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 

207-287-7718 
TABLE OF CONTENTS 

Report to the Legislature on the 

Substitution of Wood from Construction & Demolition Debris 

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 CDD 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? ........................................................................... 25
1 

I. INTRODUCTION 

This report is submitted pursuant to PL 2006 Chapter 617 (attached as Appendix A) which 

was passed as emergency legislation during the last legislative session. In part, the 

legislation directed the Department to: 

 Evaluate the feasibility of requiring source separation and 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 combustion in a boiler; 

 Evaluate the economic and technological feasibility of requiring all boilers that burn 

construction and demolition debris to use the best available control technology in 

order to minimize toxic air emissions; and, 

 Evaluate the effects of allowing the substitution of wood from construction and 

demolition debris for conventional fuels used in a boiler to exceed 50% of total fuel 

by weight combusted on an annual average basis if the following 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 available control technology as 

determined by the department; and 3. all other applicable regulatory standards are 

met with regard to the facility. 

 

II. BACKGROUND - HISTORY 

A. Biomass Energy in Maine 

Maine has numerous forest product manufacturing plants that 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 electrical power from the combustion of 

wood and wood by-products. The construction of these facilities was due in part to 

public policy that encouraged construction of renewable energy facilities. Specifically, 

state and federal law directed utilities to provide long-term purchase contracts for 

electricity from renewable energy facilities at rates that were projected to be the future 

cost for replacement power. 

The electrical rates awarded in the 1980’s to most of biomass 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 electricity prices there will not reach 

a level at which existing biomass facilities can be profitable without external support 

until 2014. Maine’s stand-alone biomass facilities have also 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 in 
2 

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

sources. These sources include wood fuel made from construction 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 forest trees.1

B. The Use of Wood from CDD in Biomass Boilers 

Throughout the 1980’s and 1990’s, Maine’s stand-alone biomass facilities burned only 

wood chips from trees and wood by-products from forest based industries. 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 submitted 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 boilers. Prior fuel substitution 

applications received by the DEP were made primarily by paper mills for combustion of 

high fuel value mill wastes in the facility’s own biomass 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 that boiler’s fuel mix. 

The Boralex Athens Energy application presented new issues and questions involving 

fuel quality and handling. At this time, the Department also considered the question of 

when a boiler is most appropriately licensed under the solid 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 substitution 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 under Maine law, new commercial solid 

waste disposal facilities (landfills and incinerators) are 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 emission 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 initiated 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, analyzed the biomass fuel stockpile 

for the physical characteristics of its wood and non-wood 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 manner, such as in the stockpile fire. 

It was further concluded that more studies were needed to better define the relationships 

between contaminants in the fuel and both fugitive and stack air emissions. The 

Department determined that it was appropriate and necessary 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 emerging 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), Boralex (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 Shield. The other biomass 

plants presently using CDD wood fuel are the Boralex plants 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 control technology” (BACT) to control 

air pollutants, that would be specifically designed to burn 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 Solid Waste Management 

Rules. Such use also requires an air emission license from the Department’s Bureau of 

Air Quality. 

Following the fuel fire in Athens, the Department determined that further research and 

evaluation concerning CDD fuel quality was necessary to form 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 wood as fuel. A study was 

designed and implemented through the cooperative efforts of 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 violations 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 Debris and Treated Wood”. 

 

The study, done under the oversight of Dr. Dana Humphrey from the University of 

Maine, included combustion studies of multiple test fuel blends and the simultaneous 

monitoring of boiler operations, stack emissions and emissions 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 worst case ambient air impact results 

were well below the Maximum Ambient Air Guidelines, leading the DEP to conclude 

that the levels of dioxin and arsenic emitted by biomass boilers burning CDD wood fuel 
4 

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 experience gained over several 

years, the Department proposed revisions to the fuel substitution provisions of the rules. 

It was concluded by the Department that the most effective way to ensure environmental 

protection when CDD wood fuel is used, is through the application of specific fuel 

quality and fuel handling standards. The proposed revisions addressed the potential 

contaminants in CDD wood fuel itself, the allowable limits for these contaminants, fuel 

handling, fuel sampling and testing, and sampling and testing of 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 fuel substitute (CMR 06-096 

Chapter 418 Section 6) is attached as Appendix B. 

