Featured Video: Direct and Conventional Filtration

A new year is often a time of reflection, re-focusing, and a return to the basics. Even if you're not someone who believes in New Years' resolutions, the turn of the calendar year can still be a great time to consider the big picture and the details in it that are important to you. If you have a little time now that the holidays are over, this can also be a great time to brush up on your drinking water treatment knowledge. This 23-minute video is a walkthrough of a direct filtration plant, but it's a lot more than that. Ty Whitman of The Water Sifu explains each treatment step in detail while providing video of the flash mix process, flocculation basins, gravity filters, backwashing, and the spent washwater reclamation process. He also discusses the differences between the direct filtration processes he's demonstrating and conventional filtration.

For more in-depth instruction on drinking water topics, visit our training event calendar and search by your state to see training offered near you.

Featured Video: Safe Drinking Water Act Anniversary

As December draws to a close, let's take a moment to commemorate the passing of the Safe Drinking Water Act 42 years ago, in December of 1974. For the fortieth anniversary, the Minnesota Department of Health released this video. The reminiscences on this landmark legislation include interview excerpts with former Vice President Walter Mondale (a Minnesota native) who was part of the Senate that passed the bill.

As we get ready to begin a new year, it's worth remembering how much public water utilities have accomplished in their vital work protecting public health. Though they may sometimes feel invisible, your efforts help protect the health and well-being of the people in your communities. Whatever else this past year might have brought you, that is certainly a reason to celebrate this New Year's Eve.

Featured Video: Use of Davidson Pie

What's a holiday season without a little pie? The Davidson Pie might not be very tasty, but it can help you work math problems assisting with chemical addition and process control at both water and wastewater utilities. This 3-minute video explains the construction of the pie and works an example problem using it.

For more water and wastewater math help, search our document database using the "Certification/Exam Prep" category filter and the word "math" (without the quote marks) in the keyword filter.

Featured Video: Will It Flush?

With the holidays coming up, a lot of your customers may be getting particularly creative with their flushing activities. After all, for a lot of us the holidays mean a lot of hectic activity and a house full of guests. When the house is full, the trash is full, and the bathroom's getting worked overtime, sometimes standards can relax a bit. And who can blame them? A lot of products do say "flushable," right there on the label.

If you think your customers could use some extra information on how several commonly-flushed products actually behave once they're out of sight, this video might help. In it, Pre-Treatment Technician Tracy Stevens from the City of Spokane Department of Wastewater Management uses a jar test setup to demonstrate the dangers to sewers and wastewater pumps posed by facial tissues, flushable wipes, dental floss, Q-Tips, feminine hygiene products, and flushable kitty litter. If you need to give someone a refresher on the flushable, this video could be a great place to start.

For more on utilities' efforts to fight flushables and fatbergs, search "flushable" (without the quote marks) in the keyword filter box of our document database. The City of Portland also has a list of items not to flush or put down your sink:

• disposable diapers
• tampons and tampon applicators
• sanitary napkins
• cotton balls and swabs
• mini or maxi pads
• condoms
• cleaning wipes of any kind
• facial tissue
• bandages and bandage wrappings
• automotive fluids
• paint, solvents, sealants and thinners
• poisons and hazardous waste
• cooking grease 

Creating O&M Manuals that Actually Get Used

This is a 2013 guest post from Angela Hengel, a Rural Development Specialist with RCAC. 

Background
Small community water systems face a variety of problems and challenges quite unlike anything their larger counterparts must face. With fewer customers to share the costs of running the system, smaller water systems suffer from economy of scale. These utilities often struggle to maintain water quality, water quantity, and system infrastructure. 

Decreased revenue also means that small water systems are often faced with the inability to provide equitable pay to their operators resulting in frequent turnover and a subsequent loss of system knowledge and experience. Adding to that problem, small systems often cannot afford the time and resources required to create adequate standard operating procedures for their system. This issue can have a devastating effect on a utility as new operators have few useful guidance documents to assist them with learning operations, maintenance and repairs. As regulations become more stringent and the associated technologies more complex, the need for well developed, user friendly operating procedures becomes even more apparent. 

The Search for a Solution
RCAC technical assistance providers work with small community systems on a daily basis and are familiar with the challenges they face. Through these relationships, it became clear that the lack of informative and easy to use operations and maintenance (O&M) manuals was a recurring roadblock for small systems striving to become sustainable. RCAC was faced with a question, how to develop an O&M manual that captures system information in a method that is easy to use and understand?

