&EPA
United States
Environmental Protection Agency
Region 1
JFK Federal Building
Boston, Mass. 02203
        Executive Summary

        Draft Supplemental
  Environmental Impact Statement
             May 1989

    Long-Term Residuals Management
        for Metropolitan Boston

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Executive Summary
Draft Supplemental
Environmental Impact Statement
May 1989
Long-Term Residuals Management
for Metropolitan Boston
Prepared by:
United States
Environmental Protection Agency
Region I
JFK Federal Building
Boston, Mass. 02203
Technical Assistance by.
Michael R. Deland
Resdonal Admlnlatrator
U.S. EPA, Region I

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EXECUTIVE SUMMARY
PURPOSE AND NEED FOR ACTION
More than 70 dry tons a day of sewage sludge, generated by 43 cities and towns in the
metropolitan Boston area, is currently being discharged to Boston Harbor. In the short-
term this discharge results in significant degradation of the water quality and aesthetic
value of the Harbor and its associated resources. Over the long-term, sludge discharges
contaminate Harbor sediments and biota, resulting in environmental impacts which
persist long after the actual discharge has ceased.
Over the last several years the Massachusetts Water Resources Authority (MWRA) and
the U.S. Environmental Protection Agency (EPA) have taken significant steps to remedy
this problem. The two agencies issued environmental documents in 1985 which
recommended that a new wastewater management system be constructed for
metropolitan Boston’s sewage, consisting of a consolidated secondary wastewater
treatment plant on Deer Island and a separate sewage sludge management system.
Following this decision, MWRA and EPA issued environmental evaluations and proposals
to address more specific aspects of the management system including: wastewater
treatment methods; construction staging; transport of construction personnel and
materials; and location and methods of effLuent discharge. The MWRA also issued an
environmental evaluation of its short-term (1991 to 1995) sludge management program
(to treat and dispose of sludge from the existing primary wastewater treatment plants on
Deer and Nut Islands).
This Draft Supplemental Environmental Impact Statement (SEIS) represents the most
recent of EPA’s environmental documents addressing the clean-up of Boston Harbor.
This document addresses the long-term (1995-2020) treatment, transport, and disposal
(collectively termed “management”) of “residuals” from the new MWRA wastewater
treatment system. Residuals include:
• grit - heavy particles settling from the wastewater stream;
• screenings - large objects screened from the wastewater;
• scum - floating material skimmed from the surface of the wastewater; and
• sludge - solids settling from the wastewater during treatment.
Between October 1988 and February 1989, MWRA issued the results of its own
environmental review of residuals management alternatives in an eight volume Draft
Environmental Empact Report and Facilities Plan (EIR/FP). This Draft SEIS is a “piggy-
back” document because it makes use of the information generated by the MWRA where
possible. The independent analyses and opportunities for public review provided by the
MWRA’s EIR/FP and this Draft SEIS offer an exhaustive review of the potential
environmental impacts of residuals management alternatives, and an opportunity to
tailor each document to fit the applicable regulatory requirements and responsibilities of
each agency.
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The purpose of this Draft SEIS is fourfold: to fulfill EPA’s commitment for further
environmental review as specified in EPA’s 1986 Record of Decision on the siting of the
new wastewater treatment plant; to assure compliance with the requirements of the
National Environmental Policy Act (NEPA); to provide an independent review of the
MWRA’s EIR/FP; and to ensure that all aspects of the plan will result in compliance with
the Federal Clean Water Act.
DEVELOPMENT AND SCREENING OF ALTERNATIVES
The EPA is required under NEPA to evaluate a reasonable range of alternatives in an
EIS. Because of the great number of available residuals processing and disposal
technologies and potential residuals processing or disposal sites, and the even greater
number of combinations of sites and technologies, it was necessary to refine the
alternatives to be evaluated in detail in the Draft SEIS. Consequently, a screening
procedure was developed to use information gathered at progressive stages of the review
process to analyze the potential alternatives under consideration and gradually reduce
their number. This screening of alternatives was an iterative process that paralleUed
MWRA’s screening, with EPA employing NEPA-mandated criteria to ensure that a full,
reasonable range of alternatives was retained for evaluation at each stage of the process.
The goal of the screening was to maintain a reasonable number and variety of
technologies, sites and site/technology combinations based on available information at
each stage of the screening process. In addition, EPA tried to maintain the maximum
flexibility to mix and match site/technology components into different integrated
residuals management plans to facilitate comparison of a full, diverse range of such
plans.
