• Twitter
  • Facebook
  • LinkedIn
  • Mail
  • Call Me Back
  • About
  • Knowledge
📞 Call us on 0330 223 31 31
Water Treatment Services
  • Home
  • Water
    • Applications
      • Boiler Water Treatment
      • Cooling Water Treatment
      • Closed Loop Water Treatment
      • Legionella Control
    • Services
      • Cooling Tower Cleaning
      • Cooling Tower Maintenance
      • Chlorine Dioxide Water Treatment
      • Commercial Water Softeners
      • Expert Witness Services
      • Pre-Commission Cleaning
      • Tank Reline & Repair
      • TMV Servicing
      • Water Chlorination & Disinfection
      • Water Leak Detection
      • Water Testing
        • Drinking Water Testing
        • Metals Testing
        • Pool Water Testing
        • BSRIA Closed System Testing
        • SDI Testing & Analysis
        • Trade Effluent Testing
    • Training
      • Water Treatment Training
      • Basic Chemistry of Water
      • Industrial Treatment
      • Pre-Treatment
      • Boiler Treatment
      • Cooling Systems
      • Closed Systems
      • Wastewater Training
      • Advanced Treatments
      • Training Dates 2021
  • Wastewater
    • Metals Testing
    • Trade Effluent Testing
    • Wastewater Training
    • Expert Witness Services
  • Air
    • Ductwork Cleaning
    • Indoor Air Quality
    • Local Exhaust Ventilation Testing
    • Mould Testing
    • Expert Witness Services
  • Energy
  • Legionella
    • Legionella Risk Assessment
    • Legionella Training Courses
      • Legionella Awareness Training
      • Responsible Person Training
      • Water Hygiene Awareness
      • Pseudomonas Training
      • Training Dates 2021
    • Legionella Testing
    • Expert Witness Services
  • Contact
  • Search
  • Menu Menu
You are here: Home1 / Knowledge2 / Energy3 / Understanding Corrosion in Water Systems
Corrosion in water systems

Understanding Corrosion in Water Systems

Recognising the different types of corrosion in water systems, understanding how and why they occur, and their effect on system metallurgy is an essential stage in the development of any effective water treatment programme for the control of corrosion in steam, cooling and closed systems.

If corrosion starts to develop in a water system it can quickly start to become a serious problem that can end up costing business owners dear, in terms of down-time, additional resources and money. Worldwide, the costs related to corrosion in water systems run into billions of pounds every year.

Corrosion in water systems

Metal loss caused by corrosion can reduce the reliability and overall lifespan of a water system and its components including distribution pipework and any associated plant and equipment. Corrosion in water systems can increase maintenance expenses and cause equipment to fail before it should. It can also reduce heat transfer efficiencies, lead to a build-up of deposits, restrict water flow and simply stop the system working efficiently. Understanding the different types of corrosion that can occur in a water system, and what causes them can help address the issues before they spiral out of control.

What are the different types of corrosion in water systems?

Corrosion experts typically class corrosion into two broad categories, generalised and localised corrosion.

  • Generalised Corrosion

    Generalised corrosion is the type of corrosion which occurs evenly across a metal surface. This sort of corrosion causes fouling of a water system more often than failure of equipment.

  • Localised Corrosion

    Localised corrosion tends to cause little depressions or pits that are visible on the surface of the metal. Usually, localised water system corrosion is a more serious problem to tackle. Localised corrosion includes pitting, under-deposit corrosion, galvanic corrosion and corrosion caused by microbiological factors such as pseudomonas. This type of corrosion can cause potentially serious breaks or cracks in the metal itself which can lead to failure of the water system.

What is galvanic corrosion?

Galvanic corrosion occurs because of a chemical reaction between two metals in a solution which acts as a conductor. The chemical differences between the two metals in effect create a simple battery, where one metal deteriorates and the other is protected from corrosion.

The speed of the chemical reaction will depend on the types of metals involved. You can use a galvanic potential chart to help predict whether corrosion is likely to be an issue, and how quickly the corrosion is likely to happen. Galvanic corrosion can be controlled by using a device such as a dielectric union to keep the two metals apart. They are typically made from galvanised steel and lead-free brass and act to break the circuit and stop electrolysis occurring.

