Tour of Alaska's Largest Wastewater Treatment Plant

The John M. Asplund Water Pollution Control Facility in Anchorage, Alaska is the state's largest wastewater treatment plant. It is owned and operated by the Anchorage Water & Wastewater Utility. This video showcases the plant's evolution since 1972 to its current capacity of 58 million gallons per day. It also provides regulatory and scientific context for the wastewater treatment process. This is a great example of how a system can use video to help the public understand what you do and why it is important. 

Preparing for Funding Opportunities

Proposed infrastructure funding has been on everyone's radar, despite uncertainty about what fine print will ultimately be passed by Congress. The new plan could be the largest investment in drinking water and wastewater infrastructure in American history and bipartisan support for these efforts means that new funding opportunities for a range of stakeholders are likely.

This makes it all the more important to know how to apply for and manage funding when it becomes available, as well as understand your needs and eligibility. Navigating the world of funding can feel intimidating, but there are many resources available to help aid the process. Preparing ahead of time is the best way to make sure your organization is ready to respond to funding opportunities. 

This preparation begins with a capacity development approach. Capacity development is a process that water systems can use to acquire and maintain adequate technical, managerial, and financial capacity. Programs have been established in every state to help public water systems continue to strengthen their capacity and you've likely crossed paths with training, resources, or technical assistance provided through these programs.

We're highlighting a selection of our favorite capacity development resources that can help systems (and those who serve them) undertake readiness efforts for potential infrastructure investment.

Managerial Capacity 

Managerial capacity for short and long term planning includes:

• Ownership accountability 
• Staffing and organization 
• Effective external linkages 

Resources:
Water System Owner Roles and Responsibilities: A Best Practices Guide
This guide can help owners and operators of public water systems serving less than 10,000 people better understand their responsibilities. 

Strategic Planning: A Handbook for Small Water Systems
This handbook was designed to help operators serving less than 3,000 people develop a strategic management plan. 

Manual for Assessing Public Water Supply System Capability
This manual goes through each of the components of capacity development, technical capacity, managerial capacity, and financial capacity. 

Financial Capacity 

Financial capacity for short and long term planning includes:

• Revenue sufficiency 
• Creditworthiness 
• Fiscal management and controls  

Resources:
Water Finance Clearinghouse
This portal was created by the U.S. EPA to help water operators locate helpful financial resources. 

Grant (Loan) Writing 101 - Right Grant, Right Time, Right Project
This 31-slide presentation explains the numerous steps that are included in writing a grant from start to finish. 

Introduction to Grant Writing
This 25-slide presentation addresses the basics of grant writing in the state of Utah. 

A Financially Healthy Water System Now and Into the Future
This presentation introduces questions that should be considered regarding the financial health of your system and how to understand your system's present and future needs.

U.S. EPA Grants Management Training for Applicants and Recipients
This online training course designed by the U.S. EPA  includes six modules that explain the grant life cycle process. 

Asset Management 

Asset management is the practice of making the most of capital assets, while also delivering the best customer service. It is essential to establishing sustainable infrastructure. Building an asset management team can lead to increased knowledge management, financial efficiency, and work efficiency. 

Resources: 
Building an Asset Management Team
This factsheet outlines the steps to take to build a functioning asset management team. 

Asset Management: A Handbook
This handbook, designed specifically for small water systems, reviews the basic concepts of asset management and lists tools to help develop a concrete plan. 

Reference Guide for Asset Management Tools
This reference guide is a collection of asset management plan components and implementation tools that drinking water and wastewater systems can use. 
 

You can find thousands of additional helpful resources in our database.

Maintaining Customer Satisfaction

Maintaining customer satisfaction can go overlooked when operators are busy tending to the daily needs of their facility, however good customer relationships are an important component to any well run utility. Community trust improves cooperation under emergencies and helps customers to do their part in caring for their system. When changes to the utility are made such as a new infrastructure project or a long awaited rate adjustments, customers will more easily hop on board. Not to mention, an unhappy customer can lead to unnecessary public relations (PR) challenges.

In Hartsville, South Carolina one business owner watched for a month as a sinkhole slowly took over her car lot. The owner first called her Water and Sewer Authority in September reaching out about her growing concerns. She made five additional calls into October until finally contacting her local news channel for help. Swiftly after the news channel reached out to the Authority, workers were sent to fix the sinkhole.

In Darlington, South Carolina a pair of homeowners brought their sewer system into the public eye under equally pressing conditions. The city received unprecedented rainstorms in October leading to excess stormwater runoff. Under these conditions, many homeowners experienced sewage backups. Despite the city's ongoing efforts to manage overflows, the backups brought the system into an unwanted spot light. A Sanitary Sewer Overflow Response Plan can help for incidents such as these.

