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BASIS OF DESIGN
REPORT
Chestnut Street PFAS
Treatment System
PRELIMINARY
DESIGN
SUBMITTAL
DWSRF #6791
40 Shattuck Road | Suite 110
Andover, Massachusetts 01810
800.426.4262
232305.00
Town of Hudson,
Massachusetts
woodardcurran.com
&
COMMITMENT INTEGRITY DRIVE RESULTS
May 2021
TABLE OF CONTENTS
SECTION PAGE NO.
1. PROJECT BACKGROUND ............................................................................................................................. 1-1
1.1 Summary of Existing Conditions ............................................................................................................ 1-1
1.2 Project Objective ...................................................................................................................................1-1
1.3 Project Schedule ................................................................................................................................... 1-2
2. SITE/CIVIL DESIGN ........................................................................................................................................ 2-1
2.1 Summary of Existing Conditions ............................................................................................................ 2-1
2.2 Design Criteria ....................................................................................................................................... 2-1
2.3 Proposed Modifications ......................................................................................................................... 2-1
3. PROCESS DESIGN ......................................................................................................................................... 3-1
3.1 Summary of Existing Conditions ............................................................................................................ 3-1
3.2 Proposed Modifications ......................................................................................................................... 3-1
PFAS Pilot Study and Temporary System Operation ................................................................. 3-2
Treatment Modifications.............................................................................................................. 3-2
3.2.2.1 Backwash Handling.......................................................................................................... 3-3
3.2.2.2 Hydraulic Analysis ............................................................................................................ 3-3
Distribution System Pumps and Piping ....................................................................................... 3-4
Chemical Feed Systems ............................................................................................................. 3-4
Procurement of GAC Vessels ..................................................................................................... 3-4
4. ELECTRICAL DESIGN .................................................................................................................................... 4-1
4.1 Summary of Existing Conditions ............................................................................................................ 4-1
Electrical Distribution System ..................................................................................................... 4-1
Standby Emergency Power System ........................................................................................... 4-1
4.2 Proposed Modifications ......................................................................................................................... 4-1
Electrical Distribution System ..................................................................................................... 4-1
Standby Emergency Power System ........................................................................................... 4-2
Fire Alarm System ...................................................................................................................... 4-2
Intrusion Detection ......................................................................................................................4-2
Lighting Systems......................................................................................................................... 4-2
Lightning Protection System ....................................................................................................... 4-2
Materials of Construction ............................................................................................................ 4-3
5. CONTROLS DESIGN ...................................................................................................................................... 5-4
5.1 Proposed Modifications ......................................................................................................................... 5-4
5.1.1.1 New PFAS Control Panel ................................................................................................. 5-4
5.1.1.2 Communications .............................................................................................................. 5-4
6. PLUMBING AND HVAC DESIGN.................................................................................................................... 6-1
6.1 Design Standards .................................................................................................................................. 6-1
6.2 Proposed Work ...................................................................................................................................... 6-1
6.2.1.1 HVAC ............................................................................................................................... 6-1
6.2.1.2 Heating ............................................................................................................................. 6-1
6.2.1.3 Ventilation ........................................................................................................................6-1
Town of Hudson i Woodard & Curran
2021.05.10 Preliminary Design Report May 2021
6.2.1.4 Dehumidification............................................................................................................... 6-1
6.2.1.5 Cooling ............................................................................................................................. 6-1
6.2.1.6 HVAC Controls ................................................................................................................. 6-1
6.2.1.7 Plumbing .......................................................................................................................... 6-1
7. ARCHITECTURAL DESIGN ............................................................................................................................ 7-1
7.1 Summary of Existing Conditions ............................................................................................................ 7-1
7.2 Existing Building .................................................................................................................................... 7-1
7.3 New PFAS Treatment Building .............................................................................................................. 7-1
7.4 Life Safety and FIre Protection .............................................................................................................. 7-1
8. STRUCTURAL DESIGN .................................................................................................................................. 8-2
8.1 Structural Design Criteria and Standards ..............................................................................................8-2
8.2 Proposed Work ...................................................................................................................................... 8-2
8.3 Pre-Engineered Metal Building .............................................................................................................. 8-2
8.4 Geotechnical and Foundation Criteria ...................................................................................................8-2
9. PERMITTING ................................................................................................................................................... 9-3
FIGURES
