P R l BOSTON HARBOR O J ,y,< 0rwJo . UnlVer c Depos\torv W For over 100 years, it was the site of a working shipyard. Now Quincy's ship in the Maritime Prepositioning

Fore River Staging Area (FRSA) will play a major role in the cleanup of Boston Fleet. This was the heaviest lift ever Harbor. accomplished by any U.S. shipyard. The launching of the Sgt. William R. A proud tradition Button, in May 1986, marked the end of shipbuilding at the General Thomas Augustus Watson — who answered the world's first telephone call Dynamics shipyard. from Alexander Graham Bell in 1876 - founded the Fore River Engine Com- pany in 1884. From its humble beginnings at a small summer house in East A new beginning Braintree, the company became one of the world's great marine engineering and shipbuilding enterprises. In November 1987, the Massa- chusetts Water Resources Authority (MWRA) purchased the 180-acre shipyard in Quincv and Braintree from General Dvnamics for $49.5 million. Now called the Fore River

Staging Area, the site is being developed for a number of Boston Harbor Project uses - construction staging, laydown and warehousing and as a base for a water transporta- tion system for trucks and cargo. Most materials and equipment for the Boston Harbor Project are being transported from the piers at FRSA to Deer Island via water, avoiding trucking over the narrow, thickly settled streets of Winthrop and East Boston. A sludge processing plant, occupying approximately five acres

For decades, the men and synonymous with quality in the of land, is also being built on the site.

women of the Quincy shipbuilding maritime industry. The facility — which will turn sludge operation turned out some of the General Dynamics Corporation into fertilizer pellets - will end the finest vessels in the U.S. Navy fleet, of St. Louis bought the shipyard discharge of sludge into Boston along with tankers and other large from Bethlehem Steel in 1964. In the Harbor by the end of 1991. Modifica- ships for private industry. At the 1960s and 1970s, the yard added tions, scheduled to begin in 1995, height of World War II, some 16,000 nuclear powered surface vessels and will convert the facility to a perma- men and women worked at the large liquified natural gas carriers to nent sludge processing plant. The

Quincy shipyard. Over 350 vessels its line of ships. work is expected to be completed by of all classes and types were built On August 18, 1984, the Goliath 1996. there, including the aircraft carriers crane - the largest of its kind in the The MWRA plans to use the Wasp and Lexington, the battleship western hemisphere and a landmark railroad tracks leading to the ship-

Massachusetts and the first nuclear on Boston's South Shore — lived up yard site to transport about 11 powered cruiser, Jie USS Long Beach. to its name by lifting a complete carloads weeklv of fertilizer pellets -- The term "Quincy Built" became 1,120 ton deckhouse into place on a about 50 tons per dav -- to markets.

Charleston n Naw Yard 1 00 First Avenue Boston. MA 02 1 29 (617)242-6000 The Fore River Railroad connects with Conrail tracks 2.7 miles away in Sludge processing East Braintree. The rail is now used solely by Procter & Gamble. As part of the Boston Harbor Project, the MWRA has adopted a long- A 70-acre section of the site has term plan for dealing with sludge, the residual or byproduct of the sewage been earmarked for use by the treatment process. A $67 million pelletizing facility, expected t< be com- Massachusetts Shipbuilders Inc. The pleted in December 1991, is under construction at the Fore Rivt taging Authority negotiated an agreement Area. The plant will permit the MWRA to convert sludge in ro rilizer. with the worker-owned corporation currently processes 450 million gallons of a day, in 1988 in an effort to return ship- The MWRA wastewater building and repair to Quincy. which results in nearly 50 tons of sludge. The sludge, made up largely of

human waste and other organic solids, is discharged daily into Boston

Construction begins Harbor. Beginning in December 1991, the Authority will ship the sludge by

The piers at the Fore River barge to the FRSA for processing at the sludge plant. Once there, the sludge Staging Area have been rehabilitated will be mechanically treated to remove excess water and to form sludge to allow the site to be used as a cargo cake. The sludge cake will then be heated in large dryers that will remove terminal for the Boston Harbor moisture and convert the sludge into small, hard pellets. At the end of the Project. Cashman, Inc. of Quincy J.M. process, the sludge will have been reduced from 97 percent to less than 5 began constructing shipvard marine percent water. It can then be easilv transported and applied as a soil condi- facilities in June 1989 and concluded tioner and fertilizer. the work in April 1990. The $6.7 The expansion and modification of the Fore River plant will be com- million project included the rehabili- pleted in 1996 to meet long-term sludge processing requirements. By the tation and upgrading of existing piers and the construction of a new roll- end of the decade, sludge will conveyed by pipeline from Deer Island to on/ roll-off ramp. The piers allow Quincy. The Fore River pelletizing facilities will end decades of dumping construction materials and vehicles, sludge into the harbor. which will be shipped to or stored at the Fore River site, to be carried by barges to Deer Island.

