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Check our Blog page regularly for continually changing info, articles, news, and more!

  • 05 Jan 2018 8:29 AM | Natalie Love (Administrator)

    As part of ongoing biomonitoring, scientists from Metro Wastewater participate in an annual electrofishing program.  This monitoring program began in 1986 and there are currently thirteen sites spread over a forty-mile stretch of the South Platte River.  The same sites are sampled annually in the fall to compare historical data and change over time.  The main purpose of the program is to gather information on the species, size, quantity, weight, and health of the fish in Segment 15 of the South Platte River.  Various entities, including the Colorado Department of Public Health and Environment (CDPHE), use the data for river assessment studies, resegmentation, and habitat and aquatic life preservation projects.


    CDPHE’s Water Quality Control Commission sets regulations to control surface water quality.  Regulation 38 establishes classifications and numeric standards for four rivers including the South Platte River and its tributaries.  Each river segment is assigned a stream classification, which may contain up to four designated uses including Aquatic Life, Recreation, Water Supply, and Agriculture.  Each combination of designations comes with ranges and standards for temperature, nutrients, and other parameters designed to protect these uses and meet the goals of the Clean Water Act ensuring every river segment is fishable and swimmable.


    Colorado Parks and Wildlife (CPW) does regular fish surveys in the upper South Platte River drainage around the same time.  CPW and Metro sometimes survey at different times of the year for a specific study or construction project.   The National Park Service in conjunction with the US Fish and Wildlife Service surveys National Parks (like RMNP) rivers and creeks every year as well. Consultants may be hired to conduct fish surveys when projects take place in or near a body of water, such a building a bridge over a river, or destroying a pond for a parking lot.  For example, GEI Consultants performs surveys for clients all over the Western US using bank shockers (like MWRD) and backpack shockers. Some dischargers in South Dakota and Idaho are required by their states to monitor the instream fish populations, so they monitor upstream and downstream for fish, bugs, and habitat. Some participating entities have long-term data sets for some rivers going back 20 years, which is valuable information when observing the transitions of fish populations over time through weather events and flood years. Graduate students and researchers may also perform fish surveys as needed.


    An electrofishing day begins by taking flow measurements.  The river flow must be below 300 cfs (cubic feet/second) on sampling days for safety concerns and accordingly, the flow is slow enough to successfully catch the fish once they are stunned.   Flags are placed along a 100-meter reach of the river to mark the sampling zone.  Two or three electrodes are connected together by power cords and held by members of the crew in the river.  These electrodes are on poles with a circular ring that is dipped into the water the entire time.  The electrodes are connected to a generator sitting in the back of a truck parked on the bank that is also attached to a cathode in the water to complete the circuit.  About 3-4 amps of alternating current hits the fish within about a 6-foot diameter area in the water.  The current temporarily paralyzes the fish much like a stun gun, thus making them easy to catch with nets.  Alternating current is used because it causes the least amount of harm to the fish and actually draws them towards the electrode so they do not float away too fast.  The amount of current will vary depending on the size of the river, flow, and conductivity levels of the water.


    Crewmembers wear waders to keep them dry and to separate themselves from the current in the water.  They should still use caution.  If the electrodes are in the water and an analyst touches the water directly, they get a shock.  Depending on their proximity to the electrode itself, they could feel as little as a slight tingle or as much as a good wake up jolt.  Serious damage could occur if the electrode was touched directly, but alternating current does offer some protection.  Analysts also watch for frogs, turtles, crawfish or other critters and try to remove them from the electrode path to save them the trauma of being unnecessarily shocked.


    The crew zigzags back and forth across the sample reach about 30 times to cover the entire area from bank to bank.  As fish are netted, they are taken to coolers of water on the banks while they recover and wait until the process is complete.  The cooler keeps the water temperature cool and closer to the temperature of their natural habitat.


    Once the shocking and collection process is complete, the counting begins.  The fish caught typically range in size from about an inch or two to a foot long, with an occasional larger fish.  Some sites have been known to house the occasional 2-foot long carp.  A total of 29 different fish species have been counted by Metro in the South Platte over the years including the typical yield of Fathead Minnow, White Sucker, Largemouth Bass, Johnny Darter, Green Sunfish, Longnose Dace, and Sand Shiner. Each fish is measured in millimeters on a fish board, weighed in grams, and identified per species.  Any unusual wellness indicators may also be noted during the counting process.  Then the fish go back into the river unharmed, although a little confused. (Similar to an alien abduction).  All the data is logged and compiled into a database for a variety of future uses.



    Michelle Neilson, Water Quality Technician, has been with Metro Wastewater for 8.5 years.  She has a B.S. in Chemistry, and has 19 years of experience in the Environmental field.  Michelle has worked for USGS, contract laboratories, and several municipal wastewater and drinking water labs prior to Metro Wastewater.


