuel produced. The effectiveness of this me thod recommends it to a broader application with all CDD wood fuel producers.

The CDD wood fuel standard most often exceeded is the fine s standard. Fines include wood, dirt, and small often unrecognizable bits of everything pr esent in the mixed CDD waste. It was established during the University of Maine st udy of the Boralex biomass plants, that the fines fraction of the CDD wood fuel c ontains a higher percentage of potential contaminants than the remainder of the fuel. The standard of <10% fines in

commercial CDD wood fuel was established to limit the c ontaminant load through a means not achievable by simply limiting recognizable plastic , metal, or treated wood. By limiting fines, the overall quality of the CDD wood fuel ha s been significantly improved. One interesting way of making this point is to note that a typical truckload of CDD wood fuel prior to the Chapter 418 rules weighed in at about 28 tons while currently the same volume load would weigh about 24 tons. Since the volume per truckload has not changed, this means approximately 4 tons of fines and conta minants have been removed

as a result of Maine’s new CDD fuel standards.

Table 3 allows the comparison of each facility’s success in r emoving treated wood. The values given are in 100% CDD wood fuel rather than the <50% CDD wood fuel blended with unadulterated wood (ie. whole tree chips) which is all owed as fuel in biomass boilers licensed to burn CDD wood fuel. The requirement for using a CDD wood blended with clean wood provides an additional margin of sa fety for all contaminants with respect to air emissions.

The two facilities sampled which exceeded the treated woo d standard have 2 options for addressing this issue to ensure that their fuel products meet the standards in the future. They can work with their customers to see that jobs ar e surveyed prior to demolition and that treated wood is batched into designated truckloads for s pecial handling at the processing facility, or they can place more resources into treated wood identification and removal within their processes17 Table 3

CDD Wood Fuel Testing

Results for Physical Parameters

(DEP Sampling – 2006)

Facility Plastic Non

- burnable Treated Wood Fine s STANDARD <1.0% <1.0% <1.5% <10% commercial

< 20% municipal ERRCO (NH) 0.1 0.0 0.9 8.0 LL&S (NH) 0.5 0.6 1.8 8.8 KTI (ME) 0.4 4.0 3.7 4.1 ARC (ME) 0.0 0.3 0.0 8.3

PondV iew . (RI) 0.1 0.1 0.0 11.7 NER (MA) 0.0 0.0 0.3 9.6 Simpson (ME) 0.3 0.8 0.3 11. 6

Plan

- It (ME) 0.0 1.1 1.4 3.0 OldTown (ME) 0.1 1.3 1.5 11.8 WMI (ME) 0.1 0.5 0.6 11.3 Augusta (ME) 0.1 1.0 1.0 4.7 Boothbay (ME) 0.1 0.2 0.0 21.3 Results are presented as the percent by weight. Shaded results exceeded Chapter 418 standards.

Table 4

CDD Wood Fuel Testing

Results for Chemical Parameters

(DEP Sampling – 2006)

Facility Treated Wood Arsenic Painted Wood Lead

STANDARD <1.5% 50 mg/kg no standard <350 mg/kg ERRCO(NH) 0.9% 81 10.0% 44 LL&S(NH) 1.8% 14.8 5.1% 314 KTI(ME) 3.7% 77 12. 2% 24 ARC(ME) 0.0% 67 6.0% 119

Pond V iew .(RI) 0.0% 41.5 1.5% 82 NER(MA) 0.3% 110 1.4% 44 Simpson(ME) 0.3% 51.8 7.9% 56

Plan

- It(ME) 1.4% 23.2 8.4% 139

Old Town(ME) 1.5% 55.3 12.9% 78 WMI(ME) 0.6% 51.2 4.9% 46 Augusta(ME) 1.0% 17.9 15.5% 124

Boothba y(ME) 0.0% 40.2 4.3% 76 Shaded results exceeded Chapter 418 standards.18

C. CDD Wood Fuel Use – Impacts

1. Ash Generation

The amount of ash generated by a biomass boiler depends upon the composition of the fuel used. For planning purposes, the standard industry a ssumption when burning 100% “green” wood (i.e., no CDD wood) is that the weight of ash will be 3% of the weight of the fuel input. No similar standard ass umptions have been developed for facilities that burn any defined amount of CDD wood fuel. To project the amount of ash that may be generated by facili ties operating in Maine, Department staff developed the following estimates based o n historic data and accounting for the significant decrease in percent fines allowed in CDD wood fuel under the new Chapter 418 standards: Ash derived form burning 50/50 CDD/greenwood = 6% Ash derived form burning 100% CDD = 8%

Table 5 shows the amounts of ash expected to be generated by each facility if it burns no CDD wood fuel and burns its maximum permitted amount of CDD

wood fuel. These numbers can be used to calculate landfil l capacity needed to

accommodate ash from the combustion of CDD wood fuel i n these biomass

boilers.