The first step in the screening process was evaluation of system alternatives, defined as
combinations of residuals processing and transportation modes (see Figure 1). At this
stage the screening relied primarily on costs; physical, legal, or institutional constraints;
and compliance with regulatory requirements. As a result of screening, five processing
technologies were dropped from further consideration: ocean disposal, direct land
application of sludge, landfilling of sludge as a primary disposal method, co-combustion
or co-composting of residuals with solid waste, and long-term privatization of the
residuals management system. Composting, heat drying, and fluidized bed incineration
of sludge, and landfilling of minor residuals (grit, screenings, and ash) were retained for
more detailed analysis. It also was determined that the residuals management plan should
be based on flexible use of at least two sludge processing technologies, based in part upon
the recognition that although “beneficial reuse” or “recycling” technologies such as
composting are desirable, they have not yet been shown to be sufficiently reliable
without adequate backup.
The second screening step combined the system alternatives with site alternatives to
establish a list of “candidate options”, or site/technology combinations, to be
considered. The site inventory under consideration included 300 potential sites, mostly
within the 43 community MWRA sewer service area. The criteria used to screen the
sites included their engineering and environmental suitability for the chosen
technologies, site-use flexibility (including a cost component), permitability and potential
site-use conflicts.
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FiGURE 1. OVERALL LOGIC OF THE SEIS
ALTERNATiVES SCREENING
Technical and Cost
Compansion of Generic Disposal
and Transportation Opticns
Technical and Envi,onmental
Evaluation of Sites and System
Alternatives
Screening Evaluation of
Candidate Options Using
Technical, Cost, Environmental
and Institutional Criteria
METCALF El EOOY

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The final screening step compared the candidate options to four categories of criteria:
technical, cost, environmental, and institutional. This screening step resulted in the
selection of those site/technology alternatives that were given detailed evaluation in the
Draft SEIS (Table I and Figure 2).
TABLE 1. SITES AND POTENTIAL USES RECOMMENDED FOR
DETAILED ANALYSIS EN THE SEIS
Site
Transfer
Dewater
Heat Dry
Combust
Compost
Landfill
Walpole MCI
X
Rowe Quarry
X
Stoughton
X
X
X
Quirtcy FRSA
X
X
X
x
Spectacle Isi.
X
X
X
X
Deer Isl.*
X
X
X
* Deer Island components carried only as secondary, or back-up options in recognition of the
burden borne by the City of Winthrop as a result of the new secondary wastewater
treatment facility.
DESCRIPTION OF TECHNOLOGIES
Four sludge processing and disposal technologies were retained for detailed analysis in
the Draft SEES. These are composting, heat drying and incineration of sludge, and
landfilling of grit, screenings, scum, and sludge or sludge products that cannot be
disposed of otherwise. Sludge digestion, thickening, and dewatering would be used in
combination with all four of the major technologies.
Digestion of the combined primary and secondary sludge will occur at Deer Island using
a two-stage, high-rate anaerobic digestion process. Sludge will be thickened both
before and after digestion to aid in handling and treatment. Dewatertng removes water
from sludge to produce “sludge cake” and reduces the volume of material to be handled.
Composting is a process that results in the decomposition of organic components of
sludge and in the reduction of pathogenic (viral) bacteria. The primary product of
composting is a soil-like material. Compost can be used to improve the workability of
soil, making it easier for plant roots to penetrate. Most compost contains only small
amounts of plant nutrients and thus is not useful as a primary fertilizer. It can,
however, be useful as an organic base (with fertilizer amendments), mulch, soil top
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Rowe Quarry
(Maiden/Revere)
b
Deer Island
Boston)
Area
we—
(Wa oIe)
Source: MDC, 1979 a d MWRA. RMFP, DEIR, 1,2, 1989
LEGEND
• Processing Site
U
Landfill Site
FIGURE 2. RESIDUALS MANAGEMENT CANDIDATE OPTION SITES

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dressing, or soil-like product for soil conditioning or erosion control. Compost can be
marketed for sale or distribution either directly to consumers or in bulk quantity
through a retailer. Once a potential user has been identified, the distance to market,
transportation costs, quality of compost, and costs of competing products must be
accounted for in determining market viability.
Heat drying uses an external heat source to increase the solids content of dewatered
sludge cake, preparing the sludge for subsequent packaging, reuse, or incineration.