While we can do our best to avoid these incidents, accidents happen. When they do, good communication and listening skills can make a difficult situation much easier. How to Keep Customers Happy in Solution H2O encourages utilities to establish a good public presence prior to these events. When services are disrupted, the article encourages utility leaders to step forward and reassure customers that their complaints are being addressed. We also recommend the supervisor follow up with impacted customers after the issue has been resolved. Many of the negative articles we see published in local news can be avoided by following the tips suggested in the American Water Works Association's publication Trending in an Instant. 

Operator Educates Millions on TikTok

This wastewater treatment plant operator has gained millions of views on TikTok after posting numerous informational videos on various wastewater topics. His most viewed video on where toilet water goes when you flush gained 12.2 million views. In some of his other videos, he shows behind the scenes at a wastewater treatment plant and what the inside of a manhole actually looks like. 

This operator is doing a good job at educating the public and specifically young people about wastewater. Wastewater operations make everyday life possible and it's great that more people are interested in what's going on behind the scenes. You can check out this operator on TikTok @waterbearops.

Do you know of any other TikTok accounts from operators? Let us know! 

Screens: An Important First Step in a Wastewater Treatment Plant

By Phil Vella

No matter what size wastewater treatment plant you have, screening equipment at the headworks is a necessary requirement. Screens or pretreatment devices are designed to remove or reduce large solids like wood, cloth, paper and plastics from the waste stream. This not only allows downstream treatment process to be more efficient but also protects the equipment such as pumps.

Several different types of equipment can be used to meet these objectives and there is no one-size-fits-all solution that can be applied to every headworks situation. Some of the limitations of small systems are low flows, space and financial considerations. The following will focus on those options most likely to fit into a small wastewater treatment plant. 

As with most equipment at a plant, screens come in a variety of sizes, capacity, automation and cost. In general screens may be classified as coarse, fine and micro and are based on the size of the screening openings. The discussion here will focus on course screen technology with openings 6 to 36 mm (0.25 to 1.5 in.).
 

Manual Bar Screens

With the limitations of small systems, a manual bar screen may be a great option. These screens have vertical bars approximately 1 to 2 inches apart to catch the incoming debris. Although very basic, they do provide a good level of protection for the plant. An example is shown in Figure 1. However, as with most basic equipment, there are limitations.

Source: Islamic University of Gaza.

The most obvious limitation is that this is a manual operation and requires dedicated manpower and can be a burden to small systems. This is especially true during high flow events such as storms that may require more frequent raking and may also create more of a safety hazard for the operator.

Automatic Bar Screens

To limit the labor involved with manual bar screens, there are several automated options available. These can be classified into different group types. Chain Driven Screens, Catenary Screens, Reciprocating Rakes, Continuous Belt Screen and many variations of them. A summary of different types of screens with their advantages and disadvantages is given in Table 1. These options also commonly use vertical bars to capture the solids and remove them with an automated raking system. Since these are automated, the cost and other operational costs must be considered. In addition, these systems are larger than the manual screen so adding this to a facility may require civil engineering to modify the influent channel or the headworks building if placed there. You may have reduced the labor cost but have increased the capital and infrastructure expense.

Although course screens can remove large material at the head works, disposal of this material becomes and added cost and requires operation and maintenance.  In addition, the wet screenings collected are smelly that can attract vermin and result in odor complaints from the community. 

Source: WEF, Manual of Practice 8, 2017

The following are examples of some of the screen options available to wastewater treatment plants.

Multi Rake Chain Driven Bar Screen (Automatic/Self Cleaning) | Source 

Multi Rake Automatic System

Reciprocating (Single/Basket) Rakes | Source

Catenary Bar Screen | Source

Arc Screen | Source

In summary, there is no right equipment choice for all headworks screening circumstances. Individual factors such as flow rate, solids loading, cost and infrastructure modifications must be considered. Choosing the correct option is important not only in protecting downstream equipment but also for efficient and effective solids removal resulting in proper wastewater treatment. 

Increasing Attention to Significant Noncompliance Dischargers

Author Jill Wallitschek and WaterOperator.org would like to thank EPA’s Office of Enforcement and Compliance Assurance for helping develop this blog post as part of its outreach to permittees about the Clean Water Act National Compliance Initiative.

