Repair Drinking Water Tanks

1. GENERAL: The intent of this project is to perform inspection, cleaning, and maintenance repairs of concrete underground water storage tanks at New Boston Air Force Station, New Hampshire. The tanks are located within the high security area, also known as Restricted Area 1. One tank is housed at Building 107, while the other tank is located at Building 135. See the attachments for work location. The work shall be accomplished according to these requirements: - 1.1. This Statement of Work. - 1.2. The American Water Works Association (AWWA) Standards, (http://www.awwa.org/publications/standards.aspx). - 1.3. The New Hampshire Department of Environmental Services (NH DES) Code of Administrative Rules (CAR), (http://des.nh.gov/organization/commissioner/legal/rules/documents/env-dw504.pdf). - 1.4. Unified Facilities Criteria (UFC) 3-230-02, Operation and Maintenance: Water Supply Systems, http://www.wbdg.org/ccb/DOD/UFC/ufc_3_230_02.pdf - 1.5. National Sanitation Foundation (NSF). - 2. LOCATION: New Boston AFS is located approximately 15 miles northwest of Nashua New Hampshire. New Boston AFS is a restricted military installation (see physical security requirements paragraph 11.3 attachments below). - 3. EXISTING FACILITIES: - 3.1. Under normal operation, water from two wells is transferred into Building 135. Building 135 houses a 100-gpm air stripper and tablet chlorinator. Water is passed through the air stripper, and disinfection of the well water is accomplished by dissolving chlorine tablets into the water stream leaving the radon stripper prior to its entering the 110,000 gallon storage tank below Building 135. The 110,000 gallon storage tank consists of of two chambers that hold 55,000 gallons each, which can be isolated, if required. - 3.2. Additional equipment at B135 includes two electric Fire Pumps, a Tank Discharge Pump, and two VFD controlled Transfer Pumps. The Tank Discharge Pump allows the ability to drain the entire 110,000 gallon storage tank or each individual 55,000 gallon tanks for maintenance or in emergency situations. The pumped water exits the building into a discharge swale to the east of Building 135. - 3.3. The transfer pumps in Building 135 send potable water to the 60,000 gallon concrete storage tank below Building 107. The tank is used for potable water storage and water reserve for fire surpression. The potable water from Building 135 enters the B107 addition where it is metered and can be disinfected prior to entering the 60,000 gallon tank. - 3.4. Building 107 houses two 100 gpm domestic pumps that draw from the 60,000 gallon storage tank into the distribution system. Building 107 also houses two fire pumps: a diesel 1,500 gpm fire pump and an electric 1,500 gpm fire pump. The fire pumps draw from the 60,000 gallon storage tank and connect to the water distribution system. - 3.5. These tanks are considered permit required confined spaces.