  • 06 Dec 2017 9:12 PM | Natalie Love (Administrator)

    When the leaves start turning colors in beautiful Colorado, it’s the signal of what is called the “shoulder” season. Shoulder season is that time when Summer and Winter vacation destination locations try to attract visitors, and offer discounted rates to convention organizers.  September and October are chalk full of industry conferences in Colorado and across the country.  This year was no exception.  I ended up crisscrossing the country for no less than 5 conferences in a period of 5 weeks.


    First up was the Rocky Mountain Water Environment Association/Rocky Mountain Section of American Water Works Association Joint Annual Conference (now there’s a mouth full!) in Loveland, CO.  This year saw the largest attendance ever at a JAC.  For those that have never had the opportunity to attend before, it is a chance to meet industry professionals from throughout Colorado, New Mexico, and Wyoming in both the water and wastewater professions.  Operators, engineers, and of course laboratory professionals all gathered for 3 days and 165 technical sessions on that one thing that we all share a passion for; water, in all its glorious forms.  This year’s conference began with an exceptional Keynote talk by Charlie Lundquist, Deputy Manager of NASA’s Orion Program.  One of the highlights of every annual conference is the annual Toilet Trivia Bowl Contest, hosted by our very own Blair Corning (yes, once ours, always ours), otherwise known as SewerDude.  Topics covered such things as WTF, Rhymes with Water, and Movies about Water.  There was a fantastic track of Laboratory talks this year covering many aspects of the analytical lab.  They attracted standing room only crowds for many of the discussions.  Tuesday night was the awards dinner, where Ms. Natalie Love received the prestigious Water Environment Federation, Laboratory Professional Excellence Award.  Congratulations Natalie!  The award was well deserved, and thank you for all that you do for the Colorado lab community.


    Next was the Special Districts Association (SDA) Conference in Keystone.  A wonderful conference in the mountains of colorful Colorado during early Fall.  There is no more beautiful place to attend a 3 day gathering of Fire Protection, Parks & Rec, and Sanitation professionals.  There were numerous technical sessions on issues that are unique to special districts, in law, community relations, politics, and management.  All of the Keynote speakers were fantastic!  The running theme for each of their talks was valuing employees.  There was something to take home from each of the talks that can be applied in all of our jobs.  The most poignant for me this year though was “You have to be present to Win”.  You can’t just “mail it in” and hope for success.  You have to show up every day, be present, and participate, whether an Analyst or Manager, to reap the benefits of team success.


    WEFTEC, a gathering of over 22,000 leading professionals in the wastewater industry from around the world.   This year’s gathering occurred in Chicago in early October.  A very large conference by any standard.  So large it can only be held in cities that have very large convention centers.  Generally, WEFTEC alternates between Chicago and New Orleans.  There were over 500 technical sessions covering every conceivable wastewater topic.  The plethora of topics covering new and innovating technologies is mesmerizing.  I found myself being drawn to over 12 different technical sessions on peracetic acid disinfection alone.  Besides all of the tremendous talks, there were over 3.5 miles of vendor booths to see on the exhibition floor, which included many representing lab equipment, and in-line instrumentation.  An annual highlight is the OPS Challenge, where over 60 teams compete nationally for prestigious awards in 5 different categories, one of which is a laboratory event.  The teams practice all year long for this competition.  Colorado was well represented this with 2 teams from Metro Wastewater Reclamation District and 1 team from Littleton/Englewood Wastewater Treatment Plant.  Both Metro and L/E have been National champions in the past.  Some members of our organization have even competed on these teams.


    Off to LA.  So the forth conference wasn’t for work.  It was the 31st Annual National Hot Wheels Convention.  Yes, there really is one, and yes it really was the 31st annual.  There were over 1500 hobby enthusiasts in attendance.  I am not going to bore everyone with the rest of the details, except to say, find your passion and play hard!  Finding your balance outside of work allows one to grow in every aspect, the yin and yang of life.


    So to that end, I rented a sports car and drove down the coast to San Diego for the Association of Lab Managers (ALMA) conference.  This is a conference that I have not attended often.  When I had attended in the past, I found that most in attendance were from research and pharmaceutical labs.  I was pleasantly surprised this year.  Over half in attendance were from environmental labs.  It was a great opportunity to connect with colleagues facing similar issues and discuss new and innovative ways for managing today’s laboratory.  The focus being on managing our most valuable asset; people.  There were many half day seminars that provided refreshing ideas on managing the multi-generations that occupy today’s lab.  I highly recommend this conference to any lab supervisor that has a chance to attend in the future, but if you go, be sure to attend the workshops prior to the actual conference.


    Well that was my Fall.  I’m tired, and ready for a long Winter’s nap!  March and PittCon in Orlando will be here before you know it!



