Public Notification & Emergency Communication

Public Notification Rule is intended to ensure that consumers will always know if there is a problem with their drinking water. These notices immediately alert consumers if there is a serious problem with their drinking water that may pose a risk to public health. They also notify customers if their water does not meet drinking water standards, the water system fails to test its water, or if the system has been granted a variance (use of less costly technology) or an exemption (more time to comply with a new regulation.) Consumer Confidence reports (CCRs) are an annual report of the status of the drinking water at a facility that are also required. However, CCRs do not necessarily report problems, but a status.

We have 731 resources (and counting) on Public Notification in our Documents Database that provide valuable information on this topic. You can search for documents about how states are responding to health advisories for water systems, ways to prepare for a drought related water shortage, advice for working with news media, boil water advisories during natural disasters, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Public Notification within our database just select "CATEGORY" in the dropdown then choose "Public Notification." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Nitrate Levels in Drinking Water

U.S. EPA regulates nitrate in drinking water to protect public health. Nitrate may cause health problems if present in public or private water supplies in amounts greater than the drinking water standard set by U.S. EPA. There is also concern about nitrate in wastewater effluent.

We have 204 resources (and counting) on Nitrate in our Documents Database that provide valuable information on this topic. You can search for documents on how to address the presence of nitrate, analytical methods recommended for drinking water monitoring of secondary contaminants, case studies on controlling nitrification in a distribution system, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Nitrate within our database just select "CATEGORY" in the dropdown then choose "Nitrate." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Compliance Monitoring for Water Systems

Regulations can require compliance monitoring at specific locations and at specific times and intervals. This can look like the collection of water samples or recording information about the system from gauges and dials. Often, samples must be shipped very quickly to the laboratory before the sample degrades. It is recommended that systems also complete voluntary monitoring for operations and maintenance purposes to diagnose potential problems.

We have 2,350 resources (and counting) on Monitoring in our Documents Database that provide valuable information on this topic. You can search for documents on sampling protocols for PFAS, comparison of coliform media, algal toxin removal capabilities of common drinking water treatment processes, Consumer Confidence Reporting (CCR) compliance checklist examples, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Monitoring within our database just select "CATEGORY" in the dropdown then choose "Monitoring." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Lead and Copper Pipe Replacement

Lead and copper enter drinking water primarily through plumbing materials. Exposure to lead and copper may cause health problems ranging from stomach distress to brain damage. The treatment technique for lead and copper requires systems to monitor drinking water at customer taps. If the action level for lead is exceeded, the system must also inform the public about steps they should take to protect their health and may have to replace lead service lines under their control.

We have 521 resources (and counting) on Lead and Copper in our Documents Database that provide valuable information on this topic. You can search for documents on how to collaborate with organizations to replace lead service lines (LSLs), case studies that analyze LSLs in small community water systems, how to reduce lead in drinking water in schools and childcare facilities, how to address lead in drinking water with the Drinking Water State Revolving Fund (DWSRF), and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Lead and Copper within our database just select "CATEGORY" in the dropdown then choose "Lead and Copper." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Drinking Water Standards: Rules, Regulations, Compliance

The U.S. Environmental Protection Agency (EPA) sets standards that, when combined with protecting ground water and surface water, are critical to ensuring safe drinking water. U.S. EPA works with its regional offices, states, tribes and its many partners to protect public health through implementing the Safe Drinking Water Act. The standards are the levels of a particular contaminant that are allowed in drinking water and still considered safe.

We have 1482 resources (and counting) on Drinking Water Standards in our Documents Database that provide valuable information on this topic. You can search for resources like an overview of the Safe Drinking Water Act (SDWA), information on how U.S. EPA develops risk-based drinking water regulations, a comprehensive list of potential contaminants in water, and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of knowledge on Drinking Water Standards within our database just select "CATEGORY" in the dropdown then choose "Drinking Water Standards." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Arsenic in Drinking Water

Arsenic is a heavy metal and a regulated contaminant in drinking water and wastewater effluent. In 2001, under the Arsenic Rule, EPA adopted a lower standard for arsenic in drinking water of 10 parts per billion (ppb) which replaced the previous maximum contaminant level (MCL) of 50 ppb. Arsenic is a semi-metal element in the periodic table. It is odorless and tasteless. It can enter drinking water supplies from natural deposits in the earth or from agricultural and industrial practices. 

