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.

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.

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.

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.

KKWWD, ME Organizational Review and Succession Planning BPE

KKWWD-waterTata & Howard conducted a Business Practice Evaluation (BPE) for the Kennebunk, Kennebunkport, and Wells Water District (KKWWD), Maine that included the following:

Task 1: Project Management and Communications

Project kickoff meeting with management staff included discussion of project approach and schedule, level of District involvement, and project deliverables.

Task 2: Organizational Assessment

Reviewed documents, facilitated individual interviews, and conducted on-site workshops to evaluate the current organization against desired business goals and industry best practices.

Task 3: Developed Draft Succession Plan for business continuity of Water District

Developed a Succession Plan based on current personnel and organizational structure. The plan shows a path forward for staff to ascend in the organization through natural progression.

Task 4: Draft and Final Organizational Review and Succession Plan

Prepared Draft and presented results of the Organizational Review and Succession Plan to KKW.  After comments were received on the draft, Tata & Howard provided the final document.

Dam Emergency Action Plans (EAPs) in Connecticut

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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.
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    Papermill Pond Dam

    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.
  • Black Pond Dam in Meriden, CT

    Preparation of a termination procedure for ending monitoring and response activities once the emergency is over.

  • 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.

Environmental Services, Wilmington, MA

environmental-servicesTata & Howard has been providing environmental services for a Site in Wilmington, Massachusetts for several years. The contaminants of concern at the Site are chlorinated volatile organic compounds (CVOCs). The CVOCs were detected in June 1994 as part of a due diligence assessment for bank financing, and the sources of the CVOCs are from prior operations at the Site that utilized chlorinated solvents to clean electronic parts. These compounds were released to the environment through improper disposal and leakage from the equipment that was used onsite.

Remedial activities were performed at the Site to reduce the concentrations of CVOCs in soil and groundwater, and in August 2000, a Class C Temporary Solution Response Action Outcome (RAO) was filed with the Massachusetts Department of Environmental Protection (MassDEP), which concludes that there was no substantial hazard to human health, safety, public welfare, or the environment caused by the contamination at the premises. That conclusion is based on appropriate assessment, testing and analyses, and includes a Method 3 Risk Characterization, which supports those findings. In August 2005, and again in August 2010 and September 2015, the Class C RAO was renewed based on the conclusion that there was, as of the date of each renewal, no substantial hazard caused by the contamination at the premises.

In May 2015, T&H filed a Release Abatement Measure (RAM) Plan for the installation of a sub-slab depressurization system (SSDS) at the Site as part of a Permanent Solution in accordance with MassDEP’s regulations. Based on more recent data, six points and radon type fans were installed in an effort to develop a negative pressure field beneath the western portion of the building. T&H also installed a remote telemetry system equipped with an alarm that will notify MassDEP, Tata & Howard, and the owner of the building if the SSDSs fail as the result of loss of power, mechanical issues, or other disruption of the system.

The building is primarily comprised of office and commercial warehouse space, and an Activity and Use Limitation will be implemented as part of the Permanent Solution to prohibit more sensitive uses in the future, such as daycare or residential.

Southern Maine Regional Water Council (SMRWC) Regional System Study

SMRWC graphicv1 - Dist-Flows

Tata & Howard was retained by the Southern Maine Regional Water Council (SMRWC) to complete a Regional System Study for the Portland Water District (PWD), Maine Water Company – Biddeford & Saco (MWCB&S), Kennebunk, Kennebunkport, Wells Water District (KKWWD), Sanford Water District (SWD), South Berwick Water District (SBWD), York Water District (YWD), and Kittery Water District (KWD). The purpose of the study was to provide a detailed update to their 2008 Regional Water System Master Plan Study, which studied possible interconnections between the water systems within the SMRWC.  A combined water distribution system regional hydraulic model was developed using the hydraulic models of each individual water system. The regional hydraulic model was used to evaluate the hydraulic feasibility and impacts of the proposed interconnections as well as the potential of transferring water from northern systems to southern systems through a completely connected and open system.  The PWD and MWCB&S have large water sources and are interested in exploring the option of providing water to southern systems. The study evaluated the needed infrastructure improvements, each system’s available water supply, and demands through the potential and existing interconnections.

The study also examined the effects that the proposed system improvements and interconnections would have on water quality. Not all water systems treat water in the same way; therefore, finished water is unique to the chemicals and treatment techniques used by each system. Specifically, pertinent available data was collected and chemicals used for coagulation, sequestering, primary disinfection, secondary disinfection, corrosion control, pH adjustment, and dental health were reviewed.  Raw and finished water parameters such as turbidity, alkalinity, temperature, pH, and total hardness were also collected.  Of the seven participating water systems in the study, three disinfect with chloramines and four disinfect with only chlorine solution. Operating the systems together as a permanent solution to water supply concerns would require modifications to the treatment processes in some if not all of the systems.  Ideally, each water system involved in water sharing would need to agree to a treatment method to give each system acceptable water quality and eliminate concerns with blending systems.

The identified improvements were based on hydraulic feasibility.  Infrastructure recommendations at the interconnection locations include construction of new water mains, pressure reducing valves, and booster pumping stations.