Figure 3-1: Chestnut Street WFP Proposed Schematic ............................................................................................. 3-3
TABLES
Table 3-1: Chemical Feed Systems ........................................................................................................................... 3-1
Table 3-2: PFAS Treatment Design Criteria............................................................................................................... 3-4
APPENDICES
Appendix A: Project Locus Map
Appendix B: List of Specifications
Appendix C: Equipment Summary
Appendix D: Geotechnical Report
Town of Hudson ii Woodard & Curran
2021.05.10 Preliminary Design Report May 2021
1. PROJECT BACKGROUND 1.1 SUMMARY OF EXISTING CONDITIONS The Town of Hudson (Town) in Massachusetts is situated approximately 30 miles west of Boston and borders Marlborough to the north. The Town is located between exits 25A and 26 of Interstate 495. Multiple rivers and streams run through the Town including the Assabet River and its tributaries along with the Fort Meadow Brook, which is fed by the Fort Meadow Lake Reservoir. Hudson has a total area of 11.8 square miles, of which approximately 11.5 square miles are land and approximately 0.3 square miles, or 2.54%, is water. The Town supplies drinking water to approximately 19,864 residents using a blend of 91% groundwater from five wells and 9% surface water. Sources include two groundwater wells located on Chestnut Street (Wells 2 and 3), the Kane Well located on Main Street, the Cranberry Well located off Parmenter Road, and surface water from the Gates Pond Reservoir located in Berlin, MA. A pair of groundwater wells including an original well and a newer replacement well (Wells 1/1R) are located on Chestnut Street as well. The groundwater from Kane Well, Cranberry Well, and all three Chestnut Street Wells is combined and treated at the Chestnut Street Water Filtration Plant (WFP), located at 72 Chestnut Street. Surface water from the Gates Pond Reservoir is treated at the Gates Pond Filtration Plant. The Town’s water system has five (5) distribution storage tanks and 10 pump stations, eight (8) of which are public and two (2) are private. Between August 2016 and June 2018, seven (7) samples were analyzed for per- and polyfluoroalkyl substances (PFAS) from the Chestnut Street WFP effluent. The sum of the concentrations of five Massachusetts Department of Environmental Protection (MassDEP) regulated PFAS compounds (PFAS5) ranged from a minimum of 34.8 parts per trillion (ppt) to a maximum of 67.6 ppt. In response, the Town designed and constructed a temporary treatment system at the Chestnut Street site to maintain operation of the facility. The system became operational in July 2019 as a MassDEP permitted temporary system and has been providing PFAS treatment until a permanent system can be installed. The temporary treatment process consists of two (2) ion-exchange (IX) resin trains, with each train including two (2) pressure vessels. Since the installation of the temporary PFAS treatment system, in October 2020, MassDEP added an additional regulated PFAS compound and established the current health guideline and new maximum contaminant level (MCL) for the sum of the concentrations of six MassDEP regulated PFAS compounds (PFAS6). The MCL is 20 ppt. 1.2 PROJECT OBJECTIVE This project includes the design, bidding, and construction of a new PFAS treatment system, which includes six (6) Granular Activated Carbon (GAC) vessels, in a stand-alone pre-engineered steel building located at the Chestnut Street WFP. A new building on a concrete slab will be constructed to the east of the existing Chestnut Street WFP. The proposed project will also include piping, chemical addition for post-treatment following the new PFAS treatment system, building systems, associated instrumentation and controls, a new emergency generator, and all necessary local and state agency approvals. Standard design practice, which the Town will follow, includes the installation of multiple treatment trains with two PFAS removal vessels in each train. With this design, breakthrough (i.e. detectable concentrations) will occur in the lead vessel effluent while effluent from the lag vessel is maintained at non-detect levels. This will provide the Town sufficient time to replace the media in the lead vessels, switch the order of the vessels, and resume the cycle. In this way the Town will be able to maintain non-detect levels of PFAS6 in the water entering the distribution system. Town of Hudson 1-1 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
1.3 PROJECT SCHEDULE Design of a new PFAS treatment system is proceeding through May 2021, with the construction of the new system anticipated to begin in late summer, and with the treatment process coming online in the fall and building construction and final site work following. The construction phase shall be coordinated with the Town to minimize any impacts to the distribution system during peak times. This project has been listed in the final list of projects being awarded for DWSRF funding. Town of Hudson 1-2 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
2. SITE/CIVIL DESIGN
2.1 SUMMARY OF EXISTING CONDITIONS
The Chestnut Street WFP is located at 72 Chestnut Street in Hudson, Massachusetts. The WFP property abuts Fort
Meadow Brook to the east, private property to the north, Chestnut Street to the west, and Main Street to the south.
The existing site is partially located within the 100-year floodplain with base flood elevations but is outside of the 200-
foot riverfront setback from Fort Meadow Brook, which is a tributary to the Assabet River.
2.2 DESIGN CRITERIA
The site modifications will be provided for accessibility for servicing of each site component. The site modifications
will not extend into any wetlands and will minimize impact to the floodplain. Site access shall accommodate drilling
rigs, chemical/carbon delivery trucks, and maintenance/service vehicles.
Limited paving and grading adjustments to the existing site access driveway along with construction of the new PFAS
Treatment Building are proposed within the 100-foot buffer zone to the bordering vegetated wetlands and within the
100-year floodplain. Site improvements will be designed in accordance with the Town of Hudson Engineering
Checklist for Site Plan Review and will have no adverse hydrologic impact. Low-impact development techniques
consisting of site planning to minimize creation of new impervious surfaces, reductions in amount of existing paved
surfaces, maintaining the existing hydrologic pattern, and restoring areas of the site presently in hydrologically poor
condition will be employed to control post-development peak runoff rates to below pre-development levels. Runoff
patterns from the site will remain unaltered and no new untreated stormwater discharges to the wetland resource
areas and associated buffer zones are proposed. Additional information about the site/civil design for this project is
described in a stormwater report that will be sent to the Town under a separate package.
2.3 PROPOSED MODIFICATIONS
The site improvements will include the following major components:
A new PFAS Treatment Building of approximately 2,800 square-feet;
Site piping between existing WFP Building and new PFAS Treatment Building;
Site piping between new PFAS treatment system and existing booster pumps;
A new Pump House Building for existing booster pumps of approximately 240 square-feet;
Minor adjustments to the existing access driveway;
Site runoff treatment using stormwater best management practices (BMPs) and sized to accommodate the
required water quality volume in accordance with the Massachusetts Stormwater Handbook standards for
critical areas;
Drywell for new PFAS Treatment Building roof and floor drains; and
New overhang over existing exterior mounted VFDs.
Town of Hudson 2-1 Woodard & Curran
2021.05.10 Preliminary Design Report May 2021
3. PROCESS DESIGN
3.1 SUMMARY OF EXISTING CONDITIONS
As noted in Section 1, the groundwater from Chestnut Street Wells 2 and 3, Kane Well, and Cranberry Well is
combined and treated at the Chestnut Street WFP. The Chestnut Street WFP, which was constructed in 1995, was
primarily designed to remove iron and manganese from the raw water through unit processes including chemical
addition and greensand filtration, using five (5) 12-foot diameter filtration vessels, as well as to provide residual
disinfection in the distribution system.
