April 2022 O&M Newsletter

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April 2022

In this issue:


Monthly Problem Set / For Practice, April


1. A common remedy for activated sludge system problems is to increase the waste activated sludge (WAS) flow rate. When would an increase of WAS rate NOT be correct?

A. When pin-point floc is observed on the clarifier surface
B. When thick, scummy foam is seen on the aeration tank surface
C. When the aeration system is critically under-loaded
D. When straggler floc is present in clarifier and settleometer

2. The aeration tank DO has been running normal (1.5 to 2.0 mg/L) the whole month. Today’s DO reading has spiked to nearly 6.0 mg/L in the aeration tank, and the clarifier and plant effluent are cloudy. What is the MOST likely cause of the rise in DO?

A. The aeration blowers were left on overnight
B. A shock load of high organic strength waste has entered the plant
C. A shock load of rain water has entered the plant
D. A toxic shock load of cyanide has entered the plant

3. PROBLEM: Plant fecal coliform counts do not meet State standards. The chlorine supply is not the problem and there is adequate chlorine feed. The chlorine contact tank has no solids buildup and the effluent flow is below design. What is the MOST likely cause of the poor fecal coliform kill?

A. High chlorine demand from excessive ammonia in effluent
B. High chlorine demand from excessive nitrate in effluent
C. High chlorine demand from excessive nitrite in effluent
D. High chlorine demand from excessive polymer in effluent

4. How many gallons will the single piston, reciprocating sludge pump discharge per minute if the piston bore (diameter) is 6 inches and the stroke length is 11 inches? The pump runs at 99 revolutions per minute. Select the closest answer.

A. 121 gpm
B. 125 gpm
C. 134 gpm
D. 171 gpm

5. Operational data is given below for a conventional activated sludge treatment plant: Plant flow: 3.6 MGD Aeration tank volume: 5.0 MG MLSS: 2,350 mg/L WAS ss: 4,800 mg/L WAS flow: 150,000 gpd Effluent TSS: 15 mg/L Calculate the MCRT

A. 1.5 days
B. 15 days
C. 23 days
D. 45 days


Enterococcus Bacteria Testing for Maine Dischargers


Bacteriological testing for MEPDES Permits/WDL permits discharging into marine and estuarine waters (SA, SB, SC) currently contain limits for Fecal Coliform to protect the designated use of “propagation and harvesting of shellfish”.

In 2018, EPA required limits for Enterococcus bacteria, in addition to Fecal Coliform, to protect the designated use of “recreation in and on the water”. These changes were formally promulgated in State law (38 M.R.S. §465 and §465-B) in 2018. In 2019, DEP communicated to all marine MPDES permit/WDL dischargers that permit limits, based on current Maine criteria, will be implemented for Enterococcus bacteria seasonally (April 15 – May 31) upon permit renewal.

Enterococcus are indicator organisms found in animal intestines that survive longer in salt water than coliform bacteria. Enterococcus testing helps ensure protection of recreation in and on marine and estuarine waters.

Enterococcus testing may be performed either in-house or by state-certified commercial labs. Testing must be in accordance with 40 CFR 136. Current approved methods include Membrane Filtration (MF) by EPA 1600 and SM9230, and Enzyme Substrate - IDEXX-Enterolert®.

Membrane Filter (MF) method for Enterococcus testing is considerably more complex than the MF test for fecal coliform. Currently there are no Maine certified labs using the MF method for Enterococcus testing.

Enzyme Substrate - IDEXX-Enterolert® requires a water bath or air incubation temperature of 41±0.5 ⁰C for 24-28 hours. Note: A dedicated incubator is highly recommended for Enterococcus testing; using the same incubator for Enterococcus and Fecal Coliform testing is discouraged.

The Permittee should determine the testing methodology that will be used for Enterococcus analysis in-house or by state-certified lab and make arrangements for testing to commence upon permit renewal.

If you have any questions about Enterococcus testing, please contact your inspector.

 


Cybersecurity Alert for Water & Wastewater Facilities


On March 21, 2022 the White House issued a statement indicating there is now evolving intelligence that Russia may be exploring options for potential cyberattacks. This new assessment is accompanied with an emphasis to act now to protect against potential cyber-attacks.

There are 16 critical infrastructure sectors whose assets, systems, and networks, whether physical or virtual, are considered so vital to the United States that their incapacitation or destruction would have a debilitating effect on security, national economic security, national public health, and safety. The Water and Wastewater Systems Sector is one of the U.S. critical infrastructures.

Under these increased threats, a greater sense of urgency is being placed on the following:

• Mandate the use of multi-factor authentication (MFA) on your systems to make it harder for attackers – including locking down privileged accounts and monitoring for anomalous account activity.

• Deploy modern security tools on your devices to continuously look for and mitigate threats.

• Make sure systems are patched and protected against all known vulnerabilities and change passwords across your networks so that previously stolen credentials are useless to malicious actors.

• Back up your data and ensure you have offline backups.

• Understand and be proficient in incident response procedures (IRPs) and emergency plans before an incident occurs, including practicing IRPs in tabletop exercises with emphasis on being prepared to maintain continuity of operations, specifically for any ICS/OT dependencies that could be disrupted and the sustaining of manual operations to maintain critical functions.

• Encrypt your data so it cannot be used if it is stolen.

