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

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

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

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

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

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.

Lead-Contaminated Soil Remediation in Falmouth, MA

The Town of Falmouth retained Tata & Howard to remediate lead-contaminated soil associated with historical firing range activities at a former gravel pit owned by the Town.  Due to the gravel pit’s location within a current drinking water source area, the objective of the remediation was to restore the release to background and remove the potential threat to the underlying groundwater quality.  In addition, the presence of estimated habitats of rare wildlife and priority habitats of rare species at the gravel pit required the filing of a Notice of Intent (NOI) with the Conservation Commission and implementing measures to protect the rare wildlife and species.  Tata & Howard prepared a site-specific scope of work for bidding purposes and managed all the field activities.  Part of the remedial action plan was to screen the soil in an effort to remove the lead bullets and facilitate disposal of the contaminated soil at a Massachusetts lined landfill.  Analytical testing of the soil revealed that some areas contained leachable lead, which required stabilization with Portland cement prior to being transported to the landfill.  During the excavation activities, Tata & Howard utilized a field portable x-ray fluorescence (XRF) analyzer to obtain real-time concentrations of lead in soil.  Use of the XRF minimized contractor down time because decisions relative to the extent of excavation required could be made in the field.  Confirmatory laboratory analytical results correlated well with the XRF data.  Tata & Howard prepared a Permanent Solution with No Conditions Statement, which documents that a condition of No Significant Risk has been achieved at the Site and that the release conditions have been restored to background.

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Water Distribution and Wastewater Collection BPE, Framingham, MA

Framingham-ma-cochituate-damTata & Howard completed a Business Practice Evaluation (BPE) for the Town of Framingham, MA.  T&H coordinated and attended a project kick-off meeting with essential Town personnel. The Town provided, as available, documents requested at the Project Kick-off meeting including reports, CIP and operating budgets, organization charts, standard operating procedures, operation and maintenance reports, O&M manuals, performance measures, job descriptions, Emergency Response Plan, procurement process, inventory control, relevant studies and reports, and similar related documents.  These documents were used both for assessment of the current practices and as documentation included in the written plan, as appropriate.  Evaluations determined the adequacy of the documents and current business practices. Documents were compiled and organized electronically for use in the project and future use by the Town.  Any critical missing information was identified and developed by Town staff or included as part of the Implementation Plan.