Table 5

Annual Maximum Fuel Use and Ash Generation from Current and Proposed CDD Wood Combustion Facilities

Facility Maximum

Tons Fuel Maximum

tons CDD

wood fuel Tons Ash

no CDD

wood fuel Tons Ash

max CDD

wood fuel Cubic

Yards Ash*

– no CDD

wood fuel Cubic

Yards Ash*

– max CDD wood

fuel

Boralex –

Livermore 396,000 198,000 11,880 23,760 9,504 19,008

Boralex –

Stratton 540,000 270,000 16,200 32,400 12,960 25,920

Red Shield

Old Town 200,000 100,000 6,000 12,000 4,800 9,600

S.D.

Warren

Westbrook 490,000 245,000 14,700 29,400 11,760 23,520

Gen Power 558,000 558,000 N/A 44,640 N/A 35,712

Totals 2,184,000 1,371,000 48,780 142,200 39,024 113,760
*Density of CDD ash averages 1.25 tons/cubic yard when landfil led.

If these five biomass boilers burned CDD wood fuel at t heir actual/proposed maximum licensed/designed capacities, 100,752 yds 3 more ash would be generated annually than if they burned only green wood and no CDD wood fuel.19 Based on historic operations, it is more likely that th e facilities which are not specifically designed to burn CDD wood fuel will burn less than 50%. If GenPower is licensed and built to combust only up to 50% C DD wood fuel and all five facilities burn a somewhat lower percentage of CDD wood fuel, assuming that the resulting amount of ash will be 5% of the fuel input, the total expected increased landfill capacity needed would be 87,360 yds 3 annually. (GenPower would generate 13,392 yds 3 more ash if it burned 100% CDD wood fuel than if it only burned 50% CDD wood fuel).

In general, ash from the burning of CDD wood fuel is simil ar to ash derived from the burning of municipal solid waste or from open-burning of CD D at transfer stations or landfills in the state, as shown in Table 6 . The levels of arsenic and lead present are significantly below the hazardous thres holds.

Table 6 Comparison of Ash Sampling Results from Biomass Boilers, Waste to Energy Facilities and Open Burn Pil es

(2005-2006 Sampling Data)

arsenic lead mercury
Hazardous Threshold 5.0 mg/kg 5.0 mg/kg 0.20 mg/kg

BIOMASS BOILERS ( burning CDD wood) Stratton (combined ash) 0.14 0.1 not detected Livermore(fly ash) 0.23 0.3 not detected Livermore.(bottom ash) 0.16 0.2 not detected

WASTE TO ENERGY FACILITIES Maine Energy (RDF*) 0.084 0.220 0.003 EcoMaine. (mass burn) 0.035 0.375 0.003

OPEN BURN PILE

ASH

Mean** 0.19 0.46 <0.20

*Refuse derived fuel ** Mean calculated from data representative of ash from 12 munici pal transfer station open burn piles.

2. Landfill Capacity

To the DEP’s knowledge, none of the residues from the out- of-state processing of

CDD wood into fuel was sent to Maine landfills. There fore, the impact on landfill capacity that out-of-state fuel had on Maine landfill d isposal capacity is limited to that portion of the boiler ash that was derived from out-of-state fuel, i.e., approximately 43,000 tons or 34,300 yds 3 (cubic yards).

Some out-of-state CDD was processed by KTI in Lewiston , Maine, and the resulting CDD wood fuel was utilized by Boralex. The wa stes from processing20 this CDD into fuel were disposed in Maine. In 2005, KTI rec eived 58,117 tons of in-state and out-of-state waste. Of this waste, 23% of the material received (13,368 tons) was non-processible waste that was landfille d in Maine. About 50% of this was derived from out-of-state material, resulting in 6,685 tons of outof-state waste landfilled in Maine after processing, usi ng about 5,347 yds 3 of landfill space.