As a matter of practice and policy, prior to the adoption of 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 conventional 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, from a regulatory perspective, 

between a beneficial use activity (fuel substitution) and a solid waste disposal facility 

(incinerator). This distinction is important since there are certain statutory restrictions 

and standards that apply solely to “solid waste disposal facilities” (landfills and 

incinerators). Among these is a ban on the establishment of any new commercial solid 

waste incinerator. PL 2006 Chapter 617 provided specifically that the Department’s rule: 

“may not allow the substitution of wood from construction 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 estimates that in 2005, Maine generated 

301,549 tons of CDD. 

 

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

facilities are of a size and have a customer base that allow for significant control of how 

the waste is delivered. They have the ability to direct delivery of relatively pure 

components of the construction and demolition debris waste stream pre-separated for 
5 

reuse, recycling or processing. At these local facilities, residents can be required to 

separate yard waste for chipping and composting, asphalt shingles to be recycled into 

road patching material, tree limbs and trunks into firewood, and “clean” CDD wood 

(without plastics, pressure-treated wood, wall-board, glass 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 typically receive a waste stream 

that is at least 95% wood. 

 

In 2005, 571,834 tons of CDD waste (both in-state and out-of-state generated) was 

landfilled in Maine’s three largest landfills having capacity available for municipal waste 

(Pine Tree in Hampden, Juniper Ridge in Old Town, and Waste Management in 

Norridgewock). Data from the Maine State Planning Office show that in 2004, 12,730 

tons of CDD waste from municipalities was recycled. Most 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 that 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 processing 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. Processing 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 materials from the process 

conveyor line that are not suitable for such recycling (such as metal, plastics, 

treated wood, shingles, aggregates, etc.). All CDD processing 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 materials that are clearly not 

suitable for further processing into a container destined for a disposal. Removal 

of oversized material is essential to efficient throughput of CDD materials and for 

protection of the processing equipment. CDD materials are 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 material (in a positive pick 

process) or to remove the non-wood material (in a negative pick process). Nonwood materials are then removed for off-site disposal or recycling. 
6 

If appropriately sized, positive pick facilities are capable of producing a higher 

quality CDD wood fuel with less effort than negative pick 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 facilities generally do not process as 

much CDD on a daily basis as negative picks, as the process sorting line is more 

heavily dependent on people than removal machinery. In general, 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 are 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, shingles, 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 achieve the fuel quality 

standards. The rule establishes specific standards for: non-combustibles, plastics, 

treated wood, fines, asbestos, arsenic, lead and PCBs. 

Plastics in the fuel may be removed by hand at the processing facility and by 

equipment such as screens or “classifiers” that separate 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-combustibles. “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 them many not employ 

screens to remove these fines. Negative pick facilities 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 demolition site by the people doing 

the construction/demolition work. It can also be carried out at the processing 

facility by people specifically tasked with spotting and removing any pressure 

treated wood that is delivered. 

Studies concerning the accuracy and feasibility of using chemical or other 

methods to differentiate CCA treated wood from non-treated wood in construction 

and demolition debris have been on-going by the University of Miami and the 
7 

University of Florida since 2001. The most recent document completed on this 

subject was a final draft of a report dated January 3, 2006, entitled titled 

“Augmented Sorting of Recovered Wood Waste Using Stain and X-ray 

Technologies”, and prepared for the Town of Medley, Florida. The report 

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 not been documented 

during either manual sorting or sorting through the traditional conveyor belt 

picking-line process. 

The conclusions of this study were the following:

 the facility hosting the study was able to effectively identify loads of wood 

that were relatively uncontaminated by CCA wood by spot-checking 

source separated loads of wood as they entered the facility; 

 visual sorting methods with no augmentation were found to be quick and 

reliable for relatively uncontaminated loads of construction and demolition 

debris wood; 

 visual sorting augmented by PAN Indicator stain was most useful for 

source-separated loads that were suspected of containing a larger amount 

of suspect treated wood; 

 visual methods augmented with PAN Indicator stain were found to be 

more time consuming and not sufficiently reliable with commingled 

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 sorting the 

wood although improvement was noticed with experience. 

