Meadow Walk Mixed-Use Wastewater Design / Engineering Services

Meadow Walk Mixed-Use Wastewater Design / Engineering Services

Tata & Howard has been providing engineering services for final design and construction documents associated with the design of a wastewater treatment facility utilizing membrane bioreactor (MBR) technology for the 50-acre Meadow Walk development at 526-528 Boston Post Road in Sudbury, Massachusetts. The site is a former Raytheon engineering and R&D facility.

National Development / Avalon Bay mixed-use residential and retail development, Boston Post Road, Sudbury, MA.

Believing the site was well-suited for mixed-use residential and retail development, in 2016 Sudbury selectmen and residents voted to approve zoning and development plans proposed by National Development and Avalon Bay. The site was in development for two years and is nearing completion. The project consists of several independent components, which collectively comprise a mixed-use development with new open space, retail, and restaurants as well as walkable access to adjacent retail, office, and other services along Boston Post Road. The project also included local roadway improvements, major upgrades to the streetscape and landscaping, wastewater treatment improvements, and improved water quality.

Tata & Howard was contacted initially to prepare studies of existing conditions and proposed modifications to enhance and then upgrade the wastewater facility and disposal area on the site. Additional out-of-scope changes included value engineered alternatives and additional design services. The existing wastewater treatment facility was over 25 years old and required increased discharge limits; conversion to an MBR system to achieve higher removal of BOD, TSS, TN, turbidity, and other wastewater constituents; additional treatment redundancy; upgrades to meet current Massachusetts Department of Environmental Protection (MassDEP) guidelines; increased groundwater recharge; odor control; replacement of old infrastructure with a new pump station, gravity lines, and force main; a change to mixed land/water use to result in wastewater generation that could be more efficiently treated at the new wastewater treatment facility; and a new leaching field.

Upgrades included infrastructure and a new leaching field.

Hemlocks Raw Water Pumping Station

Aquarion Water Company Pump Station Improvements

Hemlocks Pumps
BEFORE improvements to the Hemlocks Pumping Station.

Tata & Howard provided engineering services for design, bidding, construction administration, and resident observation to Aquarion Water Company for improvements to their existing Hemlocks Raw Water Pumping Station in Fairfield, CT. The project included refurbishing five 300 hp centrifugal pumps and motors, replacing the existing variable frequency drives (VFDs), installing new piping, check valves, and strainers for each pump.

As this facility is a source of supply for Aquarion’s Main System, it needed to be kept operational throughout the construction. The sequence of work required a single pump to be taken off line; refurbished; reinstalled with new piping, VFD, and appurtenances; tested and placed back into service prior to the next pump being taken off line.

Hemlock Pumps
AFTER improvements to the Hemlocks Pumping Station.

Another important aspect of the project was to replace the existing strainers so that they were easier for the plant operators to clean as they get clogged with eels. To simplify maintenance, new stainless steel wye strainers with bottom access to the screens were installed on the suction side of each pump.

Chamberlain Highway Receives New Water Main Connections

Chamberlain Highway Receives New Water Main Connections

The Chamberlain Highway in Meridan, Connecticut has 536 linear feet of new 16-inch ductile iron main and two new fire hydrants. After Tata & Howard completed several test pits to verify connection locations at each end of the new main, construction work started on May 3, 2018 with the installation of a 16” x 16” tapping sleeve and valve at the north end of the project. This existing water main at the north end connection was originally installed in 1894.

Chamberlain West MainWork progressed south until the new main was approximately 50 feet away from the other connection point in West Main Street. Connections to the existing main in West Main Street was performed over a 36-hour period due to the complexity and amount of utilities around the service connection, including a live 24-inch water main five feet away and multiple telephone conduits located 6 inches above the replaced main. Tata & Howard personnel on site at all times to observe that work was in performed in accordance to the plans and specifications.

Following the completion of the Chamberlain Highway water infrastructure improvement project, work to replace two water mains on the state-owned bridge crossing Sodom Brook in Meridan will begin.

UMASS Amherst Hydraulic Modeling

UMASS Amherst Hydraulic Modeling

Tata & Howard developed an extensive hydraulic model of the University of Massachusetts (UMass) Amherst campus. The model was verified under steady state and an extended period simulation (EPS) was completed.  Tata & Howard conducted a hydraulic review and criticality assessment and used the results to make improvement recommendations.  Tata & Howard also identified water distribution system sustainability projects for the irrigation, cooling tower makeup, and toilet flushing water.

