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.
CMOM Requirements in NPDES General Permit | Board of Sewer Commissioners, Winchester, NH
Tata & Howard is assisting the Town of Winchester to meet the Collection, Management, Operation, and Maintenance (CMOM) requirements in the Town’s NPDES General Permit. To date, the work has consisted of the preparation of an outline for the Full Collection System Operation and Maintenance Plan, which includes descriptions of staffing, management goals, information management, condition assessment, recent studies, and construction activities. Tata & Howard has been retained to prepare the Full Collection System Operation and Maintenance Manual, which includes updating the outline, preparing a preventative maintenance and monitoring program, identifying sources of suspected overflows and back-ups, preparing a program for preventing I/I related effluent violations, and a public outreach program regarding I/I control.
Additionally, Tata & Howard has assisted the Town of Winchester with three phases of improvements to the Winchester Wastewater Treatment Facility (WWTF), I/I investigations, repair and rehabilitation of the sewer collection system to remove I/I, and securing funding to upgrade the WWTF and sewer collection system.
Tata & Howard is providing all engineering support services related to the operation of and modifications to the Town’s wastewater collection, pumping, and treatment systems including preparation of a Comprehensive Wastewater Management Plan (CWMP) and preparation of a comprehensive Infiltration/Inflow (I/I) Evaluation. In addition, we are providing all ongoing support services related to the preparation of a Capacity, Management, Operations, and Maintenance (CMOM) program to meet US EPA’s regulations as well as technical assistance on the renewal of the Town’s NPDES permit. Included in this project is the preparation of the Town’s I/I control plan and all annual updates, preparation of the Town’s sewer use regulations and standard specifications for sewer construction, review of plans for all private developments, and review of all applications for industrial wastewater connection permits and pretreatment reports.
All services related to I/I identification, evaluation, and removal performed on the Milford’s sewer system, which consists of approximately 100 miles of interceptor sewers and mains, including an innovative sump pump removal program, has resulted in a dramatic reduction in extraneous flow to the system.
Tata & Howard is working on a five year infiltration/inflow (I/I) control plan for Cherry Valley Sewer District (CVSD) in Leicester, Massachusetts. The program consists of flow monitoring, field investigation, and rehabilitation to the wastewater collection system.
In year one of the program, continuous flow, groundwater, and rainfall monitoring took place in the spring to collect data for program analysis. Simultaneous to the monitoring, manhole inspections were performed to assess I/I potential from manholes.
Year two consisted of a data analysis of the flow monitoring results of year one. The results of this data analysis from the I/I control plan provided guidance to moving forward with I/I investigation.
Field investigation commenced in year three of the program with smoke testing being completed throughout the collection system. To follow up with results from the manhole inspection, manhole rehabilitation was performed on manholes in which I/I was evident.
Year four focused on field investigations. A large section of the collection system was inspected via closed circuit television (CCTV). Follow up building inspections were also performed in areas where sump pump connections were suspected to be an issue. Year four also focused on system operation and maintenance. Documents were created for CVSD to focus on operations and maintenance of the system, and specifically for the manhole which houses the system flow meter into Worcester.
Year five is consisting of further CCTV investigation and a final report to summarize the project and provide recommendations on moving forward with investigations. Future work is anticipated to focus around GIS aspects of the system and working with CVSD to maintain records and reduce I/I by being proactive with investigation and maintenance.
Pump Station Design and Wastewater Treatment Facility Upgrades, Barre, MA
The Town of Barre retained Tata & Howard to evaluate their existing wastewater treatment facility. Tata & Howard recommended a three phase upgrade program in order to reduce the initial impact of the construction cost on the sewer use rates. Included in the upgrade program was the design and construction of a submersible pump station that lifts the raw wastewater from an equalization tank to the biological treatment process. The pump station has a capacity of 1.2 mgd and includes variable frequency drives. The pumping station is controlled by a new SCADA system at the wastewater treatment facility. Tata & Howard also designed 8,000 linear feet of collection system sewers in the Worcester Road area of town. The project also included 500 linear feet of force main and a wet well mounted pump station. The pump station has a capacity of 200 gpm.
Tata & Howard provided engineering services including wastewater consulting services to develop a plan for the removal of existing inflow and infiltration (I/I) from the Town of Pembroke’s sewer collection system. The purpose of this evaluation was to review pertinent available information provided by the Town, develop a draft plan of approach to reduce I/I within the system over time and as funds are appropriated, develop a prioritized schedule for further investigations of I/I, and establish a protocol for the documentation of I/I removed from the collection system.
Tata & Howard has been working with the Town of Hopedale, Massachusetts for a number of years on a variety of wastewater collection and treatment projects. When the Town received an administrative order to address copper and ammonia violations at the plant, they turned to Tata & Howard for assistance. We completed the design and construction of a Wastewater Treatment Facility Upgrade project which included the installation of an automated soda ash feed system and an integrated fixed film activated sludge system (IFAS). The IFAS system is an innovative biological treatment process using thousands of special carriers designed to increase total surface area for biofilm growth without expanding the plant’s footprint. The blowers were also modified to provide better control over the aeration process.
A pilot study was conducted to test the ability of various reagents to facilitate the removal of copper from the waste stream. An automated chemical addition system was designed to improve coagulation. Additionally, a dynamic tangential filter was incorporated into the upgrade project. These improvements have allowed the Town to now meet its discharge limits for ammonia and copper.
Water and Wastewater Engineering Services: Hydraulic Modeling, Facilities Plan, WRF Improvements, Goodyear, AZ
Tata & Howard provided water and wastewater engineering services associated with the update of existing water and sewer system models using InfoWater and InfoSewer computer programs; review of the impact of proposed developments and proposed extensions to the City’s systems; verification of the hydraulic models for the City of Goodyear’s water distribution and wastewater collection systems. The water model included fire flow testing, C-value tests and calibration of the InfoWater hydraulic model. The wastewater collection system model included installation of six flow monitoring stations in three sub-basins, calibration of the model, development of a cost allocation model, and preparation of a technical report.
Tata & Howard prepared a facilities plan for the Corgett Water Reclamation Facility. The plan addressed the need for process redundancy and recommended improvements for increased flows and Class A+ effluent. Provided ongoing support services to address operational needs and to assess the impact of new developments on the system. Provided design, bidding, construction administration, resident observation, and construction services associated with improvements to the Corgett WRF including: filter system, low lift pump station, modifications to the sand filter, and instrumentation upgrades.
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