Prior to treatment at the Chestnut Street WFP, the following chemicals are used to pretreat the groundwater: 1)
sodium hypochlorite for disinfection and oxidation and 2) potassium hydroxide for pH adjustment and corrosion
control. Once inside the Chestnut Street WFP, water is treated using greensand filtration for iron and manganese
removal, then the following chemicals are added to the water 1) hydrofluorosilicic acid for dental health, 2) sodium
bisulfite is for de-chlorination, and 3) potassium hydroxide for corrosion control. Water is then filtered using two bag
filters and is treated using an ion-exchange (IX) treatment system for PFAS removal. The IX treatment system was
installed in 2019 as a temporary PFAS treatment system to be utilized until a final, permanent system could be
designed and constructed. Final chemical treatment at the Chestnut Street WFP, before water is pumped to the
distribution system, consists of sodium hypochlorite for disinfection and optional potassium hydroxide for corrosion
control.
The chemical feed systems are located in the existing Chestnut Street WFP and their components are summarized in
Table 3-1.
Table 3-1: Chemical Feed Systems
Chemical System Storage Tanks Day Tanks Pumps
Hydrofluorosilicic Acid 1,500-gallon 30-gallon 1 transfer pump
2 chemical feed pumps
Sodium Hypochlorite (1) 500-gallon (1) 30-gallon 2 transfer pumps
(1) 250-gallon (1) 50-gallon 4 chemical feed pumps
Potassium Hydroxide 3,000-gallon 100-gallon 1 transfer pump
2 chemical feed pumps
Potassium Permanganate 1,000-gallon mixing tank 250-gallon 1 transfer pump
4 chemical feed pumps
Sodium Bisulfite 225-gallon 25-gallon 1 transfer pump
2 chemical feed pumps
3.2 CHESTNUT STREET WFP IMPROVEMENTS
Improvements to the Chestnut Street WFP will include the following:
Rehabilitation of existing interior pipe and valves;
Replacement of interior pipe coating system; and
Replacement of media in greensand filter vessels.
Town of Hudson 3-1 Woodard & Curran
2021.05.10 Preliminary Design Report May 20213.3 PROPOSED MODIFICATIONS
PFAS Pilot Study and Temporary System Operation
A small-scale pilot test was conducted using GAC media (FILTRASORB® 400) and IX resin (SORBIX LC3 resin)
over an 8-month period at the Chestnut Street WFP to aid in the design of a full-scale PFAS treatment system. The
primary goal of the pilot study was to determine the effectiveness of each technology for PFAS removal to establish
full-scale design criteria. Based on the pilot study results, the removal of PFAS varied between the two different
media/resin types. Results indicated similar removal efficiencies in the first column of both medias; however, IX had a
higher removal efficiency than GAC in subsequent columns. GAC was still able, however, to remove PFAS from the
Chestnut Street water to levels below the MassDEP MCL of 20 ppt for the entirety of the study at empty bed contact
times of 9.7 minutes and 14.5 minutes.
In addition to the pilot study, a full-scale, temporary treatment system has been operating at the Chestnut Street WFP
since July 2019. The temporary treatment system was supplied by Evoqua and includes two IX resin trains. Each
train includes two, 10-foot diameter vessels in a lead/lag configuration. Each vessel contains DOWEX™ PSR2 resin.
The temporary treatment system has been removing PFAS to non-detect levels since its implementation in July
2019. However, as a result of maintenance challenges and frequent media changeouts than anticipated at the time of
installation, the Town has expressed interest in switching to GAC filtration vessels for the new PFAS treatment
system. As the Pilot study results support, GAC was also a comparable treatment technology to remove PFAS from
the raw water at this Facility to levels below MassDEP MCL of 20 ppt.
Treatment Modifications
Currently combined well water flows through the Chestnut Street WFP, which includes chemical addition, greensand
filtration, and filtration through bag filters. Following the Chestnut Street WFP, water flows through the temporary
PFAS treatment system, which includes IX and chemical addition. Finally, effluent from the temporary PFAS
treatment system flows back into the Chestnut Street WFP for backwash applications and to the booster pumps prior
to the distribution system.
The building for the new PFAS treatment system will be located east of the existing Chestnut Street WFP. The
proposed permanent system will replace the existing temporary PFAS treatment system within the process
sequence. As shown in Figure 3-1, water exiting the Chestnut St WFP will enter the new PFAS treatment system and
effluent from the permanent system will be directed to the Chestnut Street WFP for backwash applications or to the
booster pumps prior to the distribution system. The proposed permanent system will be composed of three (3) trains
of vessels, with each train having two (2) GAC vessels operating in lead-lag configuration. During normal operations,
two (2) trains will be in service with the third train for redundancy. Each vessel will be capable of holding 40,000 lbs.
of GAC media to adsorb the PFAS compounds and the process piping will be composed of 12-inch and 8-inch
diameter water mains. Chemical additions including sodium hypochlorite for disinfection and an optional injection port
for potassium hydroxide for corrosion control will be installed on the effluent side of the GAC vessels.
Town of Hudson 3-2 Woodard & Curran
2021.05.10 Preliminary Design Report May 2021Figure 3-1: Chestnut Street WFP Proposed Schematic 3.3.2.1 Backwash Handling Although GAC filtration in certain treatment processes can require backwashing, when used as adsorbers for PFAS removal, it is generally not recommended to backwash the GAC media beds as backwashing will redistribute the media and possibly allow premature breakthrough. Therefore, we anticipate that no waste stream will be generated by the new GAC treatment process during regular operation. However, the vessels will be backwashed during carbon changeout periods to adequately prepare the GAC system for operation. Chlorinated finished water will be utilized for backwash supply. Carbon manufacturers stated that backwashing of GAC media, after initial fills, with chlorinated water (< 1 parts per million (ppm)) will not have a significant impact on the useful life of carbon to remove PFAS. Backwash influent water to the new PFAS treatment system will be supplied from the finished water line following the booster pumps. The backwash effluent water will be discharged from the vessels to the existing lagoons, as shown on the preliminary site plans. 3.3.2.2 Hydraulic Analysis A hydraulic analysis was conducted for the Chestnut Street WFP to determine if the existing well pumps will be capable of providing water to the new PFAS treatment system and if the existing booster pumps will be capable of providing water to the distribution system following installation of the proposed permanent system. Based on a review of headloss for the GAC vessels, it was estimated that there is a total head loss of up to 15 psi through GAC vessels. The hydraulic grade at the influent of the Chestnut Street WFP is approximately 417 ft, the hydraulic grade at the effluent of the Chestnut Street WFP is approximately 383 ft, the hydraulic grade at the effluent of the new PFAS treatment system is estimated to be approximately 345 ft, and hydraulic grade at the effluent of the Town of Hudson 3-3 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
booster pumps is approximately 416 ft. Therefore, when the head loss from the GAC vessels is factored into the
hydraulic analysis, it was determined that both the well pumps and the booster pumps are adequately sized to
provide enough head to advance water through the proposed GAC vessels and fill the Pope’s Hill Tank.