XRF units can present a safety issue in that the x-rays were found to penetrate 

through wood and therefore the units needed to be handled carefully and 

appropriately. 

The report indicated that the relative costs per metric ton of the different sorting 

methods were influenced primarily by labor costs which ranged from $24 for 

visual sorting of relatively uncontaminated source-separated wood to $114 for 

XRF sorting of commingled wood.2 

Two existing Maine programs target contaminants that can significantly 

contaminate CDD wood generated from demolition activity. These programs 

target the treatment and/or removal of asbestos and lead containing paint from 

standing structures and from some buildings scheduled for demolition. 

 

2

 Solo-Gabriele, Helena, Gary Jacobi, Eduardo Lam and Timothy 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 conducted 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 square feet or 3 linear feet of 

asbestos containing material is present, that material must be removed by properly 

trained and licensed asbestos abatement professionals. Asbestos contained in 

materials that are intact and bound with a matrix that will minimize the potential 

release of asbestos fibers (e.g., floor tile, asphalt shingles) may be left in place 

when demolition is performed by large equipment and specific work practices and 

worker protection actions are implemented. Single family 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 asbestos fibers. 

For structures demolished by large equipment with non-friable asbestoscontaining flooring or roofing left in place, an additional processing step is 

needed to prevent asbestos contamination of wood fuel derived from construction 

and demolition debris. This additional process step must insure that asbestoscontaining roofing and flooring and the attached substrate materials are separated 

from wood that is going to be shredded or abraded. Subjecting non-friable 

asbestos-containing materials (“ACM”) to crushing, shredding or abrading will 

release previously bound asbestos fibers into the environment and contaminate 

other materials intended for use. State and federal laws 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 before 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 that 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 regulations establishing 

procedures and requirements for the certification and licensing of persons 

engaged in residential lead-based paint activities, work practice standards for 

those activities, and licensing and accreditation of lead abatement training 

programs. 

The primary risk posed by lead-based paint and lead dust contamination in a pre1978 house is the likelihood of causing lead poisoning in children and adults, with 

children under 6 (six) years of age being particularly vulnerable. Currently, the 

Maine Lead Management Regulations apply only to work performed on 
9 

residential buildings and child occupied facilities when the 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 commercial and industrial 

facilities and consequently do not serve to limit lead levels in construction or 

demolition wood that may be used as fuel. The Department has established in 

rule a specific standard for lead concentrations in blended 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 remodeling or demolition 

activities. Levels of contamination higher than 350 mg/kg are 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 facilities 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 to minimize the 

transportation and disposal costs associated with landfilling construction and 

demolition debris. Materials recovered by these facilities include aggregate from 

bricks, concrete, asphalt, rocks, and dirt; ferrous and non-ferrous metal; asphalt 

shingles, un-used gypsum board for reuse, and wood for reuse or for fuel in woodfired biomass boilers. Additionally, other CDD components not suitable for 

recycling may be mixed with the recovered aggregate materials and marketed to 

operating landfills as a soil substitute to cover waste or for shaping and grading 

material for landfill closure projects. Generally, 35-40% 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 mobile shredders that 

process stockpiles of pre-separated CDD wood into fuel at municipal collection 

sites, and by four commercial processing plants – Aggregate Recycling Corp 

(ARC) in Eliot, Commercial Paving in Scarborough, KTI Biofuels in Lewiston, 

and Simpson, Inc. in Sanford. In 2005, these facilities processed 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 produced (See Section IV-B 

for data and discussion regarding fuel quality). These facilities included the 

major commercial processors and several municipal source separation operations 

at which processing occurs through the use of mobile processing 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/Sites 

Volumes of Material Received and Produced and Processing Technology - 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 Separation 

Augusta (ME) 2,100* 2,000 Source Separation 

Boothbay (ME) 5,250* 5,000 Source Separation 

 ** Number not available 

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

Source separating non-pressure treated CDD wood at the point of its generation or 

collection can significantly simplify and facilitate the processing of this material into 

quality CDD wood fuel. At municipal transfer stations, source separation of many 

different types of materials is commonly required including the separation of newspaper, 

cardboard, plastics and glass for recycling. Similar requirements can be extended to 

individuals and companies that deliver construction and demolition debris so the wood 

suitable for processing into CDD wood fuel is pre-separated from roofing, siding, plastics 

or metal and from pressure treated wood. 