To start, RCAC looked at basic O&M manuals for small treatment plants and drew some conclusions: while they contained system information, they were often bulky, difficult to navigate, and very generic. This was particularly true when it came to manufacturers’ O&M manuals. 

Another aspect that RCAC noted was the tendency for manufacturers’ O&M manuals to be written with either too much engineering language or without any engineering thought at all. As noted by RCAC Rural Development Specialist and professional engineer Leon Schegg, “What we came across were catalog cuts from particular equipment manufacturers but very little information specific to that system,” said Schegg. “Some of the materials handed over were actually sales brochures.” As a result, these manuals were more often than not left by operators to collect dust on a bookshelf.

RCAC realized that a new approach was necessary. There had to be a way to enhance O&M manuals in a manner that is both technically sound and user friendly. For RCAC Regional Environmental Manager Dave Harvey the answer was easy. “I am a do-it-yourself kind of person,” said Harvey. “I love to tinker on my bike and my vehicles at home and my go-to place is always YouTube. I would much rather watch a video of how to repair my bike than read a manual. It’s fast, easy and accurate.” And with that, the RCAC video O&M manual was born. 

Making the Manuals
The idea of a video O&M manual was immediately welcomed by small water system managers and operators. With funding from Indian Health Service (IHS), RCAC began development of video O&M manuals for three tribally-owned small treatment plants. 

Video O&M Introduction from RCAC on Vimeo.

"Our intent was not to do away with the written manuals but rather to enhance them by integrating them with video demonstrations filmed on site at the treatment plant,” Harvey said. The result: highly individualized O&M manuals that provide not only written information, but detailed yet easy to follow video instructions on plant operations and maintenance. 

RCAC took a holistic approach to creating the manuals. Each individualized O&M manual is created through a collaborative of RCAC technicians, utility operators, IHS engineers, contractors and manufacturer technical representatives. Filmed onsite by RCAC videographers and finished in the RCAC graphic arts department, each manual is a one-of-a-kind visual training tool. With it, small system staff with limited technical skills can learn their system’s requirements and follow step-by-step maintenance procedures using a menu-driven CD containing text, photography, video and the internet. 

There were challenges to be met along the way in the creation of the manuals. “It was kind of like a movie set. We had to get all parties on site and organized and ready to go when it was time to film,” said RCAC’s Eagle Jones. “We had to deal with road noise, lighting, people forgetting their lines and just getting used to the idea of being on camera,” Jones said. “It took a few shoots and we had to go back and re-shoot a few sections, but in the end we produced some really great video.”

Bringing the video and written manual together in a cohesive and organized manner presented its own set of difficulties. “It was important that the manuals were designed in a way that would build the operators’ trust so that they actually use them,” said Schegg. “We inserted flags in the text of the manuals directing the user to a video.” 

One of the issues RCAC had to overcome was that the manuals being provided by equipment manufacturers often contained information that was different than plant operations. According to Schegg, “The videos were documenting actual maintenance procedures that were not in the manufacturers’ manuals.” This was particularly true with plant start-ups. “Problems arise during plant start-up that may not be known during the design phase or when the manufacturer put together their operations and maintenance manual,” said Schegg. “We see and resolve inconsistencies between the plans, manufacturers’ literature and recommended settings so that our manuals present the actual process and equipment operating and maintenance procedures necessary at your site.”

The Outcome
Once the video O&M manuals were completed, RCAC returned to the systems to review the manual with the operators. “We don’t just say, ‘Here’s your manual’” says Harvey. “We sit down and review every section with system operators to ensure that the information in the manual and video is completely accurate and, more importantly, that the operators understand how to use it.”

The Campo EPA department recently received a completed video O&M manual. Melissa Estes, Campo EPA Director, commented on the decision to have RCAC create the manual, “IHS recommended RCAC. The bid we received from RCAC was very reasonable compared to other consultants.  RCAC met with the Tribe’s Executive Committee and the Committee decided RCAC were experienced working with tribal governments and would do a good job, so the Committee approved the contract.   Since the Tribe and the tribal EPA had worked closely with RCAC on other projects we felt they would do an outstanding job.” 

In reference to the actual manual, Estes referred to it as being, “very user friendly,” and went on to note, “This manual will accommodate people who learn from reading, and others who learn from seeing.  The format is helpful for people who like to read directions or see them on a video. It is very helpful to have a manual specific to the system you operate, with actual demonstrations of how to operate the components.” 

RCAC knew that a video O&M manual would provide several benefits to small systems such as; increased operator technical capacity, a more effective preventive maintenance program, a more effective emergency maintenance program, a more accurate ability to budget for parts and labor, and having an enhanced training tool for new operators that acts as a safety net should the system find themselves one day without an operator. 