Because of the high solids content of heat-dried sludge, it also makes a good fuel for an
incinerator. Dried sludge is brown to olive-brown in color, and typically has an odor
similar to fertilizer. An advantage of heat drying is that the sludge product retains
useful nutrients and can be marketed as a fertilizer. Similar to compost, heat-dried
sludge can either be sold or distributed. There are a variety of constraints on the use of
such a sludge-derived product, however, from legal and institutional to environmental,
health and safety, and economic.
Combustion, or incineration, is a process of burning sludge to reduce its volume by 70
percent or more. The combustion reaction chemically combines oxygen with the
volatile solids in sludge, converting them to carbon dioxide and water that exit as
exhaust gases. Metals present in the sludge remain through the process and exit with
the exhaust ash. The heat created by the combustion process generally reduces or
destroys the toxic organic chemicals and pathogens present in sludge.
Landfilling is the method selected for management of grit and screenings from the Deer
Island wastewater treatment plant and remote headworks. It is also a potential method
for disposal of incinerator ash, dewatered sludge cake (during emergency break-downs
of the sludge processing equipment), and heat-dried pellets (if they are not
marketable). The landfill would be designed with a double liner (one of synthetic
material, a second of natural material). Leachate would be collected by two leachate
control systems, with one above each liner. Groundwater and surface water monitoring
would be conducted to ensure the integrity of the liner system. Material that is
landfilled would be covered on a daily, intermediate, and final basis. Use of cover
material minimizes disease-transmitting organism breeding and animal attraction, helps
control water and gas movement, controls odors, and improves appearance. The
operation of the landfill depends on cover to aid in compaction, decrease settling,
minimize wind erosion, increase slope stability, increase crack resistance, and provide a
good soil for vegetative growth after landfilling.
The between-site transportation requirements of the residuals management facilities
vary depending on the type of material being transported and the site combination
chosen for processing. Table 2 summarizes the transport mode options for each residual
material.
RESIDUALS CHARACTERIZATION
The quantity and quality of residuals that will be generated at the MWRA’s Deer Island
wastewater treatment plant was projected, as was as the quantity and quality of sludge
products from composting, heat drying, and combustion. These projections are
summarized in Tables 3 and 4.
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TABLE 2. POSSIBLE TRANSPORT MODE/RESIDUALS COMBINATIONS
Transport
Mode
Liquid
Sludge
Thickened
Sludge
Residual Type
Pellets!
Compost
Minor
Ash
Residuals
Dewatered
Sludge
Truck
X
X
X
X
X
Barge
X
X
X
X
X
X
Pipeline
X
X
Source: Adapted from MWRA, Tech., 1987
Similar projections were also made for the minor residuals components. Future characteristics
of these components are not expected to differ from existing characteristics. Analysis of grit,
screenings, and scum indicates that contaminant concentrations in these materials are well
below the maximum allowable limits for non-hazardous waste and would therefore be suitable
for landfilling.
EVALUATION OF ALTERNATIVES
The existing environmental conditions and the impacts of residuals management at each
alternative site were assessed in the areas of: land use; transportation and traffic; air quality
and odors; water and soils; noise; visual; aquatic and terrestrial ecosystems; public health;
historic and archaeological resources; and socioeconomics. The significant findings for each
site are summarized below.
Walpole MCI
No significant impacts are expected at the Walpole MCI site in the areas of air quality or odors
under any operating conditions. Grit and screenings could potentially generate odors; however,
they would be landfilled only in relatively small quantities. Using proper management
procedures such as daily cover, grit and screenings would not generate noticeable odors or air
quality concerns. The ash and heat-dried pellets would not contain volatile materials, which are
generally the source of odors. Thus, if brought to the landfill, these materials are not expected
to cause odors. Dried sludge cake, when landfilled, could generate odors, but these would be
controlled through the use of daily cover. Therefore, air quality and odor impacts at the site
would be acceptable.