We have 180 resources (and counting) on Arsenic in our Documents Database that provide valuable information on this topic. You can search for documents about the arsenic rule, complying with the arsenic maximum contaminant level, the reporting requirements for the annual Consumer Confidence Reports (CCR), and many other useful guides that will help you to deliver safe and clean water to utility customers. 

To access the wealth of Arsenic related knowledge within our database just select "CATEGORY" in the dropdown then choose "Arsenic." Once you make that selection, a second dropdown will appear where you can choose "HOST," “TYPE,” or “STATE” to narrow the search even further. If you have a specific search term in mind, use the “Keyword Filter” search bar on the right side of the screen.

This is part of our A-Z for Operators series.

Free Compliance Resources for Monitoring & Reporting

Our 2020 free webinar series highlighted compliance-related resources on a number of topics. This recording contains information and free resources on monitoring and reporting. Listed below are all the resources mentioned in the video.

National Primary Drinking Water Regulations

This 7-page factsheet from the U.S. EPA includes information on 87 regulated contaminants, maximum contaminants levels, potential health effects, contaminant sources, and treatment technique requirements. 

Drinking Water Dashboard

This website contains information on the number of public drinking water site visits, violations, serious violators, enforcement actions, and returns to compliance. 

Revised Total Coliform Rule

This is a 3-page quick reference guide from the U.S. EPA on the public health benefits, requirements, provisions, and assessments associated with the revised total coliform rule. 

Vermont DEC Pocket Sampling Guide to RTCR

This is a small pocket guide with information on complying with the RTCR sampling requirements. 

EPA RTCR Placards

This document includes 6 fillable place cards related to RTCR monitoring requirements designed for systems serving 1,000 or less people. 

Repeat Monitoring Requirements For Small Systems

This is a reference guide developed by the Indiana Department of Environmental Monitoring on monitoring requirements for public water systems servings less than 1,000 people. 

Flowchart for Triggered Source Water Monitoring 

This is a flowchart developed by the New Jersey Department of Environmental Protection for water systems on quarterly and monthly schedules. 

Revised Total Coliform Rule: Routine Positive Sample Flowchart (For Community Water Supplies) 

This is a flowchart from the Michigan Department of Environment, Great Lakes, and Energy on what to do when a system triggers a routine sample. 

Revised Total Coliform Rule (RTCR) Sample Siting Plan with Template Manual

This is a sample siting plan template from the U.S. EPA designed for primacy agencies to give to public water systems serving less than 1,000.

Public Notification Instructions and Templates for the Revised Total Coliform Rule (RTCR)

This is a 38-page document from the U.S. EPA that includes instructions as well as templates for reporting RTCR violations.

Ground Water Rule: A Quick Reference Guide

This is a 2-page reference guide with information on the groundwater rule. 

Ground Water Rule Compliance Help for Water System Owners and Operators
This is a U.S. EPA website with information and resources for complying with requirements of the Ground Water Rule.

Ground Water Rule Factsheet: Monitoring Requirements

This is a 6-page factsheet from the U.S. EPA with information on monitoring requirements for the Ground Water Rule. 

Ground Water Rule (GWR) Monitoring Requirements

This is a placard developed by the U.S. EPA with information on consecutive systems with their own source conducting triggered source water monitoring. 

Ground Water Rule Factsheet: Public Notification, Consumer Confidence Report, and Special Notice Requirements for Community Water Systems

This is a factsheet from the U.S. EPA with information on public notification requirements and consumer confidence report requirements. 

The Standardized Monitoring Framework: A Quick Reference Guide

This is a quick reference guide developed by the U.S. EPA with information on the standard monitoring framework for chemical contaminants. 

