Monthly Blog

Making my rounds through the Great American Beer Festival and the “Water Nerd” in my head kept thinking about all the different water sources, water quality, and lab testing that occurs to make all these great tasting beers happen. Thinking about all the different lab parameters and analytes that affect the taste and quality of beer. That’s when I figured it would be a great topic for the RMWQAA blog.

The City of Northglenn is also preparing to welcome a large-scale brewery into town called Prost Brewing Company. So, it’s also a great time to catch up on all the parameters that make beer taste refreshing, without ignoring the pretreatment side of brewing (i.e., waste) to prepare for the possible additional loading to the wastewater plant.

First off, in order to make beer that tastes great and get through the whole brewing process, it is good to know a variety of different elements and ranges of the source water that the brewery will be working with. Throughout the brewing process multiple parameters should be monitored. And different parameters actually affect the different styles of beer, from IPAs to darker beers.

A great start for any new or current brewery is to supply the Consumer Confidence Report and collaborate on any other parameters of interest that might affect the brewing process.

When beer begins the brewing process, the first step is mashing, which requires a certain pH range. Mashing is when hot water steeps the barley to prepare it for the fermentation process. There’s a pH sweet spot, between 5.2 and 5.6, where the enzymes work most efficiently. Obviously as water providers we cannot provide water that low in pH but providing brewers a constant range of pH in the distribution will help ease the beginning process.

As a brewery, they generally want to see total alkalinity less than 100 ppm and preferably less than 50 ppm. Total hardness, is preferred around 150 ppm as calcium carbonate or greater.

The two most important anions to monitor are sulfate and chloride. Sulfate brings out hops bitterness, while chloride tends to emphasize malt and sweetness. If levels get too high, the beer will pick up harsh, minerally off-flavors or worse. A good rule of thumb is to keep sulfates lower than 400 ppm and chloride lower than 200 ppm.

Another key cation in brewing is calcium which is preferred between 50 mg/L to 150 mg/L. Aside from its role in acidifying a mash, calcium helps yeast settle out, contributing to clarity and flavor stability. There are other major ions, such as sodium, magnesium, and carbonate, but they play a lesser role.

Higher iron and manganese concentrations will obviously result in taste and clarity issues. Iron and manganese begin to cause taste issues and interfere with brewing at levels above 0.05 mg/L.

Now, to the wastewater side of the brewing process.

Like any large contributor to the collection system, it’s always a great idea to monitor what is being flushed into the system. Brewery waste can consist of extremely large amounts of BOD and nutrients. Implementing local limits on the industry will help control the wastewater influent concentrations and prevent slug loads.

We were lucky enough to tour the New Belgium Brewery Wastewater Plant where they had an efficient system to bring loading down from 5,000 mg/L of BOD to roughly 5 mg/L. I’m sure Ft. Collins greatly appreciates the treatment of such a high loading.

So next time you crack a cold one, think of all the water quality and testing it takes to make it taste refreshing.

John Winterton is the Laboratory Supervisor for the City of Northglenn. He’s been working with Northglenn for over 6 years in water and wastewater treatment and water quality.

The Operations (Ops) challenge is a competition, organized by WEF, the Water Environment Federation, where teams of wastewater collection and treatment professionals compete and display their skills. 

In the competition, teams compete to earn the highest score in five different events. Each team includes four members and often a coach as well. Each event is designed to test the diverse skills required for the operation and maintenance of water resource recovery facilities, collection systems, and laboratories. The five events are collections systems, laboratory, process control, maintenance, and safety.

Safety Event

The top three teams from the regional competition advance to the national competition in October each year.  This year, I had the opportunity to judge the laboratory event for the regional ops challenge competition.  The competition is intense and fun.

Collections Event

In the laboratory event, teams conduct simulated laboratory analyses such as TSS and conductivity, using standard laboratory practices and procedures.  The event is timed and the team with the best score after deductions for errors is the winner.  There are winners for individual categories and event scores are combined to determine an overall event winner.

