Renovation of a water / sewer project in Chelmsford, Massachusetts. Completed plans call for the renovation of a water / sewer project.

The Chelmsford Water District (District) is seeking sealed bids for aeration ball replacement at the Riverneck Water Treatment Plant. This procurement is subject to the competitive bidding requirements of M.G.L. Chapter 149. All bids must be made on the forms included in these specifications. All blank spaces for prices must be filled in, either by ink or typewritten, and the forms must be fully completed and executed when submitted. The Board of Water Commissioners reserves the right to accept or reject any or all bids and furthermore reserves the right to cancel the bids and accept in part and reject in part any and all bids, and to take such action as they deem to be in the best interest of the Chelmsford Water District. The specific items requisite for this project includes, but are not limited to, the following: Riverneck Water Treatment Plant 1. Coordinate with the District on the time to remove the aerator from service while maintaining plant operations using the bypass line. Note that lines are uninsulated. Contactor will not be allowed to work during freezing conditions unless contractor can provide system to prevent water from freezing. 2. Removal and disposal of media from one (1) air stripper through the 24-inch diameter opening. Coordinate with the District on location of equipment not to interfere with operation or damage of the grounds. Ground or equipment which is damaged will be repaired at the contractor's cost. 3. Inspection of the stripping tower, noting and photographing the general conditions of the towers before and after installation. If necessary, provide crane to remove top of the aerator for access or ball installation. 4. Provide a manlift for access to the top of the towers as needed. Inspection of each distributor plate. 5. Inspection of each inlet and outlet piping connections. Inspection of seal between bottom of towers and concrete pad. 6. Inspection of air ductwork, including bolted connections, flexible bellows, filter housings, air filters, etc. 7. Inspection of all instrumentation, including blower pressure switches, differential pressure gauges, air flow measuring devices. 8. Confirm blower anchoring system, blower CFM and blower RPM. Verify blower amperage. Compare against design setpoints. 9. Inspect Gravity Dampers and Mist Eliminators. 10. Replace all gaskets from hatches that are opened. 11. Add plug on bottom drain to prevent contamination of the wetwell below. 12. Remove and dispose of the existing aeration balls. Please note that the aeration balls may be "compacted" in select locations due to the amount of iron in the raw water. 13. Pressure wash the top and bottom screens and inlet distributor to remove any iron any manganese solids. The main goal here is to fully open the screen if there is any fouling material. Remove solids at the bottom of aerator. 14. Replace the packing of one (1) air stripper tower. Packing shall be 2 inch diameter Jaegar Tri-Packs or equivalent meeting the requirements shown for 2 inch size media in the Table below. The media shall be made with prime, virgin resins with no recycled material. The injection moldable plastic to be used shall be polypropylene. The product shall meet NSF Standard 61 for use in potable water application. 15. Wash the balls as so to remove any residual plastic or compounds. The District can provide raw water and electricity at no charge to the contractor. Contactor will be responsible for electrician for any modifications required and must obtain District permission prior to the modification. Water can be discharged to an onsite retention basin. Disinfect the balls with a chlorine solution. Disinfection will be achieved when a residual of 0.2 ppm is maintained at the bottom of the aerator for 30 minutes and must be dechlorinated prior to discharge (unless going to the sewer). 16. Flow test the aerator after installation. Confirm no flooding. Confirm the unit shall remove carbon dioxide from the raw water and raise the pH to a range of 6.8 to 7.0 to from raw pH of 5.8-6.2 similar as is currently reached with the existing system. The system was designed with an air to water ratio 40:1 at 50 oF. 17. Note that sanitary sewer does exist on site. Should the contactor wish to use sanitary sewer the contactor must contact the Town of Chelmsford Sewer Department for any such disposal of liquid waste. Any sludge cannot be discharged to the on site retention pond, but must be trucked to a landfill, POTW, or sent to sanitary sewer. 18. Provide written report documenting condition of the plant as well as flow testing with any recommended updates. 19. Remove any construction debris and waste. Neutralize and dispose of according to State and Federal Regulations. Questions or requests for clarification concerning this IFB should be submitted in writing to the: Page 11 of 49 Chelmsford Water District ATTN: Andrew Reid 20 Watershed Lane Chelmsford, MA 01821 Email: areid@chelmsfordwater.com Phone: (978) 256-2931 Questions concerning this IFB must be submitted in writing and must be received by the Water Superintendent, Andrew L. Reid, at the address above prior to September 18, 2023 at 4 pm. Questions may be sent by either mail or electronic mail