Nitrate Monitoring Requirements

This is a printable poster by the U.S. EPA Printable poster designed to help operators know who to contact and what to do based on their nitrate sampling results.

12 Steps to Arsenic Compliance

This is a 1-page factsheet from the U.S. EPA with steps that public water systems should take to achieve arsenic compliance. 

Complying With the Revised Drinking Water Standard for Arsenic: Small Entity Compliance Guide

This is a 58-page guidance manual from the U.S. EPA on arsenic compliance for smaller systems that includes information on monitoring requirements, compliance determination, reporting and notification requirements, and arsenic monitoring worksheets. 

Chemical Phase II/V Rules

This 19 slide presentation from the U.S. EPA features information on key requirements, maintaining compliance, best sampling practices, and resources related to chemical phase II/V rules. 

Chemical Contaminant Notification Forms

This webpage for the Texas Commission on Environmental Quality offers numerous public notice templates on topics like chemical violations, boil order notices, and microbial violations. 

Arsenic in Your Drinking Water

This is a 2-page factsheet from the U.S. EPA on arsenic contamination in drinking water. 

Talking to Customers About Chronic Contaminants in Drinking Water 

This factsheet from the U.S. EPA was designed to help public water systems understand the importance of communicating and educating consumers about the contaminants in their water.

A-Z Index of Contaminants in Water
This webpage from the Minnesota  Department of Health features an alphabetized list of information on numerous contaminants found in drinking water. 

Chemical Contaminants in Water
This is a webpage from the Oregon Health Authority with a list of bulletins with information on the potential health effects of drinking water containing these chemicals.

Comprehensive Disinfectants and Disinfection Byproducts Rules (Stage 1 and Stage 2): Quick Reference Guide

This reference guide from the U.S. EPA has information about stage 1 and stage 2 of the Stage 1 Disinfectants and Disinfection Byproducts Rule. 

Public Notification Templates for Community and Non-transient Non-community Water Systems
This website has numerous templates to assist primacy agencies with implementing the Public Notification Rule.

Initial Distribution System Evaluation Guidance Manual

This is a 434-page manual from the U.S. EPA that covers the various components of an IDSE and provides guidance on how to conduct standard monitoring. 

Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) Compliance Monitoring Plan Template for Public Water Supply Systems

This is an 11-page template that provides instructions on what information should be included in the plan, stage 2 DBPR requirements on selecting the most appropriate sites for sampling, and developing a sketch of the distribution system.

NC DEQ Stage 2 Disinfection Byproducts Monitoring Chart

This chart lists monitoring requirements for DBPs for water systems on routine monitoring, reduced monitoring, and increased monitoring. 

Sample Collector's Handbook Stage 2 Disinfectants and Disinfection Byproducts Rule

This 21-page handbook from IL EPA was designed to assist public water systems in complying with the sampling portion of the Stage 2 DBPR.

Understanding the Lead and Copper Rule

This is a 2-page document from the U.S. EPA that gives an overview of the Lead and Copper Rule. 

Lead and Copper Rule: A Quick Reference Guide

This 2-page reference guide from the U.S. EPA provides an overview of information on the Lead and Copper Rule. 

Lead and Copper Rule Monitoring and Reporting Guidance for Public Water Systems

This is a 124- page manual from the U.S. EPA on various monitoring and reporting requirements under the Lead and Copper Rule.

Lead and Copper Rule

This webpage from the Michigan Department of Environment, Great Lakes & Energy lists a variety of videos and templates on Lead and Copper Rule compliance. 

Lead and Copper Rule

This webpage from the Utah Department of Environmental Quality provides visual depictions to better understand Lead and Copper Rule compliance steps. 

Lead and Copper Rule: Public Education and Consumer Notification Requirements for Non-Transient non-Community Water Systems (NTNCWS) 

This is a 4- page factsheet from the U.S. EPA that provides a guidance manual for NTNCWS. 

