December 2023 O&M Newsletter

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December 2023

In this issue:

Certification and Training Update


MRWA – 43rd Annual Conference and Trade Show, December 5-7, 2023

Join us for our Annual Conference and Trade Show at the Cross Insurance Center in Bangor, Maine. Located a short walk from downtown Bangor, the Cross Insurance Center is the perfect place to make new connections in the industry this year. For more information visit:

NEWEA - Annual Conference & Exhibit, January 21-24, 2024

NEWEA is excited to connect in person with our water industry colleagues at the 2024 Annual Conference & Exhibit, taking place at the Boston Marriott Copley Place, Boston, MA, January 21-24, 2024. Visit to register

MWUA – Annual Tradeshow & Conference, January 31- February 1, 2024

Maine Water Utilities Association is excited to announce our 98th Annual Tradeshow & Conference. Once again, this event will be held at the Augusta Civic Center on January 31st and February 1st, 2024. Not only will there be numerous technical training sessions, but there’ll also be many exhibitors displaying their products and who are excited to chat with you and answer your questions. Registration is coming soon, and we hope you’ll join us for valuable technical information, comradery, food, and fun. We look forward to seeing you there! Check the link here for more details:

JETCC Upcoming In-Person Training - Visit Registration for more information.

Wastewater Grades 3-5 Exam Prep

Tues-Thurs Dec 19-21, 2023, in Bangor. Taught by Patrick Wiley, Water Technology Instructor at SMCC.

The objective of this course is to prepare participants for the biological grades 3-5 wastewater operator certification exams.

Wastewater Operator School (WOS)

Wastewater Operator School is returning in January 2024. This 6-month, 12-session program is designed to give in-depth training to intermediate-level operators, technicians, and others seeking to increase their understanding of biological wastewater treatment concepts. The program includes presentations, treatment plant tours, applied wastewater math, and practice questions to help understand concepts and prepare for certification exams. Beginning January 4, 2024, classes will meet every other week at Portland Water District and other Southern Maine treatment facilities.

Basic Wastewater and Grade 1-2 Exam Prep

Monday-Thursday January 8-11, 2024, in Bangor. Taught by Tom Bahun

If you are new to wastewater treatment or plan to take the State of Maine Grade 1 or Grade 2 Biological Wastewater Operator’s Exam, this course is for you! Tom will introduce you to basic wastewater treatment and the aspects of operating and maintaining associated equipment and treatment processes.

These classes are eligible for the 50% Alfond Center reimbursement, Contact Edward Wright for more information,, (207) 227-2603.

March 1, 2024, Certification Renewals

Renewal letters were sent by mail in October to operators who need to renew their certification by March 1, 2024 (even-numbered certification numbers). If you have moved or changed your address, please contact Spring Connolly, or call 207-253-8020.

You can renew online at Also use the website to check your Total Contact Hours (TCH) totals.

Monthly Training Calendar and Training/Certification Resources

The monthly training calendar, which lists training by not-for-profit organizations is emailed to certified operators each month. It can be found at the DEP’s certification website under the Additional Materials section.

The NEIWPCC/JETCC website, provides information on signing up for an exam, training classes, and certification renewal. Contact Spring Connolly at or call 207-253-8020 for more information.

Water and Wastewater Technology Classes at Community Colleges

Whether you are pursuing an associate degree or seeking professional development, Maine’s Community College System offers Water/Wastewater classes at both South Portland’s Southern Maine Community College (SMCC) and Presque Isle’s NMCC campus.

Working full-time, and can’t attend classes in-person? No Problem. Instructors will work with you to tailor a program for your schedule and educational needs.

This exciting new program is geared toward technology and providing instruction needed to pursue good jobs in the water/wastewater field.

For more information, contact Patrick Wiley, at SMCC or Gil St. Pierre, at NMCC.

Alfond Center Offers up to 50% Training Reimbursement

The Maine Community College System (MCCS), through the Harold Alfond Center for the Advancement of Maine’s Workforce, is offering supplemental funding for training and professional development that advances frontline incumbent workers’ skills, leading to career advancement and job security. Compact organizations are eligible to receive up to a $1,200 match per employee for professional development and training. Employees must be Maine residents, 18 years of age or older, with a high school diploma or equivalent. For more information on this funding opportunity, visit the Center’s website, or contact Edward Wright at or (207) 227-2603.

