Samplegeddon - 2019

It's a wrap!

As Samplegeddon 2019 draws to a close, we want to update our readers on sampling progress statewide.

What is Samplegeddon? When the nine-year, six-year, three-year, annual, six-month, and quarterly monitoring compliance schedules all converge, that’s Samplegeddon! Because this happens just once every nine years, the department works diligently throughout Samplegeddon to remind water systems of their monitoring requirements. 

Updated Samplegeddon numbers

Based on the figure below, as of December 9, 2019:

• Overall, about 85% of three, six, and nine-year sampling requirements had been completed.
• Great news: A majority of systems sampled for nitrite, which is on a nine-year schedule! Only 6% of required samples had not been received.   
• Of the 29 systems that were on a reduced three-year sampling schedule for disinfection byproducts, 97% had sampled.
• The chemical group with the most incomplete sampling rate was synthetic organic chemicals. Only 77% of the required samples had been received. With 1,152 sampling schedules in Colorado, that is a significant amount of incomplete sampling!

Figure 1: Sampling Requirements for Reduced Schedules (3, 6, and 9 Year)

Avoid monitoring and reporting violations

To avoid any potential monitoring and reporting violations, please remember to: 

• Check your system’s monitoring schedule to see if you have any outstanding sampling requirements. Sampling requirements that have been satisfied will be stricken out on the monitoring schedule and given a **Sample Result(s) Received* label (see Figure 2).

Figure 2: Public Water System Monitoring Schedule. This figure illustrates sampling requirements that have and have not been met.

• Use your monitoring schedule to ensure samples will be collected at the appropriate sample point, during the correct collection period, and that there are not separate requirements for specific analytes within a group.
• Have enough sampling bottles on hand to address each requirement as it arises—you may even want a few extra.
• Collect and deliver your samples to a certified laboratory early in your compliance period. Be sure that the chosen laboratory will be able to process your sample results and report them to the department online. All samples are due on the 10th of the month following the monitoring period. Laboratories may be extra busy as deadlines approach, so do what you can to avoid surprises or delays! Submitting samples early helps ensure that samples will be received by the department on time, and it may also ensure adequate time to resample or correct reporting errors if needed.
• Confirm that sample results have been received and accepted by checking your system’s online monitoring schedules. Schedules are updated every Wednesday night to reflect changes.
• Contact your drinking water compliance specialist with any questions or concerns.
• Submit your data early. Remember, the best way to submit drinking water data to the department is through the drinking water portal.

➽ Nicole Graziano, P.E. and Jamie Duvall, B.S., drinking water compliance assurance

Program Manager's Message

Season's greetings from our staff!

As we wrap up our thirteenth year of Aqua Talk, I want to thank all of our readers for embracing a culture of health and protecting the people in your communities. You do this whenever you take a few minutes to read up on safe drinking water issues and news. 

The next decade will present many challenges, from the adoption of new federal rules to the next set of emerging contaminants and addressing infrastructure needs. Aqua Talk will be here to keep you informed. 

For now, though, we hope you have some time off to enjoy the holiday season, and we wish you the very best in the new year. 

Happy Holidays!


➽ Ron Falco & Aqua Talk Staff

Program Manager's Message

Per- and Polyfluoralkyl Substances (PFAS) Rule

As noted in my last Program Manager's Message, EPA is likely to begin developing a new rule in 2020 to address per- and polyfluoroalkyl substances (PFAS). PFAS, commonly used in firefighting foams, has contaminated several drinking water supplies in Colorado. Many manufacturers modified their processes to avoid using PFOS and PFOA several years ago, but hundreds or thousands of other PFAS chemicals have been used in commerce and may contaminate the environment and water supplies. 

National MCLs

In early 2020, EPA will make a regulatory determination about whether to establish Maximum Contaminant Levels (MCLs) for PFOA and PFOS (see EPA's PFAS Action Plan). The new rule’s structure will likely be similar to rules for other contaminants with MCLs. A PFAS rule would therefore include:

• The MCL values themselves, with a certain number of significant digits
• Sampling requirements including location, frequency and analytical methods
• Any opportunities for reduced monitoring or “grand-parenting” existing data
• How is compliance determined, e.g. running annual average?
• Public notice requirements for violations
• Health effects language that must be included in public notices

Colorado

Under Colorado Revised Statute (C.R.S.) Sections 25-1.5-202(3)-(4), the Water Quality Control Commission can set “minimum general sanitary standards” (MCLs) for contaminants or substances that are unregulated by the Safe Drinking Water Act, based on the division’s recommendation. Minimum general sanitary standards are Colorado’s equivalent to federal MCLs under the Safe Drinking Water Act. 