Under normal operating conditions there would be no surface or groundwater impacts because
all water from the landfill and associated contaminants would be contained on site. The
landf ill’s double liner, leachate collection system, and runoff control system should prevent
contaminants from reaching surface or groundwater. In the unlikely event that all of these
controls fail and a leak develops in the liner system, there would be the potential for
contaminants to reach adjacent groundwater
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TABLE 3. SUMMARY OF PROJECTED RESIDUALS QUANTITIES
Digested Sludge Volume of
to Process Product
(dtpd) (cu yd/day)
1995
Digested Sludge , 85 504
Heat dri Sludge a 57 98
Compost 28 354
Ash Plus Scrubber Solids C 0
1999
Digested Sludge 109 647
Heat dri Sludge a 73 125
Compost 36 455
Ash Plus Scrubber Solids C 109 112
2000
Digested Sludge 165 979
Heat dri Sludge’ 110 189
Compost ( . 55 703
Ash Plus Scrubber Solids C 165 169
2020
Digested Sludge 180 1068
Heat-dri Sludge a 120 206
Compost ( ) 60 767
Ash Plus Scrubber Solids C 180 184
Notes: (a) 67 percent of digested sludge would be heat dried
(b) 33 percent of digested sludge would be composted
(c) Assumes 100 percent of digested sludge would be incinerated
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TABLE 4. SUMMARY OF PRO5ECTED RESIDUALS
POLLUTANT CONCENTRATIONS
Digested and Heat
Dried Sludge
Compost
Combustion Ash
Concentration
Concentration
Concentration
(mg/kg)
(mg/kg)
(mg/kg)
Antimony
27
25
63
Arsenic
11
9.9
25
Beryllium
<16
<15
<38
Boron
220
210
510
Cadmium
12 to 26
11 to 24
27 to 59
Chromium
190 to 300
180 to 284
440 to 69)
Copper
910 to 1240
860 to 1172
2100 to 2862
Cyanide
190
180
440
Lead
154 to 230
140 to 209
364 to 544
Mercury
12 to 13
10.7 to 12.6
26 to 28
Molybdenum
30 to 69
28 to 64
70 to 161
Nickel
77 to 99
73 to 93
187 to 240
Selenium
74
70
170
Silver
45 to 70
42 to 65
110 to 162
Thallium
<26
<24
<60
Zinc
1895
1700
4500
PCB-1254
0.61 to 1.86
0.58 to 1.76
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and surface waters. However, more than half of the leachate from a leaking active cell would
have to reach the nearest groundwater supply wells before water quality criteria and standards
for drinking water would be exceeded, and it is predicted to take over 30 years for groundwater
from under the landfill to reach the wells. In order to doubly ensure that contamination of a
local water supply would not occur, the EPA recommends that the MWRA install a groundwater
monitoring system as mitigation. A properly designed and executed monitoring plan would
detect any landfill leaks in sufficient time to remediate any groundwater contamination before
significant impacts occurred, based on the calculated times that would be needed for
contaminants to travel to the groundwater resources of concern.
Because no significant air or water impacts are expected, there are no pathways for public
health impacts.
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Noise generated by trucks and earth-moving equipment, particularly during emergency
landfilling of dewatered sludge, could generate significant impacts for the closest receptors. At
some receptors, including the Stop River wetlands and associated wildlife habitat, the change
from a relatively quiet ambient condition creates a potentially significant impact. The EPA
recommends that noise impacts be mitigated through berm construction, using excess on-site
material, and the use of earth-moving equipment specially modified to reduce noise.
Also, during emergency landfilling of dewatered sludge there could be significant traffic and
noise impacts at the site and along the Winter Street transportation route. Under these
conditions truck traffic could more than double on local residential streets. The physical
characteristics of the streets are not well suited to heavy trucks, which exacerbates the
impact. EPA recommends that the impacts of trucking during this emergency situation be
mitigated by splitting the truck traffic between the Pine Street and the Winter Street access
routes. Adverse traffic impacts would remain but they are not expected to be significant
because they are not expected to occur for periods longer than a few days. During other
operating conditions the increased truck traffic is not expected to significantly impact traffic
or land uses along the transportation corridor.
The Walpole MCI site is relatively isolated and generally buffered from neighbortng residential
areas by wooded and undeveloped land. Also, the prisons, which are among the adjacent land
uses, are less susceptible to land use, visual, and socioeconomic impacts than are residential or
commercial uses. Consequently, landfill development at the Walpole MCI site is not expected
to generate significant adverse impacts in these areas. There are no known cultural or
ecological resources on the site, so significant impacts in these areas are not expected. There
is, however, the potential for archaeological remains at the site and an archaeological survey
would be required before construction.
The Walpole MCI site is environmentally acceptable for a landfill, however there could be
potentially significant impacts in the area of noise, traffic, and water quality. The EPA
recommends that the mitigation measures discussed above be implemented to reduce the
significance of such impacts.