“Source separation” is the most basic strategy for controlling the quality of the waste. It 

entails the sorting of usable elements of CDD at the point 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 required to sort them by component 

(wood, metal, etc.). Municipal wood piles are generally comprised 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 efficiently accomplished by having 1) 

adequate signage to educate the public on what are “suitable materials” and 2) by having 

facility staff inspect materials as they are disposed of in the smaller CDD “day pile” 

storage bins. As material is disposed of at the “day pile” by the public, facility staff are 

able effectively inspect this pile and remove any unsuitable 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 material processing into CDD 

wood fuel. 

Some facilities require source separated loads from demolition and building contractors. 

Typically, the processing facilities offer generators financial 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 construction 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 original purpose. Wood from 

demolition activity is not nearly as readily separated for reuse. This wood has 

already been attached to lumber of other types, dimensions and grades, or to other 

non-wood building materials. In order to achieve a similar degree of material 

salvage at a demolition site, a significantly more involved process must be used. 

Salvaging activities are differentiated by the scope of the salvaging operations. 

The removal of windows, doors, kitchen and bathroom fixtures, moldings, 

mantles, and other small architectural components is commonly referred to as 

“non-structural salvage”. In this context, wooden molding is reused as molding, 

mantelpieces as mantelpieces, cabinets as cabinets and lumber as lumber. The 

removal of wooden barn boards, flooring, timbers and lumber; 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 expense 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 reuse of every component 

and all materials from a building is almost never carried out. Practical, timing and 

financial considerations often do not make comprehensive deconstruction and 

materials sorting operations feasible. 
12 

The bulk of current lumber reuse activities in Maine occur through the “Maine 

Housing & Building Materials Exchange” (located in Gray and Sanford, see 

Appendix C), through private transactions like those facilitated in Uncle Henry’s

weekly publication, and through reclamation at public recycling programs and 

transfer stations. 

 2. Economic Feasibility of Building Deconstruction 

A defining characteristic of non-structural salvage is that it does not affect the 

structural integrity of the building. For example, the removal of fixtures, 

windows, doors, moldings and most cabinet will not normally weaken the 

construction integrity of the remaining structure. People can routinely still safely 

work inside the structure. Examples of this reuse or the marketing of salvaged 

items for reuse can be found each week in Uncle Henry’s “Building Materials” 

section where typically many individuals and small companies will advertise the 

sale of salvaged fixtures and building items. Other examples include the monthly 

State Surplus Sales conducted by the Maine Bureau of General Services where 

unique windows, hardware and other building materials are available for 

purchaseafter major building renovation projects. Another 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 particular municipality, region 

or state is dependent upon a number of specific factors. Factors that can 

favorably influence the feasibility of structural salvage or sorting by component 

include: 

• the building contains particularly valuable or unique raw materials 

such as unique timbers and lumber or other valuable building material; 

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

• there is sufficient space on or adjacent to the demolition site to allow 

for convenient material separation, sorting and organizing; 

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

of demolition.. 

A number of factors can hamper the degree to which materials in a structure may 

be economically salvaged or sorted by component. These factors include: 

• small, disparate projects where economies of scale are 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 pressures and timelines 

common among commercial development projects. At the same time, a military 

base often has a number of buildings consisting of similar building materials so 
13 

economies of scale may be possible. This may provide an opportunity for base 

redevelopment authorities to minimize the cost and amount of CDD waste 

associated with demolition activities on a base undergoing 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 boilers approved for CDD wood fuel 

combustion are presently burning it: Boralex- Stratton, Boralex-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 its 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 facility. Similarly, using 426,304 

tons of fuel in its power plant, Boralex - Stratton produced 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 Boralex plants was fuel that 

was processed outside of Maine and shipped as fuel to those facilities. 

Red Shield is expected to burn 200,000 tons per year of wood fuel, of which 100,000 

tons per year may be CDD wood fuel. The SAPPI biomass facility has capacity to burn 

490,000 tons of wood fuel. This facility has submitted an application 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 operating 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 waste from CDD, Maine 

municipalities supply less than 1% of the maximum annual projected 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 potentially 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 reduce the amount of 

Maine landfill capacity currently used for disposal of CDD by 133,200 yds3 annually. 