Distribution System Pumps and Piping
No changes are proposed to the existing well pumps, booster pumps and motors, or associated discharge piping,
valves, and fittings due to the new PFAS treatment system installation at the Chestnut Street WFP.
Chemical Feed Systems
No changes are proposed to the existing chemical feed systems at the Chestnut Street WFP. Chemical injection
points for sodium hypochlorite and potassium hydroxide will be installed within the building of the proposed
permanent system; however, the existing chemical feed systems within the Chestnut Street WFP will be used to
supply these injection points.
Procurement of GAC Vessels
The Town has decided to expedite the design and installation of new PFAS treatment system. The Town, with the
assistance of Woodard & Curran, is investigating if MassDEP would allow pre-procurement of primary treatment
equipment, the GAC vessels, as it is a critical path item due to the long lead times. Once procured and fabricated,
offloading and installation of the filtration equipment, as well as all other elements of construction, will be part of a
Construction Contract to be bid under standard procurement procedures. Process equipment other than the GAC
vessels, such as valves, instrumentation, and controls, have shorter lead times and therefore will be procured as part
of the Construction Contract.
The design criteria that will be used for the procurement of GAC vessels is summarized in Table 3-2.
Table 3-2: PFAS Treatment Design Criteria
Design Criteria Value
Maximum Design Flow 2,000 gpm
Average Flow 1,200 gpm
Number of Treatment Trains 3
Number of Vessels per Train 2
Total Vessels 6
Operation Lead - Lag
Design Basis TIGG CP-40K-12 or Equal
GAC per Vessel 40,000 lbs
Maximum Flow – 2 Trains Operational
Flow per Train 1,000 gpm
Loading Rate 8.84 gpm/sf
Empty Bed Contact Time ~10 min per vessel
Pressure Drop ~13 psi
Average Flow – 2 Trains Operational
Flow per Train 600 gpm
Loading Rate 5.31 gpm/sf
Empty Bed Contact Time ~16.7 min per vessel
Pressure Drop ~15 psi
Town of Hudson 3-4 Woodard & Curran
2021.05.10 Preliminary Design Report May 20214. ELECTRICAL DESIGN
4.1 SUMMARY OF EXISTING CONDITIONS
Electrical Distribution System
The existing Chestnut Street WFP is served by Hudson Light and Power via two (2) utility feeds. One service feeds
the existing WFP Building at 120/208V 3-phase via an aerial feed and is sized for 200 amps. The second service
feeds the booster pumps at 480/277V 3-phase via an aerial feed and is sized for 400 amps.
The existing 400-amp service for the Finished Water Pumping System was evaluated to verify if the system has
capacity to serve the PFAS upgrades, and it was determined to have adequate capacity. Therefore, this system will
be utilized to serve the new PFAS Treatment Building.
The existing 480/277V 3-phase aerial service may conflict with the proposed location of the new PFAS Treatment
Building and inhibit construction activities. Therefore, this aerial service may need to be relocated to accommodate
construction of the new PFAS Treatment Building. This will be further evaluated during the detailed design effort once
the exact location of the new building is confirmed.
Standby Emergency Power System
The existing WFP has A 35kW natural gas-engine-driven generator that provides standby emergency power to the
120/208V 3-phase service only via a 200A automatic transfer switch (ATS). The electrical distribution system for the
Finished Water Pumping System does not have standby emergency power available.
The existing generator does not have sufficient capacity to serve the PFAS upgrades and has exceeded its useful
life. Therefore, a new emergency generator will be provided to serve the entire site.
4.2 PROPOSED MODIFICATIONS
Electrical items proposed for the modifications to the Chestnut Street WFP are detailed in the following sections.
Electrical Distribution System
The 120/208V 3-phase electrical distribution system associated with the existing WFP will essentially remain
as-is except for the replacement of the existing ATS as outlined in Section 4.2.2.
The existing overhead utility feed that that serves the 480/277V 400A Finished Water Pumping System may
require replacement and/or relocation to accommodate construction of the new PFAS Treatment Building.
This will require further evaluation during the detailed design effort.
The new PFAS Treatment Building will be powered from the existing 480/277V Finished Water Pump
Distribution system. An existing/spare 125A enclosed circuit breaker located on the back side of the WFP
will be utilized to feed a new 480/277V Main Panelboard in the PFAS Treatment Building. The main panel
will be used to feed all 480V equipment within the new PFAS Treatment Building and will also feed a
120/208V panel via a dry-type step down transformer. The 120/208V panel will be utilized to feed
miscellaneous building loads, lighting, receptacles, HVAC equipment, instrumentation, etc.
A new structure/shed is being provided to enclose the existing Finished Water Pumping System which is
currently located outside and exposed to the elements. Several general use receptacles and LED lighting
will be provided in the shed and will be powered from the existing WFP electrical system.
Town of Hudson 4-1 Woodard & Curran
2021.05.10 Preliminary Design Report May 2021Standby Emergency Power System
The Contractor will be responsible for removal and disposal of the existing 35kW emergency generator.
The Town of Hudson will be responsible for procurement of a new Diesel-Engine-Driven Generator and
Automatic Transfer Switches to serve the entire site. Woodard & Curran will work closely with the owner
during the procurement process to ensure the new system meets the requirements of the project.
