Tata & 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.
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.
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.
Tata & Howard completed a comprehensive evaluation of the Manchester-by-the-Sea wastewater treatment plant (WWTP).
The Manchester-the-Sea WWTP was originally constructed in 1998. The plant is designed to treat an average daily flow (ADF) of 1.20 mgd. The plant includes the following treatment processes: influent pumping, influent sewage grinding, manual bar rack, grit removal equipment, aeration tanks and blowers, clarifiers, chlorine disinfection, and sludge thickening. The treated effluent is discharged into the ocean with effluent pumps through an ocean outfall pipe.
The treatment plant evaluation included a comprehensive assessment of the physical condition of the plant to provide an additional 20-year life for the facility. The evaluation included all mechanical systems and equipment, electrical systems and controls, buildings, and structures. The study included an evaluation of energy usage at the plant and developed recommendations to improve energy efficiency including replacement of influent and effluent pumps, and aeration blowers to better match plant flow requirements and system demands.
The final report includes an evaluation of existing conditions and proposed recommendations to improve current operations, upgrade aging equipment and facilities, improve energy efficiency, and provide plant hardening against potential climate change and sea level rise.
Tata & Howard, Inc. was retained by the Town of Wayland, MA to complete a water audit of the water distribution system based on data and system information for the calendar years 2013, 2014, and 2015. The project included assessing the amount of lost water using the American Water Works Association M36 water audit methods. The report estimates the volume of lost water in terms of non-revenue water, identifies potential sources of lost water, and estimates system performance indicators including the Infrastructure Leakage Index.
The AWWA water audit results found that the Town’s non-revenue water by volume was approximately 46.4% in 2013, 20.5% in 2014, and 18.5% in 2015. The associated annual costs of water lost were approximately $425,000 in 2013, $320,000 in 2014, and $398,000 in 2015. In addition, 64% of the Town’s meters are over 15 years old.
Recommendations to reduce water loss included the following: volumetrically testing master meters at multiple flow rates and performing a field to database audit of SCADA flow reported from master meters; implementation of a customer meter testing and replacement program; and documentation of unbilled and unmetered water use with the use of meters whenever possible.
To address the aging meters, Tata & Howard completed a water meter and advanced meter infrastructure (AMI) evaluation. The project included an evaluation of water meters, automatic meter reading (AMR) systems, and advanced metering infrastructure (AMI) systems for the Town of Wayland’s water distribution system. The purpose of the evaluation was to compare different AMR/AMI technologies to assist in the selection of a new meter reading system to provide a recommendation for AMR/AMI technology to best suit the needs of the Town.
Following the meter evaluation, Tata & Howard provided assistance with a request for proposal (RFP) for new water meters and AMI system including specifications and proposal evaluation criteria. Tata & Howard is currently providing assistance during the implementation of the AMI system and the installation of the water meters and RF endpoints for the Town of Wayland.
Tata & Howard, Inc. was retained by the Town of Grafton, MA to complete a water audit of the water distribution system based on data and system information for the calendar year 2015. The project included assessing the amount of lost water using the methodology outlined in AWWA’s Water Audits and Loss Control Programs, Manual of Water Supply Practices – M36, Fourth Edition, published in 2016. The final report estimates the volume of lost water in terms of non-revenue water, identifies potential sources of lost water, and estimates system performance indicators including the Infrastructure Leakage Index.
The AWWA water audit results found that the Town had total water losses of approximately 182 million gallons in 2015 and the associated annual cost of water lost was over $312,000. Of this, 11% is Unavoidable Annual Real Losses (UARL). Recommendations to reduce water loss include volumetrically testing master meters and performing a field to database audit of SCADA flow reported from master meters and interconnections, beginning a customer meter testing and replacement program, documenting unbilled and unmetered water use with the use of meters whenever possible, and conducting a third-party review of the leakage detection program. The estimated cost of recommended improvements to the District’s water loss control program was $20,000 for the SCADA audit and leakage detection program review, $129,000 to replace customer meters over 25 years old, and $7,000 in annual costs for establishing master meter and customer meter testing and replacement programs. Implementation of all recommendations would result in an expected ROI of less than one year.
Tata & Howard is providing engineering services to the Grafton Water District for the Trinity Avenue Pump Station at the Trinity Avenue Wellfield. The project included permitting, design, and bidding of the pump station as well as providing assistance with permitting, design, and reporting to the Massachusetts Department of Environmental Protection (MassDEP) for the proposed Trinity Avenue Well site. The property was owned by the Massachusetts Division of Fisheries and Wildlife (DFW).
The Grafton Water District swapped land with the DFW to obtain ownership and control of the Trinity Avenue site. Test wells were installed and short term pump tests were completed on each of the wells. Based on the results of the tests, it was recommended to install a three well configuration of 18 inch x 12 inch gravel packed wells resulting in approximately 800 gallons per minute (gpm).
The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert, and T&H assisted with the preparation of permanent easements for the installation of utilities and roadway to the well site. In addition, T&H prepared and submitted an NOI to the Grafton Conservation Commission. Design included double wythe block and interior concrete painted block with wood truss roof and asphaltic shingles; and security included chain link fence, gates, locks, intrusion alarms, and lighting. T&H also assisted with the coordination of the installation of three phase power to site. Chemical feed at the station includes KOH for pH adjustment and chlorine gas for disinfection. Standby power was included in an outdoor enclosure. The design also included a 24-inch transmission main for 4-log removal.