    Kevin Feeley, B.S. Biology, M.B.A, is the Chief of Analytical Services and has been employed with Metro Wastewater Reclamation District for 27 years. Mr. Feeley is the former Chair of the RMWEA Lab Practices Committee, a RMWQAA board participant, and on the Red Rocks Water Quality Program Advisory Board. Outside of the water and wastewater world, Kevin holds a 2nd degree black belt in Tae Kwon Do, and is the owner of 25,000+ Hot Wheels cars.

  • 02 Nov 2017 10:36 AM | Tyler Eldridge (Administrator)

    What’s my role in the Colorado Water Plan?

    By Hope Dalton

    In May 2013, Governor Hickenlooper requested the Colorado Water Conservation Board (CWCB) work with stakeholders to create a plan for managing water collaboratively to meet the demand for growing water needs for agricultural, industrial, recreational, and municipal uses.  In 2015, the CWCB released the Colorado Water Plan.  Chapter 7 of the Colorado Water examines factors beyond water supply and demand; factors that affect water availability such as natural hazards, watershed health, and water quality.

    The Colorado Water Plan established a measurable goal to create Stream Management Plans for 80% of the rivers and streams in Colorado and to create Watershed Protection Plans for 80% of critical watershed by 2030.   These plans will address a variety of concerns, including pre- and post-fire mitigation, forest mortality, water quality impairments, potential impacts of legacy mines, flood mitigation and recovery, aquatic and riparian habitat enhancement, and land use changes.  The Colorado Water Quality Control Commission (WQCC), regulatory body that develops water quality policies and regulations for surface water and groundwater, will assist in this goal by setting a strategic water quality objective to have fully supported classified uses by 2050.  These classified uses may including drinking water, agriculture, recreation, aquatic life, and wetlands.

    CWCB’s Colorado Watershed Restoration Grant Program will set aside grant funding to support the creation of Stream Management Plans and Watershed Protection Plans. Both of these plans will have a water quality component.  Some have developed a database of existing water quality data as well as reviewing the data to disseminate information, identify trends, and identify gaps or shortfalls in the data.  The plans also review the water quality data with the water quantity data to determine strategic locations for stream and wetland enhancement, stream/river restoration, and actions to take to reach water quality and aquatic life goals.

    As stakeholders gather to create these protection plans to reach Colorado’s goal by 2030, you may participate as a stakeholder, a data provider, a data analyst, or a writer/reviewer.  If you work for a regulated entity, you may also be participating in stakeholder groups working to provide the science for future WQCC regulatory hearings where policy decisions will be made to fully support classified uses by 2050.


  • 04 Oct 2017 2:04 PM | Tyler Eldridge (Administrator)

    Octo-berg Newsletter: A “Fatberg” Takes Over a London Sewage System

    Last month London sewer workers discovered what has quite accurately been dubbed a “fatberg.” Beneath the streets of East London, tucked away in a sewage system too antiquated for the living style of current Londoners, sits a massive congealed fatty mess that is only now on the final steps of removal. Fatbergs aren’t a new phenomenon, they form in pipes and sewers when fats congeal and mesh together with used diapers, wet wipes, tampons and other various flushed items. However, this fatberg made headlines due to its massive 140 ton size spanning the length of 3 football fields, dwarfing the previous largest fatberg by roughly 10 times.


     The project was estimated to take 8 workers up to 3 weeks to fully remove from the sewers, by cutting out large concrete-like blocks piece by piece. This particular fatberg may have grown to this size for a number of compounding reasons. Dr. Tom Curran of University College Dublin’s School of Biosystems and Food Engineering sees the growing population of London and its high concentration of restaurants, pubs, and hotels as a “perfect storm for the phenomenon.” He also lends credit to London’s aging sewage system.

    Photo Courtesy of Reuters.com

    The sewers of London were built using calcium-rich concrete which creates wastewater with a high calcium content. This causes saponification of the cooking grease in these systems and forms giant masses of cloth and fat.

                Though fatbergs are quite an issue in scenarios such as this massive 140 ton monster, there is the possibility of recycling fatbergs pulled from sewer systems into bio-diesel once the cloth and other contaminants are removed. This is taken a gross step further in some locations in China, where there may be an illicit trade in “gutter oil,” or recycled oil from fatbergs used in the cooking of cheap street food. It is nice to know that the bergs can be recycled into bio-diesel (gutter oil not so much) but fatbergs still remain a problem in many locations. The best way to prevent them comes down to public awareness, informing people that only toilet paper should be flushed down the toilets and any cooking grease and oils should be poured into a separate jar and disposed of in the garbage. This includes restaurants, where many in the U.S. have grease traps to help separate the oil and congealed fats so that they can be further recycled and prevent contamination of sewers.