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

burn CDD wood fuel will combust their maximum allowed amounts: 

• 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 than the 50% 

allowed. 

• There are practical limits to the amount of CDD derived wood fuel that a boiler burns 

that are related to operational costs and maintenance. 

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

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

• Processing CDD into fuel and other recycled products is a low 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 yds3) of 

out-of state CDD was sent to Maine’s commercial landfills in 2005. If this amount were 

separated and processed for CDD wood fuel production rather than 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 an equivalent amount. 

The wholesale replacement of out-of-state processing capacity by in-state facilities is 

unlikely since it is significantly less expensive to process locally (nearer the sites of CDD 

generation) and pay to transport only the portion of CDD that is processed into wood fuel 

than to transport mixed CDD into Maine for processing. The degree to which out-ofstate CDD processors can increase their operational capacity to meet increased fuel 

demand is also limited. Out-of-state processors are currently operating at close to 

capacity. 

 B. CDD Wood Fuel Quality 

Shortly after the July 2006 implementation of the revised fuel substitution rules, the 

Department conducted sampling and analysis of CDD wood fuel from 12 different 

processing facilities which are representative of the regional CDD processing industry as 

a whole. The facilities were representative of different CDD sorting/processing 

technologies: 4 negative pick processors, 3 positive pick processors, and 5 source 
15 

separation facilities. Collectively the 12 facilities produce approximately 205,000 tons of 

CDD wood fuel annually. The CDD wood fuel sampled was tested to determine whether 

the fuel met the regulatory physical standards for plastics, 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 painted wood and lead. The 

relationship between the arsenic and treated wood data does not support using the treated 

wood data to predict arsenic concentration in the CDD wood fuel. This result supports 

the conclusion of the university of Maine study that there may be sources of arsenic in the 

CDD wood fuel other than the treated wood fraction. Similarly, 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 significant corresponding 

changes in the concentration of lead in the fuel. There has been no correlation between 

the amount of painted wood in CDD derived wood fuel and lead concentration 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 plastic than usual is found in the 

CDD wood fuel the cause is often the presence of a plastic/wood composite that is 

designed to resemble wood. This can be addressed by mechanical 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 content. 

Non-burnable material exclusive of rocks, concrete and brick is reported as metal. 

Magnetic removal of small pieces of ferrous metal generally 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 with 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 feedstock. 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 and storage design at Maine’s 

transfer stations and landfills are most likely to lead to improvement in CDD wood fuel 

quality. 

CDD wood fuel samples from 2 of 12 facilities failed to meet 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 yellow-green color be seen and 

removed. Many processors have begun to reach out to their commercial customers who 

generate the CDD waste to encourage them to inspect their jobs for treated wood and to 

organize delivery of their waste by identifying particular loads 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 the quantity of treated wood 
16 

in the CDD wood fuel produced. The effectiveness of this method recommends it to a 

broader application with all CDD wood fuel producers. 

The CDD wood fuel standard most often exceeded is the fines standard. Fines include 

wood, dirt, and small often unrecognizable bits of everything present in the mixed CDD 

waste. It was established during the University of Maine study of the Boralex biomass 

plants, that the fines fraction of the CDD wood fuel contains 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 contaminant 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 has 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 contaminants have been removed 

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

Table 3 allows the comparison of each facility’s success in removing 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 allowed 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 safety for all contaminants 

with respect to air emissions. 

The two facilities sampled which exceeded the treated wood 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 are surveyed prior to demolition and 

that treated wood is batched into designated truckloads for special handling at the 

processing facility, or they can place more resources into treated wood identification and 

removal within their processes 
17 

Table 3 

CDD Wood Fuel Testing 

Results for Physical Parameters 

(DEP Sampling – 2006) 

Facility Plastic Non-burnable Treated Wood Fines

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

PondView. (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 View.(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

Boothbay(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 assumption 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 assumptions 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 facilities operating in Maine, 

Department staff developed the following estimates based on 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 landfill capacity needed to 

accommodate ash from the combustion of CDD wood fuel in 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 landfilled. 

