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Site Stormwater Management, Falmouth, MA

Long Pond Water Treatment Plant, Falmouth, MA

The Long Pond Water Treatment Plant project consists of an 8.4 mgd DAF treatment plant, ozone contractors, and raw water pump station with intakes. The site stormwater management part of the project was separated into two designs: the parts of the site under the Conservation Commission’s jurisdiction and those that are not.

FalmlouthMA_Long_Pond

The majority of the site from the entrance along the access road and around the main treatment plant building did not fall under the Conservation Commission’s jurisdiction, and therefore did not require stormwater treatment. However, we did not want to ignore the potential impacts of stormwater, so this portion of the site was designed to allow for 100 percent infiltration. Along the access road, grading allowed for water to discharge and infiltrate in undeveloped areas where it will not impact the site. The area around the main building flows over land to an infiltration basin that is designed to collect, store, and infiltrate most storm events. There is an overflow in the case that the infiltration basin is overwhelmed during a large storm event.

The construction of the raw water pump station and intakes fell within the Conservation Commission’s and other agencies’ jurisdiction. Since the only impervious area was the building, and the building did not have a metal roof, MassDEP guidelines allowed for direct infiltration. The guidelines usually require the infiltration to occur in drywells in this situation, but the local Conservation Commission agreed that having an infiltration basin with an overflow would require fewer man-made structures and therefore have less impact on the surrounding environment. The infiltration was designed to store and infiltrate the raw water pump station roof runoff, and included an overflow for large storms.

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Wastewater Pump Stations, Auburn, MA

CLIENT: Town of Auburn, Massachusetts Department of Public Works

PROJECT: Replacement of three existing wastewater pump stations

wastewater pump station
The buildings are situated on very small sites

THE CHALLENGE: The sites were very small and restricted with high groundwater levels, and there were adjacent wetlands and private property. All three buildings were also very small and had other issues such as asbestos.

THE SOLUTION: We determined that the best course of action would be to demolish the buildings and convert the concrete dry pit that housed the pumping equipment into a wetwell for new, submersible pumps. The solution saved the Town hundreds of thousands of dollars.

wastewater pump stations
An existing building is inspected during the design phase

PROGRESS: Tata & Howard provided the project design and will be putting the project out to bid this summer. We will also provide construction administration when construction begins in the fall.

8.4 mgd Water Treatment Plant Design, Permitting, Construction Administration, Falmouth, MA

DAF water treatment plant

THE CHALLENGE: More stringent USEPA and MassDEP regulations, including Stage 2 Disinfectants/Disinfection-by-Product Rule (S2 D/DBPR) and the Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR), resulted in the Town of Falmouth needing to make a decision on whether to construct a filtration facility in compliance with the SWTR or to upgrade disinfection processes only at the existing Long Pond Water Treatment Facility (LPWTF) to maintain the existing Filtration Waiver.

THE SOLUTION: Because the existing LPWTF utilized no filtration to remove bacteria, organics, and particulates, the water quality entering the distribution system was an ongoing concern with elevated turbidity and organics leading to seasonal color, taste, and odor complaints; elevated bacteria and concentrations; and elevated algae counts. In addition, the high doses of chlorine needed to maintain the disinfection residuals required for an unfiltered supply reacted with the organics in the raw water to form disinfection by-products. Therefore, the only viable option for the Town of Falmouth was a new water treatment plant. After evaluating 22 treatment processes and developing eight treatment alternatives for pilot testing, only one treatment process met all goals: Dissolved Air Flotation (DAF) clarification, intermediate ozone followed by filtration. This alternative also scored favorably on the benefit/cost analysis.

Tata & Howard provided design and construction services for the new Dissolved Air Flotation (DAF) facility with a design capacity of 8.4 million gallons per day (mgd) for the Long Pond surface water supply for the Town of Falmouth, MA. The water treatment plant (WTP) utilizes coagulation, mixing, flocculation, dissolved air flotation (DAF), dual media filtration including granular activated carbon (GAC) above sand, chemical feed systems, and an intermediate ozone feed. Building components include HVAC, plumbing, fire sprinkler, gas and electrical services. Other work included site work with exterior piping systems, exterior above and below ground tanks, sludge holding lagoons, construction of a garage, new raw water intake and pump station, directional drilling of raw water mains, and demolition of equipment and site piping at the existing water treatment facility.

As part of the project, Tata & Howard provided design and permitting of a new 8.4 mgd intake and raw water pump station (RWPS) for the WTP.  The new intake and RWPS were constructed along the eastern shore of Long Pond and replaces the existing intake and Low Lift Pump Station.  The new intake and RWPS includes a two-level intake consisting of two 8.4 mgd rated intake screens installed at elevations -3 feet below mean sea level (MSL) and -13 feet below MSL.  The 36-inch HDPE intake pipeline connects the intake screens to the new RWPS located approximately 150 feet from the eastern shore of Long Pond.  An air burst system was designed in the RWPS to provide a means for routine cleaning of the new intake screens.