The MWRA is also demolishing

II buildings at the Fore River site to clear the area for truck queuing, construction staging and laydown purposes. Other buildings will be rehabilitated for warehouse use and to provide office space for Boston

Harbor Project staff. In October 1989, Boston Towing and Transportation Co., Inc. was awarded a $29.8 million contract to provide water transportation for heavy equipment, construction vehicles and materials. In June 1990, the company began the service, which will continue until the mid- 1990s. The Authority may extend Boston Towing and Transportation's contract until the end of the century The sludge processing plant under construction at the Fore River Staging Area in Quincy. (Photo by Kevin Kirwin) when the new plant is completed and ready to begin full operations.

at cents per copy. . jxiper 7 A publication of the Massachu set ts W ater Resources Authority Printed .on recycled t Nut Island Spring 1991

BOSTON HARBOR PROJEC

Opened in 1952, the Nut Island wastewater treatment plant was de- tween the existing plant's sedimenta-

signed to provide primary treatment to 112 million gallons of sewage daily. It tion tanks and mam pumping

currently processes a daily average of 144 million gallons of sewage from 22 building, where it will not interrupt communities in the southern part of the Massachusetts Water Resources plant operations. Authority's collection system. The plant's operations include screening, grit removal, pre-aeration, primary sedimentation and disinfection. About 100,000 Pier gallons (23 dry tons) of sludge from the plant are run through digesters and In 1990, the Authority completed released into Boston Harbor daily on the outgoing tides. Effluent, or treated the construction of a pier located at wastewater, is chlorinated and discharged less than a mile from Nut Island's the tip of Nut Island. The new pier, shores. which extends 370 feet from shore

and measures 80 feet across at its

widest point, is being used to trans- port bulk construction materials and demolition debris during the con- struction of the headworks. By using the pier instead of the narrow streets of Hough's Neck, an adjoining residential area, the MWRA will lessen the burden of construction on Nut Island's neighbors. By the end of 1991, when sludge

is no longer discharged into the harbor, the pier will also be used to remove digested sludge from the island by barge. Once construction begins on the new headworks in 1992, a temporary concrete batch plant will be located on the pier. Raw materials from

From 1910 to 1952, Nut Island Once new wastewater treatment docked barges will be mixed on site (actually a peninsula connected to facilities are completed on Deer to produce concrete. Hough's Neck in Quincy) was used Island as part of the MWRA's Boston Sciaba Construction Corporation as a screen house to remove rags, Harbor Project, the Nut Island plant of Readville, Massachusetts, built the sand, gravel and tree branches from will be demolished and replaced $5.6 million pier. sewage before it was pumped into with a headworks that will remove the harbor. Before that, the island large objects, gravel and sand from Inter-island tunnel was used as a government firing wastewater bound for the new In 1991, work will begin on a range and as a marine salvage yard. primary and secondary treatment tunnel to convey the flow presently An abandoned cannon, a relic from plant on Deer Island. treated at the Nut Island plant to the days when Nut Island served as The existing Nut Island waste- improved wastewater treatment part of the country's defense system, water treatment plant must continue facilities on Deer Island. The tunnel, stands as a monument near the to treat sewage and digest sludge measuring five miles long and 1 1 feet present plant. In colonial times until the flow can be diverted to in diameter, will be bored 300 feet cattle grazed on the island and were Deer Island via the new tunnel. For below sea level through bedrock. driven back to the mainland over a this reason, the new headworks is The new tunnel will have the capa- sandbar at low tide. being built in the tight space be-

Charlestown Naw Yard 100 First Avenue Boston. MA 02129 (617) 242-6000

s s M a a c h u s c t tV. W a I c r Rcsou r c e s A u I liiLr i t y citv to transport up to 360 million gallons of wastewater daily to Deer Island. The new headworks at Nut Island will be connected to the completed tunnel by a 16-foot shaft expected to take eight months to complete. The tunnel and headworks will be completed and operational bv 1995. Headworks