    O’Sullivan, F. (2017, September 14) London’s Sewers Are Clogged With Massive Globs of Fat. Here’s Why It’s Hard to Get Rid of Them. Retrieved from https://www.citylab.com/environment/2017/09/why-theres-no-easy-solution-to-fatbergs/539817/


  • 18 Sep 2017 10:54 PM | Natalie Love (Administrator)


    I attended the RMSAWWA Conference this year in Loveland, CO. There were several different tracts for attendees to learn about the latest techniques, technologies, regulation changes, and equipment for the water industry. Before the afternoon sessions began I had the opportunity to watch the Operations Challenge. Coming from a drinking water laboratory we do not get the chance to participate in such fun activities.


    There were four teams participating: Commode Commandos, Sewerside Squad, Elevated Ops, and Heroic Hites. This particular challenge simulated a break in a line and the challenge was to see which team could successfully repair the break in the shortest time.

    Challenge set-up: the background pipe was the one with the “break”, the foreground pipe was used to cut a section for insertion into the broken pipe.

    There were a quite a few steps involved in the repair that I have simplified here mostly because of a lack of knowledge of the details. First, the area where the cuts were to be made was measured and marked.



    Measure twice, cut once!

    One crew of the team sawed through the pipe with a hand saw (no power tools were used) and the piece of pipe with the leak was removed. At the same time, another crew sawed the new pipe which was to replace the broken piece.

    Next, the new piece of pipe was inserted where the break had been removed. The repair was secured with couplers and ring clamps. The final step was clean up, putting away all of the tools back in the tool box. The time was stopped when the entire crew was back in place behind the starting line.


    As with any competition and teams that have practiced together for a while, they made it look very easy. The teams worked well together and encouraged each other even when they hit snags and speed bumps. The times for the teams to complete the challenge ranged from 2-3 minutes.

    After watching this challenge I have a new appreciation for our dedicated utility workers who keep everything flowing and flushing as it should.

  • 21 Aug 2017 1:08 PM | Tyler Eldridge (Administrator)

    Designing a new laboratory

    In late 2014, Broomfield embarked on a journey that is finally nearing completion.  This journey has lasted almost 3 years.  In late 2014, a firm was retained to complete a programming study for the existing wastewater laboratory and administrative facility.  The study determined that the existing laboratory space was approximately one-half the size that was typical for the staffing and testing performed at the facility.  

    The laboratory/administration building was constructed in 1987 to accommodate wastewater operations and laboratory staff.  Since then, the wastewater plant has gone through two plant expansions:

    • 2001-Due to growth, reclaimed wastewater initiative and more restrictive permit discharge limits, the treatment facility was converted from a secondary treatment technology to a biological nutrient removal with reclaimed wastewater treatment and pumping facility.  The capacity was expanded from 5.4 MGD to 8.0 MGD.
    • 2007-Due to growth, expanded the biological nutrient removal treatment capacity to 12.0 MGD.

    However, the laboratory/administration building had never been remodeled.  Over the years, additional equipment and personnel were added and counter work space and storage space quickly dwindled when new equipment was purchased and staffing increased to meet new regulatory requirements.  

    In the summer of 2015, an engineering firm and an architectural firm were chosen.  In September, staff attended the kick-off meeting with the engineers and architects.  Then a few months later a construction company was hired to review the architectural plans and give an estimate of the costs.  In August 2016, the contract was issued to start construction.  Due to utility lines having to be relocated actual construction of the new lab didn’t start until early 2017.  There were several objectives and requirements for the project. The largest requirement was that lab staff had to be able to continue working in the current lab while the new lab was constructed.  This was a challenge because the new laboratory was attached to the current administration/lab building.  So, construction crews had to build temporary walls to keep the two sides separate.  There were numerous days of dust and loud construction noise, but we remained upbeat because we knew that was the sound of progress.

    There were lots of fun parts with the project.  We toured several other labs and got some great ideas from them.  We got to pick out new cabinets and countertops.  We also got to assist with the layout of the new lab.  With the new lab, we were able to design a work area for all of the staff that included their own cubicles outside of the lab.  This was a vast improvement because staff had always had their work stations in the lab and were never able to eat or drink at their desks.  They also couldn’t escape from the lab noises and smells (not that wastewater is smelly)!

    So, now it is August 2017 and we are moving into our new lab August 18th.  This marks the end of Phase 1 of the project.  After all staff and equipment are moved into the new lab area, the current lab and administration building will be demoed and phase 2 will start.  In phase 2, the current administration area will be redone with new offices and a new conference room.  The men’s bathroom will be enlarged by combining it with the women’s bathroom.  A new women’s bathroom was constructed in phase 1.  The old laboratory will be remodeled into space for the stormwater and industrial pretreatment staff.  Barring too many hurdles, phase 2 is scheduled to be completed on November 17, 2017.

