Services: Study/Evaluation

Capital Efficiency Plan™ for Manchester-By-The-Sea, MA

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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Capital Efficiency Plan™ and Water Supply Study in Rowley, MA

A Capital Efficiency Plan™ was completed for the Town of Rowley in May 2017.  The study evaluated the 45 miles of the Town’s water distribution system using the Three Circles Approach, which consists of a system hydraulic evaluation, criticality component assessment, and asset management considerations. From each set of criteria, system deficiencies were identified and a 20-year recommended improvements plan was provided. Recommended improvements consisted of water main replacement projects, a pumping capacity evaluation and well redevelopment study, an interconnection analysis, and a distribution static pressure evaluation.

 

Capital Efficiency Plan™ for Avon, MA

Tata & Howard recently completed a Capital Efficiency Plan™ for the Town of Avon, MA.  As part of the project, Tata & Howard updated and verified the Town’s existing hydraulic model. The work included the completion of fire flow tests throughout the Town and allocation of demands using up-to-date billing and parcel data. The Capital Efficiency Plan™ identified and prioritized areas for improvement within the distribution system.

Our services included evaluating the condition of the existing distribution system infrastructure to determine the adequacy of meeting present and future demands, assessing and prioritizing system improvements, reviewing and evaluating typical fire flows throughout the system, creating a pipe asset management rating system, and recommending improvements to the distribution system. Recommendations included installation of two replacement wells, conducting an interconnection study, rehabilitation of the Page Street Tank, and phased distribution system improvements.

The hydraulic model was also verified under an Extended Period Simulation (EPS), which considers changes in the distribution system over time. The EPS will be used to evaluate tank operating ranges and modifications to the well operating conditions.

Capital Efficiency Plan™ for Norwalk, CT First Taxing District

Tata & Howard, Inc. was retained by the First District Water Department (FDWD) to complete a Capital Efficiency Plan™ for the First District water system in the City of Norwalk, CT.  Areas of the water distribution system in need of rehabilitation, repair, or replacement, were identified and improvements were prioritized to make the most efficient use of the FDWD’s capital budget. The study evaluated the existing water infrastructure including water transmission and distribution piping and appurtenances. In addition, water storage needs were evaluated and prioritized.

Tata & Howard evaluated the water distribution system using the Three Circle Approach, which consists of evaluation criteria including a system hydraulic evaluation, a critical component assessment, and asset management considerations.

Hydraulic improvements included recommendations that would strengthen the transmission capabilities of the system or provide an ISO recommended fire flow to a certain area. Priority 2 recommendations were identified as part of a system-wide evaluation to improve estimated needed fire flows and system looping.


A critical component assessment was performed for the water distribution system to evaluate the impact of potential water main failures on the system.  The critical component assessment includes identification of critical areas served, critical water mains, and the need for redundant mains.  Critical areas served were identified by the FDWD and include water department facilities, medical facilities, schools, and business districts. Critical water mains include primary transmission lines as well as water mains that cross over major highways, rivers, and railroad tracks. Factors that affected the decision to replace or rehabilitate a water main include break history, material, age, diameter, soil conditions, water quality, and pressure.

An asset management assessment was completed for the system. A number of factors are considered in the ratings including break history, material, age, diameter, soil conditions, water quality, and pressure, and these factors affect the decision to replace or rehabilitate a water main.

Utilizing the Three Circle Approach, improvements were recommended and prioritized based on the aforementioned criteria. Phase I improvements include any recommended improvements that fall into all three circles and are therefore hydraulically deficient, critical, and have a high asset management score.  There are approximately 16,300 linear feet of new main in the Phase I recommended improvements. Phase II improvements include any recommended improvements that fall into two of the circles. There are approximately 81,400 linear feet of new main in the Phase IIa and Phase IIb recommended improvements. Phase III recommendations include any recommended improvements that are needed hydraulically or that have a high asset management score indicating poor condition. The Phase IIIa and Phase IIIb include approximately 157,000 linear feet of new main. In addition, recommendations included soil testing for corrosivity prior to ductile water main installation, implementation of a unidirectional flushing program, and annual updating of the hydraulic model.

Capital Efficiency Plan™ and Water System Master Plan, Attleboro, MA

Tata & Howard, Inc. was retained by the City of Attleboro to complete a Capital Efficiency Plan™ and Water System Master Plan for the Attleboro water system.  The purpose of the Capital Efficiency Plan™ portion of the project was 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 City’s capital budget. The Water System Master Plan portion of the project created an inventory of the existing above ground water infrastructure assets including wells, pumping and treatment facilities, and water storage tanks. The inventory can be used to track maintenance, repair, and replacement work.  Basin safe yields were reviewed and compared to projected demands to evaluate the adequacy of sources of supply. In addition, the project included creation of an extended period simulation (EPS) hydraulic model which can be used to analyze the system and account for changes over time.