The new headworks will screen the largest and bulkiest items from the waste stream, allowing the heaviest items to settle out in grit chambers. The process will be Artist's rendering of Nut Island headworks and visitors' center designed by enclosed and operational noise will the Cambridge architectural firm, Havens & Emerson, Inc. be properly controlled. Construction of the new facility is expected to Park and visitors' new pier, will be created after the begin in 1992. The approximately 30- center new headworks has been completed foot high building will include truck and the old primary plant has been loading bays and areas for adminis- Plans for Nut Island include demolished. trative operations and maintenance. areas for passive recreation and a New landforms to be created on The building is being designed to visitors' center, as well as for waste- the island will be up to 20 feet higher harmonize with the architecture on water treatment operations. A har- than the island's present profile to nearby harbor islands. borfront park, which will include the visually screen the headworks from Hough's Neck, from points across Quincy Bay and from the pedestrian

path to be built around the island. Trees and shrubs will replace con- crete and asphalt surfaces, giving the island a more natural appearance. The pedestrian path will afford spectacular views of Boston Harbor and Hingham Bay and provide con- venient access to most of the island, including the beach on the eastern shore. The new headworks building will contain a visitors' center featur- ing displays and information about the history of Nut Island. The center, which will also be used as a meeting place for the neighboring community of Hough's Neck, will offer panoramic views of the bay

and the Boston skyline from its The MWRA's existing primary treatment plant at Nut Island in Quincy. balcony. The plant was opened in 1952. The pier was completed in 1990.

( Photo by Karen-fayne Dodge)

A publication of the/^lassachusetts Water Resources Authority. Printed on recycled paper at 7 cents per copy. Project Summary Spring 1991

BOSTON HARBOR PROJECT

The Massachusetts Water Resources Authority is building a new primary David Mazzone, who found that and secondary wastewater treatment plant and related facilities to control the wastewater discharges to Boston pollution of Boston Harbor, often called the dirtiest port in the United States. Harbor violated the Federal Clean

The Boston Harbor Project is an 11 -year, $6.1 billion effort to make the harbor Water Act. Judge Mazzone ordered suitable for swimming, fishing and other recreational and commercial uses. the construction of new primary and secondary facilities and issued a long- term timetable for the cleanup of the Chaiiestown Site harbor. That order was the culmina- tion of a series of legal actions that began in December 1982, when the City of Quincy filed suit in Massachu- Rowes Wharf setts Superior Court, charging that wastewater discharges to the harbor violated state law.

What it will cost

Most of the S6.1 billion cleanup Fore River Staging Area* will be paid for by homeowners, businesses and institutions in the 43 Current state of the communities that receive sewer ser- harbor with a capacity to treat more than one vices from the MWRA. It is estimated billion gallons per day, will replace that annual water and sewer bills for Forty-three cities and towns in two antiquated and overburdened the average Boston homeowner, now metropolitan Boston now send their primary sewage treatment plants on about $410 per household, will rise to wastewater to the MWRA's two Boston's Deer Island, off Winthrop, more than $1,000 by the year 2000. outdated primary sewage treatment and Nut Island in Quincy. The new The project will be funded primarilv plants, which together discharge primary plant will be completed by by bonds, which will make the nearly 450 million gallons of poorly 1995 and the new secondary plant by MWRA one of the largest issuers of treated wastewater to the harbor each 1999. revenue bonds in the nation during day. In addition, 50 tons of sludge are In addition to the new wastewater the 1990s. discharged to the harbor daily on the treatment plant, the project also outgoing tide. These discharges, plus includes a new headworks to replace The new plant the 10 billion gallons of untreated the existing primary plant at Nut The centerpiece of the Boston wastewater that flow into the harbor Island, a five-mile hard rock tunnel Harbor Project is a new primarv and from combined sewer overflows each between Nut Island and Deer Island, a secondary treatment plant on Deer year, have made Boston Harbor nine and one-half mile effluent outfall Island. The new plant, with a capacity- among the most polluted bodies of tunnel from Deer Island to the sea and of 1.27 billion gallons per dav (bgd) water in the nation. other facilities. Construction on the for primarv treatment and 1.08 bgd for project began in 1988 and will be secondarv treatment, will replace the The cleanup completed by 1999. Deer Island plant, built in 1968, and The Boston Harbor cleanup is the The court order the Nut Island plant, built in 1952. largest wastewater treatment project Those plants, aging and frequently m the countrv and one of the biggest The Boston Harbor Project is being unable to handle wet weather flows, public works projects ever undertaken carried out under a 1986 federal court provide onlv minimal treatment to in New England. The new facilities, order by U.S. District Court Judge A. wastewater before discharging it less

Charleston n Navv Yard 100 First Avenue Boston. MA 02129 (617) 242-6000 than a mile from shore in the shallow for Deer Island. Beginning in 1995, harbor to cleanse and restore itself.