Laboratory Event

Why participate?  The event fosters cross training, professional development, leadership, and teamwork.  Improve old skills, learn new skills, and prepare for the unexpected that is a win, win situation, so…why are there only four teams for the entire Denver Metro Area?

I wondered so I asked, “Why don’t more teams participate?”  There is a big time commitment, year round.  Teams have to practice regularly and oftentimes team members are working different shifts which makes meeting as a team for practice a challenge.  Team members still have to work, keep up with certifications and training units, take care of responsibilities outside of work, and rest.  It is just not feasible for many workers. 

I appreciate the efforts that contributed to the experience I had as a judge and hope the best for all the teams competing at the national competition in New Orleans this year.

Excerpts taken from Water Environment Federation, WEF, www.wef.org

Adele Rucker is the RMWQAA President and an Analytical Chemist in South Platte Renew’s Laboratory. 

In a blog post written back in 2019, when our problems were slightly less PFAS and COVID related, I mentioned a small, non-profit startup out of the Netherlands that had been working on a method to clean up the Great Pacific Garbage Patch. A few times a year I try to check in and see how progress is going, but one of the recent e-mail updates I received from their organization compelled me to pass some updates along to our group.

After a scuba diving adventure revealed that there seemed to be more plastic in the ocean than fish, a 16 year old, Boyan Slat began to turn his focus towards the idea of “just cleaning this up.” Following the momentum of his 2012 TedX talk, he founded The Ocean Cleanup, an organization focused on removing the mass amounts of large plastic debris that collect in various patches across the world’s oceans. The idea was multi-pronged; clean-up and remove the debris from the ocean as economically and environmentally friendly as possible, focus on recycling the plastic recovered once back on land, and do so while eliminating as much bycatch as possible.

The idea behind recovering the plastic is to create an artificial coastline to help concentrate the plastic and force it into a collection net that can later be recovered by another vessel. Imagine two boats hundreds of meters apart, with a long, shallow net between them that lags behind in a u-shaped arc. The plastic is funneled to the tail end of the “U” where it is recovered and processed on the way back to shore. Using this model, two iterations of the system have effectively been deployed, with a 3^rd iteration (3 times the size of the second) that began its transition in July. The second system, System 002, has already successfully removed over 100,000 kg of plastic from the Great Pacific Garbage Patch. While it may require 1000 more collections of this magnitude to clear this particular patch, the emergence of System 03 projects to collect plastic at potentially 10 times the rate of the previous system. The ability to upscale creates an opportunity to collect much more than 100,000 kg of plastic per year from this patch alone.

At current rates of plastic emissions, by 2050 the oceans could contain nearly 4 times the amount of floating plastic than were seen in 2020. This is a major issue, and with water quality and availability decreasing throughout many regions of the world, one could assume treatment of saltwater from the oceans may be required to bridge the gap. If the source of saltwater is also tainted with mass amounts of plastic, the microplastic issue becomes even more compounded as those larger plastics continuously breakdown. This is where The Ocean Cleanup’s goal of “90% reduction of floating ocean plastic by 2040” becomes more of a necessity than just a goal. With the deployment of System 03, their models predict that as few as 10 systems could be needed to clean the entire Great Pacific Garbage Patch. A larger, more efficient system also means that the cost per kilogram removed is reduced.

Research, development and innovation doesn’t stop here for The Ocean Cleanup. With new systems being developed seemingly on a yearly basis, they are also focusing on the source of the plastic emissions; rivers. According to their research, 1000 rivers across the world are responsible for nearly 80% of plastic pollution. Enter the new river Interceptor Barrier, Tender, and Trashfence. Already the team has deployed these devices in various rivers throughout the world, with more well on the way!

The goals are lofty, but with one major milestone surpassed, they also seem within reach. Given all the talk of microplastics and various other pollutants in our world, it’s easy to forget just how much resides in the oceans themselves. The world needed a few great minds to put their focus on an issue at the back of most of our lists, and The Ocean Cleanup is just that! I definitely recommend checking out their website and signing up for e-mail updates and newsletters, as it has given me a greater source of optimism to focus on!