Still there were other, unexpected benefits that came about during the creation of these manuals. By bringing together engineers, operators, contractors, and technical representatives and analyzing the processes, each party began to get a better understanding of their role as it interrelates to other roles. As Schegg states, “The manual brings together documented and undocumented procedures from the standpoint of an operator which proved to be a tool not only for the operator but also engineers and contractors who use the information to modify those processes in the future and hopefully have an advantage when starting a new design.”

The Future
With the success of the three video O&M manuals, RCAC has plans for not only creating more treatment plant manuals, but to expand to other utility operations. “We are currently in the process of finishing a wastewater treatment plant manual and putting together proposals for creating distribution system manuals using the same video format,” Harvey said.

As for whether or not other systems would be interested in video O&M manuals, “Almost 100% of the managers and operators I have talked with would prefer to have an O&M manual with video integrated into the text,” states Harvey. And when asked if she would recommend this style of O&M manual to other systems, Estes replied, “Yes, we would recommend this style to other water systems.” 

Developing and Implementing Tools for Small Systems to Evaluate and Select Appropriate Treatment Technologies

• Facilitated methodology that incorporates stakeholder input
• Data on innovative treatment technologies
• Relative health risk protection of treatment approaches
• Sustainability measures of treatment approaches
• Stakeholder preferences

Performance information such as treated water quality and performance data along with other characteristics, including source water quality constraints, are used to identify feasible technology alternatives. The characteristics for feasible alternatives are then fed into the analyses of health risk, sustainability, and stakeholder preferences in order to provide data to the decision support methodology.  
 
Microbial and chemical agents in drinking water can pose significant human health risks. Evaluating the combined impacts from multiple contaminants can provide new insights into how best to manage that risk and protect public health to meet regulatory compliance and achieve the greatest risk protection possible given feasible alternatives. The DeRISK Center tools utilize the Relative Health Indicator (RHI)—a semi-quantitative metric developed to harmonize the cancer and non-cancer impacts from a wide range of drinking water contaminants—to compare the relative health risks posed by multiple waterborne constituents.
 
The DeRISK Center is also focused on analyzing and improving the environmental and economic sustainability of small drinking water treatment systems. To achieve this, life cycle analysis (LCA) methodology is being used to quantify and characterize environmental impacts associated with various drinking water technologies. These impacts (using EPA’s TRACI assessment method) include ozone depletion (kg CFC-11 eq), global warming (kg CO₂ eq), smog (kg O₃ eq.), acidification (kg SO₂ eq.), eutrophication (kg N eq.), carcinogenics (CTUh), non carcinogenics (CTUh), respiratory effects (kg PM 2.5 eq.), ecotoxicity (CTUe), and fossil fuel depletion (MJ surplus). A comprehensive LCA model framework was developed utilizing water treatment data, experience, and commercial information.
 
Last, the DeRISK Center is putting these tools to the test evaluating treatment technology decisions through cases studies with actual small water systems needing to address water quality and compliance challenges. The first case studies are assessing disinfection alternatives for small water systems in New Hampshire. 

If you are interested in testing these tools and collaborating with DeRISK Center researchers to assess treatment technology alternatives for your water system, please contact Chad Seidel at chad.seidel@colorado.edu. 

In-Line Diffused Aeration to Reduce THMs in Distribution Piping

This post from University of New Hampshire's M.R. Collins is a continuation of a project update originally shared in our Technology News newsletter. 

Several methods exist for controlling THM formation, including reducing natural organic matter (NOM) prior to chlorine disinfection, and using an alternate disinfectant such as ozone, chloramines, or UV. Using these disinfectants will prevent or reduce the formation of THMs, but could facilitate the production of other potentially harmful byproducts.  Also, using ozone or UV as a disinfectant will not provide a residual in the distribution system (USEPA, 1981 & USEPA, 1999).  While effective at reducing THM formation, changing or upgrading the water treatment plant to include these control techniques could be costly and negatively affect other plant processes.

Posttreatment aeration is another strategy to control THMs, and involves removing the THMs after formation.  Countercurrent packed towers, diffused aeration in open reactors, and spray aeration in storage tanks are all viable aeration methods to remove THMs (USEPA, 1981 and Brooke & Collins, 2011).  While the above methods are viable and have been applied in the field, all require depressurization of the water, and are limited in terms of placement in the water distribution system.  Placement in the distribution system is important since THMs continue to form in the system, and often exceed regulations when at the far end of the system.  This research explores both vertical in-line diffused aeration (VILDA) and horizontal in-line diffused aeration (HILDA) to reduce THMs, which has the potential to be cost effective and conveniently placed where needed in the distribution system.