waters of the harbor. wastewater from the Authority's When the cleanup is completed in

The new plant will provide state- southern collection system that is now the year 2000, the people of Massa- of-the-art primary treatment, which treated by the Nut Island plant will be chusetts will once again enjoy a will remove 60 percent of the solids conveyed to the new Deer Island plant superb recreational and commercial and up to 40 percent of the toxins in through a five-mile tunnel from Nut resource. wastewater and reduce biochemical Island, under Boston Harbor, to Deer oxygen demand (BOD) by 35 percent. Island. Wastewater entering the Nut Secondary treatment will further Island headworks will pass through purify the wastewater removing 90 screens and grit chamDers that will Project timetable percent of solids and 50 to 85 percent remove large objects, sand and gravel 1989 - Deer Island pier and of toxins and reducing BOD by 90 from the waste stream before sending staging area completed; discharge percent. BOD measures the amount it to Deer Island for treatment. of floating pollution from Nut of oxygen used in a body of water by Construction on the Nut Island Island into Boston Harbor elimi- decomposing organic materials. This headworks is scheduled to begin in nated; Deer Island plant repairs and is a major form of pollution since 1992 and be completed by 1996. Nut Island plant improvements oxygen is needed in the water to Following the completion of the completed; construction begins on support marine life. headworks, the existing Nut Island plant to make sludge into fertilizer; Effluent from the plant will be primary plant will be demolished. residuals facilities plan completed. discharged to the ocean via the nine 1990 - On-shore piers and staging and one-half mile effluent outfall Water transportation areas completed; water transporta- tunnel and released through 55 dif- Deer Island is actually a peninsula tion system launched; planning fusers to ensure its thorough mixing connected to the town of Winthrop by completed on facilities to capture with seawater. Construction on the a thin strip of land. In order to and treat combined sewer over- effluent outfall tunnel began in 1990. transport construction materials and flows; construction begins on It is scheduled to be completed and workers more efficiently, as well as to effluent outfall tunnel and the first in operation by 1995. mitigate the impacts of construction half of the new primary plant. The sludge removed from the on the neighboring community, the 1991 - Sludge processing facilities wastewater will be thickened to MWRA has devised a system to move completed and operation begins, reduce its volume and then stabilized all construction materials and half the ending discharge of sludge to in sludge digesters for 20 days or construction workforce by water. Boston Harbor. Construction more to reduce its volume further and Piers have been completed at Deer begins on tunnel from Nut Island to to remove odor and disease-causing Island, Nut Island and the Fore River Deer Island. organisms. The sludge will then be Staging Area to allow the transport of 1993 - Construction begins on first shipped to the Authority-owned Fore personnel, equipment and materials quarter of secondary treatment and River Staging Area (former General by ferry and barge. The Authority is second half of primary treatment Dynamics Shipyard) in Quincy, using a portion of the 180-acre Fore plant. where it will be converted to fertilizer River Staging Area as a staging and 1994 - Tunnel between Nut Island pellets through a heat drying process. laydown area for the construction sites and Deer Island completed. Construction on the new primary at Deer Island and Nut Island. At least 1995 - Primary plant and outfall plant began in December 1990. The half of the 2,400 construction workers tunnel completed; full primary court schedule calls for the entire needed for the Boston Harbor Project operations begin; construction of primary plant to be completed and will travel to Deer Island from piers at remainder of secondary plant operational by 1995. Construction on Squantum Point in Quincy, Rowes begins; expansion and modification the secondary plant is to begin in 1993 Wharf in downtown Boston, and the of sludge facilities begins. and is scheduled to be completed and former Revere Sugar refinery in 1996 - First quarter of secondary operational by 1999. Charlestown. The remainder will be plant completed; partial secondary bused from the former Suffolk Downs treatment begins; expanded sludge Nut Island headworks race track in East Boston. facilitv begins operation. The existing primary treatment 1999 - Remainder of secondary plant at Nut Island will be replaced Summary plant completed; full secondary bv a headworks facility for prelimi- operation begins. The Boston Harbor Project will narv treatment of wastewater bound end centuries of abuse and allow the

A publication of the Massac husetts Water Resources Authority. Printed on recycled paper at 7 ce nts per copy-. Treatment Technologies Spring 1991

T BOSTON HARBOR PR O J E C

Wastewater treatment is a process for cleansing the water that enters a During the sedimentation pro- sewage treatment plant from homes, businesses, schools and industries. Once cess, floatable substances, such as

the wastewater is treated, it can be safely returned to the environment. grease and oil, rise to the surface and are removed by a surface Primary Treatment Secondary Treatment skimming system. The skimmed Emissions Control materials, called scum, are sent to sludge digesters for treatment along with the primary sludge, or they are stabilized by other means pnor to

disposal. Primary treatment re- moves about 60 percent of the solids and up to 40 percent of the toxins in wastewater, and reduces biochemi- cal oxygen demand (BOD) by 35 percent. BOD measures the amount of oxygen used in a body of water by decomposing organic materials.