The Contractor will be responsible for offloading and installation of the owner furnished generator, providing
a full tank of diesel fuel for testing purposes, and coordination efforts required during the startup process.
The new generator will be utilized to provide emergency power to the existing 120/208V 3-phase distribution
system serving the WFP and the 480/277V 3-phase distribution system serving the Finished Water Pumping
System via two (2) new Automatic Transfer Switches (one for each distribution system).
The existing 120/208V 3-phase Automatic Transfer Switch (ATS) within the WFP electrical room will be
demolished and replaced with one of the new ATS’s. Due to space constraints at the site, the 400A breaker
that serves the Finished Water Pumping System will be removed to accommodate installation of the second
ATS. This ATS will be furnished as a Service Rated ATS will integral main breaker and will be installed in
the location of the existing/removed 400A main breaker.
The generator will be provided with an integral double-walled-diesel-belly-tank and will be mounted on a
new concrete pad. The tank will be sized for 48 hours of operation under full load.
The generator will be furnished with a sound attenuated enclosure.
The generator will be furnished with two circuit breakers to accommodate connection to the two services
and associated transfer switches.
Fire Alarm System
A fire alarm system is not required for this facility per code requirements. However, several heat and/or
smoke detectors will be provided within the new PFAS Treatment Building and connected to SCADA to
notify the owner in the event of a potential hazard.
Intrusion Detection
Intrusion switches will be provided for all man-doors and overhead doors in the new PFAS Treatment
Building and will be connected to SCADA for alarming purposes.
Lighting Systems
Interior and exterior lighting systems will be provided with energy efficient Light Emitting Diode (LED)
fixtures. Interior lighting systems will be controlled via local on/off switches, and exterior lighting will be
controlled via photocell, timeclock and H/O/A switch to provide a means to manually override the lights ON
or OFF. Emergency lighting will be provided for egress lighting in accordance with applicable life safety
codes.
Lightning Protection System
Due to the proposed height of the new PFAS Treatment Building, a lightning protection system is
recommended to protect the facility, personnel, and equipment from damage from potential lightning strikes.
The lightning protection system will be designed per NFPA 780 requirements, constructed, tested, and
certified to receive a UL master label.
Town of Hudson 4-2 Woodard & Curran
2021.05.10 Preliminary Design Report May 2021Materials of Construction
Conduit:
PVC Schedule 40 will be specified for all underground applications.
Rigid Galvanized Steel Conduit will be specified for all exterior above-grade locations.
Rigid Galvanized Steel Conduit will be specified for all installations within the PFAS Treatment Building.
Rigid Galvanized Steel Conduit will be specified for all installations within the Chestnut Street WFP.
EMT Conduit will be specified for all installations within the Finished Water Pump Building.
Rigid Galvanized Steel Conduit will be specified for all conduit stub-ups through the concrete slab within the
PFAS Treatment Building.
Supporting Devices:
All supporting devices, fasteners and hardware will be specified as Stainless Steel for use in all locations.
Enclosures:
Exterior - NEMA 4X
New PFAS Treatment Building – NEMA 4X
Chestnut Street WFP – NEMA 12
Finished Water Pump Building – NEMA 12
Town of Hudson 4-3 Woodard & Curran
2021.05.10 Preliminary Design Report May 20215. CONTROLS DESIGN
5.1 PROPOSED MODIFICATIONS
5.1.1.1 New PFAS Control Panel
A new PFAS Control Panel, will be provided for control and monitoring of process instrumentation and
control valves associated with the new PFAS treatment system. This Control Panel will be NEMA 4X rated.
The control panel will contain an Allen Bradley CompactLogix series remote I/O communications adapter
and associated I/O cards for all process control and monitoring of the new PFAS treatment system. All
control will be handled by the existing SCADA Control Panel in the Control Room in the existing treatment
building.
The PFAS control panel will interface with the following instrumentation and equipment in the new PFAS
treatment system:
a. Differential Pressure Switches on each GAC vessel assembly (provided by Vendor)
b. Pressure transmitters on each GAC vessel (provided by Vendor)
c. Pressure transmitters on the upstream and downstream of each GAC train
d. (4) Motor operated butterfly control valves (one each on GAC vessel influent piping and one on the
common effluent pipe from the GAC Vessel)
e. (4) Magnetic Flow Meters (one each on the GAC vessel influent piping and one on the common
Backwater influent to the GAC vessels)
f. New PFAS Treatment Building Temperature and Humidity Transmitters for monitoring of Building
environment.
5.1.1.2 Communications
A Fiber optic cable will be provided between the Chestnut Street WFP and the new PFAS treatment system
for SCADA Communications.
Town of Hudson 5-4 Woodard & Curran
2021.05.10 Preliminary Design Report May 20216. PLUMBING AND HVAC DESIGN
6.1 DESIGN STANDARDS
Proposed work will be designed using the following design standards:
780 CMR, Ninth Edition (Massachusetts State Building Code)
o Mechanical based on modified version of 2015 International Mechanical Code (IMC)
248 CMR 10.00, Massachusetts State Uniform Plumbing Code
6.2 PROPOSED WORK
6.2.1.1 HVAC
The following summarizes the HVAC design conditions for the new PFAS Treatment Building.
The 99% dry bulb (DB) temperature used for heating system design is 10ºF.
The spaces will typically be unoccupied.
6.2.1.2 Heating
Gas unit heaters will provide heat in the PFAS Treatment Building.
6.2.1.3 Ventilation
The new PFAS Treatment Building will be serviced by an exhaust fan. The exhaust fan will be mounted on the
building wall. The exhaust fan will be energized to provide general exhaust airflow at a speed selected at a wall
switch. The exhaust fan will also provide heat relief. When the building interior temperature exceeds 80°F, the fan
will energize (or increase in speed) to the design heat relief airflow. The exhaust fan will be sized to maintain the
building temperature at 10°F greater than ambient.
