AUGUST 2025
Verifying the validity of data received from commercial laboratories is just as important as checking the validity of data generated at in-house laboratories. When you receive a laboratory analytical report, start by reading the cover letter and narrative. Often commercial laboratories will list out any issues that occurred during sample analysis in one or both of these sections, including if samples were received outside of temperature or hold time requirements. However, there are also several other places in the report that should always be reviewed to determine if a sample analysis is valid.
Review the reported analytical values. Do these values make sense based on the anticipated concentrations of various compounds in your effluent? If there is a detection of something unexpected or at a level significantly different than anticipated, a deeper dive into the data is warranted. The unanticipated results may be accurate, so it is equally important to look at any potential changes to influent or processes that may have caused or contributed to the unexpected result.
The reporting limit is listed along with the analytical result. Some analytes, like mercury, have very low reporting limits. If a sample requires dilution to analyze, this will increase the reporting limit. Even non-detect results can have a future impact on permit limits, if reporting limits exceed the regulatory threshold. Resampling is warranted in cases where the result is non-detect or detected below the reportable level and the reporting limit exceeds the regulatory threshold.
Detections in blank samples can indicate issues with analysis such as carryover from earlier samples or issues with the preparation of the blank. The analytical results for any blanks will also be included in the laboratory report and should be reviewed as a routine part of reviewing laboratory data. Recently, this issue has been observed most frequently with BOD samples; however, any sample can be impacted by this type of issue.
There are times when a requested analyte is missed when a sample is analyzed. The Department has observed this most frequently with the priority pollutant scan where there are many required analytes. When your laboratory packet is received, review the laboratory packet to ensure everything requested was included in the analytical results.
The final section of the laboratory report includes the quality assurance and quality control data for the sample. Issues in this section are generally flagged by most commercial laboratories. These issues are most often also included in the cover letter and/or the narrative; however, sometimes issues are missed when those sections of the laboratory report are generated, since the cover letter and case narrative are often drafted by hand.
Quality data also relies on quality sampling technique and sample handling. When collecting samples, verify you have the correct container with the correct preservative. If shipping samples, make sure they are collected and sent so they will arrive at the laboratory within hold time and are shipped so as to meet temperature requirements when received at the laboratory. It is equally important to completely fill out the chain of custody. An improperly filled out chain of custody can cause a sample to be rejected.
Ensure you review your laboratory analytical report as soon as it is received. Sometimes samples can be reanalyzed or analyzed for additional analytes if errors are detected within hold time for the sample. If the sample can’t be reanalyzed or was invalid, a new sample will need to be collected to meet compliance requirements.
If you have questions about reviewing your laboratory report, please contact Holly Ireland, Licensing and Compliance Manager at [email protected] or at (207) 451-2286.
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Copyrighted material. Reprinted with permission from Environmental Leverage, Inc. www.environmentalleverage.com. The appearance of external hyperlinks does not constitute endorsement by the Maine Department of Environmental Protection of the linked web sites, or the information, products or services contained therein.
Last month’s article discussed potential problems to wastewater plants from having too high a sludge age. This month we will discuss issues encountered in the summer months from algae, duckweed, and difficulty maintaining D.O. levels.
The combination of warmer temperature (above 60 degrees), longer detention time, and excess inorganic minerals, mainly nitrogen and phosphorus, can cause algae growth. Algae can be a nuisance in wastewater plants.
Algae growth on the final clarifier weirs can cause problems with clogging the weirs, but more significantly, small pieces of algae can carryover into the final effluent. This can lead to high TSS and/ or BOD readings and possible permit violations. Make sure to clean the weirs more often in the summer to reduce this problem.
Duckweed are small, free floating green plants that can be a problem for ponds or lagoons. They form large blankets on the surface and can grow significantly in the summertime. Duckweed has some desirable properties for water purification since it can break down and treat some nutrients, and being a plant, it releases dissolved oxygen into the water that can be taken up by aerobic bacteria. While duckweed can be beneficial and is often found on final polishing ponds, final effluent screening may be necessary to reduce solids carryover into the final effluent.
Bristle worms can also be seen more readily in the summer months as the sludge age gets older. These are microscopic worms that can turn the foam on the aeration basin or the secondary clarifier surface pink in color due to the vast numbers of these worms They are usually found in the presence of high nitrates and older, well-developed sludge. Lowering the sludge age would also reduce the likelihood of seeing bristle worms.
Another problem encountered in the summer is too high a MLSS concentration. This will lead to more dissolved oxygen required in the aeration basins, which is a real cost item due to electrical components driving the aerators or a diffused aeration system. Oxygen transfer is also more difficult to achieve in hot water than cold water.
If your D.O. is hard to maintain, try reducing the MLSS concentration you are holding in the aeration basin (via RAS change and/or by wasting). This is where keeping track of your solids balance data is very valuable!