This is a major form of pollution

since oxygen is needed in the water

to support marine life.

Barged or Piped lo FRSA tor Further Processing Secondary treatment

The wastewater that flows out Wastewater treatment usually inorganic materials such as sand and of the pnmarv basins still contains takes place in two major steps: gravel to settle to the bottom, but to some suspended solids and other primary treatment and secondary keep the organic solids in suspen- materials that are dissolved in the treatment. Primary treatment is sion. The materials removed during water. While primary treatment preceded by preliminary treatment, preliminary treatment, called grit relies on physical methods, secon- and secondary treatment is followed and screenings, are usually buried in dary treatment is a biological by effluent disinfection. a landfill. process. It creates a highly con- Preliminary treatment Primary treatment trolled artificial environment in which microscopic organisms that Wastewater conveyed to the After the wastewater receives are naturally present in the waste- treatment plant carries a wide range preliminary treatment, it enters water are encouraged to use dis- of debris in addition to smaller settling basins called primary sedi- solved pollutants as food, thus wastewater pollutants. Preliminary mentation tanks or clarifiers. Sedi- converting the dissolved solids into treatment protects plant equipment mentation tanks hold wastewater for suspended solids that will physi- from the debris. one or two hours. During that time, cally settle out at the end of secon- When wastewater enters the most of the heavier suspended solids dary treatment. plant, it passes first through a series settle to the bottom of the tanks. Secondary treatment promotes of bar racks or screens that remove There, plough-like scrapers move the the growth of millions of microor- large floating objects such as rags, solids to a sump or hopper where ganisms that work together to wood and plastics. they are sucked out of the bottom of consume wastes present in the From the screens, the waste- the tanks. These solids are called water. To succeed, the process must water travels to grit chambers, primary sludge, or residuals, and are control the temperature, oxygen which are designed to slow the flow usually pumped to sludge digesters level and contact time to allow rapid of water enough to allow the heavier for further treatment. and complete consumption of the

Charlestown Navv Yard 100 First Avenue Boston. MA 0212° (ol7) 242-6000 dissolved wastes. Secondary maintained constantly in this L and thus the volume of primary and treatment removes about 90 percent cal process, a portion of the slu^ secondary sludge. Then, the sludge

of solids and 50 to 85 percent of that contains a high concentratio is usually stabilized in sludge toxins, and reduces biochemical microorganisms (return activated digesters for 20 days or more to

oxygen demand by 90 percent. sludge) is recycled to the aeration remove odor and disease-causing

In its new secondary treatment tanks to perpetu a te the feeding organisms. Next, the sludge is

plant planned for Deer Island, the process. The r fining material, dewatered to remove most of its

MWRA will use the biological called second I waste activated) liquid through processes consisting

process that combines wastewater sludge or resu .als, is usually of filters or various kinds of presses

and microorganisms in large tanks pumped to a sludge digestion system to further reduce its volume. The with constant aeration (oxygen as the first stage of further sludge final residuals processing stage takes input) and mixing. When the treatment. the dewatered sludge, called cake,

wastewater enters the aeration and prepares it for disposal.

tanks, oxygen is added to encourage Disinfection The MWRA plans to convert the rapid growth of helpful microor- digested primary and secondary At the end of the treatment ganisms that consume the harmful sludge into heat-dried pellets for use process, the wastewater is disinfected organic matter in the wastewater as fertilizer. with sodium hypochlorite or some (measured as biochemical oxygen The process of heat drying uses other means to remove any disease demand). After about two hours, large tank-like dryers to remove causing organisms. The disinfected the mixture of wastewater and moisture from the sludge through wastewater or effluent can then be microorganisms flows to secondary evaporation. The resulting dried discharged to the ocean. clarifiers or sedimentation tanks sludge is formed into pellets and similar to those used during primary Sludge (residuals) sold as a soil conditioner. Heat treatment. Here the microorganisms treatment dried pellets can be used on golf and other suspended matter settle to courses, sod farms, for horticultural the bottom. Since a high concentra- Sludge thickening systems use and on forest land as a partial water content of sewage tion of microorganisms must be reduce the substitute for commercial fertilizers. Summary Pilot plants The purpose of treatment is to

