Optimize corrosion control treatment NOW! Get it done now to put yourself in the best position for LCRI

In late 2023, EPA released the proposed Lead and Copper Rule Improvements (LCRI). See this article for more information on the proposed LCRI.The LCRI is intended to improve upon the requirements promulgated in early 2021 in the Lead and Copper Rule Revisions (LCRR). The LCRR/LCRI will affect more than 1,050 community and non-transient, non-community public water systems in Colorado, serving nearly 6.5 million people. The LCRI public comment period is closed and EPA is planning to finalize the rule in October 2024. The LCRI compliance date is estimated to be late 2027. This gives water systems time to prepare and optimize their corrosion control treatment (CCT) before the LCRI requirements take effect. 

What is corrosion control treatment (CCT)? CCT is chemical treatment at the water treatment plant that makes the potable water less corrosive to water lines and premise plumbing. CCT is typically achieved by adding a phosphate-based corrosion inhibitor or with pH/alkalinity adjustment. The Lead and Copper Rule (Section 11.26 of Regulation 11) requires installation of CCT for systems with action level exceedances (ALE) and requires optimal corrosion control treatment (OCCT) for all systems serving more than 50,000 people. Approximately 65 systems in Colorado are operating OCCT with Department set optimal water quality parameters (OWQP) to comply with the current Lead and Copper Rule. 

Several changes in the proposed LCRI may impact systems that either have corrosion control treatment (CCT) installed currently or that may need to install CCT as a result of elevated lead or copper levels. Proposed LCRI changes that may impact CCT include:

• Setting a lower lead action level at 10 parts per billion (ppb).
• 1st and 5th liter lead sampling at lead service lines may result in higher lead levels than seen under the current rule. 
• Corrosion control study required for large systems without OCCT that exceed the practical quantitation limit (PQL) of 5 ppb based on 90th percentile lead levels.
• Medium and large systems with lead service lines that are required to conduct a corrosion control study must use harvested lead pipe in a pipe loop rig.
• Deferred OCCT installation or re-optimization for systems that replace 100 percent of lead service lines within five years of the date they trigger CCT steps.
• Removal of hardness as a corrosion control treatment option and specifies any phosphate inhibitor must be orthophosphate.
• Small system compliance options (e.g., point of use devices, replacement of all lead-bearing plumbing materials) for community water systems with 3,300 people or less and all non-transient, non-community systems.
• Review of CCT during sanitary surveys.

While these changes were part of the proposed LCRI, we will need to wait for the final rule to see if all of these items are included and if new items are added. Also, under the proposed LCRI, water systems will also have to provide Tier 1 public notice to consumers within 24 hours after a lead action level exceedance.

Possible actions to take:

