Transforming deteriorated wastewater assets

Wastewater infrastructure is exposed to a number of harsh chemicals and bacteria that cause erosion and deterioration. If left unprotected, assets such as manholes or sewers can threaten the integrity of an entire system while being costly to replace or rehabilitate. Using an appropriate protective coating can extend the life of an asset and reduce maintenance costs, ensuring the system continues to run efficiently.

Manhole rehabilitation

One of the biggest causes of corrosion in manholes is Microbial Induced Corrosion (MIC).

MIC occurs when acidophilic bacteria in the sewer system feed on sulfur in hydrogen sulfate gas, releasing sulfuric acid which can corrode mortar, steel, ductile iron and concrete, and affecting the longevity of the manhole.

When manholes are damaged or deteriorated, it can allow groundwater to enter the sewer network (infiltration) causing pipelines and treatment plants to overload, resulting in environmentally harmful spills, and costly fines and cleanups.

These potential risks can be reduced by coating deteriorating manholes to return them to a better-than-new condition.

Hychem’s TL5 coating system is designed for use in environments with high exposure to alkali and dilute acids such as manholes.

Colin Murphy, Product Manager at Hychem, said TL5 epoxy liner is ideal for use in the wastewater industry as it has a smooth finish and can be applied in just one coating.

“TL5 can be applied in thicknesses as small as 2-3mm compared to other liners which can have thicknesses up to 30mm+. It can also be applied in just one coating, reducing the time the asset is out of service.”

Concrete rehabilitation with TL5

Commonly, other products used for concrete rehabilitation require a priming coat or patching compounds when used on existing structures. The advantage of TL5 is that it can be applied directly to damaged concrete – making it a true one coat solution.

The benefits of taking advantage of a single coat solution, include:

• Rapid turnaround time: using the TL5 one coat system, an asset can be rehabilitated and back into service in as little as six hours
• Good moisture tolerance: the asset doesn’t need to be completely dried out before TL5 can be applied
• Avoidance of intercoat adhesion: two coat systems can result in intercoat adhesion where high moisture/humidity can be problematic – with only one coat to apply, this isn’t an issue with TL5
• Saves time and money: the one coat solution is fast, minimising man hours on site and the need to remobilise equipment
• Better OH&S outcomes: staff spend less time in confined spaces, minimising the potential for accidents on site

Thinking green

Hychem has also recently made available to its customers a geopolymer mortar ideal for corrosion protection and increasing the structural integrity of water and wastewater assets such as manholes and culverts.

GeoCast with Reliner MSP is made predominantly of recycled materials which reduces the amount of greenhouse gases produced in manufacturing compared to calcium aluminate cement.

“As Australia moves towards reducing greenhouse gas emissions, this is an ideal choice and doesn’t compromise on the quality and durability of the product,” Mr Murphy said.

Extending the life of the asset

Because TL5 and GeoCast with Reliner MSP are chemical and bacteria resistant, these rehabilitation solutions will stay in place with minimal erosion for years and even decades. Due to their durability, they can help asset owners decrease lifecycle costs as the need to perform maintenance and repairs are reduced.

“GeoCast with Reliner MSP has demonstrated over 20 years of proven successful installations and has a design life of over 50 years, while TL5 has been used on projects throughout Australia for over 20 years with 100 per cent success, being used to coat concrete assets within harsh hydrogen sulphide environments in the water and wastewater industries,” Mr Murphy said.

“Water authorities can be assured that when they choose TL5 or GeoCast with Reliner MSP to coat their asset, they are choosing a product that will last well into the future.”