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.
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.
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.
Licensed Site Professional (LSP) Services in Melrose, MA
In November 2015, during the replacement of the water main along Tremont Street, an odor was noted emanating from the trench excavated to install a temporary water supply to the City of Melrose Department of Public Works (DPW) building. A reportable release condition was subsequently found at the property and a former gasoline pump dispenser is the suspected source of the release.
Tata & Howard provided Licensed Site Professional (LSP) services for the project that included the observation of a test pit, drilling soil borings, installation of groundwater monitoring wells, soil sampling, and groundwater sampling. The initial soil sampling results indicate the presence of residual gasoline contaminants at concentrations exceeding the applicable Massachusetts Department of Environmental Protection (MassDEP) Reportable Concentrations. Therefore, Tata & Howard assisted the City with notifying MassDEP of the release.
Soil borings were drilled and soil samples were collected to delineate the extent of the release and to assess the source of the release, which is suspected to be a former gasoline dispenser that was removed in 1999. Tata & Howard conducted a Method 1 Risk Characterization to evaluate the risk of harm to health, safety, public welfare, and the environment posed by the presence of residual gasoline contaminants in soil. The results of the Method 1 Risk Characterization indicate that a condition of No Significant Risk exists for current and future foreseeable activities at the Site and an Activity and Use Limitation is not necessary to maintain a level of No Significant Risk. Tata & Howard prepared a Permanent Solution with No Conditions Statement to document these findings and submitted the report to MassDEP.
Lead-Contaminated Soil Remediation in Falmouth, MA
The Town of Falmouth retained Tata & Howard to remediate lead-contaminated soil associated with historical firing range activities at a former gravel pit owned by the Town. Due to the gravel pit’s location within a current drinking water source area, the objective of the remediation was to restore the release to background and remove the potential threat to the underlying groundwater quality. In addition, the presence of estimated habitats of rare wildlife and priority habitats of rare species at the gravel pit required the filing of a Notice of Intent (NOI) with the Conservation Commission and implementing measures to protect the rare wildlife and species. Tata & Howard prepared a site-specific scope of work for bidding purposes and managed all the field activities. Part of the remedial action plan was to screen the soil in an effort to remove the lead bullets and facilitate disposal of the contaminated soil at a Massachusetts lined landfill. Analytical testing of the soil revealed that some areas contained leachable lead, which required stabilization with Portland cement prior to being transported to the landfill. During the excavation activities, Tata & Howard utilized a field portable x-ray fluorescence (XRF) analyzer to obtain real-time concentrations of lead in soil. Use of the XRF minimized contractor down time because decisions relative to the extent of excavation required could be made in the field. Confirmatory laboratory analytical results correlated well with the XRF data. Tata & Howard prepared a Permanent Solution with No Conditions Statement, which documents that a condition of No Significant Risk has been achieved at the Site and that the release conditions have been restored to background.
Trinity Ave. Chemical Feed Pump Station, Grafton, MA
Tata & Howard provided engineering services for permitting, design, and bidding of the 1.3 mgd chemical injection Trinity Avenue Pump Station at the Trinity Avenue Wellfield. The project included an evaluation of alternatives for the access road including installation of a bridge or an open bottomed culvert; assistance with the preparation of permanent easements for the installation of utilities and roadway to the well site; preparation and submittal of an NOI to the Grafton Conservation Commission. The design included an access road, bailey bridge with abutments, double wythe block building, interior concrete painted block with wood truss roof and asphaltic shingles, installation of three (3) submersible pumps and pitless adaptors, approximately 1,800 linear feet of 6-inch and 12-inch water main, emergency liquid propane tanks and generator, instrumentation and controls, a SCADA system for the pump station and wells, and a 24-inch transmission main for 4-log removal. Security included chain link fence, gates, locks, intrusion alarms, and lighting. Tata & Howard also assisted Owner 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 project is currently under construction and is expected to be completed by the end of 2017.
Tata & Howard has completed a variety of hazardous waste services for a private client in Newton Centre, MA. Work included completion of the Immediate Response Action (IRA) Completion Report and Response Action Outcome (RAO) as well as obtaining indoor air samples and submitting the results to the Department of Environmental Protection (DEP) every two years. Tata & Howard also prepared and submitted Post Class-C RAO Status Reports. This involves documenting the operational status of the sub-slab depressurization systems (SSDSs) and obtaining and analyzing groundwater from three key wells to evaluate whether conditions have changed. The Status Reports are required every six months.