An intake louver and associated motor operated damper will be provided to allow outdoor air to enter the building.
The motor operated damper will be interlocked with the exhaust fan and will open when the exhaust fan is energized.
The louver will be in the building wall.
6.2.1.4 Dehumidification
Portable dehumidifiers will be provided for the new PFAS Treatment Building. The dehumidifiers will be used to
prevent condensation from forming on the pipes and GAC vessels during parts of the year.
6.2.1.5 Cooling
Cooling will be provided through the building’s exhaust fan.
6.2.1.6 HVAC Controls
Stand-alone electric/electronic controls will be provided for all heating and ventilation equipment. A standalone
thermostat will be provided and will be connected to the WFP SCADA system to notify the WFP if the building
temperature drops below 45°F.
6.2.1.7 Plumbing
Two floor drains will be provided for the building to capture any washdown or condensation from the GAC vessels.
The floor drains will be serviced by vent piping that will terminate at the building roof. The floor drain piping will exit
Town of Hudson 6-1 Woodard & Curran
2021.05.10 Preliminary Design Report May 2021the building and will drain to the nearby drywell. Plumbing materials will be per the Massachusetts State Plumbing Code, 248 CMR. Town of Hudson 6-2 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
7. ARCHITECTURAL DESIGN 7.1 SUMMARY OF EXISTING CONDITIONS The existing condition of the location of the new PFAS Treatment Building is a grassy lot surrounded by forested and wetland areas. Adjacent to the proposed building site are an existing greensand filtration building, an existing exterior pad-mounted temporary PFAS treatment system, an existing buried holding tank and an existing exterior pad- mounted generator. 7.2 EXISTING BUILDING The existing greensand filtration building will continue to be used with no modifications as part of this project. The existing building is approximately 100 ft x 48 ft with concrete masonry unit (CMU) exterior bearing walls and a wood roof. The occupancy group is Hazardous Group H-3 due to storage of hazardous chemicals which are chemically volatile and corrosive. The building is not sprinklered and has openings in the exterior walls which are presumed to be unprotected with respect to fire protection. Exterior cavity walls are 12-inch CMU with 4-inch split-face block veneer. 7.3 NEW PFAS TREATMENT BUILDING The proposed building is a 70 ft x 40 ft Pre-Engineered Metal Building (PEMB) with a fully-adhered EPDM rubber roofing system over rigid roof insulation. Prefinished insulated metal panels will be used in the exterior walls with rigid insulation at the concrete foundation to achieve energy code compliance. The foundation insulation will be covered with a fiberglass reinforced plastic (FRP) barrier to conceal and protect the rigid insulation. The roof will have a gable profile and 1:12 slope with gutters and downspouts. An 8’-0” x 8’-0” insulated steel coiling door will be provided. Future removal/replacement of GAC vessels will be via removable wall panels. The insulated metal panel wall construction will simplify removal and replacement of these panels should the need arise. The new building houses support equipment for drinking water filtration. While access for service and maintenance is required, the facility will not be a daily workplace for staff members. The building may be categorized as utility occupancy Group U. No interior partition walls are needed. Interior finishes will be prefinished metal panels full height of wall and the ceiling finish will be the underside of the galvanized metal roof deck. Galvanized steel rod bracing, purlins and girts will be exposed to view. The floor will be exposed, hardened concrete. Wall panel color(s) shall be selected by Owner. 7.4 LIFE SAFETY AND FIRE PROTECTION Per Massachusetts State Building Code the new building requires a minimum fire separation distance of 10 ft assuming Type VB construction. Due to unprotected openings in the east existing building wall and the H-3 Occupancy Group designation, a minimum fire separation distance of 15 ft is required at the existing building. The minimum total separation between the new and existing buildings is 25 ft and the new building may be constructed of combustible and non-combustible structural elements. Therefore, no fire-rated wall assemblies are required. The building will not be sprinklered. Two standard 3’-0” x 7’-0” man door exits are provided and are spaced to meet egress requirements. Town of Hudson 7-1 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
8. STRUCTURAL DESIGN
8.1 STRUCTURAL DESIGN CRITERIA AND STANDARDS
Proposed work will be designed using the following criteria, material properties and design standards:
780 CMR, Ninth Edition (Massachusetts State Building Code)
o 2015 International Building Code, Risk Category III
o American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures,
ASCE 7-10
Design strength of concrete: 4,500 pounds per square inch (psi) at 28 days
Reinforcing: ASTM A615, 60,000 psi minimum yield strength
Allowable Soil Bearing Pressure: 2,000 psf
Frost depth: 4-ft
8.2 PROPOSED WORK
The site improvements will include the following major components. GAC vessels for PFAS treatment will be
mounted to a concrete mat slab. The PEMB will house the GAC filtration system and will also be supported from the
mat slab.
New concrete foundation for PEMB and PFAS treatment system: Concrete Mat Slab with thickened
perimeter edge
Pre-engineered metal building
Demolition of existing exterior generator pad
New exterior generator pad in the same location
New Pump House Building for existing booster pumps
8.3 PRE-ENGINEERED METAL BUILDING
The PEMB will be designed, manufactured and installed by vendor. The primary structural system will be clear-span
rigid steel frames. Framing at the gable ends will be designated as post-and-beam type. Steel rod bracing will be
used to resist lateral loads in the longitudinal direction and at the gable end walls. Secondary framing includes roof
purlins and bypass wall girts to transfer roof and wall pressures to the primary structural system. The metal building
structural system will be galvanized steel.
A single concrete mat slab with thickened perimeter edge will be provided to support both the PEMB as well as
process piping and equipment. Frost protection is achieved by means of foundation insulation in accordance with
ASCE 32-01, Design and Construction of Frost-Protected Shallow Foundations. A perimeter underdrain will be
provided.
