Storage tanks are vital assets in various industries, facilitating the safe storage of liquids and gases essential for manufacturing and commercial processes. However, within these seemingly robust containers lies a hidden menace: Microbiologically Influenced Corrosion (MIC). MIC is a unique form of corrosion driven by microorganisms that can silently corrode storage tanks, compromising structural integrity and leading to leaks and product contamination. In this blog, we will decode the mystery of MIC corrosion, understand its impact on storage tanks, and explore effective strategies to mitigate its threat.
Understanding Microbiologically Influenced Corrosion (MIC)
MIC is a complex and destructive form of corrosion caused by microorganisms that thrive in the tank’s environment. These microorganisms create biofilms on the interior tank surfaces, providing an ideal environment for corrosive reactions to occur. Unlike traditional corrosion, which can be attributed to chemical or physical factors, MIC is primarily driven by microbial activity.
Microbiologically Influenced Corrosion (MIC) is a type of corrosion caused or accelerated by the activities of microorganisms, such as bacteria, fungi, and algae, in the presence of water and specific environmental conditions. These microorganisms can form biofilms on metal surfaces, leading to localized and often severe corrosion. MIC can be a significant concern in various industries, including oil and gas, water treatment, marine, and infrastructure. Understanding MIC is essential to develop effective strategies for its prevention and mitigation.
Microorganisms adhere to metal surfaces and produce a sticky matrix of extracellular polymeric substances, creating biofilms. These biofilms provide a protective environment for the microorganisms and enhance their ability to cause corrosion.
MIC can have detrimental effects on various industrial assets, including pipelines, storage tanks, heat exchangers, cooling systems, and marine structures. It can lead to costly repairs, increased downtime, and potential safety risks.
The presence of water and specific environmental conditions, such as temperature, pH, salinity, oxygen levels, and the presence of other corrosion-inducing agents, play a significant role in facilitating MIC.
The Impact of MIC Corrosion on Storage Tanks
MIC corrosion can have severe consequences for storage tanks and the industries that rely on them:
a. Structural Compromise: As MIC progresses, it weakens the tank’s walls, leading to potential leaks, spills, and even catastrophic failures, jeopardizing personnel safety and the environment.
b. Product Contamination: The metabolic byproducts of microorganisms in the biofilms can contaminate the stored product, compromising its quality and safety.
c. Increased Maintenance Costs: Repairing MIC-related damage and preventing further corrosion can result in higher maintenance expenses for industries.
d. Environmental Concerns: Leaked hazardous materials can contaminate soil and water sources, leading to environmental pollution and ecological harm.
e. Reputation Damage: MIC-related incidents can tarnish a company’s reputation, leading to loss of trust among customers and investors.
Factors Contributing to MIC Corrosion
Several factors contribute to the occurrence of MIC corrosion in storage tanks:
a. Microbial Activity: Certain bacteria and archaea species are particularly aggressive in causing corrosion.
b. Nutrient Availability: Presence of nutrients, such as oxygen, sulfur, and iron, create conducive conditions for microbial growth and corrosion.
c. Water Presence: The availability of water provides a critical element for microbial activity, as well as creating localized corrosion environments.
d. Temperature: Elevated temperatures can accelerate microbial activity, exacerbating MIC.
Detecting and Mitigating MIC Corrosion
Detecting and mitigating MIC corrosion requires a proactive and multi-faceted approach:
a. Regular Inspections: Implement a comprehensive inspection program to identify early signs of MIC corrosion. Advanced non-destructive testing methods can help detect hidden corrosion beneath biofilms.
b. Material Selection: Choose materials that are less susceptible to MIC and are resistant to microbial activity.
c. Cathodic Protection: Implement cathodic protection systems to safeguard the tank’s metal surfaces from corrosive reactions.
d. Biocide Treatments: Controlled and appropriate use of biocides can help control microbial growth and reduce the risk of MIC.
e. Proper Cleaning and Maintenance: Regular cleaning and maintenance of storage tanks can help remove biofilms and reduce microbial activity.
MIC corrosion poses a significant threat to storage tanks, compromising their structural integrity, and leading to product contamination and environmental risks. Understanding the complexities of MIC corrosion and its underlying factors is crucial in developing effective mitigation strategies. By implementing regular inspections, and preventive measures, and collaborating with industry experts, storage tank owners can safeguard their assets, protect the environment, and uphold their commitment to safety and sustainability.