Tyler Eldridge works for the City of Greeley's Wastewater Treatment and Reclamation Facility as their Data and Asset manager and prior Lab Coordinator.

For most of us in the water industry, there is a heightened level of concern about the future of water in Colorado and in the West. Images and stories of the lowered water levels in Lake Mead and Lake Powell are shocking. Those of us that remember Cape Town’s “Day Zero” can legitimately be concerned that something similar could happen here, on a much larger scale. While nobody is talking about shutting off the taps like they were in Cape Town quite yet, there are common concerns about sufficient flow being available for turbines in Hoover and Glen Canyon dams, and of course general water availability.

Into the current and future water concerns in the west comes the Colorado Water Plan (CWP, or The Plan). As a headwater state, Colorado needs to be concerned about water for its 6 million residents and also has obligations to deliver water downstream to 19 other states and to Mexico.

To be able to meet these goals, The Plan was started back in 2015. It emphasizes stakeholder input and public engagement, and is CO’s roadmap to conserve, develop, protect, and manage Colorado's water for present and future generations. The plan was first released by then Governor John Hickenlooper. It is currently being revised to meet the ever-increasing challenges of managing watersheds where demand has already exceeded supply and climate change is reducing water flow.

The Plan is based on a water vision that includes vibrant communities, robust agriculture, thriving watersheds, and resilient planning. Much of the work is by design done at the local level, and the format chosen by the Colorado Water Conservation Board (CWCB, which administers the program) is to have nine roundtables act as the local resources. The nine roundtables correlate to the main eight basins with headwaters in CO, and one representing the Denver metro area.

The Plan is quite extensive. It has a high emphasis on collaboration, innovation, and resilience to problem solving. The Plan covers future possible events and uncertainty including listing high impact drivers, the risk of future water shortages, and variability in the water supply. And of course, The Plan addresses just about all water uses from agricultural, to what is used in households, to instream water rights.

Additionally, the CWCB has a stated emphasis in inclusiveness, and they want to hear multiple voices and input into their process and decisions. There is opportunity to join with your local basin, and in fact, The Plan is based on grassroots efforts from the Colorado water community.

Figure 1: The eight CO river basin areas, as defined in the CWP.

The CWP is by far the most extensive, established, equitable, funded, and workable framework for the future of water in Colorado. It, in my opinion, represents the best current approach for guiding Coloradoans through what looks to be a challenging water future. Involvement from smart RMWQAA membership would only help improve The Plan, and would certainly be a rewarding effort.

There is an opportunity to provide your ideas to improve CO water management by submitting comments (public comment period ends September 30).

You can add public comments, share your story, or get involved here:

https://engagecwcb.org/

The Plan itself can be read here:

https://engagecwcb.org/colorado-water-plan

Rich MacAlpine is a Laboratory Supervisor at Metro Wastewater Reclamation District. 

I grew up in a small town in South Carolina and we never had to water our yards because we typically had plenty of rain, sometimes too much. We had lush green lawns that would have to be mowed at least once and week and a plethora of flowers and weeds.

My family and I moved to Colorado when I was 12 and I remember my mom complaining about having to water the yard, by hand, since we didn’t have an automatic sprinkler system. This was a new concept for my family. At that time, I didn’t think too much about it since I wasn’t the one going outside every 15-20 minutes to move the sprinklers.

Fast forward 12 years and with the purchase of my first house I had the pleasure of watering my own lawn and trying to keep the grass from dying so I didn’t get a nasty gram from my HOA. At least I was fortunate to have a sprinkler system, but I had the same clay soil that my parents had and the same problem of trying to keep the grass green without using too much water.

At that time, I became interested in gardening, and I had heard about xeriscaping. This was a term created by Denver Water in 1981 by combining “landscape” and the Greek word “xeros” which means dry. So I did a little research and removed some areas of grass and started planting flowers. I planted flowers that were recommended for xeriscaping such as yarrow, bearded iris, lavender, penstemon, and valerian to name a few. I found I had a ‘light green’ thumb and enjoyed watching the flowers grow.