Next month: Assessing sludge quality using a settleometer, and how to treat filamentous bacteria with chlorination.
DMR-QA Study 45 officially opened June 6th, 2025 and closes August 29th, 2025, at which time all results must be reported to the DMR-QA supplier. Click here to receive the announcement letter: 2025 Discharge Monitoring Report - Quality Assurance (DMR-QA) Study 45 | US EPA
Do I need to test for Enterococci?
Your facility may have received a new permit with Enterococci limits. We have been getting questions from permittees in the DMR-QA program about whether or not they need to test for Enterococci.
Does your facility need to conduct a DMR-QA for Enterococci for Study 45? The answer is no, not this year.
Since Enterococci is not included in the EPA’s Study 45 Analyte Checklist (page 15 of the study packet), the DMR-QA is not required this year. Enterococci will be a required DMR-QA parameter once EPA adds Enterococci to the Microbiology section of the announcement packet. We will let up know when EPA adds Enterococci to the list of required analytes.
Performing QC testing is always good practice, particularly for a testing method that is new to your lab. The Department is recommending permittees that have Enterococci limits in their permit perform a Water Pollution (WP) Study for Enterococci, but it is not required for 2025.
Remember, if you receive a “Not-Acceptable” score for one or more parameters, you must complete a corrective action and perform retests for all parameters with Not Acceptable results. A copy of the corrective action report and retest results must be sent to the State DMR-QA coordinator by December 5th, 2025.
If you have questions about the DMR-QA program, please contact Brett Goodrich at 207-450-5590 or [email protected].
MWUA 2025 Annual Summer Outing August 5 at Lost Valley Ski Area
Join MWUA at their Annual Summer Outing. This year's event will be at Lost Valley Ski Area on August 5, 2025 starting at 8 AM. The technical sessions include Lewiston Redundant Waterline presented by Heidi Baird, Tighe & Bond and Unidirectional Flushing Programs presented by Heather Doolittle, Tighe & Bond. They are approved for 1 TCH each.
This year's BBQ will include steak, lobsters, hot dogs, hamburgers, coleslaw, Caesar salad, and mac and cheese.
To register, go to MWUA Summer Outing - MWUA.
EPA to Offer FREE Cybersecurity Training for Maine Water & Wastewater Operators
EPA’s Water Infrastructure and Cyber Resilience Division (WICRD), in collaboration with the Maine CDC and DEP is hosting a Cybersecurity Incident Response Plan Webinar and accompanying Cybersecurity Overview and Tabletop Exercise for drinking water and wastewater utilities in Maine.
The webinars will assist Water & Wastewater utilities in developing cybersecurity incident response plans that can be tested against the cyber incident presented in the tabletop exercise. Maine public water and wastewater system owners, operators, and IT professionals are encouraged to attend.
- September 3, 9 AM – 10 AM - Developing a Cybersecurity Incident Response Plan
- September 24, 9 AM – noon – Cybersecurity Overview and Tabletop Exercise
Attendance at both the webinar and tabletop exercise is highly encouraged. Additional questions concerning this course can be directed by email to Melanie Woods, GDIT (EPA Contractor) at [email protected].
Maine’s Management Candidate School – Beginning November 5 at Portland Water District
This 11-month training program is aimed at mid-level operators with management potential. Participants gain professional development through management courses, technical courses (such as engineering basics and construction planning), and skills training in areas of personnel management, communication, working with regulatory agencies, and budget preparation.
Applications will open in September, with classes beginning November 5, 2025. The location for each program changes by year and the Class of 2026 will be held at the Portland Water District. Candidates that complete the program will be awarded a full renewal period of Training Contact Hours (TCHs) for their Maine Wastewater Operator Certification (18 TCHs) and up to 63 TCHs for their Maine Drinking Water Certifications.
JETCC’s Management Candidate School program costs $1,100 per participant. Students must commit to attend all monthly trainings and the Operator Exchange.
Recognition for completing the Management Candidate School is given to all students. A certificate of completion will be awarded during a graduation ceremony held during the Maine Water Environment Association Fall Convention.
More information and registration will be available soon at Maine’s Management Candidate School • NEIWPCC.
MeWEA's Fall Convention September 18-19, 2025 at Sunday River
The Maine Water Environment Association’s (MEWEA) Fall Convention is an annual two-day conference packed with professional development and networking opportunities for all wastewater professions and anyone who has an interest in the environment and clean water.
The in-person event taking place September 18-19 at Sunday River Resort in Newry, Maine. More information will be available soon at Events.
MRWA Administrative Summit – October 7, 2025
MRWA will hold a virtual Administrative Summit on October 7, 2025.