For six months in 1989, a trailer-mounted pilot plant processed waste- convert wastewater into relatively water to assist the MWRA in determining design criteria for the treatment clean, clear, disinfected effluent technologies to be used at the new secondary plant scheduled to be suitable for discharge into the ocean completed in 1999. Designed to simulate the processes of the full-scale or other bodies of water.

secondary treatment facility, the pilot plant enabled the Authority to test key Discharges must meet the components on a scale that was small but efficient. requirements of the National Pollut- Each day approximately 10,000 gallons of primary effluent from the ant Discharge Elimination System, a settling tanks of the existing Deer Island facility were pumped to the pilot permit process established under the

plant. There, the anaerobic selector, a relatively new and innovative Federal Clean Water Act of 1972, approach to wastewater technology, was tested to review important design which mandates secondary treat-

data and its impact on performance, including removal rates of suspended ment. Once the effluent complies solids, bio-chemical oxygen demand, effluent quality, solids settling and with these requirements, it does not residuals constituents. Numerous variations of the treatment method were pose any threat to the ocean.

tested in order to determine the most cost-efficient and environmentally Years of planning, research and

sound design for the full-scale facility. Final design calls for the capability to testing have been conducted and use both aerobic and anaerobic (oxygen enriched and oxygen deprived) other studies will be completed selectors to allow as much flexibility as possible at the new plant. before all treatment technologies are In 1993, a permanent pilot plant, capable of processing two million gal- finalized and integrated into the lons of wastewater daily, will begin operating on Deer Island. Initially the MWRA's new Deer Island facilities. plant will be used for additional testing of the selectors and to study the The new primary and secondary

stacked clarifiers that are planned for the new treatment facility. Following treatment facilities will serve nearly completion of the secondary treatment plant, the permanent pilot plant will two million people in 43 communi-

be used to monitor the full-scale facility's modes of operation and as a tool to ties and process an average of over

train plant operators. 480 million gallons of sewage daily.

publication of the Massachusetts Water Resources Authoritv JPnnted on recycled pager at 7 cen ts pt?r copy. A : Tunnels Spring 1991

BOSTON HARBOR PROJECT

As part of the Boston Harbor Project, the Massachusetts Water Resources The entire length will be exca-

Authority (MWRA) is building two undersea tunnels to convey wastewater to vated first, then it will be lined wit and from the Authority's new wastewater treatment plant on Deer Island in concrete in a separate operation.

Boston Harbor. One tunnel, nearly five miles long, will transport sewage from The finished liner, which will be ce Nut Island in Quincy to Deer Island. The second tunnel, nine and one-half within the tunnel and sealed with contact grouting, will have an 11- foot, six-inch inside diameter. Sverdrup Corporation of Bostc

designed the inter-island tunnel. L March 1991, the MWRA awarded $73 million contract for the constru tion of the tunnel to the joint ventu of the S.A. Healy Co. of McCook, Illinois and the Modern Continents

Construction Co., Inc. of Cambridg ;e. The tunnel will be completed by December 1994.

Effluent outfall tunnel and diffusers

The effluent outfall tunnel,

which will be one of the largest of its kind in the world, will discharge treated wastewater from the new

Deer Island plant to a site nine and one-half miles out into Massachu- miles long, will carry treated waste- MWRA will build a 4.8 mile tunnel setts Bay. Currently, the discharge, water from the new Deer Island to carry the south system flow from or effluent, from the Deer Island plant to the deep waters of Massa- the headworks at Nut Island (where treatment plant receives only pri-

chusetts Bay. large objects, gravel and sand will be mary treatment before it is released a removed from the wastewater) to half-mile from shore in about 20 feet Inter-island tunnel the new Deer Island plant. of water. The discharged wastewa-

The cross-harbor tunnel will be ter from the new outfall will meet all The 22 communities in the excavated from Deer Island with a state and federal water quality MWRA's southern sewer system tunnel boring machine. A vertical standards. currently send their wastewater to shaft, between 11 and 16 feet in Construction will begin with an antiquated primary treatment the diameter, will be sunk about 300 feet sinking of a vertical shaft from Deer plant on Nut Island, off Hough's below the surface of Deer Island into Island to a point about 440 feet be- Neck in Quincy. From there, the bedrock. The tunnel boring machine low the surface using conventional treated wastewater is discharged to will excavate the tunnel on an drill-and-blast methods. Then, a the shallow waters of Quincy Bay. upward slope 25,100 feet to Nut tunnel boring machine will bore a The new Deer Island plant will Island. A second, 16-foot diameter 26-foot diameter opening from the provide primary and secondary shaft will be excavated on Nut base of the shaft, out in a northeast treatment to wastewater from all 43 Island to make the connections to the direction beneath the ocean floor communities that receive sewer new headworks facility. into Massachusetts Bay. Before the service from the MWRA. The

