Nocardia Foam in Activated Sludge Systems

Nocardioforms are filamentous, Gram positive actinomycete bacteria that can cause persistent and excessive foaming in activated sludge plants during the summertime. There are nine main genus of nocardioforms. Two of these genera are involved in activated sludge foaming, Rhodococcus and Nocardia with the latter being the better known troublemaker. How to best control Nocardia foam is a highly debated topic.

Nocardioforms are known for their branch-like hyphae that extend from the cell wall similar to the hyphae found in fungi. These branches link together with other filaments and floc. Simple and complex organic material make up their diet which includes fats, oils, and grease (FOG). Nocardioforms are slow growing and utilize the aerobic conditions established by an aeration tank. These actinomycetes generally have difficulty out-competing other wastewater microorganisms, but once established they're a handful to remove.

Present in lower concentrations, Nocardia help to stabilize floc structure. The bacteria can rapidly breakdown biochemical oxygen demand (BOD) which can be beneficial to high strength wastewater. In higher concentrations, Nocardia can rip the floc apart and swiftly breakdown BOD starving out floc forming bacteria. The dense, brown foam that accompanies an outbreak forms when filaments float to the surface as a result of their low-density fatty acid membrane and the waxy, hydrophobic biosurfactant that coats their bodies. Bubbles from the aeration system can also help the filaments to float. Unlike Microthrix, nocardioforms are not often associated with sludge bulking.

Unfortunately, the conditions required for a nocardioform outbreak are still debated. In general, any change in temperature, pH, dissolved oxygen (DO), solids concentration, or nutrients might spur an outbreak. It’s believed that nocardioforms will be most favored under warm temperatures with a high concentration of FOG, low food to mass (F/M) ratio, and/or a high mean cell residence time (MCRT). Since nocardioforms grow slowly, they need ample time to proliferate, and under low F/M their larger surface area helps to secure nutrients easily. Some people theorize that anaerobic conditions in parts of the aeration tank or surfactants can encourage Nocardia growth as well.

Before deciding on a treatment solution, it helps to confirm that you are dealing with nocardioforms and not some other filament. Just because your foam is brown, doesn’t ensure that Nocardia is the culprit. Toni Glymph has developed a manual that describes how to identify filaments under the microscope. Nocardia is both Gram positive and Neisser positive, but after reading his guide you’ll find that only a Gram stain is really required for identification.

Treatment solutions for nocardioform foam are also highly debated. Using a high volume water spray will temporarily break down the foam, but be prepared for its return. A better solution is to skim off excess foam so the bacteria is not recycled back into the system. Chlorination is not highly recommended. The branching Nocardia filaments prevent sufficient disinfectant contact while healthy floc bacteria are killed. Many companies promote defoaming products, but the interlocking filaments are often too stable for these chemicals as well. Most resources recommend reducing your MCRT to under 8 days while increasing (F/M). Wastewater technician, Jeff Crowther, lists three of his own treatment recommendations on page 10 of the H2Oregon Springs 2016 Newsletter. Solids wasting may be the most common control method. Operators should learn about the life cycle of Nocardia to maintain a system that avoids future foaming incidents.

Featured Video: Replacing the Power Cord on a Sewage Pump

Submersible sewage pumps can be used for a variety of applications spanning the needs of residential homes to wastewater treatment plants depending on their size and design. A submersible pump is made up of a submerged motor filled with air or oil. Various impellers designs determine what sized solids the pump can handle.

In this week’s featured video, Chris with R.C. Worst & Co. demonstrates how to replace the power cord on a submersible sewage pump. This particular pump is designed for septic tanks and the sewage handling of commercial and residential applications. While working on the pump, he offers some tips and tricks that can help you to save money during repairs and prevent additional damage. As a bonus he discovers some unexpected factory damage and demonstrates how to repair broken wiring. If you need to fix a pump from your own system, remember that this sort of repair work should only be made by operators with the appropriate training. You can find hands-on pump training in your area by visiting our operator event calendar.