National Pollutant Discharge Elimination System (NPDES) permit compliance protects public health and the environment from the release of harmful contaminants. During FY 2018 approximately 20% of the nation's 46,000 permit holders were in significant non-compliance (SNC) violations. SNCs are designated as serious violations warranting enforcement response if not promptly resolved. These violations ranged from significant exceedances in effluent limits to reporting failures. To better defend environmental and public health, the U.S. Environmental Protection Agency (EPA) has initiated a National Compliance Initiative (NCI) for NPDES permits and, in September, released a Compliance Advisory.

The NCI uses a full range of compliance assurance tools to reduce NPDES permittees non-compliance. By FY 2022 the NCI aims to reduce SNC rates by half. Small systems, this includes you too! This NCI will target facilities of all sizes equally. More attention will be directed toward facilities approaching or already in SNC. Facilities failing to comply can be subject to increased monitoring, inspections, enforcement actions, and other compliance activities. The NCI notes that permittees that voluntarily disclose and correct violations may be eligible for a reduction or elimination of penalties.

While this initiative might feel intimidating, the NCI offers resources to those taking immediate compliance efforts. The EPA recommends permittees first assess compliance by reviewing discharge monitoring reports (DMRs) and the Enforcement & Compliance History Online (ECHO) tool. If your facility does require assistance, reach out to your NPDES permitting authority for assistance. Other organizations like Rural Community Assistance Partnership (RCAP) and National Rural Water Association (NRWA) may also be able to provide assistance. Each state implements their own NPDES programs with the exception of New Mexico, Massachusetts, New Hampshire, and areas within Indian Country which are managed federally.

Small system SNCs can originate from a variety of causes. Failure to monitor, analyze, and report wastewater samples according to your NPDES permit can lead to a violation. Alternatively, incomplete or inaccurate compliance data transferred from state systems to the EPA’s Integrated Compliance Information System (ICIS) system can result in inaccurate identification of SNC permittees. Checking your compliance status in ECHO can prevent these complications. In addition to monitoring and reporting violations, unplanned discharges such as from a sanitary sewer overflow can also result in SNC. When wastewater effluent exceeds NPDES pollutant levels, utilities will also fall out of compliance. These exceedances typically arise as a result of operational, design, or administrative issues. We recommend the following resources to help improve your NPDES compliance:

Activated Sludge Process Control and Troubleshooting Methodology
Resolve 95% of your activated sludge process control issues using this Ohio EPA manual.

EPA’s ECHO Electronic Tool
The ECHO Detailed Facility Report tool helps facilities monitor compliance and verify the cause of SNC. Learn how to use the tool through the “Intro to ECHO Webinar” and other materials on this webpage.

EPA Webinars: Technical Assistance for Publicly Owned Treatment Works (POTWs)
The EPA hosts free webinars once a month offering technical assistance to POTWs. Find these webinars on our national training calendar or at the link above.

Managing Small Domestic Wastewater Systems
This TCEQ guide helps utilities develop plans to maintain or achieve compliance. The guide includes compliance checklists and planning worksheets. For additional assistance, TCEQ has developed and referenced resources for troubleshooting anything from bacteria control to process control.

Why Is My Lagoon Not Meeting Effluent Limits?
This article from the November 2016 issue of The Kansas Lifeline summarizes how to troubleshoot lagoon effluent compliance issues.

To find solutions to more specific compliance challenges, check out the WaterOperator.org resource library and small systems blog posts.

Inspiring the Future of Women in Wastewater

Editor's Note: We would like to thank NYC Environmental Protection for permission to use this photo.

Despite such worthwhile career prospects, in 2018 women made up only 5.8%  of water and wastewater operators according to statistics by the U.S. Census Bureau. As the water workforce ages and experienced operators retire, the water and wastewater industry can benefit by recruiting more women into the field. Mutually so, inquisitive women with interests in protecting public health and sustaining our environment have much to receive from the opportunities available within the industry.

In the field of wastewater treatment specifically, professionals can exercise their curiosity in the sciences while building technical and mechanical skills. The wastewater operator career not only offers extensive opportunity for growth and advancement, but starting positions often pay well, sustain job security, and will provide on-the-job training. The duties of an operator are an essential public service that require knowledge of wastewater safety, math, chemistry, microbiology, treatment processes, and utility operations and maintenance. Those with a penchant for problem solving and mechanical skills will fare well in the field. Other skills women can develop as a wastewater operator involve communication, presentation, collaboration, and eventually, management.

In the Empowering Women Podcast, Christen Wood, wastewater operations administrator of Summit County Department Sanitary Sewer Services and three time participant of WEFTEC’s operations challenge (with two of her teams making it all the way to nationals), describes the “happy accidents” that allowed her to stumble upon the field. She explains why she continues to hold such passion for her position noting that work as a wastewater operator is a career path, not a job. Listen to Christen’s interview to get a better idea about the type of tasks involved in the day to day work of an operator and the significance of those tasks in public and environmental health.