If these five biomass boilers burned CDD wood fuel at their actual/proposed 

maximum licensed/designed capacities, 100,752 yds3 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 the 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% CDD 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 yds3 annually. (GenPower 

would generate 13,392 yds3 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 similar to ash derived from 

the burning of municipal solid waste or from open-burning of CDD 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 thresholds. 

Table 6 

Comparison of Ash Sampling Results from 

Biomass Boilers, Waste to Energy Facilities and Open Burn Piles 

(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 municipal 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. Therefore, the impact on landfill 

capacity that out-of-state fuel had on Maine landfill disposal 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 yds3 (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 wastes from processing 
20 

this CDD into fuel were disposed in Maine. In 2005, KTI received 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 landfilled 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, using about 5,347 yds3

 of 

landfill space. 

In 2005, 16,106 tons (12,885 yds3) of ash from Boralex Livermore was disposed 

of in the IP papermill landfill in Jay, Maine to increase 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 that both the ash from 

Boralex Stratton and the process waste from KTI-Lewiston were disposed in the 

Pine Tree landfill in Hampden in 2005, 22,791 tons of CDD processing waste and 

fuel combustion ash are attributable to out-of-state sources. 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 Stratton and processing of outof-state CDD at KTI was less than 3.5% of the total waste received by Pine Tree 

Landfill in 2005. Maine’s two commercial landfills, Pine Tree and Waste 

Management in Norridgewock, also received about 238,000 tons of mixed CDD 

from out of state in 2005. 

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

boilers that burn CDD wood fuel is estimated to be: 

 Pine Tree Landfill 1,026,915 yds3

 Juniper Ridge Landfill 9,500,000 yds3 

 Waste Management Crossroads Landfill 4,300,000 yds3

 (Total: 14,826,915 yds3) 

Maximum use of CDD wood fuel in the next few years would use less than 1% of 

this current remaining landfill capacity annually. Also, it is likely that some of 

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

 

V. BEST AVAILABLE CONTROL TECHNOLOGY FOR BURNING CDD WOOD 

FUEL 

A. Best Available Control Technology 

“Best Available Control Technology” as defined in 06-096 Chapter §100 means: “an 

emission limitation (including a visible emissions standard) based on the maximum 

degree of reduction for each pollutant emitted from or which 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 other costs, determines is 

achievable for such emissions unit through application of production processes or 
21 

available methods, systems, and techniques, including fuel cleaning 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 Part 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 imposition of an emission 

standard infeasible, a design, equipment, work practice, operational standard or 

combination thereof may be prescribed instead to satisfy the requirement for the 

application of BACT. Such standard shall, to the degree possible, set forth the emission 

reduction achievable by implementation of such design, equipment, work practice or 

operation, and shall provide for compliance by means which achieve 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 represents BACT. This requirement 

precludes potential applicants from shopping for areas with less stringent emission 

limitations, and also promotes the research and development 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 analyses of proposed control 

technologies and consistent procedures for reviewing BACT determinations from state to 

state. A uniform set of procedures ensures equitable treatment for prospective applicants 

and also reduces pressure on reviewing agencies to establish less 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 stringent 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 alternatives. 

B. Maximum Achievable Control Technology (MACT) 

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

in the 1990 Clean Air Act Amendments called Maximum Achievable Control 

Technology, or MACT. 

The strategy abandoned EPA’s 1977 Amendments’ risk based approach to controlling air 

toxics in favor of a new technology approach. The standards were developed based on 

control strategies used by source categories or industries 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 were 
22 

determined. This created a matrix of 174 different source categories 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 regulated under 40 CFR Part 63. 

 

EPA next began developing MACT standards for these pollutant-source combinations. 

The MACT standards required sources to meet specific emissions 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 determined 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 standards based on the control 

technologies or operational practices utilized by these top sources. 

 

After the implementation of all the MACT standards, EPA 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, EPA may implement additional 

standards to address any significant remaining, or residual, health or environmental risks. 

 

Boilers at facilities which are major emitters of hazardous air pollutants are subject to 40 

CFR Part 63, Subpart DDDDD, National Emission Standards for Hazardous Air 

Pollutants for Industrial, Commercial, and Institutional Boilers and Process Heaters. 