A Veteran’s Guide to Becoming a Water or Wastewater Operator

The career path of a water or wastewater operator is a great fit for veterans that want to continue serving the public with the skills developed during their time on active-duty. The profession requires mechanical, hands-on problem solving abilities and in turn offers job security, good pay, benefits, and professional development opportunities.

Utilities can mutually benefit by recruiting veterans. Talent gaps created by retiring operators can be filled by veterans returning home from active duty. Their military training ensures that they have the dedication, flexibility, accountability, and communication skills necessary to juggle small system needs. Furthermore, veterans are familiar with working nontraditional hours that are sometimes required to maintain smaller water systems.

Given the compatibility between veterans and the water industry, this blog will provide resources and guidelines veterans can use to become a water or wastewater operator.

Obtaining certification will be easiest if military personnel can start developing the necessary qualifications before leaving the military. Operators need to have a broad knowledge of chemistry, microbiology, math, equipment operations, and mechanics. Try to work in water operations or other positions that develops transferable skills during active duty. Request that these experiences be documented by your superiors. Saved military evaluations can also be useful to demonstrate qualifications.

Once you’ve left the military, research the certification requirements under your state. Each state’s certification requirements can vary, however many programs will convert military training into college credits or certification requirements. In the state of Virginia, “substantially equivalent” military training, education, or experience can be credited toward licensure requirements. Virginia also waives the costs for the certification exam. If you haven’t met all the requirements necessary to sit for the certification exam, use our national training calendar to find relevant certification courses and local training providers.

Veterans that are just beginning to fulfill certification requirements should consider joining a certificate program within their state. Certificate programs consist of a series of classes that take anywhere from 6 months to 2 years for completion. At the end of the program students will be prepared and qualified to take the state certification exam. The best programs facilitate hands-on training at a local utility, however these experiences can also be gained in an apprenticeship. To find an apprentice program, reach out to local water utilities, assistance providers, and the National Rural Water Association’s nation-wide apprentice program. Working at a water utility early on will ease the job hunting process after passing the exam.

For additional assistance, contact the AWWA’s veteran program. Scholarships, internships, and career advice in the water workforce can be found at Work for Water. Residents of New England states, can look into the Water Warriors Initiative to find assistance in certification, training, and internships. If you need help finding additional resources for your state’s certification program, contact WaterOperator.org and we’ll point you in the right direction.

Featured Video: Water Tower Collapse Compilation

Online trends can seem bizarre, but browsing the web is worth the effort when you stumble upon videos likes these. If you’ve ever searched for distribution maintenance videos on YouTube, you may have already encountered water tower tipping videos. Some of them have reached millions of viewers. Once you watch a few for yourself, you’ll realize why.

There are many reasons a water system might want to remove an existing water tower. Older towers have a higher probability of failing an inspection or causing safety issues to the community. When that happens, it may be easier to just remove the tower provided it’s no longer necessary for the system. If a system has already connected to a newer tower, the costs to maintain redundant towers may drive the incentive for removal. Other times, communities might remove a tower due to damage incurred from a natural disaster or because they want to open the property for other uses.

Only a very small number of tanks are tipped over like the ones in this week’s featured video. Collapsing a tower is a dangerous job only performed in wide open areas with experienced professionals. Generally most tanks are dismantled with a crane instead. Before removal the site may undergo an environmental review. Then if the tower is still in use, it will have to be disconnected from the current water and power supply. After putting out a bid and selecting a contractor, the system will coordinate the rest of the planning with them. Crane dismantling involves cutting the tower into pieces with a torch and lowering those pieces down with a crane. Often times any leftover steel can be sold to a local scrap yard.

So even though tipping a tower is much less common, please enjoy this week’s featured video. It’s hard to look away once you start!

Preventing a Bloodworm Invasion

Midge fly infestations can pose considerable challenges for activated sludge systems and lagoons. Also known as Chironomids or bloodworms in their larvae stage, these insects resemble mosquitos without the blood sucking proboscis. Adult males can be distinguished from females based on their feather like antennae. After dormancy in the winter, midge flies emerge in the summer ready to lay between 100 and 3,000 eggs per female.