Town of Hudson 8-2 Woodard & Curran
2021.05.10 Preliminary Design Report May 20218.4 GEOTECHNICAL AND FOUNDATION CRITERIA A Geotechnical Engineering Report has been provided by Northeast Geotechnical, Inc. dated April 21, 2021, which provides more information of existing soil and groundwater conditions and can be found in Appendix D. The geotechnical report provides information regarding subsurface conditions, groundwater, excavations, and foundation design recommendations. Town of Hudson 8-2 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
9. PERMITTING
Woodard & Curran will prepare the following permit applications prior to the construction and activation of the new
PFAS treatment system:
Prepare and submit an application to the Massachusetts Historical Commission (MHC).
Prepare and submit a BRP WS 25 Application for Treatment Facility Modification to MassDEP for approval.
Prepare a DWSRF Pre-Bid Construction Contract Application Checklist and submit along with one copy of
the pre-bid construction contract (plans and specifications) to MassDEP for approval.
Prepare and submit a WPA Form 3: Notice of Intent for the Wetlands Protection Act to MassDEP for
approval.
Prepare and submit a Site Plan Application and Zoning Permit Application with the Hudson Planning and
Zoning Department.
Prepare and submit an Underground Injection Control (UIC) Permit to MassDEP for approval.
Town of Hudson 9-3 Woodard & Curran
2021.05.10 Preliminary Design Report May 2021APPENDIX A: PROJECT LOCUS MAP Town of Hudson 9-4 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
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es :APPENDIX B: LIST OF SPECIFICATIONS Town of Hudson 1 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
0232305.00 Chestnut Street PFAS Treatment System
Issue Date: May 2021 Town of Hudson, MA
SECTION 00 01 10
TABLE OF CONTENTS
SPECIFICATIONS
Division 00 – Bidding and Contracting Requirements
To be determined after review of Town procurement documents.
Division 01 – General Requirements
To be determined after review of Town procurement documents.
Division 03 – Concrete
03 11 00 Concrete Forming
03 16 00 Concrete Specialties
03 20 00 Concrete Reinforcing
03 30 00 Cast-In-Place Concrete
03 30 20 Concrete Placing, Curing, and Finishing
Division 05 – Metals
05 50 00 Metal Fabrications
Division 07 – Thermal and Moisture Protection
07 21 00 Thermal Insulation
07 60 00 Flashing and Sheet Metal
07 92 00 Joint Sealants
Division 08 – Openings
08 11 00 Metal Doors and Frames
08 33 23 Overhead Coiling Doors
08 71 00 Door Hardware
Division 09 – Finishes
09 90 00 Painting and Coating
Division 10 – Specialties
10 44 16 Fire Extinguishers
Division 13 – Special Construction
13 34 19 Metal Building Systems
Division 22 – Plumbing0232305.00 Chestnut Street PFAS Treatment System Issue Date: May 2021 Town of Hudson, MA 22 00 00 Plumbing Division 23 – HVAC 23 05 00 Common Work Results for HVAC 23 05 15 Mechanical Identification 23 05 93 Testing, Adjusting, and Balancing for HVAC 23 34 00 HVAC Fans 23 82 39 Unit Heaters 23 84 16 Portable Dehumidifiers 23 90 00 Louvers and Vents Division 26 – Electrical 26 05 00 Common Work Results for Electrical 26 05 19 Low-Voltage Electrical Power Conductors and Cables 26 05 23 Control-Voltage Electrical Power Cables 26 05 26 Grounding and Bonding for Electrical Systems 26 05 33 Raceways and Boxes for Electrical Systems 26 05 43 Underground Ducts and Raceways for Electrical Systems 26 22 00 Low-Voltage Dry-Type Transformers 26 24 16 Panelboards 26 27 26 Wiring Devices 26 28 16 Enclosed Switches and Circuit Breakers 26 29 13 Enclosed Controllers 26 32 13.13 Diesel-Engine-Driven Generator Sets 26 41 00 Facility Lightning Protection 26 43 00 Surge Protective Devices 26 51 00 Interior Lighting Division 27 – Communications 27 00 00 Communications Division 31 – Earthwork 31 00 00 Earthwork 31 10 00 Site Clearing Division 32 – Exterior Improvements 32 12 16 Asphalt Paving 32 16 13 Curbs and Gutters 32 92 19 Seeding Division 33 – Utilities 33 01 10.58 Disinfection Water Utility Piping Systems 33 14 11.01 Water Utility Piping – Ductile Iron 33 14 19 Valves and Hydrants for Water Utility Service
0232305.00 Chestnut Street PFAS Treatment System
Issue Date: May 2021 Town of Hudson, MA
33 49 00 Storm Drainage Structures
Division 40 – Process Integration
40 00 00 Basic Process Materials and Methods
40 05 13 Process Pipe and Fittings
40 05 15 Process Pipe Supports
40 05 23 Process Valves
40 61 01 Instrumentation & Controls General Requirements
40 63 43 Programmable Logic Controllers
40 67 00 Control System Equipment Panels and Racks
40 70 00 Instrumentation for Process Systems
Division 46 - Water and Wastewater Equipment
46 61 13.01 Granular Activated Carbon
46 61 35 Granular Activated Carbon Vessels
END OF SECTIONAPPENDIX C: EQUIPMENT SUMMARY Town of Hudson 2 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
0232305.00 Chestnut Street PFAS Treatment System
Issue Date: May 2021 Town of Hudson, MA
APPENDIX C
EQUIPMENT SUMMARY
The following is a list of major equipment to be installed as part of this project, and manufacturer’s cut sheets are
attached to this appendix.