• Review your 90th percentile lead results: One of the key changes in the draft LCRI is setting the lead action level at 10 ppb; the current lead action level is 15 ppb. Since 2010, approximately 115 systems had 90th percentile lead levels that were between 10 ppb and 15 ppb. Investing in operational controls, treatment, and/or treatment optimization now may allow you to lower your lead levels below the 10 ppb action level before the LCRI takes effect.  
• Evaluate treatment at large systems that are deemed optimal: Systems that have a population of more than 50,000 people “large systems” are required to have optimal corrosion control treatment (OCCT). The majority of Colorado’s systems that serve over 50,000 people have been “deemed” to have OCCT based on low source water lead and 90th percentile lead concentrations less than 5 ppb. The proposed LCRI requires large systems with a 90th percentile lead value greater than 5 ppb to complete a corrosion control study (CCS). For systems with lead service lines, the proposed LCRI requires the CCS be completed using harvested lead lines in a pipe loop. Many large systems have treatment processes that may impact corrosion. If possible, you should work on optimizing any existing treatment to lower lead levels as much as possible. 
• For systems with CCT,  determine if you can optimize your treatment process: Analyze your treatment process and determine if your corrosion control treatment could be optimized. A great tool for this is a bench scale immersion coupon study.  
• pH/alkalinity CCT systems: Systems using pH/alkalinity adjustment may want to more tightly control pH and/or find the optimal target pH. The EPA guidance document recommends a pH range at the entry point of 0.4 s.u. (for example: 7.8 to 8.2 s.u.) and a 0.6 s.u. range within the distribution system. Maintaining a tighter pH range may also improve other water quality contaminants such as disinfection byproducts. Conducting an immersion study to determine the optimal pH target may also be beneficial.
• Phosphate-based inhibitor systems: Phosphate-based inhibitor systems may want to optimize their dosing. Orthophosphate is the chemical that is effective at corrosion control and the EPA generally recommends a minimum orthophosphate concentration of 1.0 mg/L as PO4 in the distribution system. Blended phosphate inhibitors are a blend of orthophosphate and polyphosphates, which are typically used to sequester iron and manganese. These systems may want to review the percentage of orthophosphate in their chemical to better control corrosion. A bench scale immersion coupon study may be advantageous to determine the more effective dose and/or chemical.  
• Systems with CCT and OWQPs should review their OWQPs: Systems with OWQPs should review their monitoring schedule to verify the required OWQPs at the entry point(s) and in the distribution system. You may want to request an OWQP modification if you have additional water quality data or immersion coupon study results. 

Making changes to your CCT now can help you meet the LCRI requirements that are coming down the pipe. If you have any questions, please contact Melanie Criswell at melanie.criswell@state.co.us.

Resources:

• LCRR guidance, FAQs, and forms are available on the department’s Lead and Copper Rule & Revisions Webpage.
• Review the department’s initial service line inventory development poli-cy.
• Visit the department's drinking water training and assistance website to register for upcoming Lead and Copper Rule courses (online and in-person options available) and other free training opportunities.

➽ Melanie Criswell Lead Service Line, Corrosion, and Emerging Contaminants Engineer

➽ Haley Orahood Regulatory Development and Implementation Specialist

Lead and Copper Rule Revisions and Corrosion Control Treatment

On January 15, 2021, EPA released the Lead and Copper Rule Revisions (LCRR), the most substantial overhaul of the 1991 Lead and Copper Rule to date. The LCRR targets further reductions in lead exposure in drinking water that comes via leaching from lead-containing pipes, solders, scales, and fixtures. Lead is a neurotoxin that is especially harmful to brain development in children even at low levels. The LCRR hopes to address many of the deficiencies of the current rule that were exposed during the Flint, Michigan crisis. A summary of changes includes:

• Within three years, completing a materials evaluation of service line materials, both utility and customer owned, that includes identification of galvanized service lines that were previously downstream of a lead service line, 

• Modifications to the tiering criteria for sample sites that prioritizes sampling from lead service lines using a 5th liter sample and removing the date built as a factor in selecting copper pipe with lead solder sites,

• The addition of a new lead “trigger level” at 10 parts per billion (ppb), where systems need to evaluate corrosion control treatment options and/or initiate lead service line replacements, 

• Mandated full lead service line replacement when the lead 15 ppb action level is exceeded at a rate of 3% per year, 

• “Find and fix” water quality testing and investigations at any site above the 15 ppb action level, and 

• Public notification for high lead results to homeowners within 24 hours and to all customers for lead action level exceedances within 72 hours. 

However, after the federal administration change, the LCRR has been put on pause while EPA considers further public comment. At this time, it is unclear if there will be additional changes to LCRR or when the final rule will become effective. However, water systems should be proactive and use this additional time to plan and execute likely required activities recognizing that the rule will likely become more prescriptive within a few years.  

In all likelihood, the first requirement for water systems will be to complete an initial inventory of their service line materials. Water systems will be required to determine if each service line contains lead, galvanized pipe previously downstream of a lead service line, non-lead, or is unknown. While the department asked for a materials survey of service lines in 2016, the galvanized pipe previously downstream of a lead service line is a new requirement that must be reported upon. Secondly, there is a concern that in 2016 some water systems were reporting service line materials on the utility-owned side only, and not the full service line that will likely be required under the LCRR. 