An asset management assessment was completed for the system. Several factors are considered in the assessment including age, material, diameter, break history, soil conditions, water quality, pressure, and whether the main was installed poorly.  These factors affect the decision to replace or rehabilitate a water main.  Using our asset management rating approach, each water main in the system was assigned a rating based on these factors. Utilizing the Three Circles Approach, improvements were recommended and prioritized based on the aforementioned criteria. Recommended improvements include the following:

  • Three phases of water main replacement projects;
  • A Water Quality and System Optimization Study to evaluate ways the City can lower the water age in the storage tank;
  • A study to evaluate improvements to maximize available yield;
  • Collection and maintenance of data on water main failures as well as pipe crushing results from water mains that have failed;
  • Testing of soil for corrosivity prior to installation of new ductile iron water mains;
  • Implementation of a Unidirectional Flushing Program; and
  • Minor repairs and security improvements to address deficiencies in the City’s above ground assets.

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Pilot Testing for Iron and Manganese Removal in Barnstable, MA

Due to elevated levels of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), 1,4 Dioxane, and iron and manganese in the three drinking water production wells at the Maher Water Treatment Facility, the Town of Barnstable is proceeding with design and construction of upgrades at the facility to treat for these constituents.

Pilot testing includes carbon, Greensand, and LayneOx filters

The Town of Barnstable is currently conducting pilot testing at the site to determine the required design parameters, treatment process effectiveness, and best technology to achieve the desired treated water.  Treatment processes associated with pilot testing include GreensandPlus and LayneOx for removal of iron and manganese, advanced oxidation (ultraviolet light with hydrogen peroxide) for removal of 1,4-dioxane, and granular activated carbon (GAC) for removal of PFOS and PFOA.  Treatment for 1,4 Dioxane is the primary goal of the pilot test in order to meet the requirements of the Massachusetts Department of Environmental Protection (MassDEP) New Technology Approval process.

The MassDEP has confirmed that pilot testing of GAC filtration at the Maher facility is not a statutory requirement due to the current use of this water treatment technology at the Town’s Mary Dunn Wells and the availability of current water quality data for treatment of PFOS/PFOA within the same water system.  However, the Town has decided to include GAC filtration with pilot testing of advanced oxidation and iron and manganese removal to evaluate the performance of all proposed treatment processes operating together.

UV reactor for pilot test

Pilot testing is being conducted by Blueleaf, Inc. as a sub-consultant to Tata & Howard, Inc.  Pilot testing was completed in 2017.

 

 

 

 

Water Treatment Plant in North Chelmsford, MA

Tata & Howard completed a test evaluation and design report for the Bomil Well site comparing ultrafiltration using ozone and chlorine dioxide as oxidants. The report also evaluated several coagulant aids to treat the organic color in the water. The design report became the basis for the 2.5 mgd water treatment facility designed by Tata & Howard. The facility uses membrane filtration with chlorine dioxide for treatment.  Construction administration was also provided by Tata & Howard.

Iron and Manganese Removal Using Greensand Pressure Filtration


Tata & Howard conducted a Water Quality Study that reviewed the Town of North Attleboro, Massachusett’s corrosion control practices, and evaluated changes in quality, specifically the increased levels of iron and manganese. The manganese concentrations in these wells had consistently increased during the past decade. The pilot treatment study for manganese removal with greensand pressure filtration was conducted at the Kelley Wells 1 and 2 and was a success. Tata & Howard completed the design of the 2.0 mgd capacity treatment facility and provided engineering services during the construction of the facility.

The design included the installation of a SCADA system for monitoring and control of the treatment facility and two well pump stations.  A second operator work station was installed at the remote Water Department office which allowed both monitoring and control of the treatment facilities from this remote site.  In addition, the operator work station was linked to the existing Autocon SCADA system which continued to monitor and control the remaining water system pumping stations and storage tanks and provide tank level signals for the establishment of start/stop setpoint controls for the new treatment facility and associated wells.

 

 

 

 

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Manganese Filtration Using Biological Pressure Filtration

The Home Farm Water Treatment Plant (WTP) in Shrewsbury, Massachusetts was originally constructed in 1989. Although the WTP is still fully functional, its treatment capabilities are limited to chemical addition and air strippers for VOC removal, and the plant is capable of treating 6.0 million gallons per day (mgd). Manganese is present at all Home Farm wells, with widely varying levels from a low 0.03 parts per million (ppm) to a high 0.7 ppm. The existing treatment plant sequesters manganese, but does not have the ability to remove it from finished water.