Rowe Quarry
As at the Walpole MCI site no air quality or odor impacts would be expected for a landf ill at
Rowe Quarry, assuming standard landfill operating practices are used such as daily cover. Also
similar to Walpole MCI, the Rowe Quarry landf ill would have a double liner and leachate
collection and runoff control systems, so there should be no groundwater or surf ace’water
impacts. Even if the liner system leaked, groundwater implications are not considered
significant because the concentrations of contaminants would be low and the groundwater in the
area is not a significant resource. A major leak in the liner system would have to occur for
there to be a risk of exceedances of applicable criteria at the nearest surface water body, the
adjacent Rumney Marsh, a significant ecological resource. Again, this possibility could be
mitigated by the installation of a groundwater monitoring system downgradient of the landf ill
and a commitment to remediate any groundwater contamination caused from a landfill leak
before it reached the marsh.
Because no significant air or water impacts are anticipated, there are no expected pathways for
public health impacts.
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Noise generated by trucks and earth-moving equipment, particularly during emergency
landfilling of dewatered sludge, could generate significant impacts for the closest receptors.
However, noise impacts already exist at receptors around the Rowe Quarry site from ongoing
quarry operations. Noise impact could be somewhat mitigated by requiring specially modified
equipment; however, other forms of mitigation are limited because material is not available on
site to construct berms and because the raised nature of the receptors relative to the landfill
operations would make berms less effective.
Although residences and other active land uses are close to the site and there is only minimal
buffer, no significant land use, socioeconomic, or visual impacts are expected because landfill
activities would not be significantly different from the current quarry operations. Similarly,
although there is a nearby important ecological area (Rumney Marsh), the change in activity
from quarry to landfill operation is not expected to alter any ecological resources or
processes. There is the potential for significant historical resources on the Rowe Quarry site,
and a survey would have to be conducted before construction to determine if the quarry or
buildings are eligible for the National Register of Historic Places.
Projected traffic along the access route to Rowe Quarry generally is not excessive and the
addition of residuals vehicles would not result in deteriorated service under any operating
conditions. The relatively small percentage increase in trucks is not seen as significant and
even this small increase would be at least partially offset by elimination of trucks associated
with quarry operation if the site is converted to a landf ill.
The Rowe Quarry site is environmentally acceptable for a landfill; however, there could be
potentially significant impacts in the area of water quality and noise. The EPA recommends
that the mitigation measures discussed above be implemented to reduce the significance of such
impacts.
Stouglnon
Some adverse air quality impacts could result from the incineration of residuals at Stoughton.
One exceedance of DEQE Threshold Effects Exposure Limits (TELs, equivalent to maximum
24-hour Allowable Ambient Limits, or AALs) is predicted. TELs are not regulatory limits but
are used as guidelines in the state permitting process, and this one exceedance is not considered
by the EPA to be unacceptable because it would not result in severe environmental or public
health impacts. No significant air quality impacts or AAL exceedarices are predicted from any
combination of heat drying and composting at the site. Composting would be the most odorous
process at the site, but the distance to the nearest receptor is far enough that no odor impacts
are expected.
There are predicted to be significant adverse water quality impacts from incineration at
Stoughton. Dry weather deposition from incinerator emissions could result in numerous
exceedances of aquatic life and human health water-quality criteria in nearby Brockton
Reservoir and Glen Echo Pond. Additional deposition of contaminants during wet weather was
not estimated but would increase the magnitude of the adverse impact. The predicted water
quality impacts would have significant adverse effects on aquatic life in the two water bodies
and could have public health impacts because Brockton Reservoir is slated to become a public
water supply. The water quality and public health impacts from deposition due to heat drying
and composting, however, are not predicted to be significant.
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If all materials handling were conducted outdoors at the Stoughton site, there would be
significant noise impacts, which in turn could potentially affect adjacent land uses. However,
the noise impacts could be mitigated by confining most of the handling operations to areas
shielded by noise barriers. There are also potentially significant adverse impacts from
processing operations; noise from fans and blowers could be particular problems. These impacts
could be mitigated by designing low noise generating mechanical systems and minimizing
building openings.
Under the maximum traffic scenario (heat drying and composting), the transportation impacts
would be significant because of the large number of trucks going to and from the site. This
impact could be at least partially mitigated by expediting the planned reconstruction of the
Route 24/Route 139/Page Street area and by upgrading and signalizing the affected Route 139
intersections. Because composting is the greatest contributor of traffic, if incineration and heat
drying occur at the site (together or alone) no significant traffic impacts are predicted. With
composting only at the site the number of trucks is reduced by about 30 percent from the
maximum. Although this would still result in adverse traffic impacts, these impacts would be
mitigated by the above Route 139 improvements.