    New solids lab


  • 21 Aug 2017 12:59 PM | Tyler Eldridge (Administrator)

    July 5, 2017


    Is Your Lab Ready to Support Nutrient Removal with Quality Data?

    Basic Nutrient removal in a Difficult Matrix


    Advances in nutrient removal and recovery seem to be coming at breakneck speed. This is especially true, perhaps, to those of us in a wastewater lab; associated with a treatment facility but not actually on the front lines of treatment. There are many new technologies available, new configurations for aeration basins, new acronyms, new (read lower) permit limits, even ‘new’ microbes. And there is always a new theory to test, a new idea on the horizon. Most of the new ideas and technologies that I hear about are accompanied by a request from the lab for data: more data on what we are currently doing, more data from a new system that is being tested, a sampling campaign to get critical data for a new technology. Flows and returns, diurnal patterns, changes in concentration and speciation of nutrients, It all must be tested, and the data needs to be as good as possible. It all got me thinking about the basics of nutrient removal, and the need for labs to be able to accurately perform analyses on the complicated matrix of aeration basins.


    By basics of nutrient removal, I am referring to traditional biological ammonia removal, in this case in a secondary basin using activated sludge. This is in itself a series of complicated reactions occurring in a complex and delicately balanced system-far from actually being basic!


    Most nitrogen coming into wastewater treatment plants is in the form of ammonia (NH3). Biological removal of ammonia from wastewater involves oxidizing it to nitrite (NO2) and nitrate (NO3) and then ultimately to elemental Nitrogen gas (N2).


    This is done by first using bacteria known as ammonia-oxidizing bacteria (AOB), which are autotrophic chemolithotrophs, and are also obligate aerobes. That is, they can make organic molecules from elements such as sunlight or chemical bonds in their environment, can oxidize inorganic substrates (NH3 in this case) for energy, use CO2 for a carbon source, and require an oxygen rich environment. These are also known as Nitrosomas, and they provide the first step in the Nitrification process that converts ammonia to nitrate:



    2NH4+ + 3O2 --------à 2NO2- + 2H2O + 4H+ + Biomass                     (Equation 1)



    The next step is performed by Nitrite-oxidizing bacteria (NOB), which convert nitrite to nitrate. These are also autotrophic chemolithotrophs, as well as obligate aerobes. Their source for energy is the inorganic substrate of nitrite (NO2):


    2NO2- + O2 --------à 2NO3- + Biomass                                               (Equation 2)



    These two reactions together are known as Nitrification, the process of converting ammonia to nitrate.


    Notice that nitrification is a purely aerobic process.


    Nitrification in a suspended growth/sludge secondary depends on many factors: pH, Alkalinity, Dissolved Oxygen (DO), the presence of any toxic chemicals, temperature, the COD:TKN ratio, and the fact that nitrifying bacteria are outcompeted by heterotrophic bacteria (bacteria that use organic Carbon, and not CO2, for growth). A pH of less than 7 is detrimental to the process of nitrification. Notice how the equation of ammonia oxidation (Equation 1) adds acidity to the basin. This is where alkalinity comes in. In fact, for each gram of ammonia nitrified, 7.2 grams of CaCO3 alkalinity are required. Each gram of ammonia nitrified also requires 4.6 grams of O2. So oxygen must be added constantly, but it must be at a controlled level since adding DO above a level of 3ppm, in general, provides no benefit and is a waste of energy and money. Toxic chemicals reduce nitrification ability, and keeping a secondary basin free from these requires a robust pretreatment program. The COD:TKN ratio is also a factor, as influent loads that are biased higher in organic load (COD) tend to decrease nitrification rates by providing an environment more conducive for aerobic heterotrophs. The slow rate of growth of nitrifiers generally means that activated sludge processes that denitrify have longer sludge retention times (SRT) than ones that only treat for carbon/BOD.


    The process of converting nitrate to nitrogen gas is known as denitrification. Denitrification completes the conversion of ammonia to nitrate to nitrogen gas. Denitrification is also bacterially driven, this time by heterotrophic (get their carbon source from organic sources, not CO2), facultative (able to use oxygen or other substrates as terminal electron acceptors) bacteria known as denitrifiers (i.e. Pseudomanas, Thiobacillus denitrificans). Denitrification-in contrast to nitrification-occurs in an anoxic environment (where nitrate is available but oxygen is not). This means that aeration basins must have different zones with different oxygen levels to accommodate the growth of both nitrifiers and denitrifiers.


    Denitrification follows the general reaction (which uses methanol as a general source of organic carbon/BOD/food):


    6NO3- + 5CH3OH   --------à 3N2 (gas) + 5CO2 + 7H2O + 6OH-                   (Equation 3)


    For every 1 gram of nitrate that is converted to dinitrogen gas, 2.9 grams of BOD are consumed and 3.6 grams of alkalinity (as CaCO3) are produced. Ideally, operators can configure their basins so that they can take advantage of the alkalinity produced from denitrification to supply some of the alkalinity needed for nitrification. To do this however, denitrification must occur prior to nitrification-another complication.