A few years later my husband and I moved to our second house, and I knew I wanted more than a yard full of grass. It was a new build, so the builder put in the front yard (grass, a tree, and a couple of shrubs) and we were responsible for the backyard. We spent that summer designing and creating our backyard retreat. We added a gazebo, garden (with many plants recommended for xeriscaping), patio, playset, and grass. We added grass because we had a small child that loved to play ball outside and also because it was much cheaper than plants.

Over time the yard has gone through some renovations. The garden has matured, the playset has been removed and a playhouse and small pond have been constructed in its place.

So, you might ask, where is she going with this story? I wanted to show you that if you want to xeriscape, you don’t have to do it all at once. You can start small, maybe with a problematic area in your yard that gets too much sun, and no matter how much you water, the grass doesn’t grow. Water efficiency is becoming more important and as our streams and reservoirs continue to dry up every drop of water that we can save matters.

Below are some photos of my garden. Maybe it will inspire someone to give xeriscaping a try!

Lesa Julian is the Environmental Services Superintendent for the City and County of Broomfield. She lives in Frederick and loves spending time with her family, traveling, trying new restaurants (especially BBQ), gardening, and reading.

South Platte Sally ready for a full conference week!

South Platte Sally visits the Joint Aquatic Science Meeting (JASM) in Grand Rapids, Michigan! This conference is mostly held every five years where all nine Consortium of Aquatic Science Societies (CASS) gather for a large collaborative conference. Those societies include: American Fisheries Society (AFS), Association for the Sciences of Limnology and Oceanography (ASLO), Coastal and Estuarine Research Federation (CERF), Freshwater Mollusk Conservation Society (FMCS), International Association for Great Lakes Research (IAGLR), North American Lake Management Society (NALMS), Phycological Society of America (PSA), Society for Freshwater Sciences (SFS), and Society of Wetland Scientist (SWS). Sally already has professional memberships in AFS, NALMS, and SFS and could not wait to meet other scientists and professionals within her passionate field of study!

South Platte Sally checking the scene from the podium.

Sally began a week of invigorating talks by listening to “Nutrients and Interactions that Impact Integrity in Surface Water,” she particularly enjoyed listening to Dr. Sylvia Seuble Lee from the EPA (Environmental Protection Agency) and her review of Response of Chlorophyll to Total Nutrient Concentration in Lotic Ecosystems: a Systematic Review. Shortly after listening to Lester Yuan present their topic, Sally had an important meeting with Dr. Janice Brahney who studies environmental biogeochemistry and paleolimnology within watersheds at Utah State University. Dr. Janice Brahney and South Platte Sally discussed several potential anthropogenic factors that could control the nutrient cycle problems within the South Platte River.

South Platte Sally and Dr. Janice Brahney catching up.

Throughout the week Sally listened to different talks from “Per- and Polyfluoroalkyl Substances (PFAS) Contamination in Aquatic Systems” to “Conservation of urban aquatic systems: Interdisciplinary solutions to complicated problems.” After listening to the lamprey nuisance within the Great Lakes, Sally knew she had to see the one in the exhibition hall being exhibited by IAGLR. Lampreys can grow approximately 3 times Sally’s height and she was thrilled to be able to sit next to one! Once the poster sessions were up, Sally perused the 550 posters to listen to different students talk about their research. A particular poster caught her attention from Daemen University called Excess chloride impairs over-winter quality of stream algal assemblages which was published by two undergraduates: Cassandra Mayle and Jessica Bieler, in BIOS. An interesting presentation to say the least!

South Platte Sally visiting the LIVE Lamprey.

Most of Sally’s evenings were spent outside the conference, looking over the Grand River which runs in the middle of Grand Rapids, Michigan and hanging with colleagues she had not seen for a long time. It was great interacting with others who are working on their own rivers within their own state and noticing the differences in work each member contributes. She cannot wait until the next JASM and is incredibly sad that it will take another five years before she sees her oceanographic and wetland friends again. 