Charlestown Navy Yard 1(H) First Avenue Boston. MA 02 1 29 (617) 242-6000

1 ilflii S U f* h ii v <» t 1 £ W.-ii t et JL- H v ii ii n t» v. A u I ka r i 1 v i B tunnel boring machine reaches the The effluent outfall tunnel was last one and one-quarter miles of the designed bv a team led by Parsons At a glance tunnel, 55 riser pipes will have been Brinckerhoff Quade & Douglas, Inc. installed through the sea floor into of New York City. A $202 million Inter-island tunnel the bedrock. The pipes will be construction contract went to the Purpose -To temporarily capped to allow for a joint venture of the Kiewit Construc- convev wastewater generated bv 22 South Shore commu- later "dry tap" connection to the tion Co. of Omaha, the Guv F. the tunnel. Diffuser caps on the pipes Atkinson Construction Co. of San nities from Nut Island headworks to the wastewater treatment will allow thorough mixing of the Francisco and the Kennv Construc- new plant at Deer Island. treated wastewater with sea water. tion Co. of Wheeling, Illinois. The

The location of the outfall and joint venture of J.M. Cashman, Inc. Length, size and cost - Approxi- diffusers was chosen after years of of Quincy and Interbeton Inc. of mately five miles, with a finished scientific investigation and signifi- Williamsburg, Virginia, was inside diameter of 11 feet, six inches. cant public input. The outfall site awarded a $77 million contract to The tunnel will cost $73 million. takes advantage of ocean currents construct the diffuser system. The Construction Method - A vertical and circulation patterns so that the tunnel and diffusers will be com- shaft, between 11 and 16 feet in discharge will not affect beaches, pleted by April 1995. diameter, will be sunk on Deer fishing areas and other resources. Island. From the base of the shaft, a TBM will excavate the tunnel on an Tunnel technology upward slope to Nut Island. A second shaft will be excavated on Nut Thousands of details must be considered in planning and constructing a Island to make the connections to the tunnel: the size, length and location or alignment; the personal safety of the southern wastewater system. workers; the environmental soundness of the design elements; the construc- tion schedule; risk management; and the movement of workers and materials Effluent outfall tunnel to and from the construction site. Each element requires careful attention to diffusers and integration with other elements of a runnel project. and the Boston Harbor Project, excavation will proceed around-the-clock, On Purpose -To discharge treated five days a week, reserving two days for maintenance. Tunnel construction effluent from the MWRA's new is done by miners, operating engineers and electricians. Many of MWRA's primary and secondary wastewater tunnel workers will commute to work via ferries leaving from sites around treatment plant on Deer Island to the Boston Harbor. deep waters of Massachusetts Bay. Tunnel design takes three principal elements into account: geology — the Length, size and cost - Nine and one- tvpe of rock in the path of the tunnel; water and its flow; and the amount and half miles long, with a finished inside tvpe of support needed. diameter of 24 feet, three inches. The The MWRA conducted extensive borings to gather information about the tunnel itself will cost $202 million and tvpe of rock and soil in the vicinity of the tunnel prior to selecting the align- the diffusers $77 million. ment and grade of the boring. The type of rock found will affect everything from the design of the tunnel boring machine to the rate of drilling progress. Special Features - A diffuser struc- riser shafts measuring 30 Water is a chronic presence in tunneling. Tunnels are drilled uphill so ture with 55 that water runs from the excavated surface to the lowest end of the tunnel inches in diameter will be drilled the sea bottom and con- where it can be removed with large sump pumps. Water also makes the through working environment very humid, and combines with the heat of the drilling nected to the final 6,600 feet of the equipment to raise ambient temperatures well above the rock's normal 55 bored tunnel.

degrees. Construction Method - The tunnel The tvpe of support needed in the tunnel and shafts depends on the will be constructed from a 30-foot characteristics of the rock, its strength, the number of joints and the orienta- diameter vertical drop shaft on Deer tion of bedding. Sometimes unsupported rock can stand alone. Steel ring Island. A tunnel boring machine will beams can be used for support where needed. Rock bolts can also be inserted be assembled in a chamber at the base into the tunnel walls to tie loose rock formations together. of the shaft. The machine will exca- Once there is sufficient space, workers will follow behind the TBM vate the tunnel slightly uphill from

excavation and line the tunnel with concrete. The Boston Harbor Project the initial depth of 440 feet to a tunnels will be bored and lined at the rate of approximately 100 feet per day finished depth ot 240 feet below the as the excavation advances beneath the Bay. seabed.