    There is clearly a lot going on even in this basic example of ammonia removal. To assist plant operators, a lab must be able to provide quality and timely values for pH, ALK, BOD, NH3, NO2, NO3, COD, TKN, and Temperature, as well as quite possibly the composition and abundance of microbes. Many of these values can be provided via inline instruments now, but even so, the fact that the lab must have accurate analyses of these parameters does not change since the instruments are calibrated to lab values.


    Thus it is very important that any lab analyzing activated sludge samples thinks about the difficulties of analyzing this difficult matrix. Bad data causes bad decision making, and an activated sludge is no place for that!


    Here, in no particular order, are some ideas to consider: Do nutrient samples need to be digested/distilled? Do standard hold times even apply in such a biologically active matrix?  Does your standard of known concentration actually represent this matrix, or are you using a clean standard that gives a false idea of how well you are doing? Can you spike a mixed liquor sample and get recovery? Are you diluting samples so much that you are raising your method detection limit to the point it is not practically useful? Does the matrix itself cause colorimetric interference? Can you digest and run the same sample twice with comparable results? Can different analysts run the sample with comparable results? Are you pH preserving the sample correctly, or is the alkalinity in the solids in the sample slowly neutralizing acid and raising the pH over time? Is your DO/pH/etc... meter subject to fouling? Are there interferences in the matrix (do reported values increase with dilution)?


    Being able to support basic nutrient removal with quality data is paramount for wastewater labs.


    Remember, it only gets more complicated from here!



    J. Rodziewicz, A. Mielcarek, W. Janczukowicz, and U. Filipkowska. Effect of COD/TKN ratio on the effectiveness of nitrogen compounds transformation in a reactor with immobilized biomass. University of Warmia and Mazury in Olsztyn, Department of Environment Engineering.


    R. Sharma and S. K. Gupta. Influence of Chemical Oxygen Demand/Total Kjeldahl Nitrogen Ratio and Sludge Age on Nitrification of Nitrogenous Wastewater. Water Environment Research. Vol. 76, No. 2 (Mar. - Apr., 2004), pp. 155-161.


    S. Okabe, Y. Aoi, H. Satoh, and Y. Suwa.  2011. Nitrification in Wastewater Treatment, p 405-433. In  B. Ward, D. Arp, and M. Klotz (ed), Nitrification. ASM Press, Washington, DC.


    Steve Polson, P.E. Nutrient Removal 101- Process Fundamentals and Operation. JTAC Presentation May 18, 2017 at AWWA Headquarters, Denver, CO.


    Richard MacAlpine holds an MS in Environmental Science (WQ Emphasis) from CU-Denver, is on the Education Subcommittee of RMWQAA, and has worked in the lab at Metro Wastewater Reclamation District for the last decade plus.


  • 21 Aug 2017 12:22 PM | Tyler Eldridge (Administrator)

    June 20, 2017


    The Argo Tunnel (Figure 1) was the primary drainage and ore transport tunnel from Nevadaville to Idaho Springs. It was excavated from 1893 and 1910, drained water from several mine workings, and allowed ore carts to be wheeled right up to the Argo Mill next door. Although the tunnel has not been used to transport ore since the 1940s, water still drains through it constantly. The tunnel discharge averages 275 gallons of acidic contaminated water per minute. Approximately 850 pounds of dissolved metals are released from the tunnel each day. The Argo Tunnel Water Treatment Plant began operating in April 1998, treating water from the Argo Tunnel. Flows from the Big Five Tunnel at the west end of Idaho Springs and groundwater from Virginia Canyon were added in 2006 (Figure 2).


     Figure1: Entrance to the Argo Tunnel                          Figure 2: Discharge from Virginia Canyon and Big

                                                                                                                   Five Tunnel


    The Argo Tunnel Flow Control Bulkhead (Figure 3) was completed In August 2015 at a cost of approximately $970,000. A pipe runs through the concrete plug so water treatment plant operators can regulate the flow and control water levels inside the mine pool. The tunnel has a history of surge events that released untreated mine water into Clear Creek. The primary contaminants include acidity and a host of heavy metals, including aluminum, copper, iron, manganese and zinc. 



    Figure 3: Bulkhead                                                            Figure 4: RMWQAA group inside the tunnel


    After flowing down from the tunnel, the influent accumulates in an equilibration basin (Figure 5) before entering the plant. From there it is mixed with recycled metal hydroxides and hydrated lime until a pH of 9.9 S.U. is achieved. The lime system includes a silo for storage (Figure 6), a slurry mix tank in the enclosure along with the silo, piping from the lime enclosure to the WTP, a day tank within the WTP and diaphragm metering pumps for feeding the lime into the treatment process. Recent upgrades converted the plant’s conventional process to a high-density sludge (HDS) process. The HDS process sends metal hydroxides into a conditioning tank where they are coated with lime and sent back through the system for up to 30 additional treatment cycles. The process is more efficient at removing metals from the water, resulting in denser filter cake and less material sent to landfills.