This project included a supplemental water supply system analysis.  Potential ground and surface water sources on campus, including existing and potentially new stormwater retention ponds, were evaluated for process and irrigation water.  In addition, Tata & Howard created a hydraulic model of the UMass reclaimed water system.

The study also examined the effects that the proposed system improvements and interconnections would have on water quality.

A Decade of Infrastructure Improvements

Wiscasset Completes Capital Efficiency Plan™ Infrastructure Improvements

The Wiscasset Water District (WWD) completed its final phase of water main replacements for the Town of Wiscasset, ME. In 2007, Wiscasset, a rural coastal town in Maine, embarked on a long-awaited infrastructure improvement program to replace the Town’s century-old waterlines. The Wiscasset Water District, engaged Tata & Howard’s services in 2010, to prepare a Capital Efficiency Plan™ (CEP), to identify areas to the Town’s water distribution system needing rehabilitation, repair, and/or replacement.

CEP reportThe Capital Efficiency Plan™ report which included hydraulic modeling, system criticality, and an asset management plan, provided the Utility with a database and Geographic Information System (GIS) representation for each pipe segment within their underground piping system. The CEP report also prioritized the water distribution system piping improvements and provided estimated costs to replace or rehabilitate the water mains.

Wiscasset Main StreetIn response to the CEP™ findings, the Wiscasset Water District retained the services of Tata & Howard, to perform design, bidding, construction administration, and resident project representation services for a series of water main projects.

Phased over 10 years, the plan included replacing 33,150 feet of 12-inch and 8-inch piping, installation of a water storage tank mixer, SCADA upgrades, and office landscaping improvements.

The final phase of water main replacements is scheduled to be completed during the summer of 2018 and will fulfill all the Priority I water main improvements identified in the 2010 CEP™ report. The projects were funded in part by a combination of USDA Rural Development grants (6 total) and loans (7 total), as well as coordination with the Maine Department of Transportation and Rural Development.

With the water main improvements nearing completion, the Wiscasset Water District has retained Tata & Howard to reevaluate its 2010 Capital Efficiency Plan™. The revised plan will update the water main inventory database and review additional recommended water distribution improvements.

Unidirectional Flushing Program, Wayland, MA

Unidirectional Flushing Program, Wayland, MA

Wayland Zone MapTata & Howard prepared a sequential Unidirectional Flushing Plan (UDF) for the Town of Wayland’s water distribution system, utilizing the existing hydraulic model to develop flushing sequences for hydrants and valves to be operated.  The sequences were updated from the original plan to review anticipated flushing velocities and identify areas of potential low-pressure concerns. Field assistance was provided during the implementation of the updated plan. A summary report was provided, identifying the amount of water used during flushing, areas of hydrant or valve mapping discrepancies, and areas with broken or inoperable hydrants and valves.

Extended Period Simulation and Hydraulic Study for Town of Avon, MA Water Division

Extended Period Simulation and Hydraulic Study for Town of Avon, MA Water Division

Tata & Howard completed an Extended Period Simulation (EPS) hydraulic model of the water distribution system for the Town of Avon, Massachusetts. An EPS model was created to account for changes in the water distribution system over an extended period to include peak and minimum demands during both the summer and winter months. These changes included tank levels, pump controls, value operation, and demand variations.

The EPS model was used to estimate the water age in the water distribution system under winter and summer demand conditions. Water age is the time water takes to travel from a water supply source to a point within the distribution system.  It is used as an indicator of water quality based on the assumption that the older the water is, the greater the likelihood that water quality has deteriorated.  According to MassDEP Finished Water Storage Guidelines, a three to five-day complete water turnover is recommended in water storage tanks.

The EPS model was also utilized to evaluate the Town’s existing system operations. The model was used to determine the optimal tank operating range and the impact of the run times on the well pumps. Simulations were performed on both the Center Street and Page Street Tanks to evaluate operations under existing and projected average day demand (ADD), maximum day demand (MDD), and peak hour demands with a minimum pressure of 35 psi maintained throughout the distribution system.

In addition to analyzing the tank optimal operating levels, changes to the existing pump operations and the effect on tank levels and water age were evaluated. Two modified pump operations scenarios were evaluated. Both scenarios were run with the existing tank water level controls and allowing the Page Street Tank to drop four feet.  A second modified pump operation scenario evaluated the Town’s lead/lag system. Results for the pump and tank level operations under these simulations were recorded for both summer and winter operations.