What is pitting corrosion?

Pitting corrosion is one of the hardest forms of metallic corrosion to predict. It’s also one of the most destructive.

Pitting corrosion occurs when specific areas of metal experience intense, localised corrosion but the majority of the surface is unaffected.

Some of the more common risk factors associated with pitting corrosion are stagnant water conditions and low velocity water flow.

Additionally, the presence of corrosive ions such as chlorides, sulphates and oxygen can increase the risks significantly. Once a pit has formed as a depression in the surface of the metal, any liquid trapped within it becomes even more corrosive and makes the problem much worse.

Under-deposit corrosion

Under-deposit corrosion is also sometimes known as crevice corrosion. It is a type of localised corrosion which occurs in a shielded area such as a crevice. Under the deposit, any trapped solution starts to concentrate and over time becomes more and more corrosive.

Certain metals and alloys such as aluminium, copper and steel which use an oxide film to protect them are more likely to suffer under-deposit corrosion. It is more commonly found at the end of the lines, on lower levels of process runs, or at points in the system where the flow of water is slower. The most effective way of preventing under-deposit corrosion in water systems is to keep all metal based systems clean and free of contamination.

Microbiologically influenced corrosion (MIC)

MIC or microbiologically influenced corrosion in water systems is a term used to label any type of corrosion which is primarily caused by bacteria which can include pseudomonas, sulphate reducing bacteria and nitrite reducing bacteria.

MIC is often a factor in corrosion tubercules forming (see below), and can be a factor in other types of corrosion too. Bacteria however do not directly attack the metal. The corrosion is caused by the by-products of the process which result from bacterial growth reacting with the metal.

Erosion-corrosion in water systems

Erosion-corrosion is a combination of abrasion and corrosion from the flow of water around the system. Nearly every metal can suffer from some degree of erosion-corrosion. However, soft metals such as those which depend on a passive layer to protect against corrosion are particularly susceptible.

Erosion-corrosion in water systems can also be caused or made worse by fluids containing suspended solids. The easiest way to prevent erosion-corrosion is to consider it at the design stage. Create a system which will maintain the speed of flow, taking into account the metals being used and how often the flow changes direction.

An alternative approach is to remove or limit the suspended solids using a filtration system such as a side stream filter.

  • Learn more about using side stream filters

What is tuberculation?

A tubercule is the name given to an accumulation of corrosion formed from by-products and other deposits. They tend to affect iron components and form over areas of lost metal. The composition of the tubercule will depend on the chemical composition of the water, the dissolved oxygen concentration, flow, water temperature and rate of corrosion. As the metal is removed, the turbercules develop and corrosion starts to build up. Usually, the corroded areas underneath tubercules are irregular and broad depressions. Don’t automatically assume that all iron oxide deposits which are red or brown in colour are tubercules. If you’re not seeing any metal loss underneath then the iron might have accumulated from elsewhere in the water system.

Expert industrial water treatment and corrosion control

Water Treatment Services offer a comprehensive range of industrial water treatment solutions for the management and treatment of corrosion in water systems. Our experts can help you optimise costs and operational efficiencies, reduce downtime, achieve water and energy savings, and increase plant reliability and safety.

With offices in London serving the South and South East England, Manchester (North West), Birmingham (Midlands), Bristol (South East England and Wales), Leeds (North and North East) and Glasgow (Scotland), supported by regional teams of specially trained technicians, in-field specialists and consultants we can offer professional, cost effective water treatment and engineering services throughout the UK and Internationally.

Contact us today to learn how our industrial water management solutions can help you.