In addition, Tata & Howard completed the installation of a telemetry system, preparation of an Activity and Use Limitation (AUL), preparation of a Permanent Solution with Conditions (PSC) report, annual inspection of the sub slab depressurization systems (SSDSs), and the replacement of a monitoring well cover. The work included updating the existing SSDSs in accordance with anticipated revisions to the MCP by adding an alarm system designed by Tata & Howard equipped with remote telemetry able to notify the the consultant, clients, tenants, and MassDEP in the event of a system failure. The work also included a metes and bounds land survey.
Tata & Howard also performed work to comply with the revised Massachusetts Contingency Plan (MCP) and developing the data necessary to support a Permanent Solution for the release of chlorinated solvents at the Site. The work included the installation of five additional soil gas monitoring points at the Site and the collection of the data. These points were required to collect additional soil gas data to evaluate whether vapor migration has been controlled. The samples were submitted for laboratory analyses. Also, Tata & Howard collected groundwater samples from seven key monitoring wells using low flow sampling. The groundwater from the wells were measured for pH, temperature, dissolved oxygen (DO), oxidation-reduction potential (ORP), specific conductance, and turbidity. This project is ongoing.
Tata & Howard, Inc. prepared a Water System Operations Plan for the Falmouth water system. As part of the Settlement Agreement between the Town of Falmouth and the Commonwealth of Massachusetts, the Town agreed to complete a Water System Operations Plan. The purpose of the plan was to evaluate seasonal demands, current source and storage tank operations and identify system and operational changes necessary to address distribution areas with low chlorine residuals.
The Town of Falmouth’s water distribution system consists of approximately 400 miles of water mains of various materials ranging in size from six to 24 inches in diameter. The Town has five active water supply sources including both groundwater and a currently unfiltered surface supply. Each source is treated with sodium hypochlorite for disinfection with the exception of Long Pond, which includes disinfection with chlorine gas. Falmouth’s water distribution system includes four water storage tanks and a Supervisory Control and Data Acquisition (SCADA) system to run and monitor operations.
The Falmouth Water Department faced a number of challenges, including the following:
Maintaining regulatory compliance
Meeting water demands
Peak summer demands could only be met with Long Pond surface supply
Long Pond is an unfiltered surface water supply
Constant struggle to maintain treatment compliance and water quality
Seasonal impacts from turnover or algae growth
Lack of treatment to address taste, odor, and color can require severe curtailment in use of the supply
Excessive source chlorine residuals needed to maintain distribution system residual chlorine concentrations, combined with source water organics results in elevated disinfection by-products (DBP – Total Trihalomethanes and Haloacetic Acids) which are regulated compounds
The study reviewed the challenges above and recommended changes to systems operations procedures to improve water quality. We used a hydraulic model to determine water age and look at its impacts on water quality. The plan was submitted and approved by Mass DEP.
Additionally, Tata & Howard completed the design of a 3.6 mgd treatment facility which utilizes air stripping and pressure filtration technology for the removal of iron, manganese and volatile organic compounds (VOCs). The facility includes an air stripping tower, three greensand filtration units, horizontal carbon contactors, chemical storage and feed facilities, gravel pack supply well, finished water storage, and backwash holding tanks.
Tata & Howard has been working with the District assisting them to come into compliance with the deficiencies noted in their Sanitary Survey. This District was once a private water company with numerous water quality, pressure, and supply issues and it finally was turned into a Fire District. The system has 45 connections and is on a water connection ban from the State. Tata & Howard prepared a Water Supply Feasibility Study with regards to addressing all of the systems issues, which are noted below:
Issues with the spring source and its spring house structure
Issues with inadequate system pressure at a few connections
No disinfection system or stand by disinfection system
Lack of source metering
Lack of source overflow metering
Lack of auxiliary well approval
Lack of system flushing hydrants
Lack of good water system map
Inadequate supply during summer months due to reduction in spring source
Failed coliform tests requiring disinfection
The solutions developed included the following:
New spring house roof and structure for disinfecting
Computer modeling for alternatives to address inadequate flows and pressures
Evaluation of the emergency well with Hoffer Consulting
Development of a source metering vault and system
Disinfection system for stand-by disinfection
Plan for metering the spring overflow
Alternatives for water system storage
Alternative to connection to other water system source
Flushing hydrants installation options
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