This Summit will provide important information for wastewater administration including audits, employee complaints, employee coaching and counseling, and negativity in the workplace.
Sessions include:
- How to be prepared for your annual audit (Nick Henry, CPA, Henry Solutions, LLC).
- How to Handle employee complaints: from the everyday gripes to the serious harassment complaints (Peter Lowe, Lawyer, Bran & Isaacson).
- Employee Coaching and Counseling (David Ciullo, CEO, Career Management Associates).
- Overcoming Negativity in the Workplace (Katie Hadiaris, Director of Talent & Career Development, Career Management Associates).
For more information contact Kate Warner [email protected] or visit Events - Maine Rural Water Association.
MWUA to offer Leadership Training
MWUA is pleased to announce their new training: The Leadership Edge: People, Purpose & Performance at Husson University in Bangor on October 7, 21, November 4, 18 and December 2, 6. The course will be held every other Tuesday from 9 AM – 4 PM.
Topics include:
- Explore the Leader Within
- Effective Leadership Styles
- Key Principles of Leadership
- Understanding the Human Side of Work
- Establishing Organizational Leadership Roles
- Transitioning as a Leader
For more information, go to MWUA Training - MWUA or contact Cindy Wade at [email protected].
Save the Date for MRWA’s 45th Annual Conference & Trade Show
Mark your calendars for MRWA’s 45th Annual Conference & Trade Show. The event will be held on December 9 - 11, 2025 at 11:45 AM at the Cross Insurance Center in Bangor.
More information can be found at; Event Registration - Maine Rural Water Association.
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1. Small pin floc observed suspended throughout a moderately turbid secondary clarifier is a strong indication of which of the following:
A. Sludge age is too high
B. Sludge may be under oxidized
C. Sludge age is too low
D. Sludge age is just right
2. Which of the following activated sludge processes are best suited for nitrification to occur?
A. Extended Aeration
B. Conventional or plug flow
C. Step feed
D. Contact stabilization
3. The ratio of chlorine to ammonia nitrogen needed for a complete breakpoint chlorination reaction to occur is approximately:
A. 1 part chlorine to 1 part ammonia nitrogen
B. 5 parts chlorine to 1 part ammonia nitrogen
C. 10 parts chlorine to 5 parts ammonia nitrogen
D. 1 part chlorine to 5 parts ammonia nitrogen
4. A thin billowing foam on the aeration basin of an activated sludge plant indicates:
A. Normal operation
B. High F/M ratio
C. Low F/M ratio
D. Old sludge
5. A wastewater treatment plant has an average flow of 3.75 MGD. If the influent TSS concentration is 175 mg/l, how many pounds of suspended solids enter the plant in a day?
A. 3,823 lbs
B. 4,908 lbs
C. 5,473 lbs
D. 7,564 lbs
6. If the influent BOD is 93 mg/l, the influent flow is 1,300,000 gpd, the MLVSS is 1,700 mg/l, and the aeration basin is 100 ft in diameter and 12 ft deep. What is the F/M ratio?
A. 0.50 lbs
B. 0.10 lbs
C. 0.05 lbs
D. 0.02 lbs
Answers
1. A.
A high sludge age in a wastewater treatment plant can lead to reduced biomass activity, poor settling, and the accumulation of undesirable substances. This can result in a cloudy effluent, pin floc (small, rapidly settling particles), and floating solids. To address this, operators can increase the sludge wasting rate, improve aeration, and optimize the return sludge rate.
2. A
Extended aeration plants are particularly effective at achieving nitrification due to their long aeration and mean cell residence time (MCRT).
The long retention times allow nitrifying bacteria (which are slow-growing) sufficient time to oxidize ammonia to nitrate.
3. B.
In wastewater treatment, the best chlorine to ammonia nitrogen ratio for breakpoint chlorination is generally 5:1 to 8:1 (weight ratio of chlorine to ammonia). This ratio ensures complete oxidation of ammonia to nitrogen gas, provided ammonia is the primary demand in the water.
4. B.
High F/M conditions, particularly when coupled with high mixed liquor suspended solids (MLSS) or mixed liquor volatile suspended solids (MLVSS), can lead to excessive foaming.
5. C.
3.75 MGD X 175 mg/L X 8.34 = 5,473 lb/day
6. B.
First, find the pounds of BOD entering the plant:
1.3 MGD X 93 mg/L X 8.34 = 1008 lb/day.
Next, find the pounds of biomass in the aeration basin:
Volume of aeration basin = 0.785 X 100 ft X 100 ft X 12 ft X 7.48 = 704,616 gal. Round to 0.705 MG.
Find the pounds of biomass in the aeration basin:
1,700 mg/L X 0.705 MG X 8.34 = 9,995 pounds
F/M = 1008 lb/day / 9,995 pounds = 0.1
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