In 2005, 16,106 tons (12,885 yds 3 ) of ash from Boralex Livermore was disposed of in the IP papermill landfill in Jay, Maine to incre ase the stability of the landfilled paper mill sludge. The amount of IP’s landfill capacity used in that year for Boralex-Livermore ash derived from out-of-state CDD wood fuel was less than 4% of the capacity used that year. Assuming th at both the ash from Boralex Stratton and the process waste from KTI-Lewis ton were disposed in the Pine Tree landfill in Hampden in 2005, 22,791 tons of CDD proces sing waste and

fuel combustion ash are attributable to out-of-state so urces. Pine Tree Landfill received a total of 672,317 tons of waste (all types) in 2005. Therefore, the waste

attributable to out-of-state CDD wood fuel from Stratto n and processing of outof-state CDD at KTI was less than 3.5% of the total wa ste received by Pine Tree Landfill in 2005. Maine’s two commercial landfills, Pin e Tree and Waste Management in Norridgewock, also received about 238,000 tons o f mixed CDD

from out of state in 2005.

Remaining capacity for the landfills that are licensed t o accept ash from biomass

boilers that burn CDD wood fuel is estimated to be:

 Pine Tree Landfill 1,026,915 yds 3

 Juniper Ridge Landfill 9,500,000 yds 3

 Waste Management Crossroads Landfill 4,300,000 yds 3
(Total: 14,826,915 yds 3 )

Maximum use of CDD wood fuel in the next few years would use less than 1% of this current remaining landfill capacity annually. Also, i t is likely that some of

the ash from the biomass boilers will continue to be d isposed of in generatorowned landfills to add stability to papermill sludge.

V. BEST AVAILABLE CONTROL TECHNOLOGY FOR BURNING CD D WOOD

FUEL

A. Best Available Control Technology

“Best Available Control Technology” as defined in 06-096 Chapt er §100 means: “an emission limitation (including a visible emissions standa rd) based on the maximum degree of reduction for each pollutant emitted from or whic h results from the new or modified emissions unit which the Department on a case- by-case basis, taking into account energy, environmental and economic impacts and oth er costs, determines is achievable for such emissions unit through application of pro duction processes or21

available methods, systems, and techniques, including fuel cl eaning or treatment or innovative fuel combination techniques for control of each pollutant. In no event shall application of BACT result in emissions of any pollutant which would exceed the emissions allowed by any applicable standard under 40 CFR Par t 60 and 61 or any applicable emission standard established by the Department. If the Department determines that technological or economic limitations on the application of measurement methodology to a particular emissions unit would make the i mposition of an emission standard infeasible, a design, equipment, work practice, o perational standard or combination thereof may be prescribed instead to satisfy t he requirement for the application of BACT. Such standard shall, to the degree pos sible, set forth the emission reduction achievable by implementation of such design, equi pment, work practice or operation, and shall provide for compliance by means which a chieve equivalent results.”

BACT analyses for the criteria air pollutants (nitrogen oxides, sulfur dioxide, carbon monoxide, particulate matter and volatile organic compounds) have been required since the 1977 Clean Air Act Requirements became effective. The program required that, regardless of existing air quality, new emission sources subject to the EPA New Source Review program would be controlled to a level that repres ents BACT. This requirement precludes potential applicants from shopping for areas with less stringent emission limitations, and also promotes the research and developm ent of more efficient and more economic alternative technologies.

The Northeast States for Coordinated Air Use Management (NESCAUM) developed a BACT Guideline in June 1991 to promote consistent analyse s of proposed control technologies and consistent procedures for reviewing BACT determinations from state to state. A uniform set of procedures ensures equitable treatm ent for prospective applicants and also reduces pressure on reviewing agencies to establish l ess stringent controls compared to similar projects located elsewhere.

The NESCAUM BACT Guideline employs a “top down” approach. The starting assumption for the top down approach is that the most s tringent control possible is BACT. The burden of proof for applying a less stringent level of control rests in the applicant’s case specific evaluation of the control alt ernatives.

B. Maximum Achievable Control Technology (MACT)

The Environmental Protection Agency adopted a new strategy f or dealing with air toxics

in the 1990 Clean Air Act Amendments called Maximum Achieva ble Control Technology, or MACT.