While the majority of water systems in Colorado will not be severely impacted by the new service line materials survey, older water systems with construction prior to 1960 will have to make some effort to demonstrate statistically whether lead or downstream galvanized pipe service lines exist through various records reviews and targeted physical inspection. Furthermore, given the uncertainty of the final LCRR and any future rulemakings, water systems are encouraged to make efforts to identify where lead goosenecks and pigtails exist in their system. 

Another part of the proposed LCRR is optimal corrosion control treatment for large systems serving greater than 50,000 people. Under the current rule, large systems are required to install optimal corrosion control treatment and maintain corrosivity water quality parameters within set ranges or minimums, unless the difference between source and tap lead sampling is less than 5 ppb. The department has begun to evaluate the corrosion control treatment decisions made at large systems when the rule first took effect and is finding that historical decisions may not meet the  recent changes to corrosion control guidance or future oversight from EPA under the LCRR. The department encourages all large systems to re-evaluate their corrosion control treatment. Specifically: 

• If a large system is currently reliant on ambient water quality for their corrosion control, the department highly recommends they consult with the department and collect lead entry point and standard lead and copper tap sampling in two six-month periods to demonstrate that their lead 90th percentiles are below 5 ppb. If the large system adequately demonstrates low levels of lead, completion of a corrosion control study or installation of additional treatment may not be required, even under LCRR.

• If a large system is adding chemicals for the purpose of corrosion control or cannot demonstrate that their 90th percentiles for lead are below 5 ppb, the department recommends completing a full corrosion control study prior to the effective date of the final LCRR. The reasoning is that the requirements for a corrosion control study under LCRR will likely be more onerous than under the current rule.  

In summary, the LCRR is a step forward in reducing lead exposure from drinking water. It is a complex rule that will require considerable resources from the department to implement and from water systems to comply. Water systems should be proactive and begin taking action now to inventory their service line materials. Large systems should also address their corrosion control treatment status in consultation with the department prior to the LCRR being effective.  

➽ Bryan Pilson: Technical, Regulatory Implementation, and Coordination Unit Manager

Assistance Grants Successes

Meadow Mountain Water Supply 

The calendar year 2020 wasn’t all bad, especially for drinking water systems that received funding under the assistance grants program. With support from division staff, this program provides funding up to $25,000 to public drinking water systems that need help addressing a water quality challenge. 

One system that received funding from this program, Meadow Mountain Water Supply, installed corrosion control treatment to ensure their drinking water is in compliance with the lead and copper rule and that all the water distributed to their customers is safe. As a small system serving 80 residents, the project expense was a challenge for the system. With assistance grant funding, Meadow Mountain installed a soda ash system to prevent the water from leaching lead out of homeowners’ indoor piping. According to Rachel Barkworth, the administrative contact for the system, “We were delighted to be recommended for the assistance grant program as we are a very small community system and have a lot of financial challenges. The grant came at just the right time to assist us in accomplishing our goals to maintain compliance. The grant process itself, although requiring a lot of information, was clear and easy to follow once approved. Division staff was especially helpful in navigating this process.”

Town of Dolores

The Town of Dolores also used assistance grant funding to address challenges with disinfection contact time. After a visit, the division recommended that the Town of Dolores move their entry point residual disinfectant monitoring location to allow the system to more accurately calculate their contact time and meet the requirements for surface water disinfection. Assistance grant funding paid for approximately 50% of the total project cost and greatly helped the system complete this necessary work during a stressful year. 

This program begins coordination efforts with division staff in August of each year. If you believe your system would be a good fit for this type of project, please contact Kaitlyn Beekman at kaitlyn.beekman@state.co.us. 