Pilot test setup

Three treatment methodologies were piloted. The first two were greensand and pyrolucite, both commonly implemented catalytic media options for removing manganese and iron. The third was Mangazur®, a new technology. Mangazur® filter media contains the microscopic organism leptothrix ochracea, which consumes manganese and is naturally occurring in groundwater. Through consumption, the microbes oxidize the manganese to a state where it can precipitate onto the media. Unlike other media, Mangazur® does not require regeneration due to the continuous growth of microbes within the filter. Mangazur® technology also does not require chemical addition for pre-oxidation, minimizing the amount of chemical required for the plant.

Pilot testing for the biological treatment was performed over five one-week trials. Test parameters included a long shut-down on the filters, adding pre-oxidant, and adjusting pH or dissolved oxygen. The results of the testing indicated that although the Mangazur® does require a correct dissolved oxygen level and pH, it does not require a pre-oxidant, making the only chemical addition necessary for pretreatment potassium hydroxide for pH adjustment. Filter backwash efficiency is also a major benefit of the Mangazur® technology for the Home Farm application. With loading rates twice that of traditional catalytic media and filter runs exceeding 96 hours; the Town would only need to backwash the four filters once every four days rather than eight filters every day, saving a significant amount of water. The backwash flow rate and duration are also significantly lower for Mangazur® filters than for other traditional filter options. The results of the pilot tests indicated that all technologies were viable options to reduce manganese levels below 0.05 ppm; however, the biological treatment was the most efficient and attractive option.

Ground breaking on the new WTP took place in July 2017.

Initially, the Town was only considering constructing filters along with the required backwash holding tanks in a new building and utilizing the chemical feed systems in the existing treatment facility. However, as the project progressed it was determined that it would be more cost effective to replace the existing aging air strippers rather than to continue to rehabilitate them, and eliminate the need to re-pipe the flow since the existing strippers added too much dissolved oxygen prior to the biological units. Since the existing chemical feed equipment in the plant is aging and the existing building itself was also in need of rehabilitation, the decision was made to construct an entirely new standalone 7.0 mgd facility. The new facility also contains three deep bubble aerators for VOC removal.

While Mangazur® technology has been approved in one other municipality in Massachusetts, there are few treatment plants in the northeast using this technology, and of those treatment plants, none have a design capacity above 5.0 mgd.  Home Farm has a much higher design capacity and will be the largest Mangazur® water treatment plant in the northeast once completed.  The Mangazur® filters at Home Farm will have the second highest design capacity in the country, after a 26.0 mgd treatment plant in Lake Havasu City, Arizona.

 

 

You may download the complete whitepaper by clicking here.

 

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Dam Emergency Action Plans (EAPs) in Connecticut

dam-eaps
Quillinan Reservoir Dam

Tata & Howard has prepared numerous dam emergency action plans (EAPs) for Connecticut dams in accordance with CT DEEP regulations. Between 2015 and 2017, we have completed 52 EAPs for significant and high hazard dams throughout Connecticut. Our clients have included municipalities, private dam owners, and the CT DEEP. The EAPs include the following:

  • Preparation of an inundation map and flood inundation summary table for the EAP based on the dam failure analysis. The inundation maps include the limits of potential flooding (LoPF), selected cross sections, estimated time to peak stage, and the water depth at selected locations within the LoPF. For dams with no dam failure analysis, Tata & Howard prepared inundation maps for a hypothetical dam failure using hydrologic routing techniques.
  • Preparation of a list of roads and addresses at risk and subject to flooding based on the inundation map.
  • Preparation of dam monitoring procedures including identifying the persons responsible as well as procedures for monitoring the dam during periods of heavy rain and runoff, or when conditions develop that warrant closer monitoring, such as increased or new seepage, cracking, settlement or sabotage. The EAP provides dam specific information to assist the dam owner or operator in determining the appropriate emergency level for the event.Preparation of a formal warning notification procedure to alert the local authority responsible for acting on a warning or determining whether to evacuate residents and businesses within the inundation area after an unusual or emergency event is detected or reported at the dam.
  • Preparation of notification flow charts with emergency contact information of federal, state, and local agencies that are responsible for providing emergency services. The flow charts depict the order and circumstance under which the contacts should be notified. The EAPs also include a list of other emergency services contacts, such as the National Weather Service and local media, as well as the addresses of the local emergency operations center (LEOC) and shelters available to residents during an emergency per CT DEEP requirements.
  • Preparation of a termination procedure for ending monitoring and response activities once the emergency is over.
Black Pond Dam in Meriden, CT
  • Preparation of criteria to review and update the EAP at least once every two years, or more frequently as necessary to reflect significant changes to the dam structure or downstream area, including verification of contacts in the emergency notification charts. The criteria also include guidance for the dam owner to conduct an exercise or test of the EAP concurrent with the review.
  • Preparation of aerial, location, and watershed maps for the dam.