South Platte Sally exploring the excellent student poster session.

Blanca Hinojosa is a Water Quality Scientist at Metro Water Recovery in Denver, Colorado.  Blanca moved from Houston, Texas where she monitored 144 different stream sites in the Greater Houston Area while working as a specialized Water Pollution Investigator for the Bureau of Environmental Health in the Houston Health Department.

Happy Earth Day!!  But what is Earth Day really?  The first Earth Day goes back to 1970 and starts with the organization of campus teach-ins to raise awareness about air and water pollution. The day of choice was April 22^nd which fell in between spring break and final exams in order to achieve maximum student participation. The effort expanded nationally across a number of organizations and the day was officially deemed Earth Day. At the time, 20 million Americans were inspired to demonstrate against the deterioration of the environment and all across the nation, rallies and protests were organized. By the end of 1970, the United States Environmental Protection Agency (USEPA) was created from which environmental laws such as the Clean Air Act and the Endangered Species Act were written and passed by Congress. In 1990, Earth Day became a global phenomenon which further increased the focus to address environmental issues such as enhancing the efforts towards recycling.

As the years went by, Earth Day continued to provide a stage for many environmental campaigns and further bolstered the environmental movement all over the world. Today, Earth Day has evolved into a day of action that engages more than a billion people every year to improve the health of our planet. With the growing urgency for a clean environment made apparent by the growing adverse effects of climate change, Earth Day has become more important than ever. For more on Earth Day and what you can do to help build a healthier planet for generations to come, Earthday.org is a great resource to keep engaged within the environmental community and provides volunteer and donation opportunities in support of a more sustainable and green future.

Link to the website:     https://www.earthday.org

Image from Pixabay.com

Ashley Romero is the Laboratory Manager at GEI Consultants, Inc. and has a background in ecotoxicology.

Spring has sprung!  Like many gardeners, I am spending my weekends starting seeds, purchasing compost, and readying my beds for the upcoming growing season.  Before entering the wastewater field, I had not anticipated that this hobby could be so closely tied together with my profession.  While I was familiar with using animal manure as a garden amendment, I hadn’t realized that a byproduct from wastewater treatment could also be used to enrich my soil.

During the wastewater treatment process, liquids get separated from solids during primary and secondary treatment.  Those solids are treated physically, chemically, and biologically to produce a nutrient-rich “sewage sludge” or “biosolid”.  The solids can be disposed of as a waste, or they can be further processed, tested, and used as a source of nutrients for agricultural land and reclamation sites.  This has many benefits, including:

• Adding nutrients without the use of synthetic fertilizers
• Improving soil structure and preventing erosion
• Diverting solid waste from landfills

For biosolids to be used for land application, they must meet federal and state requirements.  This includes limiting concentrations of pathogens and pollutants such as heavy metals, as well as reducing the material’s attractiveness to vectors such as flies and mosquitoes.  The biosolids are classified as Class A or Class B.  The different classes have different treatment methods (e.g., digestion, composting, drying) and different requirements for contaminant levels and land application. 

• Class A Biosolids are treated in a way that significantly reduces fecal coliforms, along with other bacteria and viruses.  Class A’s strict limits must be met for the biosolids to be publicly available.  Exceptional Quality (EQ) Class A biosolids can be bagged and sold to the public and can be applied to home lawns and gardens.
• Class B Biosolids have higher contaminant limits compared to Class A.  As a result, site restrictions are necessary.  Public access must be limited for a time period after land application.  On agricultural land, there are also “resting periods” after application before harvesting and/or grazing can occur.
  
  

The EPA annual biosolids reports estimates that over 4.75 million dry metric tons of biosolids were produced in the U.S. in 2019.  Over half of this (~2.4 million dry metric tons) was beneficially used for land application.   A survey from the National Biosolids Data Project breaks down biosolids use for each state and estimates that Colorado beneficially reuses a larger portion of our biosolids – with 86% going to land application.