Veolia Academy Offers Free Water/ Wastewater Online Training

Workforce is one of the top three stressors among all water and wastewater utilities in the United States. It all starts with finding qualified candidates, a barrier to entry that holds many back from achieving operator status.

To address this industry-wide problem, Veolia Academy is now offering online water and wastewater training classes FREE OF CHARGE. Many of these classes are approved by the Maine DEP for continuing education credit.

For more information about the online, self-paced education platform, visit

Monthly Problem Set / For Practice, December

1. Calculate the volume, in gallons, of a tank that is 75 feet long, 20 feet wide, and 10 feet deep.

a. 15,000 gallons
b. 112,200 gallons
c. 150,000 gallons
d. 224,400 gallons

2. An empty atmospheric storage tank is 8 feet in diameter and 32 feet high. How long will it take it fill 90% of the tank volume if a pump is discharging a constant 24 gallons per minute into the tank?

a. 7 hours 31 minutes
b. 8 hours 21 minutes
c. 8 hours 23 minutes
d. 9 hours 17 minutes

3. Two columns of water are filled completely at sea level to a height of 88 feet. Column A is 0.5 inches in diameter. Column B is 5 inches in diameter. What will two pressure gauges, one attached to the bottom of each column read?

a. Column A: 3.8 psi, Column B: 38.0 psi
b. Column A: 8.8 psi, Column B: 8.0 psi
c. Column A: 20.3 psi, Column B: 20.3 psi
d. Column A: 38.0 psi, Column B: 38.0 psi

4. A ditch that is 4.5 feet wide, 6 feet deep, and 120 feet long has to be dug for a water line. How many cubic yards of material must be removed?

a. 120 cubic yards
b. 240 cubic yards
c. 850 cubic yards
d. 1200 cubic yards

5. What Is the surface area of a rectangular tank that is 20 feet long by 15 feet wide and 10 feet high?

a. 200 square feet
b. 300 square feet
c. 400 square feet
d. 500 square feet

6. Calculate the chlorine demand using the following data.

• Raw water flow 0.75 MGD
• Chlorinator feed rate 4.0 mg/L
• Chlorine residual is 1.8 mg/l

a. 0.8 mg/L
b. 2.2 mg/L
c. 4.0 mg/L
d. 5.8 mg/L

Pre-rulemaking notice for revocation or suspension of Wastewater Operator Certification

In 2021 the legislation was enacted 32 M.R.S. § 4175-A, giving the Maine Department of Environmental Protection (DEP) authority to revoke or suspend wastewater treatment plant operator certifications through an administrative process. In 2023 Board of Environmental Protection repealed and replaced Chapter 531: Wastewater Treatment Plant Operator Certification, which included criteria for revocation and suspension of operator certification.

The Department is now developing a new rule Chapter 534, that will specify the procedure for the Commissioner’s consideration of revoking or suspending a wastewater treatment plant operator certification through notice and opportunity for a hearing. The new rule will be based on the requirements of the Maine Administrative Procedures Act, 5 M.R.S. §§ 8001-11008.

Please contact Matthew R. Hight at or (207) 719-0703 with any comments or concerns before December 15, 2023. After this initial comment period the Department plans to proceed with rulemaking. To keep informed about the rulemaking process you may sign up for email notices here or visit the Department’s rulemaking page at

Quality Control in the Laboratory

To generate valid and defensible data labs must incorporate appropriate QA/QC practices into the routine operations at their facility. This can seem like a daunting task, one that is complicated by terminology that can be easily confused or misunderstood.

Many test methods require the routine analysis of replicate and/or duplicate samples. These terms are sometimes used interchangeably, while they are similar there are some important distinctions that are worth noting.

A replicate is a sample that is divided into subsamples after collection. The subsamples are analyzed and the results are compared to assess laboratory measurement precision. Some methods specify criteria for how close replicate analysis results must be, if the method does not give criteria then the lab has to generate their own criteria using internal QC data.

A duplicate is a sample that is collected at the same location and time as another sample, each in individual containers. Comparing the results of duplicate analyses not only assesses laboratory measurement precision but also includes the additional uncertainty due to sampling procedures.

The term precision mentioned above is often mentioned in conjunction with accuracy. Both are important when assessing the validity of laboratory data.

Precision refers to the repeatability of test results in your laboratory. An analogy that is often used is that of a dart board, if your lab results have good precision your darts will all be close to one another on the dart board, but not necessarily close to the bullseye.