Regional Intermunicipal Interconnection Evaluation, MA

Northampton interconnection mapThrough a grant from the Pioneer Valley Planning Commission, Tata & Howard was retained by the City of Northampton Department of Public Works (Northampton) and the City of Easthampton Water Works (Easthampton) to complete a Regional Intermunicipal Interconnection Evaluation for the Easthampton, Hatfield, Northampton, Southampton, and Williamsburg water systems.  The purpose of the study is to evaluate potential water distribution system intermunicipal connections and emergency water supply.  A combined water distribution system regional hydraulic model was developed and used to evaluate the hydraulic feasibility and impacts of the proposed interconnections.  The study evaluated the needed infrastructure improvements, system available supply and demands, and available supply through the potential interconnections.

Potential interconnection locations between Northampton and Easthampton were considered at four locations, between Northampton and Hatfield, between Northampton and Williamsburg, and between Easthampton and Southampton.  Infrastructure recommendations at the locations include construction of new water mains, meter pits, flow meters, pressure reducing valves (PRV) and portable pumping systems. The Massachusetts Department of Environmental Protection (MassDEP) Water Management Act (WMA) permitted and registered pumping volumes for each system’s sources was evaluated for potential supply to other communities.  Northampton and Easthampton have surplus supply, while Hatfield, Williamsburg, and Southampton are approaching their WMA permit or registration allowable withdrawal volumes.

The study determined the following:

  • Three of the four potential interconnection locations between Northampton and Easthampton could be utilized in an emergency by isolating portions of Northampton’s system. An interconnection that could serve all of Northampton would require a pumping system.
  • A pressure reducing valve would be required to supply Hatfield from Northampton and a pumping system would be required to supply Northampton from Hatfield.
  • Due to the location of the Williamsburg interconnection along Northampton’s transmission main route, and the limited amount of water available from Williamsburg, an interconnection from Williamsburg to Northampton is not feasible.

There is an existing hydrant to hydrant interconnection between Easthampton and Southampton that has been utilized to supply water to Southampton during periods of high summer demands. To supply the entire Southampton system, a pumping system would be required, and a PRV would be required to maintain adequate pressures if Southampton were to supply Easthampton.

Bellemont, AZ Water Treatment

bellemont-water-system-az-chlorine-injection-768x399Tata & Howard provided general engineering services to Bellemont Water System associated with responding to Arizona Department of Environmental Quality (ADEQ) violations and preparing an Application for the Groundwater Compliance 4-Log Removal of Viruses. Randall Pellatz, P.E., from Tata & Howard’s Flagstaff office, served as Project Manager.

Located west of Flagstaff in the unincorporated community of Bellemont, the water system served approximately 100 customers — the majority of whom receive water hauled by truck to cisterns at their homes — as well as a few businesses, including a strip mall. The system also provides some fire protection. After the system repeatedly tested positive for E. coli bacteria and total coliform bacteria, a boil water notice was issued in August of 2012. In June of 2013, ADEQ issued a compliance order that required the Bellemont Water System to notify all customers of the boil water advisory and to install a treatment system that satisfactorily removes bacteria and viruses from the water. The source of the contamination was unknown.

Tata & Howard’s scope of services included providing a response to ADEQ’s compliance order and developing a preliminary plan of action for maintaining 4-Log Removal of Viruses for the Bellemont Water System. In addition, a preliminary schematic plan for a chlorination system was developed to provide a residual chlorine concentration throughout the Bellemont Water System. Tata & Howard also provided design services for the proposed disinfection system and completed an assessment of the existing conditions of the Bellemont Water System, including recommendations, in a letter report.

The system’s operator, Jeremy McCabe, installed the disinfection system, and in June of 2016, the Bellemont Water System underwent their final field inspection from ADEQ for chlorine residual and 4-log removal. They passed easily, and ADEQ was pleased to remove the boil water requirement. Mr. McCabe commented on how well the system now operates, and the system’s customers have expressed how happy they are to once again have safe, clean water.

Raw Water Transmission Main Replacement in Stamford, CT

awc-laurel-street-raw-water-mainOwner: Aquarion Water Company, Shelton, Connecticut

Tata & Howard provided professional engineering services for surveys and mapping; subsurface explorations; preliminary and final design; bidding; and construction phase services, including resident project representation, for the partial replacement of Laurel Reservoir Raw Water Transmission Main located on Lakeside Drive in Stamford, CT. The main was replaced after a history of multiple pipe failures. This project included replacing approximately 3,670 feet of an existing 13,540 feet of 42-inch diameter prestressed concrete cylinder pipe (PCCP) used to transfer raw water by gravity from Laurel Reservoir to the Stamford Water Treatment Plant (WTP). The pipe was replaced with 48-inch Class 52 ductile iron pipe.  Three existing 8-inch blowoffs and two existing 4-inch diameter automatic air release valves in this section of main were replaced and upsized with new 12-inch diameter blowoffs and 12-inch diameter valves. The main was encased in concrete at three culvert crossings. Additionally, two 24-inch diameter access openings were installed in the existing 42-inch diameter main that was not being replaced to allow for inspections while the pipe was drained and out of service.  The project also included replacement of four existing automatic air release valves on the existing 42-inch diameter PCCP that was to remain in service.

Interceptor Sewer, Danbury, CT

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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.