Table B-1: Equipment for Chestnut Street PFAS Treatment System
Item Equipment
Location Quantity Manufacturer Model Number Design Criteria
No. Name
GAC PFAS
3 Trains TIGG Corp CP-40K-12 40,000-lb dual
1 Adsorption Treatment
(6 Vessels) or Equal or Equal vessel
System Facility
PFAS
2 Generator Treatment 1 Milton CAT TBD TBD
Facility4 3 2 1
N6
N3
VENT EL. 294"
OPTIONAL
M1
CARBON FILL EL. 2791 2"
90°
B N3 B
N1
N6
N4
N11
N10
N9
144"Ø
N8
80" 78" 180° M2 N1 N2 0° 107"
268" M1 N6
N7
N8
N4
N9 216"
N11 SAMPLE - 4 2" 150# FLANGE SIDE SHELL
N10
N10 SAMPLE - 3 2" 150# FLANGE SIDE SHELL
M2 N9 SAMPLE - 2 2" 150# FLANGE SIDE SHELL
N11 N8 SAMPLE - 1 2" 150# FLANGE SIDE SHELL
N2 11 4" N7 DRAIN 2" 150# FLANGE BOTTOM HEAD
128"
120" ANCHOR HOLE N6 VENT 3" 150# FLANGE TOP HEAD
110" 270° N5 CARBON OUT 4" 150# FLANGE BOTTOM HEAD
92" N4 CARBON OUT 4" 150# FLANGE SIDE SHELL
80" 107"
74" N3 CARBON IN 4" 150# FLANGE TOP HEAD
64"
N2 OUTLET 8" 150# FLANGE SIDE SHELL
PLAN N1 INLET 8" 150# FLANGE SIDE SHELL
M2 MANWAY 20" 150# FLANGE W/ BLIND SIDE SHELL
141 16" M1 MANWAY 14"x18" ELL. MANWAY TOP HEAD
N5 MARK SERVICE DESCRIPTION LOCATION
N7 NOZZLE SCHEDULE
REVISION HISTORY
ELEVATION REV
0
DESCRIPTION BY DATE
PROJECT
A VESSEL STANDARDS: A
VESSEL MATERIAL: SA-516-70
CK-40K-12
TIGG LLC.
• HEAD THICKNESS: 5/8" HEAD TYPE: 2:1 ELLIPTICAL
• SHELL THICKNESS: 5/8"
COATINGS:
• INTERIOR LINING: PLASITE 4110 – DFT 35-45(MAX) PROJ. NO. STANDARD
• EXTERIOR COAT: EPOXY BASE W/ URETHANE TOP PO. NO.
INTERNALS: THIS DRAWING AND DESIGN ARE THE PROPERTY OF TIGG LLC.
AND SHALL NOT BE REPRODUCED IN WHOLE OR IN PART.
• 304 STAINLESS STEEL NOR EMPLOYED FOR ANY PURPOSE OTHER THAN
VESSEL PROPERTIES: SPECIFICALLY PERMITTED IN WRITING BY TIGG LLC. THIS
DRAWING LOANED SUBJECT TO RETURN BY DEMAND.
• MAWP: 125 PSIG / -15 PSIG AT 150 f
• EMPTY SHIP WEIGHT: 25,500 LBS
DRAWN BY JB GENERAL ARRANGEMENT
DESIGN BY JB
• TOTAL VESSEL VOLUME: 1,866 FT³ CHECKED BY BB
DATE
SCALE
4/12/2017
NTS CP-40K-12-GA-001 0
4 3 2 1APPENDIX D: GEOTECHNICAL REPORT Town of Hudson 3 Woodard & Curran 2021.05.10 Preliminary Design Report May 2021
GEOTECHNICAL ENGINEERING REPORT
PROPOSED GAC FILTER BUILDING
72 CHESTNUT STREET
HUDSON, MA
Prepared For:
Woodard & Curran
40 Shattuck Road, Suite 110
Andover, MA 01810
Prepared By:
Northeast Geotechnical, Inc.
166 Raymond Hall Drive
North Attleborough, MA 02760
Project No. O425.00
April 21, 2021April 21, 2021 Project No. O425.00
Srivalli B. Sukuru, P.E.
Project Engineer | Associate Principal
Woodard & Curran
40 Shattuck Road, Suite 110
Andover, MA 01810
SUBJECT: Geotechnical Engineering Report
Proposed GAC Filter Building
72 Chestnut Street
Hudson, MA
Dear Valli:
Northeast Geotechnical, Inc. is pleased to present the results of our geotechnical engineering studies
performed in support of the proposed building project at the subject site. The purpose of our studies
has been to assess the subsurface soil and groundwater conditions in the area of the proposed building
and based on our findings, provide geotechnical engineering recommendations for use by the project
team in design and construction. Our studies have been performed in accordance with our proposal
dated February 2, 2021. This report is subject to the Limitations and Service Constraints included in
Appendix A.
We have prepared recommendations for use in planning and performing earthwork construction
activities to support the proposed building using standard spread footing foundations and a floor slab
on grade.
The attached report contains a summary of our studies and presents our findings, conclusions and
recommendations for use in design and construction of the proposed project. Please feel free to contact
Glenn A. Olson, P.E. at 508-274-0887 or at golson@northeastgeotechnical.com if you have any
questions or need anything further.
Sincerely,
Northeast Geotechnical, Inc.
Christian B. Rice, P.E. Glenn A. Olson, P.E.
Senior Project Engineer Principal EngineerTABLE OF CONTENTS
1.0 INTRODUCTION .................................................................................................................. 1
2.0 SUBSURFACE EXPLORATIONS......................................................................................... 1
3.0 LABORATORY TESTING..................................................................................................... 2
4.0 SUBSURFACE CONDITIONS .............................................................................................. 3
5.0 CONCLUSIONS AND RECOMMENDATIONS .................................................................. 3
5.1 Building Area Earthwork ............................................................................................... 3
5.2 Off-Site Fill Materials .................................................................................................... 5
5.3 Foundations .................................................................................................................... 6
5.4 Floor Slab ....................................................................................................................... 7
5.5 Seismic Design Criteria .................................................................................................. 7
6.0 CONSTRUCTION OBSERVATION, TESTING AND REVIEW ......................................... 7
FIGURE
1 Subsurface Exploration Location Plan
APPENDICES
A Limitations and Service Constraints
B Test Boring Logs
C Laboratory Soil Test Results
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