Periodical maintenance of biological vacuum sewage treatment plant is required to ensure biological treatment process is running as designed and there is no malfunctions with the risk of anaerobic process resulting formation of methane gas and toxic fumes (IMO MSC/CIRC. 648 -1994.06.06.).
- Observe that the treatment unit is operating normally and there is no alarms displayed.
- Check that sludge flows through the sludge return hose (by air lift) when the air blower is running.
- Check a smell of the unit. If the unit is smelling, it is most probably that aeration is not working and treatment process has changed to anaerobic.
- If the chemical dosing system is in use, check the chlorine content in the effluent water regularly.
- Test sludge content in activation chamber I to ensure that mineral sludge content is within acceptable limits.
Take a sludge content test at least every week or every time when sludge “SLUDGE ALARM” is displayed.
- Check that there is no obstruction in the aeration piping and in the air distributors.
- Check that there is no obstruction in the overflow between the aeration chamber II and the settling chamber.
- Check that there is no obstruction in the overflow between the settling chamber and the disinfection chamber.
- Check that there is no obstruction in the venting line.
- Inspect the tank’s external and internal coatings for corrosion.
- Check vacuum function.
- Empty and clean the unit.
- Make sure that the unit is well ventilated and there is enough fresh air in the chamber if you have to go inside to avoid inhaling toxic fumes and suffocation. One person must stay outside of the tank and keep eye on person who is working inside the unit.
- Make sure that the waste water is lead to a proper holding tank (hull tank or collection tank) during shutdown or maintenance break.
- Perform the maintenance for the components of the unit according to the component maintenance program.
Reference: EVAC Environmental Solutions Marine Sector Operation Manual