As mentioned before, replicate analyses are one way to monitor your laboratory’s precision. There are several ways to calculate analytical precision, one of the simplest is finding the percent difference between the 2 numbers. To calculate the percent difference of 2 replicate values, subtract the lower value from the higher value, divide this number by the average of the 2 replicate values, then multiply this number by 100 to get the percent difference.

Once you have this number, knowing what to do with it is the next step. Some methods give criteria for replicate analysis results, for example SM5210B for 5-day BOD test specifies replicates should be within 30%. If the percentage difference between 2 replicates is greater than 30% SM5210B says to identify the results on the report as not meeting quality control criteria. Basically, the result is determined to be unreliable due to low precision. In this instance it would be a good laboratory practice to evaluate all steps of the test procedure to identify potential causes for the low precision. It could be something as simple as the analyst forgetting to put in a reagent or using the wrong amount of the sample; but it could also be a larger issue that requires a corrective action, such as contaminated dilution water.

An example of this calculation with actual data could be replicate 1 result of 221 mg/L and replicate 2 result of 176 mg/L:

High Result minus low result (Replicate Difference): 221 - 176 = 45

Average of replicates: (221+176) / 2 = 198.5

Replicate Difference divided by Average times 100: (45/198.5) * 100= 23%

Therefore, replicate results of 221 mg/L and 176 mg/L for the BOD test would be acceptable using criteria found in SM5210B, since the percentage difference is less than 30%.

Accuracy shows how close your results are the to the bullseye. Accuracy is assessed by analyzing a sample with a known value and comparing the results to established acceptance criteria for the known sample. Analysis of the DMR-QA samples is an example of using a sample with a known concentration to determine the accuracy of a test method. Certified reference material (CRM) can be used on a more frequent basis to monitor laboratory accuracy. CRM, also commonly referred to as QC Standards, are available from most proficiency test providers and come with a certificate of analysis showing the acceptable range for results. These standards can be analyzed weekly or monthly to verify the analytical method is being performed with the appropriate level of accuracy.

While there are other elements necessary to ensure valid data, routine monitoring of your laboratory’s accuracy and precision is an integral part of laboratory operation. Monitoring these results can be particularly useful in helping to spot trends that indicate potential problems before they become major issues. Control charts are a very useful for identifying trends in data for both replicate and QC standard analyses.

Generating valid data is a primary goal of any laboratory. There are many tools available to customize a system that works in your laboratory. If you would like more information on incorporating additional QC measure into your laboratory please contact DEP technical assistance, Brett Goodrich 207-450-5590 or

Cold Weather Operations Part 1

Get Ready for Cold Weather!

For 5 to 6 months of the year, Maine operators face an environment of cold, snow and ice at their wastewater treatment facilities. These conditions present enormous challenges that are rarely encountered in warmer climes.

Very little specific help has been published for wastewater operations in cold weather climates. Maine operators have faced and overcome a wide variety of problems over the years and have developed innovative solutions. Operators need to be creative and plan ahead. Here are a few “tricks of the trade” gained through operator experiences.

Planning for low temperatures includes insulating and protecting critical water lines (chemical feed, samplers, etc.), assuring heating systems are in place and operational, and winterizing exposed mechanical systems. Operators should conduct as much exterior maintenance as possible during late fall prior to the onset of winter. Tasks include:

• Clean up - pick up hoses, extension cords, trash, tools and store materials undercover.
• Mark low structures like culverts, curbs, driveway edges, lagoon liner edges, hatches and manholes that could be damaged by plows and loaders. Grade stakes work well for this.
• Pre-locate critical access points.
• Make sure stored equipment (valves, pumps, pipes) are completely drained or winterized with antifreeze to assure functionality when needed.

If you didn’t know this already, water freezes! This will affect the efficiency of wastewater treatment processes and mechanical systems, as well as presenting hazards to workers, including falling ice and slippery walkways. Expansion during ice formation can damage concrete, masonry, and burst pipes.

Condensation can also be a big problem in winter, causing ice-up on doors and windows which can lead to many sprung hinges when these are forced open or closed. Make sure to insulate and or ventilate areas with condensation problems.

Many parts of Maine can expect 100+ inches of snow each winter, covering manholes, hatches, curbs, and tools. It is important to maintain access to facility treatment structures, pump stations, storage buildings, hatches, and sampling locations.

Plan ahead for snow removal! Know where you will put removed snow. Establish plow lanes and snow dump areas. Avoid piling it against walls and fences. Also, consider where melt water will go to avoid icing problems and flooding during thaws. Have your plow trucks, snowblowers, shovels, roof rakes ready to go and accessible. In some cases you may want to maintain snow cover in places to provide insulation for underground water lines.