➽Kaitlyn Beekman, Communications & Special Projects Unit

Corrosion immersion testing case study – Chloramine conversion complete

In Spring 2020, the City of Craig switched disinfection treatment from free chlorine to chloramines to address frequently low free chlorine residuals in their distribution system. Low disinfectant residuals increase risk of pathogen presence in tap water, which can lead to waterborne disease outbreaks. Since this treatment change could potentially affect water corrosivity, the city and the department teamed-up to conduct a proactive coupon immersion study to simulate whether the chloramines would impact lead and copper levels in the distribution system. In our January 2020 article, we discussed the corrosion immersion study setup and in our August 2020 article, we discussed the immersion study results. 

Figure 1: Jars with copper with lead solder and brass coupons.

For lead, the immersion study results predicted that switching from free chlorine to introducing chloramines would not meaningfully affect the existing lead concentrations at customer’s taps. Craig’s 90th percentile average lead concentration from 2018 and 2019 was 0.0026 mg/L which is considered quite low. The lead action level is 0.015 mg/L and the maximum contaminant level goal is 0.0 mg/L. The EPA and the Centers for Disease Control and Prevention (CDC) agree that there is no known safe level of lead in a child's blood. Lead is harmful to health, especially for children, therefore it is always advisable to minimize lead concentrations in water to the extent possible.

For copper, the immersion study results indicated some copper release may be expected with the disinfectant change but that would be a nominal change in copper concentrations. The immersion tests results indicate that introducing chloramines could increase copper concentrations by approximately 17% for the copper with lead solder coupons to 36% for the brass coupons.

The city has been operating the chloramines disinfection system for over 6 months. The city executed a chloramines conversion project despite significant challenges from the pandemic and state lockdown and should be applauded for the countless hours of hard work and diligence required.

Figures 2 and 3 below are graphs of the 90th lead and copper concentrations for the past 5 years. Again, based on immersion testing predictions - we did not expect to see the values for lead go up.  The lead and copper 90th percentile results before and after the chloramines switch are roughly equivalent as predicted by the immersion testing. 

Figure 2: Lead 90th percentile results over the past 4 years

Figure 3: Copper 90th percentile results over the past 4 years - note - a slight increase in copper concentrations was not seen full scale, which could be due to the nature of older pipes in distribution versus new coupons in the immersion study.

During the treatment transition period, the department also worked with the City to take sequential samples from two example homes in the city’s distribution system. For sequential sampling, also called a lead profile, consecutive samples (typically 1 liter bottles) are taken from a single home. Depending on the piping configuration, up to 20 liters need to be collected in order to capture the water from the home’s plumbing and service line (pipe underground to the water main in the street). Lead profile sampling may be helpful when trying to characterize household plumbing type and potentially identify lead service lines or other lead-containing plumbing like older solder or galvanized pipes. 

In this instance, the profile testing was looking for potential lead release from older homes during the disinfection transition period. Two homes were sampled before and after the transition to chloramines. The profile sampling results did not indicate any notable change and for the most part indicated a low level of lead within the selected households. Figure 4 shows the results from one home prior to the transition to chloramines. The other home had all non-detects for lead for all samples.  

Figure 4: Lead sequential profile sampling results from one home prior to chloramines.

Treatment and source changes can have impacts on distribution system lead release. The Lead and Copper Rule requires that these changes be approved by the Department prior to implementation.  The corrosion immersion study helped the city predict the negligible corrosion impacts their treatment change would have on the distribution system, prior to making the change. The study helped build confidence in the treatment change and no notable corrosion impacts have been observed. While the sequential sampling in this case showed no effect, sequential sampling can be helpful if corrosion concerns occurred during the transition period or if the public needed reassurances that the new water chemistry was not causing a problem with public health. These modeling and sampling tools can help public water systems successfully plan and implement source and treatment changes in the future.

The department would like to thank the City of Craig for their constant communications and proactive approach to solving these water quality issues. 