Buying Biosolids

Some wastewater treatment facilities sell their Class A compost directly to consumers.  The City of Santa Fe mixes biosolids from their wastewater treatment plant with other material to create their “Santa Fe Biosolids Compost”.  Others send their biosolids to commercial composters.  In Colorado, A1 Organics advertises that their compost product BioComp® contains biosolids and other organic material that might otherwise be disposed of in landfills (such as brewery and food waste).

PFAS and Steps Forward

While the positives of land application of biosolids are plentiful, it’s probably no surprise that the “forever chemicals” PFAS (per- and polyfluoroalkyl substances) are an upcoming concern for biosolids – just as they are everywhere else in the industry.  These persistent chemicals have been used since the 1940s and are found in many common products such as household cleaners, floss, food packaging, and clothing.  PFAS are not utilized in the wastewater treatment process, but may be present in the waste stream received by the facilities. 

New studies have identified trace levels of PFAS in biosolids, which has sparked fear in some.  However, biosolids have not been found to be a primary exposure pathway for PFAS. The concentrations being reported are generally very small, below the most stringent direct contact standards for soils. 

While the PFAS spotlight is largely on drinking water, much research is still being done on the impact of PFAS in biosolids.  The EPA plans to complete a risk assessment of PFAS in biosolids by winter of 2024, which will serve as the basis for determining whether regulation of PFAS in biosolids is appropriate. 

Reducing PFAS in biosolids will best done by preventing their introduction to the waste stream in the first place.  Reducing the commercial use of PFAS and stopping their discharge through industrial pretreatment programs will significantly reduce the PFAS received by wastewater reclamation facilities, and will therefore reduce their concentrations in biosolids.

References:

• 1.     https://www.ecfr.gov/current/title-40/chapter-I/subchapter-O/part-503
• 2.     https://www.epa.gov/biosolids/basic-information-about-biosolids
• 3.     National Biosolids Data Project, 2022. Data on biosolids management in the U. S.: Colorado Biosolids Management 2018, https://www.biosolidsdata.org/colorado, visited 03/20/22.
• 4.     https://www.metrowaterrecovery.com/business/metrogro-biosolids/
• 5.     https://www.santafenm.gov/purchase_compost
• 6.     https://a1organics.com/product/biocomp/
• 7.     https://www.epa.gov/pfas/pfas-strategic-roadmap-epas-commitments-action-2021-2024
• 8.     https://www.nebiosolids.org/pfas-biosolids

Jessica DeHerrera is an Analyst II at Metro Water Recovery, where she is responsible for the laboratory’s metals analyses.  She has 10 years of experience working in the water quality field.  She enjoys hiking, cuddling her dog Pearl, and leading her neighborhood community garden.

Anyone working in an environmental laboratory can tell you that the work occasionally feels more detrimental to the environment than helpful. It’s difficult to feel like you’re working in favor of the Earth when ending a task means throwing away plastic pipettes and tips, cups, sample containers, and of course, nitrile gloves. This feeling isn’t unjustified either; the wide-spread use of single-use plastics and nitriles in laboratory work create an estimated 5.5 million tons of plastic waste in a single year [1]. This equates to almost 2% of all plastic waste created annually across the globe, despite researchers and scientists making up only 0.1% of the population [2]. Between plastic pipettes, pipette tips, tubing, plastic cups, disposable sample containers, and nitrile gloves, it can seem that there is little used in daily lab life that isn’t single-use, but how did the research field come to rely on these materials so heavily, and how can we steer toward a greener, more eco-friendly future?

It is difficult to deny that plastic is a convenient, reliable material that works well for many scientific purposes. Plastics gained popularity in lab settings due to their low cost, durability, sterility, and disposability, and in many labs single-use plastics continue to make up a majority of equipment. Plastic beakers and cylinders will not shatter when dropped, plastic pipettes do not need sterilization before and after use, plastic sample containers are lightweight and easily disposed of, and yet it’s hard to ignore that throwing all of these things away feels, and is, bad. In pursuit of a more eco-friendly field, we as scientists are beginning to seek out ways that we can implement ‘reduce, reuse, and recycle’ in our daily activities.