Still not convinced? NYC Water offers an excellent summary of the benefits a wastewater career will offer to women interested in the field. If you get anything out of this video, we hope its that you start to consider how you can fit into the wastewater industry! Find more information about the experience of women in the water industry at the Words on Water Podcast’s Inspiring Women in Water podcast series. The same podcast produced a separate interview with Mel Butcher, an engineering consultant at Arcadis. Her interview discusses how challenges that women do face as minorities in the industry can be overcome through honest conversation. 

Workforce diversity leads to new ideas, innovation, and progress. Consider how you can bring your skills to wastewater treatment.

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.

Managing Dissolved Oxygen in Activated Sludge Plants

Sustaining optimal dissolved oxygen levels in activated sludge plants is necessary for biological treatment of organic material and ammonia. While raw wastewater often contains some amounts of oxygen, aeration systems can increase dissolved oxygen (DO), mixing, and the suspension of microbes through mechanical agitation or diffused aeration. Aerobic microorganisms use this oxygen to breakdown organic waste into inorganic byproducts. The amount of dissolved oxygen consumed by microbes during biological treatment is referred to as biochemical oxygen demand (BOD). According to an article by Triplepoint Water, approximately 1.5 pounds of oxygen is consumed for every pound of BOD oxidized. To oxidize one pound of ammonia, that value increases to 4.57 pounds of oxygen. Most plants aim to maintain around 2 mg/L of DO which allows microbes contained within the center of floc to receive oxygen.

Wastewater operators should regularly monitor oxygen availability in the form of dissolved oxygen. Insufficient oxygen levels will allow aerobic and nitrifying microbes to die and floc to break up. At DO concentrations under 1 mg/L, the potential for filamentous growth increases. On the other end of the spectrum, too much oxygen increases power consumption and, at very high levels, inhibits settling. Research has estimated that aeration can use up to 45 to 75% of a treatment facility’s overall electricity use. With an online DO analyzer equipped to automated controls, the EPA reports that energy costs can be reduced by as much as 50%.

Where and when an operator samples for DO will be determined by the requirements written in the facility’s National Pollutant Discharge Elimination System (NPDES) permit and basic process control. To compare dissolved oxygen levels throughout the day, samples should be collected at the same location. The Ohio EPA’s Activated Sludge Process Control and Troubleshooting Chart Methodology recommends that systems sample within 1-2 feet of the surface water near the discharge of the aeration tank into the clarifier. By collecting multiple samples in the same location throughout the week, operators can reliably determine if DO concentrations are sufficient for treatment while developing a DO profile. In addition, measuring DO at multiple depths and locations in the aeration tank can help find dead spots.  

To supply adequate DO, the Ohio EPA manual includes how to determine blower runtime based on organic loading and system design. We should  still note that temperature, pressure, and salinity can all influence the solubility of oxygen. Additional sampling locations can include the raw wastewater, aerobic/ anaerobic digester, and final effluent. Final effluent with high dissolved oxygen can cause eutrophication in the receiving waters, however low DO can harm aquatic organisms. Some permits set a minimum DO level for effluent to ensure aquatic organisms have the necessary oxygen levels to sustain life.

While every technique and tool has its strengths and weaknesses, operators can measure DO through a Winkler Titration test (see Michigan DEQ Laboratory Training Manual pg.91), electrochemical sensor, or optic sensor. The two sensors mentioned can be purchased as portable handheld meters or stationary devices. For automated blower control and continuous sampling, an online sensor is used. For NPDES compliance monitoring, measurements must be taken through an EPA approved method at the frequency specified in the permit.

When using any DO sensor, the EPA’s Field Measurement of Dissolved Oxygen (SESDPROC-106) procedures require that the equipment be well maintained and operated per manufacturer instructions. Upon initial purchase, probes should be inspected, calibrated, and verified for accuracy. During each additional use the instrument should be calibrated and inspected again. The EPA recommends checking instrument calibration and linearity using at least three dissolved oxygen standards annually. All maintenance and sampling activities should be documented in a logbook per NPDES requirements. Any time a measurement is taken, the temperature of the water and any notable wastewater conditions should also be recorded in the logbook. 

Dissolved oxygen is a frequently monitored parameter in wastewater treatment systems. Operators should have a firm understanding of how dissolved oxygen is involved in wastewater processes and how they can manage DO to achieve compliance. Check out our online document library to find useful resources to learn more.