No significant visual, land use, or socioeconomic impacts are expected from residuals processing
at the Stoughton site because the industrial nature of the site and surrounding area are
generally compatibLe with residuals processing; thus no substantial change is expected to occur
as a result of developing the site for any combination of heat drying, composting, or
incineration. Also, much of the operation at the site could be buffered from any sensitive visual
resources.
The Stoughton site is environmentally acceptable for either heat drying or composting, alone or
in combination. Incineration is not acceptable at the Stoughton site because even though state-
of -the-art air pollution control equipment is proposed for the incinerator, it is not presently
predicted to be sufficient to mitigate the predicted water quality im acts from an incinerator
on the site. For heat drying and compost there is a potential for significant impacts in the
areas of traffic and noise. The EPA recommends that the mitigation measures discussed above
be implemented to reduce the significance of such impacts.
Quincy FRSA
No significant air quality impacts are expected from heat drying and composting at Quincy
FRSA, either alone or in combination with impacts from other sources in the area. However,
significant odor impacts could result from the composting operation, particularly because of its
proximity to potential receptors. Such odor impacts can be mitigated with good engineering
practices including monitoring of the scrubber to ensure control of mercaptan, the main odorous
compound of concern.
No significant water quality impacts are predicted for the Quincy FRSA site either. Deposition
of air pollutants would not be significant because any pollutants deposited into the Weymouth
Fore River would be sufficiently flushed and diluted by the river so as not to exceed water
quality criteria. Due to the absence of predicted significant air and water quality impacts, no
pathways for public health impacts are predicted.
Noise impacts are expected to result from residuals processing and handling at Quincy FRSA.
The noise impacts are minimal at the heat-drying and off-loading facilities because of the
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distance from these facilities to receptors. Operating noise at the compost facility can
generally be mitigated by designing low noise generating mechanical systems and by minimizing
building openings. Materials-handling activities, particularly at the compost facility, could also
be noisy. This impact could be mitigated by enclosing all loading and off-loading areas and by
providing a bermed area for idling trucks that are waiting to load or off-load. Use of enclosed,
insulated pipes for conveying materials would also mitigate noise impacts.
There would be increases in truck traffic resulting from residuals processing activities at
Quincy FRSA, and the traffic could overlap truck traffic generated from the MWRA’s use of the
site as a staging area for construction of the new secondary wastewater treatment plant on
Deer Island. The site access route is already heavily used by truck traffic, and the impacts
from the additional traffic related to residuals facilities are not considered to be significant.
Potential land use and visual impacts at the site are not significant, largely because the site has
a long history of intense industrial use and residuals processing would be a similar use of the
site. Similarly, the industrial nature of the site has generally preempted the existence of
ecological resources at the site; thus, use of the site would not have significant ecological
impacts. Long-term residuals processing at Quincy FRSA would not have significant
socioeconomic impacts and could potentially decrease effects of the departure of General
Dynamics on the local commercial community by making at least part of the site active again.
It has been determined that the Quincy FRSA is eligible for the National Register of Historic
Places as an historic district. One building in the composting area is considered as contributing
to the historical significance of the shipyard, and thus mitigation measures would need to be
developed if demolition or other adverse effects to the structure would result from construction
of the compost facility.
The Quincy FRSA site is environmentally acceptable for transfer, dewatering, heat drying and
composting (alone or in combination); however, there could be potentially significant impacts in
the area of odor, noise, and historic resources. The EPA recommends that the mitigation
measures discussed above be implemented to reduce the significance of such impacts.
Spectacle Island
One exceedance of DEQE Threshold Effects Exposure Limits (TELs, equivalent to maximum
24-hour Allowable Ambient Limits, or AALs) is predicted from incineration at Spectacle
Island. TELs are not regulatory limits but are used as guidelines in the state permittLng process,
and this one exceedance is not considered by the EPA to be unacceptable because it would not
result in severe environmental or public health impacts. The DEQE recently established annual
average AALs; however, annual average concentrations from incineration at Spectacle Island
have not been predicted. The combination of heat drying and composting with no incineration
would not have significant air quality impacts.
Since no water quality impacts are predicted from processing at Spectacle Island (any pollutants
deposited in the harbor around the island would be diluted and would not exceed water quality
criteria), water quality would not impact public health. As discussed above, the one predicted
exceedance of a DEQE TEL is not considered to be unacceptable. Further analysis would need
to be conducted to determine potential exceedances of annual average AALs (and therefore
potential public health impacts).