Implementing the Lead Public Education Provisions of the Lead and Copper Rule: A Guide for Community Water Systems

This is a 114- page guide on public education resources on the Lead and Copper Rule for community water systems. 

Consumer Confidence Report Rule: A Quick Reference Guide

This is a 2-page reference guide from the U.S. EPA that gives an overview of the Consumer Confidence Report Rule. 

Best Practices Factsheet: Consumer Confidence Report 

This is a 16-page guide on best practices for developing an effective Consumer Confidence Report.

Consumer Confidence Report (CCR) Basics

This is a 26-minute webinar from the Michigan EGLE on the components of a CCR, the language that should be used, and tips on writing an effective report.

Revised Public Notification Handbook

This is a 180-page guidance document from the U.S. EPA with instructions on how to develop public notification.

The Public Notification Rule: A Quick Reference Guide

This is a 4-page reference guide from the U.S. EPA that provides an overview of the Public Notification Rule. 

Please note that we are not able to provide certificates for watching a webinar recording.

Free Compliance Resources for DBPs

Our 2020 free webinar series highlighted compliance-related resources on a number of topics. This recording contains information and free resources on DBPs. Listed below are all the resources mentioned in the video.

Comprehensive Disinfectants and Disinfection Byproducts Rules (Stage 1 and Stage 2): Quick Reference Guide
The 4-page fact sheet overviews both the Stage 1 and Stage 2 Disinfection Byproducts Rules. Operators will learn about each rule's requirements including monitoring requirements, MCLs, MCLGs, compliance determination, and the contaminants included under each rule.

Stage 1 Disinfectants and Disinfection Byproducts Rule
This four-page fact sheet provides detailed information on Stage 1 of the Disinfection Byproducts Rule and its history. 

Fact Sheet: Stage 2 Disinfectants and Disinfection Byproducts Rule
This is a four-page fact sheet that uses questions and answers format to help water systems understand what stage 2 of the Disinfection Byproducts Rule entails. 

Regulating Disinfectants and Disinfection Byproducts 
This 2-page fact sheet created by the Washington State Department of Health is geared towards new water operators that are interested in learning more about Disinfection Byproducts Rule. 

Initial Distribution System Evaluation Guidance Manual For The Final Stage 2 Disinfectants and Disinfection Byproducts Rule
This is a 434- page manual from the U.S. EPA that covers various components of an initial distribution system evaluation. 

Stage 2 Disinfectants and Disinfection Byproducts Rule (Stage 2 DBPR) Compliance Monitoring Plan Template For Public Water Supply Systems
This is an 11- page template with information from the U.S. EPA on public water supply systems and operations instructions on selecting appropriate monitoring sites for TTHM and HAA5. 

North Carolina DEQ Disinfectants and Disinfection Byproducts Rule Template 
This website page from the North Carolina DEQ includes a 15-page template and an 8-page instruction manual with information on how to monitor for TOC, chlorine dioxide, chlorite, bromate, and DBP precursors. 

Monitoring Plan for the Disinfectants/ Disinfection Byproducts Rules
This 27-page template and 10-page instruction manual from the Pennsylvania DEP includes a monitoring plan as reference. 

Stage 2- Disinfection Byproducts Monitoring Chart
This is a one-page fact sheet from the North Carolina Department of Environmental Quality that lists monitoring requirements for disinfection byproducts. 

Disinfectants / Disinfection Byproducts (DBP) Rules Monitoring & Reporting Requirements For Public Water Systems
This 16-page factsheet from the Pennsylvania Department of Environmental Protection provides monitoring requirements for DBPs, disinfection residuals, and TOC. 

Sample Collector's Handbook Stage 2 Disinfectants and Disinfection Byproducts Rule
This 21-page handbook from the Illinois Environmental Protection Agency outlines monitoring requirements, reduced/ increased monitoring, determining MCL compliance, performing and OEL, and sample collection tips. 