An accelerated 11 month design and permitting schedule, followed by contractor prequalification, bidding, and award, were completed in time to qualify the Town for >$3M in principal forgiveness.

Design included the following:
• 300 Drawings
• 1,200 pages of Specifications
• SRF PEF application
• Monthly project meetings
• Coordination with Building Department
• Coordination with Board of Health
• Coordination with Town IT Department
• Coordination with Police and Fire Departments
• Coordination with Gas and Electric Utilities

Permits included the following:
• Wetlands Protection Act-Local Conservation Commission
• Board of Health
• Remediation General Permit (NPDES)
• Massachusetts General Permit
• Environmental Notification Form
• Massachusetts Historical Commission: Intensive Archaeological Survey including 200 test holes
• MassDEP Approval to Construct WTP: BRP WS 24
• DWSRF PAC
• 401 Water Quality Certification
• NHESP – Turtle Protection Plan
• Chapter 91 Waterways License
• U.S. Army Corps of Engineers General Permitdji_0051The construction of the Long Pond Water Treatment Plant progressed on schedule and was completed in 2017. The plant included numerous sustainability and energy efficiency initiatives including the following:

  • Recycling spent backwash water to head of plant and back into the treatment process, after it passes through a plate settler to remove solids.
  • Recycling laboratory analyzer and filter influent piping gallery analyzer discharges back into the treatment process.
  • Using filter-to-waste water after a filter backwash sequence as supply water for the next backwash, instead of using finished water for backwashing.
  • Discharging cleaner supernatant water off the top of the lined lagoons to an unlined infiltration lagoon and back into the ground to minimize residuals.
  • Use of local/native plants for landscaping, including an irrigation system using collected rainwater from roof drainage.
  • Interior and exterior LED lighting fixtures.
  • Variable Frequency Drives (VFDs) on HVAC equipment and process equipment motors.

The plant went online on October 18, 2017. The work was funded under the SRF program. The Long Pond Water Treatment Plant received an ENR New England 2017 Best Project Award in the Water/Environment category, and an Associated Builders & Contractors of Massachusetts Eagle Award in the Public Works – Environmental category.

For a drone video of the new water treatment plant taken by the general contractor, Methuen Construction, please see below:

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NPDES MS4 Annual Report Services

NPDES Phase II Small MS4 General Permit Annual Report Services

The purpose of the MS4 annual report is to document the status of NPDES Storm Water Management Program (SWMP) implementation with information including the following:

  • A self-assessment review of compliance with the permit conditions;
  • An assessment of the appropriateness of the selected BMPs;
  • An assessment of the progress towards achieving the measurable goals;
  • A summary of results of any information that has been collected and analyzed;
  • A discussion of activities for the next reporting cycle;
  • A discussion of any changes in identified BMPs or measurable goals; and
  • Reference to any reliance on another entity for achieving any measurable goal.

Tata & Howard has provided MS4 Annual Report services to the following municipalities:

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Dover, Massachusetts

Tata & Howard assists the Town of Dover, MA with MS4 compliance.  Services have included completion of the annual report, facilitation of an educational training session with municipal leaders, review and updating of stormwater infrastructure, and education on the upcoming MS4 Permit. We are currently assisting them with preparing the Notice of Intent required for coverage under the new 2016 Massachusetts MS4 General Permit.

Manchester-by-the-Sea, Massachusetts

Tata & Howard reviewed stormwater information and provided a Year 11 annual report to the Town of Manchester-by-the-Sea, MA.

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Leicester, Massachusetts

Tata & Howard assists the Town of Leicester, MA with MS4 compliance. Services have included creation of an IDDE program including written statement of IDDE responsibilities, outfall inspection and mapping, and educational presentation to Town leaders on illicit connections. In addition, Tata & Howard helped the Town create and pass a bylaw related to illicit connections required by the MS4 Permit and produced the MS4 Annual Report for the Town. We are currently assisting them with preparing the Notice of Intent required for coverage under the new 2016 Massachusetts MS4 General Permit. Moving forward, we will be assisting the Town with additional mapping and catchment area identification.

Site Stormwater Management, Wayland, MA

Happy Hollow site stormwater management

The Happy Hollow Chemical Feed Station design consisted of a small chemical feed building and equipment, well pump and water main installation, and associated utilities and site work. The only impervious surface on the site was the new building. Since building roof was a membrane and not metal and there was no paving, MassDEP guidelines allowed for direct infiltration of the stormwater runoff from the roof. This was accomplished by pitching the roof to one side and collecting the runoff into two 4” PVC drain pipes that discharged into an infiltration system consisting of four Cultec infiltration chambers.

