Meadow Walk Mixed-Use Wastewater Design / Engineering Services

Design / Engineering Documentation for MBR Wastewater Treatment Facility for Mixed-Use Development in Sudbury, Massachusetts

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.

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

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.

Wastewater Treatment Plant Evaluation, Manchester-By-The-Sea, MA

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.

 

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.


 

 

Read the whitepaper below:

 

SaveSave

SaveSave

SaveSave

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.

Business Practice Evaluation (BPE), North Texas Municipal Water District

NTMSD
North Texas Municipal Water District (NTMWD) Wylie Treatment Plant, courtesy of NTMWD

Tata & Howard Provided management consulting and leadership skill building for the North Texas Municipal Water District.  Project included meeting with each of the nine wastewater treatment plant Superintendents and Chief Operators and wastewater collection system management one-on-one as well as meeting with supervisors and managers.  Two briefing workshops were conducted to discuss the findings, overall observations and potential opportunities for improvement that benefits the treatment and collection system facilities.  In addition, a management, operation and maintenance (MOM) workshop was conducted that discussed effective business practices that were compared to industry standards.

 

SaveSave

Odor Control at Wastewater Treatment Plant, Lyndon, VT

The wastewater treatment plant in Lyndon, Vermont was experiencing excessive odor issues. The existing odor control system relied primarily on chemical treatment, which was difficult for the operators to manage. Tata & Howard’s project design consisted of a bio-filter with root mulch to remove the odors, which are primarily ammonia, that are generated from the Auto Thermophilic Aerobic Digestion (ATAD) sludge treatment vessels. The ATAD system is a system that results in class A sludge that can be spread anywhere as a fertilizer, and it reduced the annual volume of sludge produced at this facility by 65%. The new system includes fans that pull the air off the top of the ATAD unit vessels through a cool down water wash tank, which knocks down the ammonia, and then pushes the air through PVC piping up through the root bio-filter shown in the picture. The total cost was under $300,000, for which Tata & Howard procured the Town a 100% grant.

The second part of the design project included a nitrogen reduction system for the secondary aeration process that may be necessary in the near future.  The design includes a recirculation pump system from the Anoxic zone back to the Oxic zone. The Contractor was T. Buck Construction of Maine.

lyndonvt_odorcontrol_wwtf_interior

Interceptor Sewer, Danbury, CT

interceptor_sewer
Jacking a 48-inch steel casing under I-84 in Danbury, CT

The Oakland Avenue sanitary sewer project consists of jacking a 48-inch steel casing pipe through the Interstate-84 embankment in Danbury, CT and installing a new 24-inch sanitary sewer to replace the existing 16-inch sewer that is undersized. The project will alleviate the restriction that is causing sewer overflows. Services included surveys and mapping, review of easements, review and updating of original design, preparation of plans and specifications, bidding, construction administration, and resident observation. Construction is currently underway and the project is expected to be completed by the end of this October. The new sewer line installation will complete an interceptor project that was constructed in 1994.

Infiltration/Inflow Investigations in Milford, MA

Milford, MA wastewater treatment plant
Milford, MA wastewater treatment plant

Tata & Howard has been conducting Infiltration/Inflow (I/I) investigations for The Town of Milford, Massachusetts for the past several years within their collection system, which consists of approximately 90 miles of 4-inch diameter to 36-inch diameter gravity sewers and force main, ten pump stations and a 4.3 million gallon per day (MGD) advanced wastewater treatment facility.  Throughout the investigations, I/I sources such as broken service connections, broken pipes, cracks, roots, and illegal connections have been identified.  The I/I ranged from 144 gallons per day (gpd) to in excess of 400,000 gpd.  Based on the results of previous I/I investigations, the Sewer Department was able to remove a direct connection from the street drainage system to the sewer system that resulted in the removal of an estimated 450,000 gpd of extraneous water from the sewer system, therefore regaining 10 percent of available capacity at the treatment facility.

As a result of conducting these I/I investigations, the Town has the ability significantly reduce the amount of extraneous water entering the collection system, as well as free up capacity at the treatment facility.  The Town of Milford has also incorporated a 5:1 removal policy within the Town Bylaws, which requires Contractors/Builders to remove 5 gpd of I/I from the system for each gallon of wastewater proposed to be discharged, which minimizes repair costs for the Town and their residents.