Sampling Procedures for TTHM and HAA5
This 14-minute video from the North Dakota Department of Environmental Quality lists components of a sampling kit, proper techniques and considerations when collecting TTHM and HAA5 samples, and chlorine residual sampling as well. 

How To Collect A Drinking Water Total Trihalomethanes (TTHM) Sample
This is a 3-minute video on proper TTHM sample collection following EPA Method 524.3.

How To Collect A Drinking Water Haloacetic Acid (HAA5) Sample
This is a 2-minute video on proper HAA5 sample collection following EPA Method 552.2.

Stage 2 Disinfectants and Disinfection Byproducts Rule Operational Evaluation Guidance Manual
This is a 180-page guidance manual from the U.S. EPA on requirements for operational evaluations, guidance for documents and reporting forms for OEL exceedance, and guidance on minimizing future OEL exceedances.

Water Quality Assessment Software (WQAS)
This is an excel sheet from the Department of Environmental Quality that can help water systems track DBP data (TTHM, HAA5), parameters affecting DBP formation (Water chemistry), and system-specific parameters. 

Regulating Disinfectants and Disinfection Byproducts
This 2-page fact sheet from the Washington Department of Health includes a table of disinfectants as well as advantages and disadvantages for each disinfectant. 

Recommended Treatment Techniques for Controlling Disinfection By-Products
This is a 20- page guidance document from Florida Rural Water Association on treatment techniques for small to medium-sized water systems. 

Disinfection By-Products Troubleshooting Guide
This is a 4-page factsheet from the Florida Rural Water Association on troubleshooting process changes in water treatment, distribution system, and source water changes.

Public Notification Templates for Community and Non-transient Non-community Water Systems
This website provides a list of public notification templates to assist primacy agencies with implementing the Public Notification Rule.

Complying With the Stage 1 Disinfectants and Disinfection Byproducts Rule: Basic Guide
This 50-page guidance manual from the U.S. EPA provides information about the health risks associated with DBPs, monitoring requirements of the Stage 1 DBPR, how to determine if systems are in compliance, how to maintain compliance, reporting requirements, and how the Stage 1 DBPR compliance can affect other rules.

Complying with the Stage 2 Disinfectants and Disinfection Byproducts Rule: Small Entity Compliance Guide 
This 57-page guidance manual from the U.S. EPA provides information on Stage 2 DBPR requirements, compliance monitoring requirements, how to select monitoring sites, operational evaluation, locating and fixing problems, financial assistance information, and public notice requirements.

Simultaneous Compliance Guidance Manual for the Long Term 2 and Stage 2 DBP Rules
This 462-page manual from the U.S. EPA provides information on how to identify and mitigate issues that systems will face when implementing changes necessary to comply with the Stage 2 DBPR and LT2ESWTR while still being required to comply with other SDWA regulations.

Stage 2 Disinfectants and Disinfection Byproducts Rule Consecutive Systems Guidance Manual 
This 73-page guidance manual from the U.S. EPA provides information on stage 2 DBPR requirements for consecutive systems, compliance options for consecutive systems, communication strategies between consecutive and wholesale systems to improve water quality from wholesale systems, and developing consecutive system compliance strategies to meet the stage 2 monitoring requirements.

EPA Small Systems Monthly Webinar Series Disinfection Byproducts (DBPs): Regulatory Issues and Solutions
This 54-minute webinar provides a review of the Stage 2 DBPR monitoring and reporting requirements and of small system DBP challenges in the State of Washington while highlighting a few success stories.

EPA Small Systems Monthly Webinar Series Stage 2 Disinfection Byproducts Rule and Simultaneous Compliance Webinar
This 70-minute webinar provides a review of the Stage 2 DBPR and EPA’s 2018 In-Depth Analysis and of challenges water systems face during simultaneous compliance between the Stage 2 DBPR and other NPDWRs.

Stage 2 Disinfectants and Disinfection Byproducts Rule (DBPR) and Consecutive System In-Depth Analysis
This is a 35-page report from the U.S. EPA on approaches to optimize systems and reduce DBPs through EPA’s Area-Wide Optimization Programs (AWOP).

