Corrosion is a well-known challenge in industrial water systems, but not all corrosion is created equal. Some of the most aggressive and costly forms are driven not by chemistry alone, but by biological activity. This is known as Microbiologically Induced Corrosion (MIC), and it is a growing concern for industries relying on water for cooling, processing, and heat exchange.
MIC is complex, but the consequences are simple and costly. From pipe failures and safety hazards to efficiency loss and unplanned shutdowns, this hidden form of corrosion can compromise system integrity without warning. Fortunately, there are solutions. That is where Rolfes Water plays a key role.
What is MIC?
MIC refers to corrosion that is caused or accelerated by the presence and metabolic activity of microorganisms. These are often bacteria, but can also include fungi and algae. The process typically begins when microbes attach to a surface and begin to form biofilms. Once established, these biofilms create micro-environments that support corrosion in ways that traditional chemical analysis might miss.
Certain microorganisms, such as sulphate-reducing bacteria (SRB), thrive in low-oxygen environments and produce hydrogen sulphide as a by-product. This substance is highly corrosive to steel and other metals. Other bacteria, such as iron-oxidisers and acid-producers, can also contribute by forming deposits or lowering the pH at the metal surface.
What makes MIC particularly troublesome is that it is not always easy to distinguish from other types of corrosion. It may occur in isolated areas, often appearing as deep pits or localised scaling. This means that regular inspections and water quality monitoring are essential for identifying risks early.
Where Does MIC Occur?
MIC can affect a wide range of industrial systems, particularly those involving stagnant or low-flow water, organic material, or inconsistent disinfection. Common problem areas include:
- Cooling towers and associated pipework
- Heat exchangers and condensers
- Closed-loop circuits
- Water distribution lines
- Process tanks and clarifiers
These environments provide the conditions that allow microbial colonies to develop. Once established, the corrosion they cause can proceed quickly and lead to costly failures.
Even systems with standard corrosion control in place are not immune. If microbiological growth is not properly monitored and managed, it can undermine the effectiveness of inhibitors and accelerate metal loss.
Signs of MIC
Because MIC operates at a microscopic level, it is often difficult to detect until damage has occurred. Early signs include:
- Unusual pitting in metals
- Localised scaling or deposits
- Slime layers or foul odours
- Reduced heat transfer efficiency
- Increased demand for chemical treatment
- Unexpected failure of corrosion-resistant materials
Once identified, remediation can be costly, requiring mechanical cleaning, system downtime, or even full component replacement. The long-term costs of unplanned shutdowns or system replacements make prevention the more economical approach.
How Rolfes Water Helps Manage and Prevent MIC
At Rolfes Water, we understand that corrosion is not just a technical issue. It is a business risk that affects production reliability, compliance, and long-term asset value. Our solutions are designed to help clients manage microbial activity before it escalates into damage.
1. System Cleaning and Disinfection
We offer comprehensive cleaning and disinfection services that target biofilm formation and microbial growth. By removing the organic material that supports MIC, we help clients reset their systems to a more manageable baseline. Routine cleaning not only addresses current issues but helps prevent future colonisation.
2. Specialised Biocides
Our chemical portfolio includes oxidising and non-oxidising biocides suitable for a range of industrial applications. These products are selected based on water chemistry, system materials, and the type of microbial risk identified. When applied correctly, biocides help maintain water hygiene and extend the lifespan of your infrastructure.
3. Integrated Water Treatment Programmes
In cooling systems, MIC risk is closely linked to other factors such as scaling and pH. Our water treatment programmes are designed to control all these elements holistically, using corrosion inhibitors, dispersants, and monitoring tools to ensure full system protection. Proper system balance is key to reducing microbial habitat.
4. Ongoing Technical Support
Rolfes Water does not just supply chemicals. We provide ongoing support to track system performance, adjust dosages, and identify early warning signs before they become major issues. Our team works closely with clients to ensure treatment strategies remain aligned with changing conditions and operational needs. Site-specific support and audits are also available.
Why It Matters
Left unchecked, MIC can significantly shorten the lifespan of assets, disrupt operations, and result in unexpected costs. As industries push for more sustainable and cost-effective water use, the importance of protecting systems from all forms of corrosion, including biologically driven types, becomes even more critical.
With increasing regulatory scrutiny around water quality and discharge, businesses also have more to lose from non-compliance. The presence of MIC not only threatens physical infrastructure but can also lead to permit violations and operational fines.
From a sustainability perspective, efficient use of water and protection of critical infrastructure supports long-term operational resilience. It also strengthens stakeholder trust and positions businesses as responsible corporate citizens.
Microbiologically Induced Corrosion may be invisible to the eye, but its effects are far-reaching. It requires awareness, expertise, and proactive intervention. At Rolfes Water, we bring all three.
Our goal is not just to solve corrosion problems when they occur. It is to help our clients prevent them entirely. Through effective cleaning, targeted biocide use, and system-wide treatment planning, we support the long-term integrity of water systems in industries across South Africa and beyond.