The strategy abandoned EPA’s 1977 Amendments’ risk based approa ch to controlling air toxics in favor of a new technology approach. The stan dards were developed based on control strategies used by source categories or industrie s and are comprised of three components. In the first phase, EPA developed a list of 188 hazardous air pollutants (HAPS) and the industries or source categories emitting those pollutants were22

determined. This created a matrix of 174 different source c ategories covering major emitters of the 188 HAPS. EPA also designated a list of seven carcinogenic or persistent bioaccumulative toxins (PBT’s) which would also be regul ated under 40 CFR Part 63.

EPA next began developing MACT standards for these pollutan t-source combinations. The MACT standards required sources to meet specific emiss ions limits that are based on emission levels already being achieved by similar sources in the country. To accomplish this, EPA surveyed a source category or industry and deter mined the top 12% best controlled facilities. For categories with less than 30 sources, EPA looked at the top five best controlled facilities. EPA developed emission stan dards based on the control technologies or operational practices utilized by these t op sources.

After the implementation of all the MACT standards, E PA will return to a risk-based approach to assess how these technology-based emission limits are protecting public health and the environment. Based on this assessment, EP A may implement additional standards to address any significant remaining, or residual, health or environmental risks.

Boilers at facilities which are major emitters of ha zardous air pollutants are subject to 40 CFR Part 63, Subpart DDDDD, National Emission Standards fo r Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters. New units at these facilities must meet 0.025 lbs per milli on Btu for particulate matter, and existing units must meet 0.07 lbs per million Btu. All e xisting units in Maine subject to this MACT standard presently meet the 0.07 lbs per millio n Btu limit and most already meet the 0.025 lbs per million Btu standard required of new s ources

C. Air Toxic Regulation in Maine

There are few air toxics in Maine which have ambient air quality standards (MAAQs) developed and contained in statute. Other air toxics are evaluated using risk based, Maine Ambient Air Guidelines (MAAG) developed by the Depart ment of Health and

Human Services’ Center for Disease Control and Preven tion, Division of Environmental Health (DEH). The DEH uses a risk-based approach for dev eloping MAAG values that are set to be protective for both carcinogenic and non-car cinogenic effects. When considering the non-carcinogenic toxicological effects, the levels are set that represent a

minimal risk of a deleterious effect from lifetime ex posure even for sensitive subpopulations.

For carcinogenic or probable human carcinogens the MAAG v alues are derived using a quantitative estimate for the chemical’s inhalation car cinogenic potency which is used with the target incremental lifetime cancer risk over background rates of a cancer risk of

one in one-hundred thousand to calculate the MAAG value. Thus, a lifetime exposure

above the MAAG concentration value could result in a cancer occurrence of one in one

hundred thousand individuals.23

D. BACT for CDD in Maine

There are presently seven facilities in the State li censed by Department’s Bureau of Air Quality (air emission licenses) to combust CDD wood fue l. These facilities are;

 Red Shield in Old Town
 Greenville Steam in Greenville
 SAPPI in Westbrook
 Wheelabrator Sherman in Sherman; and
 Boralex - Stratton,
 Boralex - Livermore Falls
 Boralex - Ashland.

These facilities may utilize between 5% and 50% (by weight on an annual basis) CDD as

their total fuel fed to the boilers.

BACT for boilers utilizing CDD wood as a fuel has included hi gh efficiency particulate control in the form of electrostatic precipitators. Air toxic emissions, namely metals and dioxins, adhere to particulate matter and can be effectivel y removed in this manner. Electrostatic precipitators generally perform at greate r than 99% efficiency for removing particulate matter from the flue gas stream. The ele ctrostatic precipitators can also meet Subpart DDDDD, MACT limits. Another form of high effic iency particulate control is through the use of a baghouse. Baghouse control can achie ve a slightly higher efficiency than electrostatic precipitators and would likely be requi red of a new source proposing to

combust CDD wood fuel.

E. Fate of Dioxin and Arsenic from CDD Burning

The University of Maine study resulting in the report entit led, “Fate of Dioxin and

Arsenic from the Combustion of Construction and Demolition Debris and Treated Wood”, as described in Section II(C) above, was evaluat ed by the Bureau of Air Quality. The study determined that the worst case ambient air qualit y impact results from the Livermore Falls facility were only 30% of the Maine Amb ient Air Guideline (MAAG)

value for arsenic and 0.47% of the MAAG value for dioxin. F or the Stratton facility, the worst case impact levels were 3.5% of the MAAG value fo r arsenic and 0.24% of the

MAAG value for dioxin. These values were calculated ba sed on Industrial Source Complex Simple Terrain (ISCST3), refined air dispersion modeling using 5 years of hourly off-site meteorological data.