Reducing Disinfection Byproducts through Optimization Webinar Series
This is a 4 part webinar series from ASDWA that shares optimization-based tools and approaches for DBP control from various states.

Please note that we are not able to provide certificates for watching a webinar recording.

Opinion: Challenges Quantifying COVID-19 Cases Using Wastewater

Editor's Note: The views expressed in this post are the sole opinion of the author and not those of WaterOperator.org, our sponsors, or the University of Illinois.

In the May 5, 2020 edition of the WaterOperator.org newsletter, we highlighted ongoing research that uses wastewater-based epidemiology to monitor the spread of SARS-CoV-2, the virus that causes COVID-19. Especially in locations where no confirmed cases have been identified, any samples positive for SARS-CoV-2 viral RNA implies that there are people infected in that community excreting it. For that purpose, wastewater monitoring shows real promise as an approach to early detection. By monitoring wastewater influent, scientists hope we can develop an advanced warning system for outbreaks.

There has been significant buzz about using wastewater to quantify the actual number of people infected within a given service area, but there are some issues with quantifying cases I want to discuss. In our newsletter we highlighted MIT research aiming to quantify the number of infected from a large area in Massachusetts. In that article, the researchers point to concerns about meeting the litmus test of sound science.

The wastewater system they studied had 450 confirmed cases at the time of sampling. Results from this monitoring suggested the number of people infected could be much higher. They estimated somewhere between 2,300 and 115,000 infected people. A range this wide does little to help planners or health officials prepare for what might be coming during a pandemic.

Quantifying the number of people infected with COVID-19 using wastewater samples requires a much more comprehensive data set that we cannot gather today in any cost effective way. Here are a few of the problems I see in quantifying the positive COVID-19 population within a given wastewater system:

• Not everyone excretes the viral RNA:
  A recent study published March 30 in the American Journal of Gastroenterology found that some COVID-19 patients exhibit gastrointestinal symptoms, with those patients more likely to produce a positive stool test. In other words, COVID-19 positive patients may not have ANY viral RNA in their stool. How do we identify those people?
• Wastewater varies throughout the day and throughout the week:
  The influent coming through a plant varies based on the discharges from the users. A lot of variables can affect wastewater characteristics at the specific time a sample is collected. The time of day, time of week, and even the time of year can affect the flow into a plant depending on the types of users in the system.
• Every system has a variety of sources for their wastewater:
  What percentage of the wastewater is residential? Are there commercial or industrial facilities that are discharging to the community system? If so, how much, and what types of businesses? In some communities, commercial and industrial users could make up a significant portion of the wastewater treated. In a rural area, the regional hospital may be in a smaller community making it a significant source and contributor. Other communities could be almost completely residential.
• Sampling time and frequency can skew the results:
  Sampling time matters, as do the number of samples collected. How do we decide what is representative? Once an hour? Once a day? Sampling may need to be continuous to really understand the variability.
• Wastewater collection systems leak:
  Leaking can occur both ways. Some wastewater leaks into the environment through the collection system while, at other times, a high groundwater table may be leaking groundwater into the collection system. I looked at approximately 50 smaller systems in Illinois to compare the amount of wastewater discharge to the amount of groundwater they withdraw from drinking water wells. (You would expect the amount withdrawn from wells to be more than that treated at the wastewater plant because of consumptive use.) In many cases systems were treating more wastewater than the raw water being used for their community supply and, in some cases, it was 2-3 times a much. This would be significant factor when using any volumetric approach to evaluating COVID-19 sampling results.
• We have no benchmark to compare results:
  Without having data for a number of communities where the total number of residents with active COVID-19 infection is known, there is no way to validate assumptions and calibrate estimates built into the method. This would not be possible without a consensus understanding about the rate of asymptomatic cases.

If researchers must accept such a high degree of uncertainty, how can this method ever be accurate or useful? Many factors would have to be considered to quantify the number of positive cases for a given community and these would be unique to the individual system. That said, these are not likely new considerations for the talented researchers working on this effort. 