New units at these facilities must meet 0.025 lbs per million Btu for particulate matter, 

and existing units must meet 0.07 lbs per million Btu. All existing units in Maine subject 

to this MACT standard presently meet the 0.07 lbs per million Btu limit and most already 

meet the 0.025 lbs per million Btu standard required of new sources 

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 Department of Health and 

Human Services’ Center for Disease Control and Prevention, Division of Environmental 

Health (DEH). The DEH uses a risk-based approach for developing MAAG values that 

are set to be protective for both carcinogenic and non-carcinogenic effects. When 

considering the non-carcinogenic toxicological effects, the levels are set that represent a 

minimal risk of a deleterious effect from lifetime exposure even for sensitive 

subpopulations. 

For carcinogenic or probable human carcinogens the MAAG values are derived using a 

quantitative estimate for the chemical’s inhalation carcinogenic 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 licensed by Department’s Bureau of Air 

Quality (air emission licenses) to combust CDD wood fuel. 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 high efficiency particulate 

control in the form of electrostatic precipitators. Air toxic emissions, namely metals and 

dioxins, adhere to particulate matter and can be effectively removed in this manner. 

Electrostatic precipitators generally perform at greater than 99% efficiency for removing 

particulate matter from the flue gas stream. The electrostatic precipitators can also meet 

Subpart DDDDD, MACT limits. Another form of high efficiency particulate control is 

through the use of a baghouse. Baghouse control can achieve a slightly higher efficiency 

than electrostatic precipitators and would likely be required 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 entitled, “Fate of Dioxin and 

Arsenic from the Combustion of Construction and Demolition Debris and Treated 

Wood”, as described in Section II(C) above, was evaluated by the Bureau of Air Quality. 

The study determined that the worst case ambient air quality impact results from the 

Livermore Falls facility were only 30% of the Maine Ambient Air Guideline (MAAG) 

value for arsenic and 0.47% of the MAAG value for dioxin. For the Stratton facility, the 

worst case impact levels were 3.5% of the MAAG value for arsenic and 0.24% of the 

MAAG value for dioxin. These values were calculated based 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 levels were observed during one of the 

stack test runs for particulate matter at the Boralex Livermore Falls facility. One of the 

four electrostatic precipitator fields (ESP) was shut off during the run, leaving only three 

fields energized. Additional testing runs using all ESP fields 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 burning CDD wood will likewise 

not pose unreasonable public health risks. The Department is presently evaluating that 

data. 

 F. Ongoing Air Toxics Investigation into CDD Wood Fuel 

In November of 2005, the Bureau of Air Quality (Bureau) convened a meeting with those 

facilities in Maine that were burning CDD wood fuel. At that meeting, the Bureau 

expressed its concern about the relationship between arsenic emissions and electrostatic 

precipitator operations, as well as the need for increased stack emission testing for 

additional chemicals and compounds. Those in attendance acknowledged 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 times 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 additional stack 

testing requirement. 

The chemicals and compounds to be stack tested for are antimony, arsenic, cadmium, 

chromium, copper, lead, mercury, nickel, selenium, vanadium, hydrogen chloride, and 

dioxin. 

The results of the stack testing will be used with facilities’ previous site specific air 

dispersion modeling analyses to determine that the Maine Ambient Air Guidelines are 

being met. Further, the Department indicated that it would evaluate the data after the first 

two years of sampling to determine future testing requirements. 

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 performed on the mill’s #20 

power boiler and shows the predicted impacts from the seven metals and compounds 

listed to be well below either the Maine Ambient Air Quality Standard or the Maine 

Ambient Air Guideline. 
25 

Table 7 

 Westbrook Stack Testing – Metals 

(2006 data) 

Metal 

Maine Ambient 

Air Standard 

(ug/m3) 

Bureau of 

Health Ambient 

Air Guideline 

(ug/m3) 

Impact 

(ug/m3) 

% 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 precipitator 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 unless all of the fields of the 

electrostatic precipitator are fully operational. Any future BACT determination for CDD 

combustion at existing facilities utilizing electrostatic 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 emission 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.