QA - FY26WTRTNKKT - Water Tank Survey.docx

Questions and Answers FY26WTRTNKKT – Water Tank Survey Closed 24 Feb 2026 1000hrs

· They need to follow the AWWA C652 Tank Cleaning & Disinfection Instructions!

1. Are the tanks required to be drained for cleaning or could they be cleaned while full with divers or ROV?

According to AWWA guidelines C652, it is essential to ensure both the thorough draining of the tank for manual cleaning and the engagement of certified commercial divers for expert underwater maintenance. This dual approach not only enhances safety but also guarantees optimal cleanliness and operational efficiency.

2. If the tanks are required to be drained is scaffolding available to set up inside the tanks for cleaning?

According to the AWWA guideline C652, scaffolding may be set up and repaired; however, all scaffolding materials, planks, and tools must be clean/disinfecting and safe, and must be removed from the tank upon completion to prevent contamination.

3. Can the removed sediment/sludge be discarded on site?

The disposal of sediment and sludge must take place off-base due to potential hazards associated with these materials. The NDEP enforces strict regulations contingent upon contamination levels. It is highly advisable to transport the materials to a licensed landfill or incineration facility for proper disposal.

4. Item 4. on the SOW states a vendor shall be a Certified Water Operator. This is generally a certification that the facility would own, not a third-party contractor. Please advise if this is required.

The AWWA D102-24 standard for Tank Cleaning outlines procedures that are both professional and sanitary, frequently in alignment with OSHA standards. This process generally includes a thorough inspection of the tank, the removal of sediment, and the disinfection of the tank utilizing materials that are certified under NSF/ANSI 61. Moreover, the involvement of a certified water operator is typically mandated to oversee or execute the cleaning activities, thereby ensuring compliance with the standards set forth by the Safe Drinking Water Act (SDWA).

5. Would it be possible to have these completed within 3 weeks or would water usage requirements need a different schedule?

The project timeline will be subject to various influencing factors, including weather conditions, water consumption, the timing of contract awards, team mobilization, and our schedule for THM sampling. Moreover, we encounter challenges in effectively isolating each tank to ensure appropriate separation. Should we fail to achieve this, we may need to consider the implementation of instant water main valves as an alternative solution.

6. Will the facility allow for sodium hypochlorite to be the disinfectant on this project? If not, what is the preferred chemical and ratio for this project?

We are allowed to use sodium hypochlorite for cleaning the tank; however, it’s vital to thoroughly flush the tank after the cleaning process is completed. This flushing step is crucial to avoid any volatile reactions and toxic fumes that can arise from mixing sodium hypochlorite with calcium hypochlorite. This requirement is one of the key reasons why the contractor needs to have water certification to safely handle these chemicals. For every 1,000 gallons of tank capacity, the contractor should apply 2 gallons of 5.25% unscented household bleach (sodium hypochlorite).

7. Does the tanks sediment/debris need to be removed off site or is there a designated area within the site that it can be dumped?

The contractor is responsible for removing sediment and debris from all tanks and disposing of it at an off-base site.

8. Can you please advise on the type of debris anticipated in these tanks? Will it be sand, sediment, sludge, etc.

Although I cannot assert this with complete certainty, my experience in tank cleaning indicates that such tanks frequently contain a combination of calcium compounds, sand, organic debris, rust particles, metal shavings, fragments of plastic, and occasionally, even small aquatic life such as fishes and mussels.

9. Is the water in the tanks filtered prior to entering the tank?

No

10. Is the tank supplied from a clearwell or a treatment facility?

Tank 1721 and 1725 receive water supplied by the water agency from its treatment facility, while the other tanks get their water from various clearwells located throughout the base. In the case of Tank 562, the water source is a well, but the transmission line is approximately 5.6 miles away.

11. Are the 2015 reports available to show the type and amount of sediment in each tank?

We don’t have the reports.

12. Is water available onsite for the washing crew to use and is there a cost associated with usage?

Water will not be available on site. Crew should plan accordingly or use nearest accessible facility with a restroom. There would be no cost.

13. Does the cleaning solution and/or rinsing water used require collection and disposal?

The contractor is tasked with collecting and properly disposing of cleaning solutions and rinsing water, particularly when these substances are hazardous or contain toxic chemicals typically found in industrial or commercial cleaning. It's crucial that they follow NEDP regulations and avoid simply dumping tank cleaning water on the ground or into storm drains. Ensuring that these materials are properly contained and disposed of is vital for protecting groundwater.

14. Can the lat/long locations for the tanks be provided?

We possess the information, but it's vital for base security. The Emergency Management Team at the base might be in a better position to provide you with answers. If this is a necessity, Ms. Konstanzer will verify with the EM Team for this answer.

15. Are ladders available on the ground storage tanks so we can get to the top?

Our tanks come with access ladders, but it's important for the contractor to bring their own ladder to safely reach these access points. This requirement is in place to address safety and liability concerns.