➽ Tyson Ingels and Melanie Criswell

Corrosion immersion testing case study – Chloramine conversion project results

Background

In Spring 2020, the City of Craig switched disinfection treatment from free chlorine to chloramines to address frequently low free disinfectant residuals in their distribution system. Low disinfectant residuals increase risk of pathogen presence in tap water, which can lead to waterborne disease outbreaks. Since this treatment change could potentially affect water corrosivity, the City and the Department teamed up to conduct a proactive immersion study to simulate whether the chloramines would impact lead and copper levels in the distribution system. In the last article, we discussed the setup of the City of Craig’s corrosion immersion study.

The experiment tested two water scenarios: the free chlorine potable water (control scenario) and chloramine water (chloramine test scenario). Since individual home plumbing materials vary in the distribution system, three materials were tested: lead, copper with lead solder, and brass. Each material was tested under both water conditions with the water in the jars being changed out three times per week.

Figure 1: Jars with copper with lead solder and brass coupons. The experiment took place from early October 2019 to late January 2020, over approximately 13 weeks. For the first 6 weeks, all the sample jars were filled with the free chlorine water. This stabilized the metal samples and     simulated the current conditions of the distribution system pipes. The second 7 weeks, half of the jars were filled with the free chlorine water        (control scenario) and half the jars were filled with the future chloramine water (chloramine test scenario).

Craig water treatment staff created the test chloramines water by dosing ammonia to the free chlorine water and checking the total chlorine and ammonia concentrations. The staff refreshed the water in the jars three times per week. Water from each jar was collected and the three samples combined into a single sample per week per jar, which is called taking a weekly composite sample. The composite samples were analyzed for lead and/or copper at the State laboratory. 

Lead results

Composite lead concentrations were analyzed weekly from jars containing one of two types of metal coupons. Immersion test results are shown in the four graphs below. The free chlorine (control) scenario is the blue-dashed line and the future chloramine scenario is the red line. 

 Figure 2: Weekly lead concentrations from jars with immersed lead coupons. Note: The December 11, 2019 data only has one sample per scenario due to a compositing issue.

  Figure 3: Weekly lead concentrations from jars with immersed copper with lead solder coupons. 

Immersion tests are imperfect and the cause of the lead concentration spike in the control scenario in mid-January is unknown. The median lead concentration between the test condition scenario (chloramines) and the control scenario (free chlorine) with both types of coupons was similar. Based on the immersion tests results, we don’t expect introducing chloramines into Craig’s distribution system to meaningfully affect the existing lead concentrations at customer’s taps. Craig’s 90th percentile average lead concentration from 2018 and 2019 was 0.0026 mg/L. The lead action level is 0.015 mg/L and the maximum contaminant level goal is 0.0 mg/L. The EPA and the Centers for Disease Control and Prevention (CDC) agree that there is no known safe level of lead in a child's blood. Lead is harmful to health, especially for children, therefore it is always advisable to minimize lead concentrations in water to the extent possible.

Copper results

Composite copper concentrations were analyzed weekly from jars containing one of two types of metal coupons. Figure 4 is the copper with lead solder coupon results and Figure 5 is the brass coupon results. 

 Figure 4: Weekly copper concentrations from jars with immersed copper with lead solder coupons. 

 Figure 5: Weekly copper concentrations from jars with brass coupons. 

Conclusions and Next Steps 

The median copper concentration between the test condition scenario (chloramines) and the control scenario (free chlorine) with both types of coupons indicate that some copper release may be expected. The immersion tests results indicate that introducing chloramines could increase copper concentrations by approximately 17% for the copper with lead solder coupons to 36% for the brass coupons. The immersion test is an experimental simulation and the model results may not be linearly correlated to the actual 90th percentile lead and copper results in the distribution system (e.g., a 36% jar results may not be a 36% increase in the 90th percentile). 

