January 2024 O&M Newsletter

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In this issue:

Cold Weather Operations – Part 2.

Cold Weather

Last month we discussed some of the operational challenges faced by wastewater personnel during cold weather. This article will address thawing and runoff events, limited daylight, and safety issues presented by winter weather.

Large amounts of precipitation water are stored in the snowpack. Most thaw events are high runoff events resulting in high flows to treatment facilities. In addition, ice jams on receiving waters can flood facilities and damage outfall structures. Small thawing events can cause nuisances and slip hazards when the melted water refreezes.

How does an operator prepare for the thaw? Develop a wet weather operations plan and stick to it. Make sure you are maintaining the collection system and working to reduce inflow and infiltration. In preparation for the thaw, make sure CSO points, pump stations, headworks, extra tankage, and treatment units are ready to go. Marking culverts and storm drains in the fall will help to locate them if freeze up should occur. Carefully monitor the weather and keep staff informed.

Another challenge to winter weather is the limited day length. Many parts of Maine receive only 9 hours of daylight in the early winter. The sunlight intensity is much less in winter due to the low angle of the sun in the winter sky. These short day lengths and low intensity limit the outdoor workday, as well as making indoor work more difficult. These factors make proper lighting even more important during the winter months.

Lighting should be checked in all work areas. Clean fixtures and replace bulbs regularly. Add fixtures in inadequately lit areas. Have portable work lighting available for emergency work. Consider using headlamps for task lighting a good idea. You may need to increase work lighting both outside and indoors.

Another issue with limited light that can affect workers is called Seasonal Affective Disorder (S.A.D.). The decrease in sunlight can disrupt our body's internal clock and, in some cases, lead to fatigue, depression, or social withdrawal. Light therapy can help, as well as taking steps throughout the year to keep your mood and motivation steady.

If your plant is considering upgrades, what role can the operator have in designing for cold weather operations? Consider cold weather operations when reviewing project plans. Make sure the design works FOR the operator and communicate any concerns BEFORE construction.

Some common design problems include: No thought about snow removal (dead ends, fencing at driveway edges), no protection for low structures, exposed mechanical systems and work areas, sampling points and lines susceptible to freeze up, condensation issues not being considered, and ventilation problems during cold weather.

Winter operations at wastewater facilities are difficult, uncomfortable, and sometimes hazardous. That is why it is prudent to plan ahead to recognize hazards and minimize risks. These include slip, trips and falls, hypothermia and exposure, overexertion, and dehydration. And falling ice and snow.

Slips and falls are the #1 injury. We work where there is water and cold temperatures, which means lots of ice. Operators must be responsible for their own safety and minimize the risks. Slips into tanks or lagoons in winter can be fatal.

Some tips to preventing slips and falls include keep steps and walkways free of snow and ice, improve traction with gravel or sand, provide good drainage, direct melt water away to avoid icing, remove snow from roof with roof rakes, if possible, wear ice creepers when working on icy surfaces, and remember to use handrails!

Take your time and work and move slowly. Snow and ice tracked indoors will melt and create a slip hazards. Provide non-slip mats at entrances and mop up regularly.

Hypothermia is a condition that occurs when the body temperature drops to a point where muscle and brain function are impaired. This can lead to poor decision-making, which in turn lead to secondary injuries like slips and falls. Signs of hypothermia include shivering, lethargy, and mild confusion. Those suffering from severe cases can become dazed and irrational with slurred speech. Anyone suffering from the effects of hypothermia should seek immediate medical attention.

Factors that inhibit the body’s ability to respond to cold and increase the risk of hypothermia include Inadequate or wet clothing, certain medications, nicotine, or caffeine, and exhaustion and immobility.

Frostbite is an injury caused by freezing of the skin and underlying tissues. First your skin becomes very cold and red, then numb, hard and pale. Frostbite is most common on the fingers, toes, nose, ears, cheeks, and chin. Exposed skin in cold, windy weather is most vulnerable to frostbite. Affected areas appear white and are cold to the touch. Anyone exhibiting these symptoms should seek medical attention immediately.

To prevent exposure-related injury, operators should be trained to recognize symptoms and learn how to treat victims. Prevention includes proper Personal Protective Equipment (PPE), engineering controls, and safe work practice.

Those working in cold weather should use three layers of insulation, paying special attention to hands head and feet. Footgear should be insulated and waterproof, and a change of clothes should be kept available in case you get wet. Did you know that 70 percent of heat loss is through the head? “Feet cold? Put on a hat!”.

Consider purchasing tools with insulated handles to protect hands and fingers. It is best to work with a coworker and have a radio or other source of communications available.