In the future I hope an approach to accurately quantify an infected population using wastewater-based epidemiology becomes a reality. It would be a tremendous asset. In the meantime, however, I believe our focus should be on evaluating the pitfalls mentioned above and working toward technologies/protocols needed within a wastewater plant to reduce uncertainty and move us closer to our common goal of protecting public health.

A Look at Protozoa in Wastewater Treatment Systems

Wastewater treatment is fundamentally a biological process. When influent enters the microbial ecosystem of a treatment plant, nutrient removal is accomplished through the consumption of organic matter by microorganisms. The bulk of all nutrient removal is performed by bacteria, however protozoa and metazoa balance these bacterial populations and offer insight into wastewater conditions. Operators who understand the varying roles of wastewater microbes and the conditions that favor their growth can foster an ecosystem that promotes optimal treatment. In this week’s blog post we will review the niche protozoa fill in wastewater systems to enhance monitoring efforts and inform process control.

Roughly four percent of a wastewater system’s microbial ecosystem is made up of protozoa. Protozoa are single celled microbes both larger in size than bacteria and more complex. The most common types of wastewater protozoa include amoeba, flagellates, and ciliates. By consuming free bacteria and small, unsettled floc, protozoa enhance the clarity of the final effluent. Observing protozoa populations under a microscope can also alert operators of treatment conditions and sludge age.

Amoeba are predominant under a young sludge age because they require high nutrient levels or low competition to grow. Under shock loads of biochemical oxygen demand (BOD), high concentrations of particulate matter, toxic conditions, or low dissolved oxygen (DO), amoeba can also dominate. The latter two conditions generally trigger the amoeba to develop a protective gelatinous shell that gives them an advantage over other microbes. Furthermore, their slow movement reduces oxygen demand required for growth and reproduction.

Flagellates are typically present under a young sludge age as well. Since flagellates compete poorly with bacteria for the same soluble nutrients, their growth is favored at the younger sludge age before bacteria have had a chance to populate. As such, a wastewater sample relatively high in flagellates can indicate high soluble nutrient levels also known as a high food to mass (F:M) ratio.

Ciliates are favored under a healthy sludge age. While they do not consume organic matter, they do feed on bacteria making them excellent indicators of healthy floc formation and useful clarifying agents. Without ciliates, bacteria and algae populations can grow out of control in the wastewater microbial ecosystem. Among the three types of ciliates common to wastewater, each group has different conditions under which their populations are favored.

Swimming ciliates start to form as flagellates disappear. They may experience a spike in population when levels of free bacteria are abundant for predation. If too many free bacteria are present, the ciliate population surge can ultimately result in a cloudy effluent. Crawling ciliates dominate when those free bacterial populations begin to stick together forming floc through a secreted slime layer. This slime layer is produced when dissolved nutrients become limited. Since swimming ciliates cannot readily pick off bacteria within the floc, crawling ciliates begin to out-compete them. As they feed on bacteria, crawling ciliates can improve flock structure. A more mature sludge age with reduced BOD allows stalked ciliates to compete with crawling ciliates. Stalked ciliates anchor themselves to floc using the cilia surrounding their mouth structure to create currents that draw in bacteria. Once their food levels have diminished significantly more, stalked ciliates begin to branch into colonial units to acquire food more efficiently. If sludge continues to age, stentors and vaginocola protozoa grow in abundance.

For more information on wastewater protozoa and how to monitor them, we’d like to recommend the following documents. These resources and others like them can be found using our online, resource library.

Bacteria Protozoa – Toni Glymph
The guide overviews basic wastewater microscopy, slide preparation, sample collection, and the microbiology of activated sludge plants.

Wastewater Microbiology & Process Control - Wisconsin Wastewater Operator’s Association
Learn the about microscopes, slide preparation, and the microorganisms found during wastewater treatment.

Protozoan Count – Toni Glymph
This guide describes how to sample protozoa for observation under the microscope.