A schematic of an in-line diffused aeration system is depicted in Figure 1. The basic components consist of an air compressor, air-water reactor, air injector, air release system and associated air and water flow meters. The basic difference between VILDA and HILDA systems is the configuration of the air-water reactor. The VILDA system will utilize a countercurrent arrangement where air is injected in the bottom of the vertical reactor while the water enters at the top of the reactor. The HILDA will have air and water flowing concurrently through the horizontal reactor.

Figure 1. Schematic of basic in-line diffused aeration system. 

The most efficient air-water reactor is one where equilibrium or saturation THM removals can be achieved. The work of Matter-Müller et al. (1981) provides a mass balance method which allows equilibrium or saturation THM removal values to be predicted as depicted in Equation 1:

Equation 1:                             

where Q_G = the gas flow in (m³/s), H_cc = the dimensionless Henry’s law constant of compound, and Q_L= the liquid flow rate (m³/s). Hence, the higher the air/water ratio, the greater the removals of THMs.

For Equation 1 to be applicable to distribution piping conditions, the Henry’s Law Constant will have to be adjusted for both temperature and pressure. The former has been well documented in the literature but the latter had to be determined during this research. Basically, a second order relationship as shown in Equation 2 was used to correct for pressure (Zwerneman, 2012).

Equation 2:                                

where H_cc  = the dimensionless Henry’s law constant at system pressure, H_cc,o   = the dimensionless Henry’s law constant at atmospheric pressure, P = the system pressure (psi), and k= the experimentally determined rate constant (psi^-1).

HILDA REACTOR DESIGN. The most problematic concern with a HILDA system was to configure an air-water reactor where equilibrium or saturation conditions will be achieved since injected air in a horizontal pipeline will have a strong tendency to raise to the top of the pipe and not be mixed with the water sufficiently to reach saturation. Through trial and error, Komax static mixers were determined to provide adequate air-water mixing to approach saturation removal conditions provided fluid turbulence or mixing intensity was high enough. A modified Reynolds Number (Re’) was developed to capture the magnitude of fluid momentum and mixing intensity and can be seen in Equation 3 (McCowan, 2015).

Equation 3:                                           

where, v= velocity of water (ft/s), d=pipe diameter (ft), L_m=length of reactor (ft), and v=kinematic viscosity (ft²/s). Figure 2 shows a graphical representation of % removal vs. Re’ at 10:1 and 20:1 A:W ratios.  Re’ appears to be a good indicator of when saturation values are achieved and could be used to design of the HILDA reactor.

Figure 2. HILDA model predictions of THM removals for various A:W ratios as a function of modified Reynolds Number.

VILDA REACTOR DESIGN. Equilibrium or saturation removal conditions in a VILDA system is easier to achieve than with a HILDA system although a HILDA system could be easier to install in the field. The countercurrent flows in a VILDA reactor encourages adequate contact time between the air bubbles and bulk water to achieve saturation conditions quickly as depicted in Figure 3. Basically, in-line diffused aeration is a fast treatment process.

Figure 3. Influence of A:W ratios on VILDA EBCTs required to reach saturation THM removals.

SUMMARY. Both HILDA and VILDA have shown potential to achieve significant reductions in THMs in distribution pipelines especially if the most dominant species is chloroform. Research on bench and pilot scale versions of these posttreatment aeration systems have resulted in prediction models that could be used to design HILDA and VILDA reactors in the field. Field assessment and treatment verification of this innovative technology are currently being explored and developed. Opportunities to participate in these assessment studies are still available. Please inquire within.

REFERENCES

Brooke, E. & Collins M.R., 2011. Posttreatment Aeration to Reduce THMs. Journal AWWA, 103:10.

Komax Systems, Inc. Triple Action Static Mixer. http://www.komax.com/triple-action-static-mixer/ (accessed 3/31/15).

Matter-Müller, C.; Gujer, G.; Giger, G., 1981. Transfer of Volatile Substances from Water to the Atmosphere. Water Research, 15:1271.

McCowan, M.L.,2015. Developing a Horizontal In-Line Diffused Aeration System for Removing Trihalomethanes from Water Distribution Mains. Master’s Thesis, University of New Hampshire, Durham, N.H.

USEPA (United States Environmental Protection Agency), 1999.Alternative Disinfectants and Oxidants Guidance Manual. EPA 815-R-99-014.