Based on the results from each operational modification, Tata & Howard made several recommendations for improvement to the water distribution system. These included allowing the water level in the Page Street and Central Street tanks to drop an additional six feet to improve water age during both the summer and winter demands.

In addition, to help improve the water age in the tanks to an optimal three to five-day complete water turnover as recommended by MassDEP Finished Water Storage Guidelines, Tata & Howard suggested installing mixing systems in each tank.

City of Flagstaff AZ Energy Audit of Water and Wastewater Systems

City of Flagstaff AZ Energy Audit of Water and Wastewater Systems

Tata & Howard conducted energy efficiency studies for the City of Flagstaff on their water and wastewater systems. Initial testing showed that modifications to these systems had the potential to save the City approximately $350,000 in annual electrical costs and $445,000 in Arizona Public Power System (APS) rebates if systems were modified with newer technology and upgraded. Pumping systems had efficiencies as low as 5.2% and the wastewater blowers as low as 19.5% where efficiencies of greater than 65% are attainable. Energy usage on the wastewater treatment side per million gallons treated showed 2,170 KWH/MG with cogeneration and 2,804 KWH/MG at the Rio plant. The national average usage is 1,750 KWH/MG.  Much of the equipment was oversized to meet peak and future demands but was not efficient at low flows or off-peak flows.

From this study and evaluation, the City retained Tata & Howard to provide design and construction administration services for replacing the existing aeration blowers at the Rio De Flag Water Reclamation Plant (WRP). Design services included the layout of the new screw compressors in the existing aeration room, as well as associated electrical, air intake and new piping to the existing aeration basins. The project was completed in December 2017; APS provided a rebate of $83,000 and preliminary annual power savings of roughly $73,200.

On the water system, the review included most of the wells, pressure reducing valves, boosters, and zone splits for energy savings. To date, eight (8) facilities have been upgraded, resulting in $256,000 in APS rebates and two of the facilities resulting in $109,000 of annual power costs. The other facilities have not been calculated. The total for both the water and wastewater systems has resulted in $490,000 in APS rebates and power costs savings of greater than $198,000 with additional projects available to extend these numbers. In addition to the power savings and rebates; operations, and reliability of the facilities have improved, and staff has an increased knowledge and awareness of power costs.

Air Piping Improvements – Flagstaff, AZ

Air Piping Improvements – Flagstaff, AZ

Flagstaff, AZ – Tata & Howard provided professional engineering design services to the City of Flagstaff, AZ for the replacement of three aeration units, as well as interior air piping improvements for the Rio De Flag Wastewater Reclamation Facility (WWRF). In addition, approximately 400 linear feet of existing air piping were replaced at the Rio De Flag WWRF.  The exterior pipe was visibly leaking air.  For technical and operational reasons, screw compressors were chosen over turbo blowers. Tata & Howard provided design services including preparation of plans, specifications, and bid documents for the installation of the new screw compressors.

The existing air flow exterior pipe gaskets had deteriorated with the heat of the existing compressed air to where the piping was a safety problem and was also wasting energy. Tata & Howard worked with the City to provide shop approvals and assisted the City’s inspector to ensure the project met the plans and specifications.

The existing blowers at the plant were 25 years old, had reached the end of their useful life, and did not ramp up and down with the wastewater flow. The new aeration units will flow pace with the changing incoming flow and saved the City enough electrical energy that it is projected to pay for the upgrade in eight years. The electrical power company (APS) offered a large rebate to reward Flagstaff for taking this energy and money saving opportunity.

Burbank Tank Rehabilitation – Millbury, MA

Burbank Tank Rehabilitation – Millbury, MA

The Burbank Tank is a 110-year-old buried fieldstone tank located in Millbury, MA.  Due to concerns from MassDEP on the age and condition of the tank, the Aquarion Water Company contracted Tata & Howard to provide design specifications and DN Tanks was selected as the tank rehabilitation contractor for installing shotcreting lining to the fieldstone walls, pouring a new concrete floor and removing pipes within the tank that are no longer in use.  While the proposed work is not a structural fix for the tank, shotcreting the walls will reduce potential root intrusion, seal up areas of lost mortar, and reduce the potential for leakage.  The rehabilitation was undertaken in early 2017 and completed in 8 weeks.

The Burbank Tank is the only storage tank in the water distribution system.  Therefore, careful planning and evaluation of the system using the hydraulic model was required to review the options for operations without storage for an extended period of time.