Engineering controls can provide onsite heat sources to shield work areas from drafty or windy conditions and can provide heated shelter in areas where prolonged exposure may occur. Be aware of hazards! Carbon monoxide (CO) is generated by some heat sources, generators, and vehicles, and ventilation is more likely to be inadequate with everything closed in for winter. Signs of CO poisoning include fatigue, headache, and dizziness.

Driving in winter weather requires constant attention to watch for changing conditions. Slow down! Winterize vehicles, batteries, tires, wipers, windshield washing fluid and antifreeze. Secure loads so they don’t become trajectories if you end up in the ditch. 

We think more about overexertion and dehydration in the summer, but they can occur in the winter as well. Operators performing strenuous tasks such as snow shoveling or even walking through deep snow, can cause overexertion, muscle strains and even heart attacks. It’s easy to become dehydrated in cold weather. Remember to work slowly, take breaks, and drink warm liquids, (while avoiding caffeine).

We all tend to cut corners when working in uncomfortable conditions. Don’t rush work. Working in heavy PPE in cold conditions is slow. Allow plenty of time for the job, take breaks to warm up and rest, and most importantly recognize your limits.

Certification and Training Update.


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

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  https://annualconference.newea.org/ 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: https://mwua.org/mwua-annual-tradeshow-conference/

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

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 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. Safe work and security practices/procedures and management responsibilities will be emphasized. After each course lesson, you will be offered the opportunity to analyze and accurately solve applicable multiple-choice sample exam questions. In addition, Tom will devote ample time and instruction for you to refresh and improve your basic math skills. Basic math topics will include order of operations, use of formulas and conversion factors, and the systematic process to solve word problems. Tom will demonstrate and you will practice calculating linear measurements, area, volume, detention time, removal efficiencies, flow, chemical feed rates, motor/pump/wire-to-water efficiencies, BOD/TSS/MLSS pounds calculations, and more!

Biological Nutrient Removal (BNR) with Michael Gerardi

Tuesday and Wednesday, January 16-17, 2024 - Virtual

This 6-hour course is an in-depth review of the bacteria and operational conditions that are involved in the removal of nitrogen and phosphorus from the activated sludge process. The course reviews nitrification, the different forms of nitrification, troubleshooting nitrification and operational measures to promote nitrification. We will also review denitrification, the occurrence of denitrification or an anoxic condition, troubleshooting denitrification, and operational measures to promote denitrification. Biological phosphorus release in an anaerobic/fermentative zone and biological phosphorus uptake in an aerobic/oxic zone by poly-P bacteria are presented as well as operational conditions to promote biological phosphorus removal.

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

RCAP Management and Finance Webinar for Small Systems

RCAP Solutions is hosting a FREE webinar on Tuesday, Jan. 16 from 8:00 AM – 12:00 PM titled Management & Finances for Small Systems (ME). This 4-hour workshop is approved for 2 operations and 2 management  wastewater TCHs and 4 drinking water TCHs.

The course will cover key areas of management, boards and stakeholder roles, asset management, budgets and the importance of reserves and rate setting, including Maine State Revolving Loan Fund (SRF) Principal Forgiveness Programs.

To registration, go to this link:  https://bit.ly/Mgmt-Fin-ME.

MWUA Apprenticeship Program - Building Our Industry Workforce.

MRWA’s Apprenticeship Program is a nationally recognized program for candidates with limited or no experience. It is divided into two different tracks, Water and Wastewater. Each apprentice is assigned a mentor during their time in the program. Our staff will work with utilities to help select mentors, provide coaching, and create a nationally recognized schedule of work. We will also provide the apprentice with technical training, including certification prep for professional licensure.

Wastewater Operator 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, certification@neiwpcc-jetcc.org or call 207-253-8020.

You can renew online at https://jetcc.org/index.php.  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  https://www.maine.gov/dep/water/wwoperator/ under the Additional Materials section.

The NEIWPCC/JETCC website, https://jetcc.org/index.php provides information on signing up for an exam, training classes, and certification renewal.  Contact call Spring Conolly at certification@neiwpcc-jetcc.org 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, pwiley@smccme.edu at SMCC or Gil St. Pierre, ngstpier@nmcc.ed at NMCC.

Alfond Center Offers 50% Training Reimbursement

The Alfond Center for the Development of Maine’s Workforce is offering a 50% math for Workforce Development training.  For more information on this funding opportunity, visit the Center’s website, https://www.mccs.me.edu/workforce-training/maine-workforce-development-compact or contact Edward Wright at ewright@mccs.me.edu 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 https://academy.veolia.us/.

Cybersecurity Update: Exploitation of Unitronics® PLCs used in Water and Wastewater Systems.