• Educate your employees to common tactics that attackers will use over email or through websites and encourage them to report if their computers or phones have shown unusual behavior, such as unusual crashes or operating very slowly.

• Drop the threshold for the sharing of information regarding suspicious network activity – engage proactively with your local FBI field office or CISA Regional Office to establish relationships in advance of any cyber incidents. Organizations should report incidents and anomalous activity to CISA [waterisac.org] and/or the FBI via your local FBI field office [waterisac.org] or the FBI’s 24/7 CyWatch at (855) 292-3937 or CyWatch@fbi.gov [waterisac.org].

Visit CISA’s website https://www.cisa.gov/water-and-wastewater-systems-sector for resources to help prepare your facility against cybersecurity attacks.


DMR-QA Update


EPA has recently notified State DMR-QA coordinators that DMR-QA study will tentatively open on April 15, 2022 and close on July 15, 2022. The formal study announcement should be ready by the first week in April.

The Maine DEP NetDMR coordinator will keep facilities updated on when the 2022 announcement letter is sent to make sure participants receive a copy of the study package.

If you have any questions or need to update your contact information, please contact Brett Goodrich at Brett.A.Goodrich@maine.gov or call 207-287-9034.


Get Ready for Seasonal Chlorination


Many facilities across the state will begin seasonal chlorination soon. Don’t wait until the last minute to prepare. It is a good idea to start early so there is time to make adjustments/repairs as necessary.

Your chlorine contact chamber (CCC) may have accumulated water/solids during the winter that needs to be cleaned-out/emptied. Do a thorough inspection of the chlorination system to ensure the integrity of the entire system. Meter accuracy can be verified by pumping into a bucket or barrel of known volume and comparing it to the meter readings. Tank(s) should be visually inspected for corrosion and physical damage. Verify treatment chemicals are stored to capture any leaks in a secondary containment area.

Start-up procedures for chlorination include:

o Check that all valves are in their proper position and tagged
o All piping should be inspected and found to be in operating condition
o Feed and safety equipment should be checked and found in operating condition
o Procedures should include a program to sequentially open valves, and start equipment

Once operating, the operator must verify that chemical feed rates are correct. Make sure your residual chlorine monitoring equipment is properly calibrated and/or verified. Test the total chlorine residual (TRC) at least twice on separate days and evaluate results to ensure target doses and residuals are being met. Make adjustments as needed.


Which Laboratory Methods Can I Use for my MEPDES Permit Analysis

Permittees are required to use approved laboratory methods when performing wastewater analysis for permit compliance. EPA publishes the list of approved methods for use by NPDES permittees under the Clean Water Act in 40 CFR Part 136.3.

EPA periodically updates the list of approved methods by issuing a Method Update Rule (MUR). The most recent MUR was issued in May of 2021, and changes were incorporated into 40 CFR Pat 136.3 in the fall of 2021. Table IA lists approved biological methods (i.e., E.coli, fecal coliform, enterococcus, whole effluent toxicity) and Table IB provides a list of approved inorganic test procedures (BOD, residual chlorine, pH, etc.). The year after the method number shows the most current approval or editorial update of the method. The approved version would include any version or editorial revision with the date listed in CFR 136.

To help wastewater facilities navigate CFR 136 and locate the correct method, DEP has prepared a summary table below that lists the approved methods for the most common parameters analyzed by wastewater treatment laboratories.

Jodi L Meader

The table includes the approved methods as well as the specific versions or revisions that can be used. For example, the BOD5 test is approved for Standard Methods (SM) 5210-2016, AOAC 973.44 and USGS I-1578-78, In-Situ 1003-8-2009 and Hach 10360 for the testing of wastewater.

The table cross references both the printed and online version(s) of Standard Methods that have an approved version of the test method. If you are downloading online editions of Standard Methods, pay attention to the method approval and editorial revision dates. Verify that the approval dates you are using correspond to the most recent version listed in CFR 136, as EPA doesn’t always adopt new revisions as soon as they’re publish by Standard Methods.

In the laboratory, it is important to be following, and have access to an approved version of each method that is performed for compliance testing. Make sure you are using the correct, approved method that is listed in the most current version of 40 CR 136.
If you have any questions, contact your Compliance Inspector or DEP Technical Assistance at 207-287-9034.


Monthly Problem Set / For Practice Answers, April


1. D. Straggler floc would indicate a young sludge; therefore, WAS would not be increased.

2. D. The toxins killed or reduced the microbe, leaving high DO and poor settling.

3. C. The plant is experiencing partial nitrification.

4. C. Find the pump volume: 0.785 X 0.5 ft X 0.5 ft X 11/12 ft = 0.18 cubic ft
Convert to gallons: 0.18 cu ft X 7.5 gal/cu ft = 1.35 gal
Find flow rate: 1.34 gal X 99 rev/min = 134 gpm

5. B: First, find pound of solids in A.T: 5 MG X 2,350 mg/L X 8.34 = 98,000 lb
Next, find pounds solids wasted/day: 0.150 MGD X 4800 mg/L X 8.34 = 6000 lb/day
Find the solids lost in the effluent: 3.6 MGD X 15 mg/L X 8.34 = 450 lb/day
Add total solids lost from the system/day = 6000 + 450 = 6450 lb/day
Divide pounds in system by pounds removed/day = 98,000 lb/ 6450 lb/day = 15 days