Contact Us Today

Further reading…

More information about our industrial water treatment solutions … here →

Tags: Boiler Feedwater, Closed loop water systems, Closed Systems, Cooling Water Treatment, Corrosion Control, water treatment
You might also like
Rainwater harvesting systems guide Guide to Rainwater Harvesting Systems
Hydrotherapy pool water safety Managing Hydrotherapy Pool Water Safety
Controlling biofilm in cooling water systems Controlling Biofilm in Cooling Water Systems
Boiler feedwater treatment All About Treating Boiler Feedwater
All about wastewater and sewage All About Wastewater & Sewage
Boiler carryover in steam generating systems Managing Boiler Carryover in Steam Generating Systems
Closed system water treatment guide Closed System Water Treatment Options for Heating & Cooling
Controlling bacteria in closed systems Controlling Bacteria in Closed Systems

Search…

What’s New

  • PWTAG Code of Practice for Pool Water Treatment

    PWTAG Code of Practice for Pool Water Treatment

    In this pool guide the water management experts at …
  • In-Field Wastewater Testing for Plant Operators

    In-Field Wastewater Testing for Plant Operators

    In this article the industrial wastewater specialists at WTS …
  • Guide to Testing Swimming Pools and Hot Tubs

    Guide to Testing Swimming Pools and Hot Tubs

    In this pool guide the water management experts at …
  • How Boiler Water Treatment Affects Performance

    How Boiler Water Treatment Affects Performance

    In this article the industrial steam boiler specialists at …
  • Improving HVAC Energy Efficiency

    Improving HVAC Energy Efficiency

    This article examines how businesses can optimise energy consumption, …
  • What is Waste Acceptance Criteria or WAC Testing?

    What is Waste Acceptance Criteria or WAC Testing?

    In this article the industrial waste specialists at WTS …

REVIEWS

4.8
Rated 4.8 out of 5
Water Treatment Services is rated 4.8 out of 5 stars (based on 97 reviews)
Read our reviews

Free Newsletter

Receive exciting features, news, latest research and special offers! Just add your email address and we'll do the rest.

Contact us

Water Treatment Services

[email protected]

Tel: 0330 223 31 31

© Copyright 2022 - EDG Ltd. Operating as Water Treatment Services
  • Twitter
  • Facebook
  • LinkedIn
  • Mail
  • Home
  • About
  • Careers
  • Privacy
  • Environment
  • Reviews
  • Sitemap
Understanding Workplace Exposure Limits, COSHH & EH40Workplace exposure limits, COSHH & EH40Volatile organic compounds & indoor air qualityVolatile Organic Compounds, Indoor Air Quality & Health
Scroll to top

This site uses cookies. By continuing to browse the site, you are agreeing to our use of cookies.

OK

Cookie and Privacy Settings



How we use cookies

We may request cookies to be set on your device. We use cookies to let us know when you visit our websites, how you interact with us, to enrich your user experience, and to customize your relationship with our website.

Click on the different category headings to find out more. You can also change some of your preferences. Note that blocking some types of cookies may impact your experience on our websites and the services we are able to offer.

Essential Website Cookies

These cookies are strictly necessary to provide you with services available through our website and to use some of its features.

Because these cookies are strictly necessary to deliver the website, refusing them will have impact how our site functions. You always can block or delete cookies by changing your browser settings and force blocking all cookies on this website. But this will always prompt you to accept/refuse cookies when revisiting our site.

We fully respect if you want to refuse cookies but to avoid asking you again and again kindly allow us to store a cookie for that. You are free to opt out any time or opt in for other cookies to get a better experience. If you refuse cookies we will remove all set cookies in our domain.

We provide you with a list of stored cookies on your computer in our domain so you can check what we stored. Due to security reasons we are not able to show or modify cookies from other domains. You can check these in your browser security settings.

Google Analytics Cookies

These cookies collect information that is used either in aggregate form to help us understand how our website is being used or how effective our marketing campaigns are, or to help us customize our website and application for you in order to enhance your experience.

If you do not want that we track your visit to our site you can disable tracking in your browser here:

Other external services

We also use different external services like Google Webfonts, Google Maps, and external Video providers. Since these providers may collect personal data like your IP address we allow you to block them here. Please be aware that this might heavily reduce the functionality and appearance of our site. Changes will take effect once you reload the page.

Google Webfont Settings:

Google Map Settings:

Google reCaptcha Settings:

Vimeo and Youtube video embeds:

Other cookies

The following cookies are also needed - You can choose if you want to allow them:

Privacy Policy

You can read about our cookies and privacy settings in detail on our Privacy Policy Page.

Privacy
Accept settingsHide notification only