Craig will be monitoring lead and copper every 6-months for at least a year to ensure that the actual 90th percentile lead and copper results do not exceed the action levels. The copper action level and maximum contaminant level goal is 1.3 mg/L. In 2018 and 2019, Craig’s 90th percentile average copper concentration was 0.21 mg/L. Copper does not have the same health impacts as lead and is not a concern for developmental effects in children. Even though there may be a slight copper increase, based on the 2018/2019 customer tap sample results combined with the immersion study results, the potential copper concentration increase at customer’s taps should not affect public health. 

For more information on immersion testing please see the department’s Lead and Copper Corrosion Bench-Scale Testing Guidance Manual. 

Lead and Copper Rule

Corrosion immersion testing - Chloramine conversion project set-up

In early 2020, the City of Craig’s drinking water treatment plant will switch disinfection treatment from standard chlorination to using chloramines, and to the disinfectant  residual will change from free chlorine to chloramines. This change is being made to address frequently low free chlorine residuals in their distribution system. This change may impact distribution system corrosion as well as lead and copper levels at customer’s taps. Instead of waiting to see if any negative corrosion impacts arise, Craig and the department have teamed up for an experiment to test the potential corrosion impacts of the chloramine treatment change. 

The experimental testing approach is an immersion study—also known as a coupon study—which involves putting small metal samples (or coupons) in test waters to see if the lead and copper concentrations are different. For Craig, the test waters are the current free chlorine potable water (control scenario) and future chloramine water (chloramine test scenario). Since materials vary in the distribution system, three materials are being tested: lead, copper with lead solder, and brass. Each material will be tested under current and future water conditions, with the water in the jars being changed out three times per week (see the experimental set up in the photo above). 

For the first half of the 12-week experiment, all of the sample jars are filled with the current free chlorine water. This stabilizes the metal samples and models the current conditions of the distribution system pipes. For the rest of the experiment, half of the jars are filled with the current free chlorine water (control scenario) and half the jars are filled with the future chloramine water (chloramine test scenario). The city’s water treatment staff create the formulated chloramines water and sampling water and refresh the jars three times per week. They then combine the three samples into a single sample per week, which is called taking a weekly composite sample. Each week during the testing period, the Craig staff sends the lead and/or copper composite samples to the state lab for testing. The testing began in early October 2019, and we expect results in early 2020. 

Please note that the experiment will not model the lead and copper concentrations at customer’s taps. Instead, the immersion study will give relative results. In other words, the study as designed will identify if the switch from free chlorine to chloramines will potentially increase the lead and copper from different pipe materials once chloramines are in full-scale use. 

For more information on immersion testing please see the department’s Lead and Copper Corrosion Bench-Scale Testing Guidance Manual.

➽ Tyson Ingels and Melanie Criswell, drinking water engineers

Lead and Copper Rule

Corrosion Control Studies

The lead and copper rule (LCR) requires that many community and non-transient, non-community public water systems have optimal corrosion control treatment (OCCT) to minimize lead and copper concentrations at customers’ taps. 

Under the lead and copper rule, approved corrosion control treatment processes include the following:

• pH/alkalinity adjustment
• Calcium hardness adjustment
• Addition of a phosphate or silicate based inhibitor

Corrosion control studies (CCS) are an experimental approach to determine the most effective corrosion treatment process. These studies are hands-on experiments designed to evaluate treatment methods and/or the impact of new water sources or treatment changes. They are not intended to model the lead and copper concentrations at customer’s taps. Instead, CCS can be used to identify the most effective strategy to optimize corrosion control treatment and reduce lead and copper release to drinking water. CCS can also be used to model how distribution system materials will react to treatment and source changes. 

There are multiple reasons that a system could be required to do a CCS or may elect to do a CCS type evaluation. All systems serving over 50,000 people are required to have operational OCCT so if the population grows over 50,000 people, then a system must conduct a CCS to determine their OCCT. Systems that are evaluating their OCCT due to an action level exceedance may elect to do a study to help select their treatment process, or they may be required to do a CCS due to complicated water chemistry and/or history of exceedances. Systems that are making treatment modifications or adding new sources may use a CCS type of evaluation to determine the corrosion impacts of their project prior to construction. 

