Corrosion Control for Water Treatment Facilities

We recently received an inquiry on our cathodic protection FAQ asking about “the best corrosion control protection for above-ground steel tanks treating wastewater.” Well, corrosion control for water treatment facilities is such an interesting and relevant topic that it warrants an expanded response, so here goes.

Wastewater treatment facilities generally have many tanks storing and processing wastewater through multiple treatment stages. These tanks and vessels are subject to corrosion, and there are a range of strategies to extend their service life.

Corrosion control for water treatment facilities' tanks and vessels

Corrosion Protection Strategies for Water Treatment Tanks and Vessels

These strategies fall into four broad categories: material selection, chemical treatment, coatings, and cathodic protection.

Wastewater Tank and Vessel Material Selection

From a material selection perspective, most wastewater treatment vessels are carbon steel. However, some chemical wastewater treatment facilities may require more “exotic” materials early in the treatment process due to the wastewater feed material.

Once the wastewater feed material has been treated and/or neutralized, the remaining process tanks and vessels are likely to be carbon steel construction.

Corrosion Protection via Chemical Treatment

The next broad category of corrosion control strategies is chemical treatment. While chemical treatment is an integral part of the wastewater process, specifically in terms of pH neutralization and chlorination processes, the chemical treatment performed during the treatment of wastewater is not typically intended to control corrosion.

One area where chemical treatment might be a viable corrosion control strategy is with the use of vapor corrosion inhibitors (VCIs) to protect the underside of steel storage tanks.

Coatings for Corrosion Control of Water Treatment Tanks and Vessels

The appropriate selection and application of coatings is a key corrosion control strategy for wastewater treatment facilities.

Coatings are particularly effective in protecting carbon steel structures including above ground piping, atmospheric external tank shells, wetted internal tank walls, submerged steel structures, and many other structures.

Coatings, however, are not perfect and they have a finite life. For structures that are easy to access, inspecting and re-coating are often the sole means applied to protect against corrosion.

Cathodic Protection

The final corrosion mitigation strategy that can be effectively employed to protect wastewater tanks and process vessels is the use of cathodic protection.

Cathodic protection can be used to protect bare steel structures, or in conjunction with coatings.

There are two basic types of cathodic protection, galvanic (often termed sacrificial) and impressed current. Some typical cathodic protection applications in wastewater treatment facilities include protecting the soil side bottoms of large above ground storage tanks and vessels, and protecting the internal wetted surfaces of tanks and process vessels including rotating equipment such as rakes and wiper arms.

MATCOR has extensive experience designing, supplying and installing cathodic protection systems for wastewater tanks and process equipment, including several proprietary impressed current anode systems that are especially well suited for these applications.


Have questions or need a quote for corrosion prevention materials or services? Contact us at the link below. For immediate assistance, please call +1-215-348-2974.

Contact a Corrosion Expert

Linear Anodes for Hard-to-Reach Places [Rusty Talks]

Rusty and Josh Johnston chat about a recent project and case study involving the use of linear anodes for hard to reach places.


This month, MATCOR exhibited at the AMPP Central Area Conference held in Kansas City. MATCOR’s Mr. Josh Johnston, along with Mr. Chad Farris of Energy Transfer, jointly presented a paper—a case story using linear anodes as a shallow horizontal anode bed installed along two pipelines in central Kansas.

Rusty: Josh, tell us how it felt to finally be in a real-life conference interacting with people in person after the last year and half of cancelled conferences and virtual conferences.

Josh: It is always great to get to interact with our friends and industry colleagues, clients, suppliers and competitors to share information and discuss the challenges that our industry faces—especially given the events of the past couple of years. Presenting this paper was a great opportunity to highlight the use of linear anodes to protect hard to reach areas on older pipelines.

Rusty: Can you describe the problem that you covered in your presentation?

Josh: Energy Transfer had two older pipelines that were not meeting criteria in a rural location. As is typical in a lot of pipeline cathodic protection applications, the pipelines were being protected by impressed current anodes located at road crossings where power was readily available. The roads ran parallel to each other and were located one mile apart. The pipeline traversed these two roads and the area in between was mostly farmland. As a result of the age and coating condition, the shallow horizontal anode beds, located at the road crossings, were not able to project much more than a ¼ mile from each end, leaving approximately ½ mile in the center under protected. This was clearly identifiable in the close interval survey (CIS) data.linear anodes hard to reach places

Rusty: Couldn’t they simply increase the current output of the existing shallow ground beds at each end of the pipeline to drive more current to the center section in between?

Josh: They tried that approach, and it did not work, raising concerns that driving excessive current onto these older pipelines could actually make the situation worse by further disbanding any coating close to the existing ground beds.

Rusty: So where did MATCOR come into this project

Josh: MATCOR proposed linear anodes be installed parallel to each of the pipelines in the area between the two roads. MATCOR developed the very first MMO (mixed metal oxide) linear anodes over 30 years ago and we have the most experience designing linear anode CP systems.

Rusty: So it sounds easy, you take a couple of ½ mile segments of linear anode, trench them in parallel to pipeline and run a couple of long extension cord cables back to the road where there is power.

Josh: Well it does sound easy; however, in practice it is critical that any linear anode design carefully addresses voltage drop, and that the power feed cabling is configured so that each anode segment output is balanced. If this is not engineered properly, you could have a large disparity in the voltage being applied on one end of the anode segment relative to the other end. This would result in a very uneven distribution of current. Discussing the design considerations for the power feed cabling was the primary focus of this presentation.

Rusty: So how did it work out?

Josh: MATCOR was able to use some creative cabling analysis and routing to assure that the voltage difference from one end of an anode segment to the other was no more than a 10% variance. The post installation and commissioning CIS data delivered an outstanding current distribution.

Rusty: Thanks for providing a very quick overview of your presentation—any final thoughts or comments?

Josh: When designed properly, linear anodes can be a real problem-solving solution for older pipelines with current distribution and attenuation issues.

Oh yeah, Kansas City BBQ still rocks!

Have questions or need a quote for linear anodes or installations services? Contact us at the link below. For immediate assistance, please call +1-215-348-2974.

Contact a Corrosion Expert

MATCOR Wins Gold Score on Safety Audit

MATCOR’s Chalfont manufacturing facility recently scored a Gold Link award, scoring a 96% from our parent company, BrandSafway, during a Gold Link Audit.

The BrandSafway Gold Link Audit evaluates BrandSafway job sites and facilities around the US and at BrandSafway locations across the globe.

The Audit is an extensive review of a site’s safety programs and processes based around the company’s 7 Safety Links.

BrandSafway’s 7 Safety Links

  1. EHS Administration
  2. Safety Culture and Commitment
  3. Safety Meetings and Training
  4. Safe Work Planning
  5. Health and Hygiene
  6. Safety Program Compliance
  7. Service Specific Safety Compliance

MATCOR’s Chalfont manufacturing facility has earned a strong reputation for its safety programs. We have not had a lost time incident in over ten years.

We take great pride in MATCOR’s world class, ISO Certified quality cathodic protection and ac mitigation products. All MATCOR proprietary CP materials are built in the United States, in our Gold Link certified safe facility.


Have questions or need a quote for cathodic protection or AC mitigation materials or services? Contact us at the link below. For immediate assistance, please call +1-215-348-2974.

Contact a Corrosion Expert

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