The redundant effluent tank was being converted to a sludge storage tank, including an enclosure. The tank required repair and protection for this change of use as when sewerage tanks are enclosed the gas space is particularly aggressive to concrete surfaces as a result of hydrogen sulphide and biogenic sulphuric acid.
Remmers Epoxy WHG had been specified as the tank lining material to be used. From experience we put together a full recommendation to also resolve the other defects in the structure prior to the tank lining application.
Vacuum controlled diamond grinding
Following drain down and cleaning by others we prepared all surfaces to be coated by method of vacuum controlled diamond grinding to ensure good adhesion of the new tank lining.
There were several cracks in the tank walls that required repair. These were expressed using a vacuum controlled diamond saw prior to repair using a high strength epoxy mortar.
Coating the surfaces
All surfaces to coated were treated using Remmers Sulfatex grout to fill irregularities and blow holes in the concrete. Blow holes cannot be filled with paint alone.
The first coat of the tank lining was Remmers Epoxy MT100 – a highly damp tolerant epoxy primer which can tolerate moisture contents of up to 6%.
This was followed by two coats of Remmers Epoxy WHG in contrasting colour as per best tank lining practice. The climatic conditions were monitored throughout the tank lining process to ensure compliance with the manufacturers recommendations.
As part of our standard quality assurance the new tank lining was checked for porosity using a DC holiday spark tester and where found defects rectified using the same tank lining material.