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The isolated nature and public ownership of Spectacle Island render the noise, land use, visual
and socioeconomic impacts of any residuals-processing scenario on the island minimal. The
ecology on Spectacle Island reflects decades of disturbance, and although a large nesting bird
colony was reported to exist on the island it appears to have been abandoned, so ecological
impacts from residuals facilities would not be significant.
Barge transportation to and from the island is not predicted to result in any significant
impacts. Use of piers constructed by the DPW would minimize or eliminate any additional
impacts from construction of piers for residuals facilities. Construction of a pipeline from Deer
Island to Spectacle Island could have significant impacts on water quality and aquatic life during
dredging operations. In order to mitigate these impacts, the planning and design for the pipeline
would have to consider and minimize impacts in the areas of dredging and construction methods,
location of pipeline route, quality of dredged material, and dredged-material disposal sites and
methods.
Spectacle Island is environmentally acceptable for heat drying and composting (either alone or
in combination) and is also acceptable for incineration (subject to further analysis to assess
predicted annual average pollutant concentrations relative to annual average AALs and to
determine the significance of any predicted exceedances). EPA recommends that the
mitigation measures discussed above be implemented to reduce the significance of the potential
impacts.
Deer Island
As at Stoughton and Spectacle, one exceedance of DEQE Threshold Effects Exposure Limits
(TELs, equivalent to maximum 24-hour Allowable Ambient Limits or AALs) is predicted from
incineration at Deer Island. TELs are not regulatory limits but are us d as guidelines in the
state permitting process, and this one exceedance is not considered b EPA to be unacceptable
because it would not result in severe environmental or public health impacts. DEQE recently
established annual average AALs; however, annual average concentrat ions from incineration at
Deer Island have not been predicted. Any combination of digestion, dewatering, and heat drying
with no incineration would not have significant air quality impacts at Deer Island. The
pollutants emitted from an incinerator or a heat dryer would not be the same as those emitted
from the new wastewater treatment plant, so no impacts are predicted from interactions
between these emissions.
Since no water quality impacts are predicted from processing at Deer Island (any pollutants
deposited in the harbor around the island would be diluted and would not exceed water quality
criteria), water quality would not impact public health. As discussed above, the one predicted
exceedance of a DEQE TEL is not considered to be unacceptable. Further analysis would need
to be conducted to determine potential exceedances of annual average AALs (and therefore
potential public health impacts).
There are no significant environmental impacts in any other areas predicted for any of the
processing options at Deer [ stand. The island is already designated for wastewater treatment
and it is publicly owned, so no land use, visual, socioeconomic, or ecological impacts are
anticipated. All transportation of sludge and sludge products would be by barge using pre-
existing piers, and thus no transportation impacts are expected. The residuals area of the island
is far removed from any noise receptors, so the elaborate noise mitigation measures employed
for the wastewater treatment plant (which is much closer to the receptors) would be adequate
to prevent noise impacts.
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Deer Island is environmentally acceptable for digestion, dewatering, and heat drying (either
alone or in combination) and is also acceptable for incineration (subject to further analysis to
assess predicted annual average pollutant concentrations relative to annual average AALs and
to determine the significance of any predicted exceedances).
ACCEPTABLE RESIDUALS MANAGEMENT OPTIONS
Based on the above environmental evaluation of sites and residuals management processing and
disposal options there are several site/technology alternatives which EPA believes would be
acceptable as components of the MWRA’s long-term residuals management program (Table 5).
The MWRA, as the entity that will have to build and operate the residuals facilities, has the
primary voice in determining what combination of acceptable sites and processes would most
optimally serve its needs for residuals management. The EPA’s role is to evaluate the MWRA’s
proposed program and alternatives to it in accordance with NEPA and to ensure that the sites
and technologies chosen are environmentally acceptable and will result in long-term compliance
with the Clean Water Act.
TABLE 5. ACCEPTABLE SITE AND TECHNOLOGY COMBINATIONS
Site Transfer
Dewater
Heat Dry
Combust
Compost
Landfill
Walpole
MCI
X
Rowe
Quarry
X
Stoughton
X
X
Quincy
FRSA
X
X
X
X
Spectacle
Island
X
X
X
X
Deer
Island
X
X
The MWRA Board has chosen as its recommended plan a combination of heat drying and
composting of sludge at the Quincy FRSA and landfilling of grit, screenings and dewatered
sludge (on an emergency basis) at the Walpole MCI site. Each of these components was found to
be acceptable in the Draft SEES evaluation (which also recommended appropriate mitigation).