USEPA (United States Environmental Protection Agency), 1981. Treatment Techniques for Controlling Trihalomethanes in Drinking Water. EPA/600/2-81/156, Washington, DC.

Zwerneman, J., 2012. Investigating the Effect of System Pressure on Trihalomethane Post-Treatment Diffused Aeration. Master’s Thesis, University of New Hampshire, Durham, N.H.

Common Distribution System Deficiencies

This article was first published in the Winter 2012 issue of Spigot News, the Ohio EPA's drinking water program newsletter. Many thanks for allowing us to republish it! You may also be interested in the articles Common Source Water Deficiencies and Common Treatment Deficiencies. 

Backflow and Backsiphonage
A “backflow event” is when non-potable water is forced by pressure into the potable water supply due to a direct cross-connection. All distribution systems must maintain a minimum pressure of 20 psig and a 35 psig working pressure during all water demands including fires. Distribution systems that fall below these minimum pressures may experience a backflow event if an overpowering pressure differential is experienced by a competing cross-connection within the system. 

Tribal Utility News Subscribers Give Us Insight into Tribal System Needs

My Problems Are Your Problems

While there are unique challenges facing tribal utilities, some of the common themes from the survey results address challenges faced by small utilities all over the country. Many small systems struggle to find and keep certified operators, raise the money to keep the system going, and keep the board engaged with the utility’s needs and responsibilities. While the specific ways in which those challenges crop up may be specific to tribes, a lot of resources intended for small rural systems could be helpful to tribal utilities as well.

Tribal Challenges

That said, tribal systems also face unique challenges related to sovereignty, government, federal support, and tribal issues and attitudes.

Remoteness and Isolation
Survey respondents mentioned that some tribal systems may not recognize that there are opportunities to cooperate or reach compromises with nearby non-tribal systems. In some cases, non-tribal water utilities might provide support that’s more conveniently located than tribe-specific assistance providers in the region. On the flip side, some tribes are in such secluded areas that they may be inaccessible to state and county support. And some tribes may wish to work with state entities but be facing other roadblocks.

Support From Tribal Government
As with many small rural utilities, tribal utilities sometimes struggle to get meaningful support from those in charge. Sometimes the tribal government doesn’t understand the need for qualified operators to run the system. Sometimes the tribal council doesn’t want to get involved in the utility at all, or ends up using utility job appointments for political patronage. Sometimes there just isn’t interest in water and wastewater issues.

One possible solution to these challenges was mentioned by a few survey respondents: utility boards. For most tribes, the water utility is under the direct control of the tribal council. Creating a separate water board allows the tribal council to focus on other governance issues while still ensuring that the utility receives guidance and oversight.

Dependence on Federal Entities
Some tribes don’t want to take ownership of their utilities, preferring to rely on federal support. Other tribes may want to be engaged, but find themselves dependent on slow-moving federal bureaucracy and assistance.

Tribal Issues and Attitudes
A number of factors related to the broader culture and conditions on the reservation could affect the performance of a tribal utility. Reservations with high unemployment might see their newly trained operators leave the utility for a better-paying job elsewhere. Sometimes there is resistance to working with non-tribal systems or working with outside entities to deal with problems or repairs. Some tribes may have restrictions in place that make it difficult for non-tribal operators to find someplace to live on the reservation. And finally, as with any small community, sometimes tribal politics affect the utility’s operation and management.

Tribal Education Needs and Resources Follow From These Challenges

Help is Out There

You're Not Alone

Tribal Resources from WaterOperator.org and USEPA

At WaterOperator.org we recognize that small tribally-owned and operated public water systems often face unique challenges, beyond what impacts other small and rural communities. Because of this, we have created a number of ways to find information that is specific to tribes. This video provides an overview of our document and event databases, tribal newsletter, tribal assistance provider list, and the tribal contact manager.

For tribal drinking water systems:

• Building Water System Capacity: a Guide for Tribal Administrators
• Lead and Copper Rule Minor Revisions: Fact Sheet for Tribal Water System Owners and Operators
• Preventive Maintenance Tasks for Tribal Drinking Water Systems: Guide Booklet

For tribal wastewater systems:

• Primer for Municipal Wastewater Treatment Systems
• Tribal Management of Onsite Wastewater Treatment Systems

And for tribes concerned about protecting their source water:

• Drinking Water Quality in Indian Country: Protecting Your Sources

Check out the video for more on the resources we collect and offer, and if there’s a tribal resource you think we really need to know about, tell us in the comments!