Canaan, VT and Stewartstown, NH Energy Efficient Wastewater Treatment Plant Upgrades

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.  The 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.


 

 

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Ozone Water Treatment Plant in Franklin, MA

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.

 

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 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

Pilot testing includes carbon, Greensand, and LayneOx filters

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.   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 is scheduled for completion in September 2017.

 

Water Main in Palmer, MA, funded by a CDBG

Tata & Howard provided design of 1,400 linear feet of 12-inch diameter water main on Griffin Street, High Street, and Stewart Street. Work included the preparation of design plans and specifications, hydraulic modeling to determine main size, and letter and cost estimate to the Palmer Community Development Department. Tata & Howard also provided construction administration and resident observation services. The project was funded by a USDA Rural Development Community Development Block Grant (CDBG).

Funding Assistance for WWTF Upgrade in Lyndon, VT

Upgrade for a 750,000 gallon per day extended aeration wastewater treatment facility to an A/O biological facility.  Assistance included acquiring State CWSRF planning grants and USDA Rural Development grant for extensive improvements including separation of combined sewer/stormwater collection systems (CSO), advanced Class A sludge treatment, and reconstruction of original 1970’s treatment facility to new Anoxic/Oxic Treatment System.  Total grant funds were $7,275,000.

UST Removal in Melrose, MA

UST-removalTata & Howard assisted the City of Melrose, MA with the removal of two underground storage tanks (USTs). Tata & Howard engaged the services of a qualified environmental contractor to excavate, remove, and dispose of an out-of-use UST on City property. During the excavation, a team member from our environmental services group observed a second fill pipe indicating the potential presence of a second UST. Upon further investigation, a second undocumented UST was found and the decision to remove both at the same time was made. Tata & Howard team members observed the UST removal activities, submitted confirmatory soil samples for laboratory analyses, prepared the MassDEP UST removal forms and submitted the forms to MassDEP and the Melrose Fire Department within 30 days of the UST removals. Tata & Howard also prepared a summary letter report for the site, which includes a summary of activities performed and conclusions and recommendations with regard to Massachusetts General Law c. 21E and the Massachusetts Contingency Plan.

 

 

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