To establish minimum general sanitary standards, the division must first “annually establish and revise a priority list of contaminants or substances for which standards may be considered and shall submit the list to the commission for review and approval.” In September 2019, the division submitted a priority list of contaminants to the commission for consideration (see Section D of our 2019 Annual Report to the commission), which included several PFAS compounds. The commission approved the priority list in October 2019. 

The division believes that including PFAS chemicals on the priority list was warranted to support the department’s PFAS action plan.This does not set MCLs or minimum general sanitary standards for PFAS, and it does not necessarily mean that the division will pursue standards for these compounds in the near future. However, failing to establish a priority contaminant list that includes PFAS would unacceptably reduce the division’s flexibility for taking action to protect public health and address human exposure to PFAS. If the division should decide to move forward with setting state MCLs (minimum general sanitary standards) for PFAS, that process would start with considerable outreach and a stakeholder process to gain needed input. 

Priorities

We prioritized the following compounds because of their confirmed presence in drinking water supplies and sources in Colorado, as described in the statute’s ranking process considerations: 

• Perfluorooctanoic acid (PFOA) Chemical Abstract Service Number (CAS No.) 334-67-
• Perfluorooctane sulfonate (PFOS) CAS No. 1763-23-1.
• Perfluorohexane sulfonic acid (PFHxS) CAS No. 355-46-4.
• Perfluorononanoic acid (PFNA) CAS No. 375-95-1. 

Ranking 

The ranking process considerations, which are detailed in the report to the commission, included:

• Presence or threat of contamination
• Identified contamination pathway
• Analytical techniques
• Availability of information about health effects and treatment
• Magnitude of health risks
• National primary drinking water regulation
• Environmental fate and transport
• Populations and drinking water supplies at risk
• Level of effort to develop standard

Overall, this effort would likely involve numerous staff over many months prior to the actual rulemaking. If the commission adopted a rule, then the division would also need adequate resources for implementing and enforcing it and for providing compliance and technical assistance. 

Please stay tuned as the department moves forward in implementing the PFAS action plan. 


➽ Ron Falco, safe drinking water program manager

Booster Pump Stations

Booster Pump Station Wet Wells - are they reviewed?

Most Colorado water professionals already know that we have long focused our review efforts on new and modified facilities. We do not typically review booster pump stations unless the station includes treatment, such as the addition of a chemical to boost the disinfectant level. What many do not realize is that, because many booster pump stations include wet wells that meet the regulatory definition of a finished water storage tank under section 11.28 of Regulation 11, such tanks require division approval prior to construction or modification.   

11.28(1)(c) “FINISHED WATER STORAGE TANK” means a tank or vessel owned by the supplier that is located downstream of the entry point and is not pressurized at the air water interface. Pressurized storage tanks are not included in the definition of finished water storage tanks.   

The most direct way to determine if a booster pump station has a wet well is by looking at how water is supplied to the booster pump. Booster pump stations are either fed directly from the pressurized potable water distribution system piping or from a finished water storage tank. When fed directly from the distribution piping, the booster pump station does not break the inlet head in a finished water storage tank (wet well) and the incoming water does not have an air-water interface. These types of pump configurations may be termed “in-line pumps,” “barrel-” or “can-style” pumps.  They are not subject to the storage tank rule. 

At times, booster pump stations must break the source water pressure prior to pumping.The source water typically enters an onsite wet well, which means that it has an air-water interface that could potentially expose the finished water to contaminants. Booster pump stations with wet wells can have a variety of potential configurations, but most commonly use vertical turbine pumps. In all cases, though, the booster pump station has a wet well with an air-water interface that meets the definition of a finished water storage tank. These vessels are subject to the storage tank rule, which includes periodic inspections.

According to Regulation 11, they also must receive design approval from the division prior to construction or modification. Unfortunately, due to a department oversight, the current design criteria for potable water systems do not have well defined requirements for this type of finished water storage tank. We plan to develop design criteria during the next stakeholder process, but until then, we will only be evaluating booster pump station wet wells in the following cases:

• We will begin accepting and reviewing construction applications for all booster pump station wet wells following adoption of the next design criteria revision.
• We will complete design reviews for any booster pump station tanks if they are part of a larger infrastructure project subject to the design review application process.
• We will investigate booster pump stations during sanitary surveys but will not issue violations for sanitary defects until 2022.

Have questions? 

If you are planning to construct or modify an existing booster pump station wet well and you want additional information, contact 

Bret Icenogle, engineering section manager 

bret.icenogle@state.co.us

303-692-3278 

➽ Bret Icenogle, engineering section manager

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