Cyber Security

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) released an alert responding to active exploitation of Unitronics programmable logic controllers (PLCs) used in the Water and Wastewater Systems (WWS) Sector. Cyber threat actors are targeting PLCs associated with WWS facilities, including an identified Unitronics PLC, at a U.S. water facility. In response, the affected municipality’s water authority immediately took the system offline and switched to manual operations—there is no known risk to the municipality’s drinking water or water supply.

According to the CISA website (www.cisa.gov), WWS Sector facilities use PLCs to control and monitor various stages and processes of water and wastewater treatment, including turning on and off pumps at a pump station to fill tanks and reservoirs, flow pacing chemicals to meet regulations, gathering compliance data for monthly regulation reports, and announcing critical alarms to operations. 

Attempts to compromise WWS integrity via unauthorized access threaten the ability of WWS facilities to provide clean, potable water to, and effectively manage the wastewater of, their communities.

The cyber threat actors likely accessed the affected device—a Unitronics Vision Series PLC with a Human Machine Interface (HMI)—by exploiting cybersecurity weaknesses, including poor password security and exposure to the internet. To secure WWS facilities against this threat, CISA urges organizations to:

  • Change all default passwords on PLCs and HMIs and use a strong password. Ensure the Unitronics PLC default password “1111” is not in use. 
  • Require multifactor authentication for all remote access to the OT network, including from the IT network and external networks.
  • Disconnect the PLC from the open internet. If remote access is necessary, control network access to the PLC.   
    • Implement a Firewall/VPN in front of the PLC to control network access to the remote PLC. A VPN or gateway device can enable multifactor authentication for remote access even if the PLC does not support multifactor authentication. Unitronics also has a secure cellular based long-haul transport device that is secure to their cloud services. 
    • Use an allowlist of IPs for access.
  • Back up the logic and configurations on any Unitronics PLCs to enable fast recovery. Become familiar with the process for factory resetting and deploying configurations to a device in the event of being hit by ransomware.
  • If possible, utilize a TCP port that is different than the default port TCP 20256. Cyber actors are actively targeting TCP 20256 after identifying it through network probing as a port associated to Unitronics PLC. Once identified, they leverage scripts specific to PCOM/TCP to query and validate the system, allowing for further probing and connection. If available, use PCOM/TCP filters to parse out the packets.
  • Updated Dec. 19, 2023:

CISA and WWS Sector partners have developed numerous tools and resources that water utilities can use to increase their cybersecurity. Please visit:

For Practice.

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

  1. 15,000 gallon
  2. 112,200 gallons
  3. 150,000 gallons
  4. 224,400 gallons

2.  An empty 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?

  1. 7 hours 31 minutes
  2. 8 hours 21 minutes
  3. 8 hours 23 minutes
  4. 9 hours 17 minutes

3.  A belt filter press processing secondary sludges. Some of the sludge is squeezing out from between the belts and contaminating the effluent by falling into the filtrate trays.  How would you correct this problem?

  1. Blend primary sludge with the secondary sludge to add fibrous material.
  2. Build baffles to contain the falling sludge.
  3. Clean the belts.
  4. Move the filtrate trays.

4.  Given the following data regarding a primary sedimentation tank,

  • Raw sludge pump runs for 10 minutes each hour.
  • Raw sludge has 7% total solids at start of pumping cycle and 5% total solids at end of pumping cycle.
  • Sludge collectors run constantly.
  • Deep sludge accumulation over entire tank floor.

What changes would you make?

  1. Install a larger pump.
  2. Increase the sludge pumping cycle.
  3. Decrease the number of tanks in service.
  4. Measure the sludge blanket depth.

5.  Calculate the chlorine demand in mg/L using the following data:

  • Raw water flow 0.75 MGD
  • Hypochlorite feed rate 4.0 mg/L
  • 12% hypochlorite solution
  • Chlorine residual is 1.8 mg/l
  1. 0.8 mg/L
  2. 2.2 mg/L
  3. 4.0 mg/L
  4. 5.8 mg/L


Question 1.  Answer #2.112,200 gal

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

Question 2.  Answer #1. 7 hours, 31 minutes

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

Question 3.  Answer #1. Blend primary and secondary sludge to add fibrous material.

Question 4.  Answer #2. Increase the sludge pumping cycle.

Question 5.  Answer #2. 2.2 mg/L

Chlorine Feed (Dosage) =  Chlorine Demand + Chlorine Residual

        Rearrange the formula to solve for Chlorine Demand:

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

Happy New Year.


Wishing you all the best as we enter 2024. We look forward to working together throughout the upcoming year.