Reduction of single-use plastics is the clearest way to ensure that labs create less pollution. One option for this is to replace disposable plastic equipment with reusable glassware. Our WET testing lab has become more reliant on plastic over the last five years and is currently in the process of switching back from 12 oz. disposable plastic cups to 300 ml glass bowls for our Pimephales promelas tests, saving at least 30 plastic cups from the energy-intensive recycling process each time we run a test with the bowls instead. Sure, 30 cups may not seem like a substantial amount but we run up to 6 of these tests a week, every week of the year.

Even if only two P. promelas tests are run every week of the year, a total of 3,120 cups would be saved by using bowls. When plastic-ware cannot be replaced it can often be optimized to create the least amount of waste. Making these sort of changes isn’t necessarily easy or convenient (for example, the plastic cups are easier to decant effluent from and don’t require washing at the end of a test like the bowls do), and it certainly costs more initially to outfit a lab with glassware rather than plastics, but the reduced cost on the environment makes the monetary cost and effort well worth it.

Reuse of plastics in laboratory settings is often not feasible or safe due to the threat of contamination. Often times laboratory samples must be kept separate and sterile, and any cross-contamination could jeopardize the integrity of tests or experiments. That being said, keeping some materials, such as plastic pipettes, to be used multiple times with the same sample is an easy way to reduce single-use plastics while maintaining sample integrity.

Not all laboratory plastics can, or should be recycled, however, every step should be taken to properly dispose of the ones that can. Educating laboratory technicians on which of their materials are recyclable and not, as well as providing any necessary instruction on their disposal is a key part of ensuring a more environmentally-friendly lab. Keeping handy reference lists or guides for what materials can be recycled can be helpful in empowering employees to be more confident about their disposal decisions.

The responsibility of making these changes to create a more eco-friendly field lies on all of our shoulders. We can all make conscious choices in the designs of our experiments, our use of materials, and our allocation of funds to create workplaces that maintain efficiency and credibility while also becoming more sustainable.

[1] Urbina, M. A., Watts, A. J., & Reardon, E. E. (2015). Labs should cut plastic waste too. Nature, 528(7583), 479–479. https://doi.org/10.1038/528479c

[2] Facts and figures: Human resources. UNESCO. (2015, December 8). Retrieved February 18, 2022, from https://en.unesco.org/node/252277

[3] Niraula, A., Gautam, K., Gazda, M. A., & Krause, M. (2020, May 5). Reducing plastic waste in the lab. Chemistry World. Retrieved February 18, 2022, from https://www.chemistryworld.com/opinion/reducing-plastic-waste-in-the-lab/4011550.article

Ivy Sklenar Murphy is a laboratory technician at GEI Consultants, Inc., where she helps conduct Whole Effluent Toxicity (WET) testing for clients across the United States. She lives in the Denver area with her family and a myriad of animals, and enjoys spending time camping, foraging, and looking at things under her microscope.

As water treatment facilities are faced with ever-increasing challenges, it is important for utility staff to proactively evaluate treatment plant performance and implement actions to improve operations, energy efficiency, and treated water quality. The jar test is recognized throughout the water industry as a valuable and proven tool for treatment process optimization. Jar tests are routinely conducted by water treatment plant operators, laboratory staff, consultants, and chemical suppliers. The jar test is conducted in the laboratory and is used to simulate full-scale conventional treatment processes. Laboratory staff can work together with operators in conducting these tests, particularly in the preparation of stock solutions, in which operators may have little or no experience.

 

Jar testing may be carried out for a variety of reasons including but not limited to the following: 1) to optimize chemical dosages and / or points of application, 2) to determine the effectiveness of alternative coagulants or coagulant aids, 3) to optimize mixing times and intensities, or 4) to evaluate the impact of other changes in water chemistry and conditions. A typical jar test apparatus (Figure 1) consists of four to six jars with sample ports and paddle mixers,   

which can be programmed to stir at particular speeds for particular amounts of time, to simulate the coagulation, flocculation, and sedimentation processes. Stock solutions of treatment chemicals are prepared ahead of time and added to the jars in the same sequence and dosage as they are added in the full-scale plant (additionally, the plant dosage is typically bracketed by higher and lower dosages during the jar tests to determine the optimal dosage).