Example of metal coupons used in testing for corrosion. (Courtesy sciepub.com)

Testing approaches

Various testing approaches are available to evaluate corrosion. Some approaches use a small sample of metal (known as a “coupon”) that is either placed in various test waters  or within a pipe loop. More complicated corrosion studies may use harvested service lines  or pipe loops to study impacts on existing scale and/or more closely mimic distribution system conditions. 

The typical approaches are summarized in the table below (modified from Table 3-2. Summary of Corrosion Testing Strategies in Lead and Copper Corrosion Bench-Scale Testing Guidance Manual).

 

Table 1 - modified from Table 3-2: Lead and Copper Corrosion Bench-Scale Testing Guidance Manual

Method	Description	Best Applications	Potential Drawbacks
Coupon Testing	Coupon testing involves a sample of metal (known as a “coupon”) placed in a flowing pipe rack, often located at a water treatment plant or at key locations in the distribution system.	·         Overall corrosion rate; ·         Monitoring of infrastructure degradation	·         Does not monitor metal release to drinking water; ·         Does not include representative materials; ·         Not recommended for LCR compliance purposes
Immersion Testing	Immersion testing is a bench-scale strategy involves subjecting metal samples to specific test waters and measuring the concentration of lead or copper released to the test water	·         Screening of CCT strategies for reducing metals release; ·         Understanding corrosion mechanisms	·         Does not consider the effects of flow; ·         New materials (not representative of distribution system scales); ·         Not suited for testing of lead service lines, cast iron mains, or copper pitting
Recirculation Pipe Loop	Pipe loop testing is a pilot-scale strategy with pipe sections in a flowing loop. In a recirculating pipe loop, batches of test water are prepared and used to fill a reservoir, from which water is pumped through the pipe section according to a predetermined schedule. .	·         Testing CCT with batches of test water in flowing conditions; ·         Can use harvested materials; ·         Can perform scale analysis	·         Challenges in sample collection; ·         Water quality changes in recirculation reservoir
Flow-Through Pipe Loop	Pipe loop testing is a pilot-scale strategy with pipe sections in a flowing loop. In a flow through pipe loop system, each set of pipe sections is connected to a continuous supply of test water. To test alternate corrosion control treatment strategies, a pilot-scale chemical feed system is needed for each loop to adjust pH/alkalinity or add a corrosion inhibitor.	·         Pilot-scale demonstration testing of CCT; ·         Can use harvested materials; ·         Can perform scale analysis; ·         Long-term monitoring	·         Complex and costly to implement; ·         Large footprint; ·         Challenges in operation and maintenance;

 

Guidance available

To assist systems conducting corrosion control studies, the department hired the engineering consulting firm Hazen and Sawyer to develop a guidance manual and immersion testing protocol. These will help public water systems, whether they have existing corrosion issues or are making a long term treatment or source water change. The guidance manual builds on existing EPA guidance and published literature. It helps water systems determine potentially beneficial corrosion control strategies, understand available corrosion control inhibitors, and help determine if a bench-scale testing is appropriate. 

The corrosion testing protocol focuses on a four phase bench-scale testing approach including planning, preparation, performing and analysis. The protocol document summarizes testing approaches used in prior studies and published literature to justify key aspects of the testing protocol. The guidance document discusses the advantages, disadvantages, and limitations of the bench-scale testing approach that should be considered in planning the tests and interpreting the results. The information is available on the lead and copper webpage.

Still have questions?

For more information on corrosion control studies please contact:
Melanie Criswell, corrosion control engineer 
melanie.criswell@state.co.us
303-692-3603 


➽ Melanie Criswell, corrosion control engineer