    Figure 5: Equilibration basin                                                                     Figure 6: Lime storage silo


    This mixture is sent to a sludge thickener where the precipitates settle by the force of gravity from the water, and the clarified water flows off the top. A polymer (Figure 7) is added in a low dose to improve settling and filtration performance. The overflow water is polished using a sand filter, and then treated with hydrochloric acid to achieve a discharge pH of approximately 8.5 S.U. (Figure 8). The precipitates are pumped from the bottom of the sludge thickener and then sent to a plate-and-frame filter press. The solid filter cake contains approximately 35-40% solids and passes testing of the Toxicity Characterization Leaching Procedure (TCLP), characterizing it as a nonhazardous waste and is disposed of in a municipal landfill.


    Figure 7:  Mary Boardman showing polymer system    Figure 8: Outfall


    Special thanks to Mary Boardman with the Colorado Department of Public Health and the Environment for giving the RMWQAA group the tour!


    Lindie Aragon is the Chemist at the City of Westminster's Wastewater Lab. She is the head of the RMWQAA scholarship committee and coordinated the Argo tour.  


  • 21 Aug 2017 12:11 PM | Tyler Eldridge (Administrator)

    May 6, 2017 


    Chlorophyll a. Standard Methods 10200H. EPA 445-447. Straightforward, right? Follow the method, and get the concentration of chlorophyll a in the sample. This seems straightforward, but I would argue, and many other scientists would agree, that it is not straightforward at all.


    Chlorophyll a is a surrogate measurement for algal biomass at the community level, and is often used to evaluate the effects of nitrogen (N) and phosphorus (P) additions to a waterbody. Algae incorporate carbon (C), N, P, and other elements, leading to growth, proliferation, and more chlorophyll contained within the waterbody. While this process is fairly definitive, the composition of chlorophyll is not.



    The photosynthetic pigments in freshwater algal cells include the chlorophylls (i.e, a, b, and c), the carotenoids (i.e., carotenes, fucoxanthin, and xanthophylls), and depending on the type of algae (i.e., cyanophyta and pyrrophyta), can also include phycobiliproteins or bacteriochlorophylls (Kirk 1994, NALMS 2017). Thus, when a lab is asked to measure chlorophyll a in a water sample, how confident are they that the reported concentration is only chlorophyll a, and not all these other components?


    The basic chlorophyll a methods listed above try to account for the numerous other colorful components of algae (pigments) that could potentially be recognized by the spectrophotometer or fluorimeter which may confound the chlorophyll a concentration. In addition, photosynthetic pigments begin to degrade soon after collection so knowing the quantity of active versus degraded pigments is important. Acidification can account for the degradation of chlorophyll to pheophytin, but how can a lab be certain that the chlorophyll a concentration measured with one method is equivalent to the concentration measured with a different method?


    The logical answer is a chlorophyll a standard. Chlorophyll a standards are available through a number of sources, but their actual concentration “as chlorophyll a” is not always clear. The standards are typically created through pulverization of spinach, or other chlorophyll-rich leaves, and can be in the form of a solid or liquid. Instructions on how to use the standard are rarely provided, and manufacturers provide little detailed information for their use.  Often, these standards do not result in a specific concentration of chlorophyll a, only a concentration of ground spinach leaves. Numerous labs can measure the same “standard”, but who is to say the actual concentration of chlorophyll a?


    These uncertainties in quality assurance provided the impetus for the Chlorophyll a Round Robin Event conducted by the City of Northglenn in 2015 (Taylor, et al. 2015). The RMWQAA’s concern in this methodology is not unique, as The State of Florida reiterates the same concerns regarding the numerous available methods and the variety of ways the data can be handled in “Applicability of Chlorophyll a Methods” (FLDEP 2011). A total of 11 analytical laboratories participated in the event, each reporting their chlorophyll a result for a laboratory split sample. The “corrected” (i.e. pheophytin correction taken into account) chlorophyll a values ranged from 77.6 to 162 mg/L, while labs reporting uncorrected chlorophyll a had a much larger range from 10.8 to 178.9 mg/L. These results highlight the uncertainty in laboratory and methodological approaches and confounds the true answer.