Figure 1: Northglenn Jar Test Apparatus

It is critical that the conditions used in the jar test accurately simulate the full-scale plant. This requires knowledge of the hydraulic characteristics of the plant as well as the properties and dosages of any chemical additions. However, even when theoretical conditions (e.g., velocity gradient, detention times, and surface loading rates) are matched closely, there is often a need to empirically tweak the parameters to make the jar test results match the full-scale results. Therefore, customizing a jar testing procedure so it can yield results indicative of plant performance is iterative and can be time consuming. Facilities with successful jar testing procedures have often used the theoretical parameters as a starting point and then made minor adjustments by trial and error until the full-scale plant results are accurately simulated by the jar test¹.

The City of Northglenn Water Treatment Facility (WTF) is in the process of calibrating their jar test procedure. Once the jar testing procedure has been successfully dialed in, the tests will be used to optimize the dosage of chemical coagulants (i.e., alum and polymer) and oxidants (i.e., sodium permanganate). Optimal coagulant dosages are critical to proper floc formation and filter performance. Higher coagulant dosages do not necessarily provide more effective removal of contaminants, such as particles and organic compounds. In fact, a law of diminishing returns often applies with the addition of coagulants (Figure 2), where further increases in coagulant dosage can reduce total organic carbon (TOC) removal. In addition, coagulant dosages that are too high can result in the production of excess sludge, which increases the cost of sludge disposal. It should also be noted that the coagulant dosage which results in the best turbidity removal does not always correspond to the best TOC removal (Figure 3). Therefore, jar tests can provide comprehensive insight into the relationship between particle and organics removal, and how it relates to chemical dosage, cost, and sludge production.

Figure 2: Law of Diminishing Returns with Coagulant Dosage²

Figure 3: Turbidity and TOC Removal by Coagulant Dosage²

Once successful, the jar testing procedure will be used to optimize the addition of other treatment chemicals used at the Northglenn WTF, such as sodium permanganate. Sodium permanganate is a chemical oxidant used to remove iron and manganese, and to control taste and odor compounds. It can also help to reduce the formation of disinfection byproducts (DBPs) by oxidizing precursors and reducing the demand for disinfectants, such as chlorine. High dosages of sodium permanganate can result in pink water, which can be avoided through dosage optimization with jar tests.

The processes downstream of pretreatment will also operate more efficiently when pretreatment processes are optimized. For example, filters succeeding an optimized pretreatment process will have longer filter run times between backwashes, which results in less energy and finished water use. Further, enhanced TOC removal due to pretreatment optimization helps water plants meet DBP regulations, since organic material is a precursor to DBP formation.

In addition to the potential to dramatically improve treatment process operations, energy efficiency, and treated water quality, the total cost savings associated with optimized treatment can be significant. The City of Englewood saved greater than $100,000 in one year in chemical and sludge disposal costs by optimizing their pretreatment process with jar testing results². Armed with the knowledge gained from conducting jar tests, water plants can ensure the plant is optimized to the fullest extent possible and deliver the highest quality water to customers.

References

[1] American Water Works Association. 2011. Operational Control of Coagulation and Filtration Processes.

[2] American Water Works Association California-Nevada Section. Improved Jar Testing Optimization with TOC Analysis. https://ca-nv-awwa.org/CANV/downloads/2015/afc15presentations/ImprovedJarTesting.pdf. Accessed: January 19, 2022.

Emily von Hagen is the Laboratory Technician at the Northglenn Water Treatment Facility. She has a Master’s Degree in Environmental Engineering and a Class C Water Treatment Plant Operator license in Colorado. She is passionate about everything water and lives in Denver with her parrot, Zappa.