It was reported in the study that elevated arsenic lev els were observed during one of the stack test runs for particulate matter at the Boralex L ivermore Falls facility. One of the four electrostatic precipitator fields (ESP) was shut o ff during the run, leaving only three fields energized. Additional testing runs using all ESP fi elds resulted in arsenic levels that were approximately 3.5% of the MAAG value for arsenic. As a result of that information, Bureau of Air Quality staff has amended the air emission licenses for those utilizing electrostatic precipitators to require that all fields be in operation when burning

CDD wood fuel.24

The study determined that arsenic and dioxin emissions from the combustion of CDD wood do not pose an unreasonable risk to public health based on the Maine Ambient Air Guidelines. It is the Department’s expectation that the concentrations of metals and compounds currently being tested for at the facilities bur ning CDD wood will likewise not pose unreasonable public health risks. The Departmen t is presently evaluating that

data.

F. Ongoing Air Toxics Investigation into CDD Wood Fuel

In November of 2005, the Bureau of Air Quality (Bureau) conv ened a meeting with those facilities in Maine that were burning CDD wood fuel. At th at meeting, the Bureau expressed its concern about the relationship between ars enic emissions and electrostatic precipitator operations, as well as the need for increa sed stack emission testing for additional chemicals and compounds. Those in attendance a cknowledged the need for additional air toxics data on stack emissions and agreed to sample for the following metals and compounds based on the frequency noted below, as well as to submit applications to amend their air emission licenses to make the additional testing agreements enforceable:

 For facilities burning between 25 to 50% CDD, stack test two t imes per year for two years spaced six months apart;
 For facilities burning between 10 to 25% CDD, stack test once per year for two years; and
 For facilities burning less than 10% CDD there is no addit ional stack testing requirement.

The chemicals and compounds to be stack tested for are an timony, arsenic, cadmium, chromium, copper, lead, mercury, nickel, selenium, vanadi um, hydrogen chloride, and

dioxin.

The results of the stack testing will be used with faci lities’ previous site specific air dispersion modeling analyses to determine that the Maine Ambient Air Guidelines are being met. Further, the Department indicated that it wo uld evaluate the data after the first two years of sampling to determine future testing requiremen ts.

Some stack testing data had been obtained and a preliminary review of one data set for the SAPPI Westbrook facility is show below in Table 7 . The data was used in concert with previous ISCST3, refined air dispersion modeling perform ed on the mill’s #20 power boiler and shows the predicted impacts from the sev en metals and compounds listed to be well below either the Maine Ambient Air Qua lity Standard or the Maine

Ambient Air Guideline.25 Table 7 Westbrook Stack Testing – Metals

(2006 data)

Metal Maine Ambient

Air Standard (ug/m 3 ) Bureau of

Health Ambient

Air Guideline (ug/m 3 ) Impact

(ug/m 3 ) % of Guideline

or Standard

Arsenic 0.002 0.00062 31%

Cadmium 0.006 0.000039 0.65%

Chromium 0.3 0.00029 0.65% Copper 2 0.00039 0.02%

Lead 1.5 0.034 0.23% Manganese 0.05 0.00088 1.8% Mercury 0.3 <0.00029 0.1%

G. Conclusion: What is BACT for CDD?

BACT for CDD wood fuel combustion will vary depending on the type and configuration of the facility proposed.

For facilities combusting CDD wood, the study noted above identified a direct correlation between arsenic emissions and electrostatic precipitat or operation. Upon discovery of that correlation, the Department moved to amend the air emission licenses of those facilities with electrostatic precipitators which were combusting CDD wood. These facilities are now required to cease CDD wood combustion unle ss all of the fields of the electrostatic precipitator are fully operational. Any fut ure BACT determination for CDD combustion at existing facilities utilizing electrostati c precipitators will contain this requirement.

BACT for new sources applying to use CDD wood as fuel shall be the use of a baghouse for high efficiency particulate control and the emiss ion unit shall be subject to the requirements of 40 CFR, Part 60, Subpart DDDDD, National Emission Standards for Hazardous Air Pollutants for Industrial, Commercial, and Institutional Boilers and

Process Heaters.