The Towns of Canaan, Vermont and Stewartstown, New Hampshire operate a shared wastewater treatment facility, which required significant upgrades. The existing facilities were 40 years old and although a few upgrades were performed in the 90s, the facilities were not performing well, did not meet Life Safety codes, and required significant maintenance. The upgrade met all of the goals of the Client by providing for simple operation and maintenance requirements, meeting the Life Safety codes, eliminating confined spaces, lowering of electrical power costs, and meeting discharge parameters through production of high quality effluent. The solutions developed for the upgrade to this facility were also economical.
Control building insulated concrete forms
One of the primary elements of the design was the consideration of the economics of energy reduction. The design incorporated insulated concrete form construction for the building walls with R-49 insulation rating in the ceilings. The design also included a wood pellet boiler with a pellet silo and hot water heating system, which allowed for reduction of explosion proof heaters in the headworks building. All of the windows were low-E and highly insulated, and an outer glassed-in entry way increased the solar gain retention of the building and reduced heat loss. he process headworks and operations buildings were constructed as single story structures, increasing operator safety.
The lagoon aeration system is now a fine bubble, highly efficient process with additional mixing provided by solar powered mixers that help reduce aeration requirements, improve treatment, and allows for the addition of septage, all at no cost due to solar power. The pump station upgrades were designed to eliminate daily confined space entry by the operator by the conversion to submersible pumps. For sludge removal, a unique and simple “Sludge Sled” system was incorporated, which allows the operators to easily remove the sludge at their convenience. Sludge treatment is accomplished with a geo-bag system that allows the sludge to be freeze dried, reducing the volume by almost 50% with no energy consumption.
The influent pump station was designed with three pumps instead of the normal two-pump system in order to meet both present and future design flows, allow for lower horsepower pumps, improve flexibility, reduce replacement costs, and reduce energy costs. The other four deep dry pit pump stations were converted to wet wells and submersible pumps, eliminating confined spaces, and are equipped with emergency generators, eliminating the need for operator attention when power is lost.
Solar mixers for lagoons
The incorporation of highly energy efficient building components resulted in reducing annual operation and maintenance costs, which resulted in lower user rates and a more sustainable facility. All building components are virtually maintenance free. All of the equipment and processes were selected to reduce both annual and future replacement costs.
The treatment system is a 3-cell aerated lagoon system, and the solar powered mixers were installed to enable reduction of the aeration needs and horsepower during the summer months when septage is added. The aeration blowers, which are housed in insulated enclosures, reduce noise and were sized to allow for the addition of septage to the lagoons, which is not common in Vermont. The aeration blowers are controlled with Variable Frequency Drives (VFDs), which allow for greater operator control of aeration and provide energy cost savings. The operation is simple and safe for operators and others who need to maintain the facility and equipment. The design has provided flexibility to the operators and has resulted in an energy efficient, sustainable solution for this community.
Tata & Howard provided design and construction services for a new water treatment facility that houses a 1.2 mgd ultrafiltration system and completed a pilot test that consisted of an evaluation of two separate ultrafiltration technologies. Franklin Wells No. 1 and 2, located off Hayward Street in Franklin, Massachusetts were installed in the 1940’s with a combined safe yield of 1.2 million gallons per day. Due to high concentrations of iron and manganese in the groundwater, the wells were only used to meet peak water demands during the summer months. The construction of the water treatment facility recaptures the yield from these two sources.
The water treatment facility consists of a main building which houses static mixers, ozone feed equipment, chemical feed equipment, prefilters, membrane filtration equipment, instrumentation and controls. Treatment consists of ozone oxidation followed by membrane ultrafiltration. The project was funded in part by the Massachusetts Water Pollution Abatement Trust through a low interest state revolving fund loan.
The overall treatment scheme is as follows: ozone injection, oxidation of iron and manganese in an ozone contact tank, prefiltration, treatment through two ultrafiltration membrane skids, chlorination prior to a clearwell, and fluoride addition prior to discharge into the distribution system. The plant is designed to recycle backwash water and membrane recirculation water to the head of the plant utilizing two decant tanks. Ozone is produced on site utilizing compressed air, while a LOX tank is available to allow for the production of additional ozone if required in the future.
Tata & Howard, Inc. was recently retained by the Town of Manchester-by-the-Sea to complete a Capital Efficiency Plan™ for the Town’s water system. The system was evaluated to identify areas of the water distribution system in need of rehabilitation, repair, or replacement, and to prioritize improvements to make the most efficient use of the Town’s capital budget. The study evaluates the existing water infrastructure including water transmission and distribution piping and appurtenances. In addition, water storage and supply needs were evaluated and prioritized.
The analysis and improvements in this report are based on the Three Circles Approach for optimum capital efficiency, which combines hydraulic and critical component considerations with an asset management rating system to evaluate the condition of the water mains in the distribution system. Each circle represents a unique set of evaluation criteria for each water main segment. From each set of criteria, system deficiencies are identified. System deficiencies from each circle are then compared. Any deficiency that falls into more than one circle is given higher priority than one that does not.
\Using the Three Circle Approach, recommended improvements will result in the most benefit to the system. In addition, the Three Circle Approach allows us to identify any situations that mitigate a deficiency in one circle and eliminate a deficiency in another circle. By integrating all three sets of criteria, the infrastructure improvement decision making process and overall capital efficiency are optimized.
Recommendations included a siting study for a second storage tank, Phase I-III distribution system improvements, and the continuance of scheduled maintenance programs such as hydrant flushing, leak detection, and meter testing. The Town’s pavement management plan was also taken into consideration to best prioritize and coordinate utility work with roadway reconstruction.
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