Microbial induced corrosion can seriously reduce the service life of concrete sewer structures and wastewater treatment plants.
• Long retention sewer lines
• Headworks and lift stations
• Drop structures
• Force main outflows
• Enclosed sewage plant structures
For maximum protection of concrete in severe sewage conditions.
Xypex Bio-San C500 is a unique way of protecting concrete in harsh sewage conditions with high levels of hydrogen sulphide that cause microbial induced corrosion. No other admixture combines potent antimicrobial properties with Xypex crystalline waterproofing technology to offer complete protection of concrete sewer and wastewater structures.
Xypex Bio-San C500 contains mineral solids that remain permanently fixed within the concrete throughout the life of the sewage structure. These kill acid-generating microbes such as Thiobacillus that proliferate in high H2S conditions thus preventing microbial induced corrosion (MIC). Combined with Xypex’s proven crystalline technology, Bio-San C500 will protect concrete from infiltration and exfiltration as well as resisting acid and sulphate attack. After placement and curing, the crack-healing properties of Xypex will continue to function throughout the service life of the concrete.
As with all Xypex Admix products, Bio-San C500 is added at the time of concrete batching, avoiding the potential quality issues of liners or coatings and eliminating schedule delays for surface preparation. As a one-component product, Bio-San C500 simplifies the production process for pre-cast structures.
Xypex Bio-San C500 is recommended for use in sewage systems especially in areas where H2S gas is likely to accumulate. This includes sewer lines with long retention times (flat, long, low flow) and sealed or unvented manholes. It will also include areas of high turbulence such as lift stations, drop structures, force main outflows and head works as well as various areas within wastewater treatment plants.
Kills the acid-generating microbes present in sewage environments
Independent testing showed that in concrete treated with Xypex Bio-San C500 the presence of the sewer bacteria Thiobacillus Novellus (Starkeya Novella) was substantially reduced.
Protects concrete in high concentrations of H2S
Specimens of concrete treated with Xypex Bio-San as well as untreated concrete were hung in the enclosed sedimentation tanks at a wastewater facility with H2S concentrations of over 50 ppm. The photos of the untreated concrete show the extent of the microbial induced corrosion after 6.5 years. After 10 years the concrete treated with Xypex Bio-San had 9 times less corrosion than the untreated concrete, and continued to function at full efficacy.
Contains Crystalline Technology
Xypex Bio-San C500 contains the same unique crystalline technology as all Xypex Admix products. Xypex treated concrete resists extreme hydrostatic pressure, protects concrete against aggressive chemicals such as acids or sulphates and self-heals static cracks up to 0.4 mm.
In a site test, Xypex treated and untreated samples were analyzed using Scanning Electron Microscopy. Xypex treated samples showed conclusive evidence of the dense crystalline matrix typical of Xypex Crystalline Technology.
Self-heals cracks up to 0.4mm
Concrete panels were cast and then cracked by force after which they were subjected to the ponding of water to measure the flow through the crack. After four days the 0.38 mm crack on the Xypex treated sample had stopped leaking completely. The 0.25 mm crack in the control sample continued to leak after 25 days.
Protects concrete in acidic conditions
Cement mortar samples containing Xypex were subjected to 5% sulphuric acid for up to 12 weeks. Compared to untreated control samples, the weight loss caused by acid attack was reduced by 48%. In a further test on a 30% fly-ash mortar, the weight loss was reduced to 53%.
Protects concrete in sulphate environments
Samples of both Xypex treated and untreated concrete were placed in a highly concentrated sulphate solution. After 4 months the untreated samples experienced a weight loss of 4,800 g/m2whereas the Xypex treated samples only lost between 5 g/m2 and 50 g/m2, showing no visible signs of surface deterioration.
Prevents infiltration & exfiltration of liquids even under extreme hydrostatic pressure
When subjected to 107 m (350 ft) of hydrostatic pressure Xypex treated samples completely resisted the flow of water and only allowed water penetration of 1.5 mm (0.06 in). Conversely, untreated control samples started leaking within 24 hours.
Bio-San C500 Projects
Xypex Bio-San C500 was chosen because it provides the precast sewage elements with protection against microbial induced corrosion and aggressive chemicals, as well as waterproofing and crack healing properties. The precast manufacturer reported that there were no operational or fabrication issues associated with including Xypex Bio-San C500 in the wet cast mix.
Due to the potentially high levels of H2S in the Bioreactor McKim & Creed, a high build acid resistant coating was specified to protect the concrete. Bowen Engineering proposed to the engineers that Xypex Bio-San C500 as an alternate because it contains Xypex’s antimicrobial crystalline technology. This technology also protects the concrete from microbial induced corrosion by killing the acid-producing bacteria. Thus, Xypex Bio-San C500 provides similar protection of the concrete while eliminating the long term maintenance requirements associated with periodic replacement of protective coatings.
For this sewer line extension, the manholes along the force main required protection from microbial induced corrosion. Liners or coatings would normally be used to perform this function. As these are expensive and time consuming to install, the engineers decided to specify the inclusion of Xypex Bio-San C500 admixture in the pre-cast concrete. Apart from the performance features of Bio-San C500 it is also added at the time of concrete batching which means there is no need for the installation and welding of liners; this brings significant savings in time and expense.