Since it was not feasible to install an overflow for these chambers, the infiltration system was designed based on a 100-year storm event in order to have the capacity to collect, store, and infiltrate the largest storms that the site could potentially encounter. The chemical feed building also housed a re-agentless chlorine analyzer that required a constant supply of sampling water and therefore produced a constant waste flow of clean water. This analyzer waste flow was also included in the sizing of the infiltration system.

Stormwater Field Engineering, Grafton, MA

 

Manhole cover

Tata & Howard has provided the Town of Grafton, MA with extensive stormwater field engineering services. Services have included the completion of stormwater infrastructure mapping in accordance with the Massachusetts NPDES MS4 Permit, Illicit Discharge Detection and Elimination Program. Mapping services included outfalls and interconnections, manholes, catch basins piping, and establishment of catchment areas.  Follow-up work will continue with outfall inspection, screening, and dry weather sampling.

Stormwater Site Design Engineering, Marlborough, MA

Tata & Howard provided engineering services for Marlborough, MA for a redesign of the Town’s Public Works Facility. The work included a stormwater management design and program to reduce the contamination of stormwater runoff and prohibit illicit discharges as required by current regulations and as required by the latest draft MS4 permit.

The project also included a proposed site plan showing the proposed drainage improvements for the site including new drainage system infrastructure, stormwater detention and treatment facilities, existing and proposed grade, and all building and features. The project also included an erosion control plan and drainage report appropriate for various environmental permitting submissions including and erosion control plan with boundaries of any resource areas and associated buffers. Lastly, Tata & Howard assisted with permitting assistance and obtaining Conservation Commission approval of the project.

 

Stormwater Engineering Services, Leicester, MA

 

Tata & Howard provides ongoing stormwater engineering services to the Town of Leicester, Massachusetts in support of their status as a NPDES Phase II Municipal Separate Storm System (MS4) community. Work involves outfall mapping and inspection, illicit discharge detection and elimination, development of annual reports, and compliance with documentation and reporting components of the MS4 Permit.

In addition, Tata & Howard assisted the Town of Leicester Highway Department with mapping and inspection of stormwater outfalls and produced a unique record of each outfall including photographs. Tata & Howard also developed a report summarizing the outfall inspections.

 

Milford Water Treatment Facility, Milford, MA

Milford-Dilla-DAF

Tata & Howard provided construction administration, resident observation, and start-up services to the Milford Water Company for the construction of the Dilla Street Water Treatment Facility. The 5.2 mgd facility treats water from a combination of lake, river, and wells, utilizing dissolved air flotation (DAF) clarifiers and granular activated carbon (GAC) filters. The facility will replace the existing slow-sand and diatomaceous earth (DE) treatment currently utilized to treat the existing surface and groundwater sources, respectively. The facility was required to address and satisfy an Administrative Consent Order (ACO) issued by MassDEP.

Tata & Howard also completed design and oversight of a redundant cast-in-place chlorine contact tank, and has been contracted to provide engineering services for project review and construction oversight for the installation of raw water screens on intakes of both the lake and river sources. These improvements were mandated by MassDEP as part of the approval of the Dilla Street facility design.

Water Treatment Plant, Iron and Manganese Removal, Wayland, MA

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Tata & Howard completed pilot testing, design, permitting, bidding, and construction management services for the Town of Wayland’s Baldwin Pond Water Treatment Plant which included iron and manganese removal. The facility received MassDEP approval to go online and became Wayland’s first public building to receive an occupancy permit in the last 30 years. The need for the facility arose from high iron and manganese content in Wayland’s water. The facility also addressed any concern over the three Baldwin Pond wells which were under close scrutiny to determine if they were “under the influence of surface water.” The 7,500-square-foot, 1.5 million gallons per day, state-of-the-art water treatment facility was constructed to meet current and future regulations for many years ahead. The design included ozone oxidation, ultrafiltration membranes, waste recycle, and chemical feed for coagulation, pH adjustment, fluoridation, and disinfection. The treatment facility utilizes ozone oxidation and ultrafiltration to remove iron and manganese from the blended raw water from the three water supply wells.  Although other constituents are also removed through this process, the basis of this plant is to optimize the removal of iron and manganese.

The Baldwin Pond Water Treatment Facility project was highly successful through good communication and teamwork between Tata & Howard’s construction management team, the general contractor Methuen Construction, and the Town of Wayland. With less than 1% of the contingency budget applied to change orders towards the end of the project, the Town was able to do additional work. The additional work included replacing raw water mains and upgrading the existing garage onsite. A dedication ceremony for the facility was held with Representative Scott Brown, and representatives from MassDEP, Methuen Construction, and Tata & Howard joining the Town of Wayland in commemorating the completion of the facility.

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