To protect low structures from damage by loaders and plows, install concrete pylons, spacing them closer together than the narrowest plow!

Snow adds weight loads to structures. You may need to relieve snow loads from building roofs and tank covers. Weight depends on density of snow and can be deceptive. Aging structures can fail under snow loads that they previously withstood. It is critical to maintain an even distribution of weight during the removal process (domes and arches). Clearing off roofs can be dangerous! Work should be performed from the ground with roof rakes when possible.

Ice cover can cause significant damage to lagoons. Ice blocks and shelves can be hung on lagoon sides during drawdown These can slip off during melting, which can tear and puncture the liner and shear off lines, baffles and aeration headers. Seasonal discharge and snowfluent storage lagoons are the most susceptible.

Rocks and gravel from roadways can become sandwiched between liner and ice layer and slice through liner as ice moves vertically. Lateral movement of ice sheets can tear out baffle anchors and impact concrete structures, leading to costly and time-consuming liner and structure repairs. Plan ahead by clearing gravel and rocks off lagoon liner edges, removing and storing unneeded surface aerators, lines and floats prior to freeze up, monitoring curtain baffles, and planning for gradual drawdown.

As water freezes it expands about 10%. Pores, holes and cracks in concrete and masonry allow water to soak in, which expands and contracts during freeze and thaw cycles, putting tremendous stress on structures. Spalling occurs when ice forms beneath surfaces, causing large pieces of concrete to flake off.

Air-entrained concrete can help reduce these problems. The air voids provide pressure relief sites during a freeze event, allowing the water inside the concrete to freeze without inducing large internal stresses. Make sure concrete is properly sealed to prevent water absorption and freeze/thaw damage. De-icing agents can actually cause additional damage to concrete because they increase the number of freeze/thaw events, so it is better to use gravel and sand where possible.

Repair chipped and cracked concrete with commercial grade sealer, seal exposed anchor holes, shovel stairs and walkways ASAP, and address drainage and drip problems to prevent buildup and need for de-icing agents.

Another hazard encountered by wastewater operators during cold weather application is wind. It moves snow, causing drifting and unevenly distributed snow-loads on buildings. It can tear off unsecured doors and hatches. Mitigate the effects of high winds by securing tarps, bulk bags, empty barrels, etc. that could be blown into treatment units. Consider establishing snow fencing or planting windbreaks in areas where drifting snows create problems, such as exposed work areas, tank walkways and sampling points.

And remember to protect yourself against increased cooling effect from wind chill. For example, if the air temperature is 20 degrees and the wind speed is 25 mph, using the formula 20 - (25 x 0.7) the wind-chill temperature is 2.5 degrees! Make sure to button up!

Next month’s article will discuss designing plants for cold weather operations, safety considerations for operators, and planning for melt water and spring thaw.


Monthly Problem Set / For Practice Answers, December

1. b.
2. a.
3. d.
4. a.
5. b.
6. b.

1. Volume = Length X Width X Depth = 75 ft X 20 ft X 10 ft X 7.48 gal/cu ft = 112,200 gal

2. First find the volume of the tank:
Volume = 0.785 X (Diameter squared) X height = 0.785 X 8 ft X 8 ft X 32 ft 7.48 gal/cu ft = 12,025 gal.
Next find the volume if the tank is 90% full: 12,025 X 0.9 = 10,823 gal
Now use the pump capacity to find the time: 10,823 gal / 24 gal/min = 451 minutes
Change to hours: 451 minutes/60 min/hr = 7.52 hours = 7 hours, 31 minutes

3. Since the height of water in the two columns is the same, the pressure is equal, even though the diameters are different.

Use the conversion 1 psi = 2.31 ft of head

88 ft / 2.31 ft/psi = 38 psi

4. Volume = 4.5 ft X 6 ft X 120 ft = 3,240 cu ft

Since 1 yd = 3 ft, then 1 cu yard = 3 ft X 3 ft X 3 ft = 27 cu ft

Convert the volume to cubic yards: 3,240 cu ft X 1 cu yard/27 cu ft = 120 cu yards

5. Surface area = L X W = 20 ft X 15 ft = 300 sq ft

6. Chlorine feed – Residual = Demand

Demand = Feed – Residual 4.0 mg/L – 1.8 mg/L = 2.2 mg/L