A publication of the Massachusetts Water Resources Authority. Printed on recycled paper at 7 cents per copy. Water Transportation Spring 1991

BOSTON HARBOR PROJECT

The Massachusetts Water Resources Authority is using ferries, buses, The piers at Deer Island and the barges and tugboats to move workers, equipment and material for the Boston Fore River Staging Area are equipped Harbor Project. The water transportation system has been developed to avoid with ramps that allow trucks to be car and truck traffic on the narrow and winding streets of Winthrop and East driven or rolled on and off the barges. Boston during the construction of the new primary and secondary treatment plant on Deer Island. Personnel ferries

During the peak years of construc- tion on the Boston Harbor Project, half the work force, or 1,200 workers per day, will travel to Deer Island by ferry.

Leaving each of the three sites at about 6:30 each morning, the ferries operate year-round, with heated, enclosed passenger seating areas. The ferries are equipped with marine radios and

radar and meet all Coast Guard

requirements. Because the harbor is sheltered by the outer islands, the trip

is a smooth one most of the time. The ferry terminals were chosen to permit different kinds of access. The Charlestown and Quincy sites provide ample parking for workers who drive,

while Rowes Wharf is convenient for workers who use public transporta-

tion. Workers are assigned to specific

sites to ensure that the system works

efficiently. The development of a system of in Boston. The former Revere Sugar The Authority has contracted with water and bus transportation is one of refinery on the Mystic River in the Boston-based joint venture of the conditions of the federal court Charlestown will be used starting in Modem Continental Construction Co., order that guides the Boston Harbor 1992. Construction equipment and Inc., Alternate Concepts, Inc. and Project. Water transportation was also vehicles, such as trailers and trucks, Harbor Cruises, Inc. to provide the a mandatory mitigation measure are being shipped to the Deer Island ferry service for five and one-half required by the U.S. Environmental construction site from the Fore River years of the project. The cost of the

Protection Agency, and the Authority's Staging Area in Quincy. service is $24.9 million. commitment to a water-based system of transportation was instrumental in New piers Materials transportation winning the necessary state and The first step in developing the Limited space at the island federal permits for the project. water transportation system was the construction sites required the devel- The Authority's water transporta- construction of piers at Deer Island, opment of off-site storage areas for tion system currently carries construc- Nut Island and the Fore River Staging construction materials and vehicles. tion workers to Deer Island from two Area (formerly the General Dynamics The water transportation system locations around the harbor — Squan- Shipyard) and Squantum Point in connects Deer Island and Nut Island tum Point in Quincy and Rowes Wharf Quincy. with the Fore River Staging Area,

Charlestown Navy Yard 100 First Avenue Boston. MA 02 1 29 (617) 242-6000

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where 54 acres have been set aside Each of the two barges c: The Authority has contracted with tor storage and laydown purposes. accommodate up to 24 tractor Boston Towing and Transportation Vehicles, equipment and materials trailers per trip. The barge operator Co., Inc. for the transport of vehicles, are transported to the construction supplies yard tractors and drivers to equipment and materials. The cost sites on barges that berth at new load and unload vehicles. During for five and one-half years of the

Deer Island and Fore River roll-on/ peak constructior e barges will barge service is $29.8 million. roll-off piers. rr e at least tv and-trips daily.

The Laura, a 348-passenger ferry, carries Boston Harbor Project construction workers to Deer Island from Squantum Point in Quincy each day. Beginning in 1992, a similar ferry will carry workers from the former Revere Sugar refinery in Charlestown. During

the peak years of construction or. the project, ferries will operate five to six days a week, up to 24 hours a day and transport approximately 1,200 workers daily to the construc- tion site. The Laura travels the I distance between Squantum Point and Deer Island in approximately 20 minutes.

(Photos by Karen-fayne Dodge)

Trucks and other construction vehicles travel on barges to Deer Island from a cargo terminal at the Fore River Staging Area (the former General Dynamics Ship- yard) in Quincy. Piers at both locations are equipped with ramps that allow trucks loaded with materials to be driven or rolled on and off the barges. The stern of each barge is designed to fit the bow of a tugboat. The tug pushes the barge between FRSA and Deer Island. Each one-way trip takes about three hours, including loading and unloading.