However, the EPA is not fully convinced that this plan by itself will adequately provide for the
treatment and disposal of all residuals generated during the planning period (1995 - 2020).
MWRA’s recommended plan relies on the beneficial reuse of sludge products with projected
contaminants in concentrations that could jeopardize its marketability, especially in New
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England. In addition, competition from other generators of similar products could decrease the
potential market available to the MWRA. MWRA would have to successfully distribute at least
60% of the sludge products it produces over the 25 year planning period, and heat dry the rest
prior to landfilling, in order to avoid using all the available backup capacity in the Walpole MCI
landf ill prior to the year 2020.
Although EPA supports the goal of 100 percent reuse of sludge through the production of
compost and heat dried sludge, EPA also believes that it is imperative that the recommended
residuals management plan reasonably ensure that sludge discharge to Boston Harbor does not
resume. The following steps would help guarantee that adequate sludge product distribution will
take place throughout the planning period.
1. MWRA should commit (in its Final Environmental Impact Report) that, in the event it is
unable to successfully market its sludge products and needs to use the Walpole MCI
landfill as a backup sludge disposal option, to maximize landfill capacity it will heat dry
that sludge prior to landfilling.
2. MWRA should enter into agreements with or obtain commitments from the Massachusetts
Department of Public Works (which maintains the state highway system), the
Massachusetts Department of Environmental Management (which maintains the state park
system) or other governmental agencies to use MWRA’s compost or heat dried sludge
product for their landscaping, fertilizing or soil enhancement needs. These agreements or
commitments should be described in MWRA’s Final Environmental Impact Report (EIR).
3. Prior to issuance of its Final EIR, MWRA should obtain a classification from the
Massachusetts Department of Environmental Quality Engineering of the compost being
produced by the compost pilot plant currently operating on Deer Island, and should begin a
program of significant distribution of that compost.
4. For metals which potentially exceed regulatory standards for distribution of sludge
products (mercury, copper, cadmium and molybdenum) the MWRA should present in its
Final EIR a plan for first confirming the projected levels of these chemicals through
additional sludge and influent monitoring and then, if confirmed, for reducing these levels
through pretreatment, source reduction or targeted enforcement.
5. MWRA should also present in its Final EIR a marketing strategy for sludge products which
describes the methods that MWRA will use to contact potential buyers, to advertise its
product, to transport its product and to assist buyers in obtaining appropriate permits if
necessary.
Like MWRA, EPA supports beneficial reuse of sludge and sludge products. However, without
the assurances listed above or other equally effective measures that MWRA can provide, EPA
does not believe, based on current information, that the MWRA Board’s recommended plan
establishes a reasonably adequate program for residuals management for the full 25 year
planning period. Should such assurances not be forthcoming in the Final EIR, EPA believes that
there are two alternative residuals management plans which can provide an adequate program
for the full planning period.
The first alternative combines heat drying and composting at the Quincy FRSA (MWRA’s
preferred site) with landfilling at both the Walpole MCI and Rowe Quarry sites. If a significant
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portion of the sludge products were not successfully distributed and were heat dried, adequate
capacity would exist to dispose of all sludge in the two landf ills.
The second, and less desirable, alternative combines heat drying and composting at Quincy
FRSA and landfilling at Walpole MCI with incineration at either Spectacle Island or Deer
Island. This alternative is contingent on the results of additional air quality analysis for
incineration (to determine potential annual average AAL exceedances) being acceptable. If this
alternative were chosen, Spectacle Island would be preferred over Deer Island as the incinerator
site because the Town of Winthrop (which could be impacted by incinerator emissions) already
hosts the MWRA’s wastewater treatment plant, and fairness concerns dictate that it should not
have to bear further waste treatment burdens beyond those currently planned unless absolutely
necessary.
PUBLIC PARTICIPATION
The Environmental Impact Statement process ensures that the public is offered the opportunity
for involvement in assessing projects subject to environmental review under NEPA. The public
participation program for this Draft SEIS provided the public with information on the EIS
process and the progress of related studies, and created opportunities for the public to provide
input and consultation to the SEIS study team and responsible agencies.
Upon release of the Draft SEtS, public hearings will be held by EPA in the areas affected by the
project. These hearings will be held to solicit public comment (which will be recorded) in order
to determine any additional public concerns regarding the Draft SEES. The Final SEES will be
prepared taking these and any written comments submitted into account, and will contain a
summary of the public comments and the EPA’s responses to the issues raised.
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