Though midge flies do not suck blood like mosquitos, they disrupt communities in other ways. Swarms annoy both local residents and operators by flying into unsuspecting mouths and flooding outdoor lighting. A study by Selden et al. (2013) found that wastewater operators can develop allergic reactions from midge fly exposure. Chironomids can also cause quite a startle to the public when bright red larvae make their way into drinking water systems.

When it comes to maintaining treatment systems, wastewater operators may be most concerned with the larvae stage of midge flies. Their sticky red bodies cling to suspended solids encasing them in a cocoon of decaying organic matter. Under the protection of these cocoons, they can consume considerable amounts of sludge, bacteria flocc, and nitrifying bacteria. An infestation will cause sludge clumping, rising solids, or foaming issues. In one small town a bloodworm invasion wreaked havoc on an activated sludge plant over a single weekend. The wastewater operator found sticky clumps of eggs had congested the system’s pumps while larvae had eaten away at his mixed liquor suspended solids (MLSS).

Facultative lagoons and secondary clarifiers are a favored breeding ground for these pests. Midge flies prefer to lay their eggs in still, high-nutrient water with fixed media, floating scum, or algae. Once the eggs hatch, larvae will likely sink to the bottom to feed on organic matter and sludge. The hemoglobin that gives bloodworms their red color also allows them to live in low dissolved oxygen (DO) conditions.

To avoid bloodworm infestations, operators should focus on encouraging circulation and limiting food sources. Systems can start midge fly control with mixing, limiting surface scum and algae, installing bug zappers, attracting bats and swallows, or turning off lights at night. Introducing a predatory fish can also help. Lagoon operators can encourage circulation by cutting back overgrown vegetation. Any dead spots in circulation should be addressed. When these methods don’t work, some systems will use larvicides and chemical agents as a last resort. Operators should check that the control methods they’ve selected are approved by their local regulatory authorities before use.

When summer starts make sure your treatment system is kept clean and free of obstructions to circulation. With good preventative maintenance, you can spare yourself the nightmares of a bloodworm invasion.

Featured Video: Tech Review: Liquid Flow Velocity

Knowledge of flow velocity, volumetric flow rate, and pipe diameter can assist operators in selecting, installing, and troubleshooting flow meters. This week’s featured video will guide operators in the math used to calculate flow velocity using volumetric flow and or pipe diameter.

Brent Baird with Instruments Direct demonstrates three techniques that will estimate flow velocity. The old school method utilizes a flow calculator slider ruler. With Brent’s particular ruler, by sliding to the known value for the inside pipe diameter (ID) in inches, the velocity in feet per second (FPS) can be read above the known value for volumetric flow in millions of gallons per day (MGD). Alternatively, the inside pipe diameter can be estimated by lining up the known values for velocity and volumetric flow and then looking at the value indicated under pipe diameter. Brent demonstrates that a cross reference chart performs the same calculations using a different visual.

Both of these tools are based off the equation GPM=2.45*ID²*FPS. If neither of his reference tools are available, plugging in the known FPS value for velocity and the inside pipe diameter in inches will calculate the volumetric flow rate. By rearranging the equation to solve for FPS, the flow velocity can be calculated using FPS=GPM/(2.45*ID²). Remember to follow PEMDAS. To calculate the internal pipe diameter with known values for FPS and GPM, rearrange the equation to solve for pipe diameter: ID= √(GPM/FPS/2.45). If the value for the internal pipe diameter is unknown, Brent demonstrates how an ANSI chart can be used to find that value.

With the video's final explanation of basic flow meter requirements, these calculations can be used to spot and avoid problem areas for flow metering in your distribution system.

Guidelines for Public Water Systems in Submitting Public Comments on Regulatory Proposals

Submitting comments on proposed regulations can help the Environmental Protection Agency (EPA) to establish inclusive rules that consider the perspective of your public water system. Just one effectively written and well supported comment can create a much bigger impact than hundreds of poorly written arguments.