    While the true concentration remained elusive, the real concern comes in to play when regulatory agencies are making decisions based on these data. Total Maximum Daily Limits (TMDLs) for nutrients are being determined from the chlorophyll a data resulting in more stringent nutrient limits for dischargers to these waterbodies. Thus, the question arises… Are regulatory decisions based on data from comparable chlorophyll a methods, or are different methods being used, potentially skewing the results? Furthermore, are laboratories confident in their results for chlorophyll a and do data users understand the uncertainty associated with the results? All of these questions should be considered before implementing regulatory decisions such as a TMDL that could dramatically impact limits for dischargers.



    Florida Department of Environmental Protection (FLDEP). 2011. Applicability of Chlorophyll a Methods. DEP-SAS-002/10. October 24, 2011.


    Kirk, T.O., 1994. Light & Photosynthesis in Aquatic Ecosystems, Second Edition. Cambridge University Press, New York, NY, 509 pages.


    North American Lake Management Society (NALMS). 2017. Chlorophyll Analysis. The Secchi Dip-In. From: http://www.secchidipin.org/index.php/monitoring-methods/chlorophyll-analysis/ accessed 5/1/17.


    Taylor, E., Guilmette, C., Rhodes, E. 2015. Chlorophyll-A Round Robin. City of Northglenn Water Quality Laboratory.


    Natalie Love is the Laboratory Director for GEI Consultants, Inc's Laboratory. GEI conducts Whole Effluent Toxicity (WET) testing, benthic macroinvertebrate identifications, and low level nutrient analysis for Regulation 85 and other local monitoring. 
  • 21 Aug 2017 12:09 PM | Tyler Eldridge (Administrator)

    Interpreting Discrepancies between Analysis Methods, Machines, and More.

                   As advancements in Water and Wastewater Treatment technologies continue to emerge and regulations provide municipalities with more hurdles in meeting increasingly stringent standards, we also see potential for misinterpreting data and how it affects these complex treatment processes. This idea has not escaped us at our Water Pollution Control Facility in Greeley.

                   One particular instance arises in the analysis of measuring Volatile Acids. For the last few years our lab has relied on a single method of measuring Volatile Acids, as well as using certain equipment for measuring these results. This method has been a valuable indicator when it comes to determining the health of our anaerobic digester systems, especially in the winter when we experience the most complications in the treatment process.

                   Recently, with the addition of new treatment processes and new employees that see value in other methods, we have begun to examine alternatives to our original procedure. These alternatives include, but are not limited to using a different method as well as using a different instrument to analyze the data. Our findings were a bit unsettling and confusing.

                   Although we have only recently begun this study and it is still in progress, we do tend to see relatively significant differences. Now, there is a need to acknowledge that it is no world-changing finding to say that different methods and different instruments can provide different results on duplicate samples. However, the point is that there are certain parameters that exhibit greater discrepancies in results, and these can be difficult to interpret and put to use for operators and analysts alike.

                   Our initial investigation into this process began when we found an alternative method from the same company that provides our reagents for the original method. This new method appealed to us in that it was a simpler, less time consuming process. However, the spectrophotometer (spec) used to analyze the results was different than the spec used in our original method. Fortunately, the instrument used in the new method could be equipped with an adapter to analyze our original method, so we had the ability to analyze both methods on the same spec.

                   Here’s where our troubles surfaced: we didn’t know which results to take as our final number when it came to adjusting the operation of different processes in the plant. We had been using the same method for so long and using it as our proverbial ‘canary in the coal-mine,’ that when it came to new methodologies we had no baseline or warning limits to go by. Granted, if our results were close enough between methods and could be considered ‘apples-to-apples’ we wouldn’t need to worry about this. Yet Murphy’s Law had something different to say about this, and we began to see results of the new method on the new spec at 20% and sometimes even 50% higher than the original method on the old spec. Furthermore, this nascent study has shown that the new method produces more accurate results with our stock standard when compared to the old. So, where does this leave us?

                   It seems that logic would dictate that when it comes to making significant changes in operating procedures we should make our adjustments based on the original method with the support of historical trends to back the decision. This has been our stance as we fight through worrying conditions in a push to stabilize the system before a more predictable and manageable period during the spring and summer.

                   Fortunately, we will be entering a transition period with the construction and installation of a new primary digester. With this new change and somewhat of a blank slate to work with, we feel justified in converting over to the newer method with its perceivably more accurate results. Suffice it to say, we will continue to run the original method in conjunction with the new method to further establish some semblance of trends to compare.

                   In closing, there is a desire to point out that this is but one small case study on a topic that any and all plants can be subjected to when put under certain stresses. Whether it be new analysts coming in to a lab, new equipment or methods being instituted by necessity or preference, or even changes to method rules as seen in March’s MDL writing, variability in a lab and its methods can lead to considerable impacts on a treatment plant’s performance and the decisions made in that right.


    Zach Dahlgren is a Water Quality Analyst at the Water Pollution Control Facility in Greeley. He has been with the City of Greeley going on 4 years and with the RMWQAA as Website Chair for over 3 years.


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