Handling and Disposing of Blackwater

Workers should have hepatitis shots prior to working with blackwater.Blackwater, or sewage, is more dangerous than greywater. 

Onboard ships, it is contained and can be subjected to primary treatment.  Additional precautions need to be taken when the system requires maintenance or servicing and needs to be opened.

Working with Blackwater Pipes or Tanks

Before working with blackwater pipes or tanks:

  1. Temporary ventilation. BC Ferries Richmond BC 2014.The system must first be locked out or de-energized if it is still hooked into the ship's power.
  2. Personnel onboard the ship should be notified not to use the toilets or 'heads'.
  3. When opening the piping, filters, or any other part of the system, buckets should be placed under all connections and have spill containment and rags close by. 
  4. The tank lids should be carefully removed and either carefully stored or taken off the ship to be steam cleaned or re-gasketed.
  5. Those workers going into the areas must be suitably protected with disposable coveralls, respirators, gloves, safety glasses and face shields. 
  6. The work areas should be cordoned off with barrier tape to ensure other workers are aware of the potential hazards.
  7. The immediate vicinity should have signage that alerts other workers to the hazards.
  8. Temporary ventilation should be constructed to remove obnoxious odours.
  9. Any parts of the blackwater system, including removed pipes or filters, should be handled carefully and bagged before being taken off the ship.
  10. If the work only includes pumping down the tank, the lines should be sealed and bagged and taken off the vessel.

Entering Blackwater Tanks

In cases where workers have to enter blackwater tanks to replace piping, sensors, screens or to break up large accumulation of solids, the hazardous confined space entry procedure must be observed.

While authorization procedures to enter the tank will vary from shipyard to shipyard, what follows is an overview of a typical approach.

  1. As above, the system will be locked out and an announcement will be piped over the ship's PA system not to use the blackwater system.
  2. Workers will open the tank lids and properly stow them out of the way.
  3. Temporary ventilation will be properly positioned inside the tank (usually at the opposite corner) to draw fumes away from the opening and create the proper draft inside the tank).
  4. There will be workers assigned to monitor those entering the tank, the fluid levels, and the work in general to ensure those who enter the space are not in any immediate danger.
  5. Proper PPE is necessary for all those involved in the process and those inside the tank will usually have rubber suits, gumboots, full face respirators, and heavy gloves to keep them isolated from the contents of the tank.
  6. Large fire hoses or other suitable pressured lines for breaking up the solids will be used and there will also be some sort of remote suction line from a blackwater pumping barge or sullage truck that will extract the liquids and solids in the tank.
  7. On completion of the work, PPE clothing is washed or sprayed down with clean water and usually bagged before being taken off the ship.
  8. Before the tank lid is re-gasketed and closed up, fresh water will usually be run through the system to prove the repairs.
  9. Once the repairs have been confirmed, all lines and equipment will be cleaned as well as they can in situ, or bagged for removal from the ship. Most shipyards will steam clean and disinfect all tools that were used to complete the work.
  10. Showers may or may not be provided for workers, but are highly recommended along with a change of clothing to prevent any contamination of the worksite, shops, or vehicles.
  11. It is also important to note that blackwater tanks can generate methane gas. There should be no welding, burning or other spark making activity in the immediate area of the open tanks until a safe-to-work chit has been issued.

    12.  

When work is to be done inside clean or dirty tanks, the atmosphere should always be checked for explosive gases and for oxygen content. It cannot be overstated how important it is for workers to adhere to the protocols associated with going into these types of spaces.