Your best opportunity to submit a comment for a drinking water or wastewater regulation is offered after the Agency releases a Notice of Proposed Rulemaking (NPRM) to the Federal Register. A copy of the proposed rule and supporting documents will be available on the EPA’s electronic public docket system, Regulations.gov, where the public can also submit comment. To comment on a rule with Regulations.gov you should know the Docket number, title of the regulation, or some title keywords. Once you search for the regulation, select ‘comment now’ or ‘Open Docket Folder’ under the correct rule. The docket folder includes information about the proposed regulation, its supporting documents, and other public comments.

An effective comment will be written concisely with clear, professional language and sound reasoning. You will want to provide examples that support your stance citing data driven evidence, publications, case studies, or technical resources when possible. Explain the impact of the proposed regulation from the perspective of your water industry experience. If the impact includes a cost analysis, make sure to include how those costs were calculated. A well written argument for or against the regulation will consider both sides of story. When you oppose a particular regulatory action, suggest potential alternatives. Comments that address particular wording or actions within the regulation should cite their exact page number, column, and paragraph from the register document. 

When submitting the comment, you can choose to attach supporting files, however be sure to read through the restrictions associated with attachments. Finally, remember that anyone can view your comment. Once the public comment period has ended, your decisive utility perspective will inform the revision considerations to the final rule.

Featured Video: Clean Water Is So Close for Tulare County's Tooleville

Tooleville, a rural community in the San Joaquin Valley of California, lacks reliable access to safe drinking water. For over 10 years Tooleville has been working on a consolidation campaign with the neighboring city of Exeter to access clean water through a connection to their system. Like many rural towns in the area, Tooleville’s groundwater has been contaminated with nitrates, pesticides, and hexavalent chromium. Given the city’s financial limitations, meeting drinking water compliance and customer satisfaction has been precarious.

While hexavalent chromium (chromium-6) was evaluated under the third round of Unregulated Contaminant Monitoring (UCMR 3), there is currently no federal drinking water regulation. A regulation does exist for total chromium which includes all forms of chromium. The total chromium standard of 0.1 mg/L assumes that the chromium sample is composed entirely of its most toxic form, chromium-6, to safeguard against the greatest potential risk. In 2017 California withdrew the state standard of 0.01 mg/L of hexavalent chromium. Chromium-6 exposure through drinking water has been linked to cancer and skin reactions in some research studies.  

For nitrates the EPA has set both the maximum contaminant level goal (MCLG) and maximum contaminant level (MCL) at 10 mg/L. Consuming water above this level can cause methemoglobinemia in babies and other health conditions.

Though the town has met federal limits for nitrates and total chromium, its 2017 consumer confidence report indicates compliance issues with total coliform. Within the last year, the city of Exeter has agreed to evaluate the capacity of its own water treatment system to access the possibility of providing water to Tooleville. This recent progress offers hope to many residents who have pushed for consolidation. 

As negotiations move forward, two options have been identified. Exeter could use a master meter to bill monthly water use while Tooleville continues to operate its own system. Alternatively, Exeter could consolidate Tooleville’s system entirely. Regardless of the option, Exeter will require new infrastructure to make the connection possible. For now Tooleville must wait for an evaluation to be completed. Once Exeter has a better understanding of their system capacity, the final decision will be left in the hands of the Exeter City Administrator and City Council.

A Microscopic Look at the Role and Life Cycle of Daphnia in Wastewater Lagoons

Knowledge of lagoon microbiology can provide proactive insight into the present conditions of your wastewater treatment processes. Since we have already covered general wastewater microbiology in a previous featured video, this week’s blog post will highlight the specific roles of Daphnia in wastewater digestion.

Daphnia, also known as water fleas and Ceriodaphnia, are metazoan crustaceans that maintain a useful position in the wastewater digestion food chain if controlled by a limiting food source or the careful addition of hyacinths. These one-eyed crustaceans can consume yeast, algae, bacteria, protozoa and occasionally sludge during the winter. In the wild Daphnia are a food source for small fish, tad poles, and aquatic insects. General stressors for water fleas include cold temperatures, overcrowding, low dissolved oxygen (DO), high ammonia levels, and high pH.

