Black spore fungi & osmotic blistering of GRP tanks

Black spore fungi are common in GRP tanks and are notorious for spreading, predominantly where there is a combination of water and air at an ambient temperature. These spores tend to multiply very quickly and produce a grey or black jelly-like growth on the internal GRP surface.

Black spore fungi can be as a results of osmotic blistering of the GRP substrate due to water permeation. This can lead to deterioration of the gel coat and, subsequently, a surface which is highly likely to harbour and promote the growth of micro-aquatic organisms which cannot be removed by cleaning.

Even with regular cleaning and disinfections , bacteria such as micro-aquatic organisms will continue to multiply as they are protected in the habitat provided by air filled cavities and fine cracks that often cannot be seen with the naked eye.

These cavities and cracks in the internal substrate allow bacteria to nest and proliferate. The problems start to occur when the water molecules migrating into the GRP tanks encounter other chemicals inside the laminate, primarily water-soluble materials (WSMs) such as the emulsion binders used to hold the glass mat together before it is moulded.

The water molecules can then have a chemical reaction with these substances, forming larger molecules of a new chemical, often acidic – which unlike the original small water molecules, cannot carry on passing through the GRP. These larger molecules are then trapped. This is the point at which osmosis actually starts. Osmotic blistering of the GRP substrate due to water permeation can also lead to deterioration of the gel coat and, subsequently, a surface which is highly likely to harbour and promote the growth of micro-aquatic organisms.

It should be considered that, if not looked after and ignored, such internal water osmotic blisters can burst contaminating the CWST.

Where identified we would usually recommend relining the tank using a WRAS approved solvent free technology which is proven to resist the growth of bacteria such as micro aquatic organisms and black spore fungi. The process leaves a surface which has a tough, easy clean, ceramic, tile-like surface combined with elongation properties of up to 35% which will adequately cope with any potential movement of the plastic tank and comes with a 10 year Warranty.

Benefits:

• WRAS/DWI approved.
• Completely Solvent Free Technology.
• Superb adhesion to plastic tank substrates.
• Prevents steel fasteners from corroding.
• Provides a completely waterproof membrane, preventing any potential ingress of water which can cause osmotic blistering, air filled cavities and cracks.
• Leaves a surface which has a tough, easy clean, ceramic, tile-like surface combined with elongation properties of up to 35% which will adequately cope with any potential movement of the plastic tank.
• Proven to resist the growth of bacteria such as micro aquatic organisms and black spore fungi.
• Provides protection of the existing mastic between the plastic tank joints against potential attack from chemicals and subsequent deterioration and consequential leaks.
• High levels of impact and chemical resistance.
• Reduced downtime due to extremely fast cure times.
• Long life performance with minimal maintenance.
• Superb anti-erosion/corrosion properties.
• Long term 10-year guarantee on completion.
• Excellent track record having been utilized for the repair and relining of plastic tanks including those that provide drinking water.
• Water Immersion After 24 hrs or in compliance with WRAS and drinking water regulations.