The Town of Marshfield started construction of its sewer system in 1939, when sewers were constructed in a small portion of the beach area of Brant Rock. At that time, approximately 3,400 linear feet of gravity sewers were installed. The sewer terminated at an ocean outfall extending into Massachusetts Bay from Brant Rock.
In 1960, a wastewater treatment plant was constructed to provide settling and disinfection of wastewater collected from the beach area. The sludge collected from the original treatment plant was spread on sludge drying beds which occasionally became flooded during extreme tidal conditions.
In 1974, the Engineering firm of Coffin and Richardson conducted a study of the Town's wastewater needs. Their report, entitled "Comprehensive Wastewater Report for the Town of Marshfield, MA ", set the stage for construction of a new wastewater treatment plant, which would provide a secondary level of treatment; and the expansion of the sewer system, which includes the present service area and those areas associated with the Route 139 sewer system expansion.
In 1978, a new plant was built that had the capacity of treating 2.1 million gallons of wastewater per day. Since, the new plant utilized mechanical dewatering; there was a reduction in the volume of sludge produced. The drying beds were abandoned and the dewatered sludge was disposed of at the Towns’ MSW landfill.
On December 16, 1987, the Commonwealth of Massachusetts through the Department of Environmental Quality Engineering (now known as the Department of Environmental Protection), issued the Town an Administrative Order concerning septage and grease disposal practices. At that time, the Town allowed septage haulers to dispose of septage and grease in two lagoons at the MSW landfill. Periodically, one of the lagoons would be taken out of service and allowed to dry. The solids would then be removed from the lagoon and disposed of with the MSW. The Order required the Town to take the necessary steps to eliminate these violations and comply with the applicable laws and regulations.
As a result of this Order, the Town constructed new septage and grease handling facilities at the WWTF. The septage facility went on line July 8, 1991. Because of operational problems, however, the new grease facility did not begin operation till several years later. The plant is designed to receive an average of 15,000 gallons of septage per day and 15,000 gallons of grease per week. This project also provided a grit chamber at the WWTF and a sewer Vactor/jet rodding vehicle to remove grit at the WWTF and clear blockages within the sewer system.
The end of the 20th century also brought an end to the Towns ability to dispose of its WWTF residuals at the Towns municipal solid waste (MSW) landfill which was being closed and ultimately converted to a transfer station. As a result the Town was faced with the task of identifying the most cost effective means to dispose of its sludge and other byproducts which, till this point, were disposed of in its own facility. In 2000 the engineering firm of Fay, Spofford and Thorndike (FST) evaluated disposal options available to the Town in order to identify the most cost effective means to dispose of their sludge and the best means for the Town to prepare for this method through modifications and equipment at the WWTF.
In July of 2001 the WWWTF began shipping its liquid sludge off-site by tanker truck for remote disposal through a contracted disposal company which utilizes various DEP approved locations for their shipments. Disposing of sludge in this manner, though the most cost effective option, is still costly for the Town when shipped as a dilute liquid. In 2002 the Town began installation of sludge thickening equipment at the Treatment facility which removes excess water from the sludge prior to shipment offsite. The new equipment reduces the volume of sludge being shipped offsite to approximately ¼ of that when disposed without thickening. The result is that this equipment saves the Town a substantial amount in transportation costs.
Other projects and improvements made to the Towns WWTF during the latter part of the 1990’s and early 2000’s included:
· Influent Pump Station Grinder - In 1991, a new channel mounted grinder was installed at the influent pump station to replace the original comminutor that was damaged during a power outage. The new grinder was hydraulically driven for protection should the pump station flood. All electrical motors associated with the unit are above ground
· Removal of underground storage tanks – In @1993 all in ground diesel fuel chemical storage tanks at the WWTF and pump stations were removed and replaced with above ground double walled units.
· Outfall stabilization- In @1999 the Town contracted realignment and stabilization of the diffuser area of the WWTF outfall which extends off of the Brant Rock area of Town. The outfall consists of one 30 inch diameter concrete outfall pipe that runs for approximately 3190 feet beneath the seafloor into Massachusetts Bay. The outer 240 feet of the outfall pipe serves as the outfall diffuser manifold containing twelve 12-inch diameter pipe diffusers, six per side.
· Ultraviolet disinfection – In @ 2000 the Town contracted the removal of Chlorine Gas disinfection which was replaced with Ultraviolet light disinfection. This resulted in removal of an extremely dangerous chemical from the WWTF and also created a more environmentally friendly method of disinfecting effluent from the WWTF prior to discharge. This project was precipitated by changes in the Towns NPDES (National Pollutant Discharge Elimination Systems) issued by EPA and DEP.
· Clarifiers Drive Mechanism – In @2000 the aging original chain driven clarifier mechanisms were replaced with gear driven units. The original structures are still in service with renewed mechanical equipment.
· Digester Aeration Replacement - In 2002 the aging original digester blowers, mixers and course air diffuser were replaced with a diffused air system.
· Meadowview sewer – in @2000-2001 a sewer extension was installed in the roads off of Meadowview which head down toward the river. During this project a pump station was installed on Homestead Avenue.
· Aeration Tanks Aeration – Town meeting in April 2002 approved a project to replace the original aging mechanical surface aerators on the Plants three (3) aeration basins with a diffused air system. This project should get under way sometime in 2003-2004.
· SCADA – the term stands for Supervisory Control and Data Acquisition. All equipment control and monitoring systems in the WWTF and its pumping stations are original and were designed in the early 1970’s. IT was a proprietary system requiring service from limited approved facilities and the company which manufactured the pump station communication system went out of business years ago. It was temperamental and provided the operations staff with limited information which, among other things, created unsafe situations where an operator would be responding alone to unknown alarm conditions at all hours of the day. The old system is being replaced using more current technologies which
along with being more serviceable will provide the operations staff with much improved information and control capabilities.
· Route 139 Sewer Extension – More commonly referred to as “Sewer 2000” this project extends the sewer collection system from its terminus at old colony lane to the center of Town at the intersection of Route 139 and Moraine St. including the side streets which are passed along the way. This project, currently under construction, is planned to add three pump stations to the sewer system at Anderson Drive, Macker Terrace and Homeland Drive.
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