To provide context for Daphnia's role in lagoon treatment requires a review of the wastewater food chain. Bacteria are at the heart of waste digestion breaking down organic material into settleable particles. Protozoa feed on these bacteria populations reducing the organic load. Metazoan organisms like Daphnia keep the populations of protozoa, bacteria, and algae in check.

Daphnia can be useful to wastewater operators under healthy lagoon conditions. These water fleas control green algae populations in the summer. As long as cyanobacteria weren't competing with those algae populations, overall pond health will improve by a reduction in total suspended solids (TSS), cloudiness, and turbidity. At the cost of growing Daphnia populations, dissolved oxygen levels decrease.

Water fleas are often indicators for low dissolved oxygen and water toxicity. Under low DO, Daphnia produce hemoglobin to increase oxygen efficiency. This hemoglobin turns water fleas reddish-pink causing red streaks to appear in your lagoon. When operators see red water fleas, they should consider treating the lagoon with aeration or mixing. Given their low tolerance to toxicity and short generational cycles, Daphnia are also used in the EPA's whole effluent toxicity tests (WET).

Now that we have a better understanding of water fleas, we can appreciate this microscopic view of Daphnia as told by Sacramento Splash. The video reviews the natural life cycle and anatomy of these helpful water crustaceans.

Data Protection and Cybersecurity for Small and Medium Systems

Many water utilities rely on online technology and computer systems to increase their working efficiency. In the office space, data management software, pay roll systems, customer billing programs, utility websites, and social media improve customer services and provide an organized method to retain and access utility information. On the operational side, employees may rely on remote access control systems such as SCADA or smart metering to monitor or control systems while performing maintenance in the field. These control systems allow for improved response times and monitoring.

Yet as we all learned from Spiderman, with great power comes great responsibility. Without sufficient cybersecurity measures, systems risk the health and security of their customers. Successful attackers can steal customer personal data such as credit cards, social security numbers, and contact information. They may attempt to deface utility websites compromising customer confidence. If your system uses online process control systems, hackers could lock out utility access, alter treatment processes, damage equipment, and override alarms. The American Water Works Association (AWWA) has listed a variety of cyberattacks and their consequences in its 2018 Cybersecurity Risk & Responsibility in the Water Sector Report. These attacks resulted in leaked customer information, considerable financial losses, altered chemical dosing, and even source water contamination. Just recently staring in May of 2019 the City of Baltimore has been held hostage by an ongoing three week cyberattack that demands $100,000 in Bitcoin to free city files and water billing data.

There are many types of cyberattacks including password hacking, the exploitation of software vulnerabilities, denial of service, and malware. Common malware includes ransomware, spyware, trojan horse, viruses, and key loggers. Attacks can even happen through opportunity theft, improper disposal of computer equipment, or phishing attempts where thieves pose as legitimate organizations requesting confidential information.

To prevent cyberattacks, start by identifying vulnerabilities, developing a multi-tier security plan, and actively enforcing that plan. The EPA has developed a guide explaining 10 key components for a cybersecurity plan that includes planning worksheets and information on how to respond in the event of an attack. Systems should plan to update software regularly and require strong passwords that are different for each account. Installing anti-virus software and firewalls is also effective. A security plan should include measures to educate employees on cybersecurity awareness and limit access to security information based on job function.

For an in-depth list of security practices, read through WaterISAC’s 2019 guide to reduce exploitable weaknesses or the EPA’s Incident Action Checklist. The AWWA’s guide on Process Control System Security Guidance for the Water Sector can aid systems using smart technology. To improve social media and website security, start with Hootsuite’s social media security tips and Sucuri’s website security tips.

If a data breech does occur, utilities will want to have and established protocol to resolve and mitigate potential damage. The Cyber Security Adviser Program with the Department of Homeland Security (DHS) offers regional affiliates that will assist systems in vulnerability assessments, plan development, and informational support. While the costs associated with response, forensics, and legal fees can be expensive, waiting to take action can incur an even greater cost. Remember to keep an active cybersecurity plan and, if incidents should occur, report them to local law enforcement, the DHS, and WaterISAC.