July 2019 O&M Newsletter

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July 2019

In this issue:


July 16 - MRWA - Proper Sampling Procedures, Bar Harbor, BLWSO 3 TCH

July 23 - MRWA - Proper Sampling Procedures, York, BLWSO 3 TCH

August 13 - MRWA - Proper Sampling Procedures, Millinocket, BLWSO 3 TCH

August 20 - MRWA - Proper Sampling Procedures, Wiscasset, BLWSO 3 TCH

August 20 - MRWA - Groundwater System Sanitary Survey Course for Water Operators & Public Water System Inspectors, North Berwick, BLWSO 6 TCH

August 21 - MRWA - Groundwater System Sanitary Survey Course for Water Operators & Public Water System Inspectors, Searsport, BLWSO 6 TCH

August 29 - MRWA - Groundwater System Sanitary Survey Course for Water Operators & Public Water System Inspectors, Mexico, BLWSO 6 TCH

Monthly Problem Set / For Practice, July

1. A Rotating Biological Contactor (RBC) is –

a. Fixed film biological treatment process
b. Addition to most Activated Sludge Plants
c. New filter media aerobic digester
d. Variable speed Recirculating Biological Contact Unit
e. Reconditioned Biological Containment Unit

2.  Which of the following need to be checked regularly to properly operate an
activated sludge treatment plant?

a. De-foaming agents
b. Overflow rate in the primary clarifier
c. Aeration equipment and mixed liquor solids
d. Aeration equipment, Chlorine concentration, and Suspended solids
e. All the above

3.  An aeration basin holds 5000 gallons of mixed liquor, the MLSS is
4000 mg/l and the inflow is 200 gallons per hour. Calculate the detention
time of the aeration tank in hours. (D.T. = V divided by Q)

a. 2 hours
b. 4 hours
c. 12 hours
d. 24 hours
e. 25 hours

4.  Calculate the volume in gallons of a rectangular aeration tank that is 60
feet long, 30 feet wide, and 20 feet deep. (V=L X W X H X 7.48)

a. 26,928
b. 269,280
c. 36,000
d. 360,000
e. 4,812

5. An operator’s flow meter at the plant indicates there was 2.6 MGD flow
through the plant. What is the GPM?

a. 1805
b. 18,055
c. 1083
d. 10,833
e. None of the above

6. Point source discharges are –

a. Discharges that show up in the system and at the plant from an
unidentified or explained source.
b. Discharges that come from pipes or ditches that are monitored,
controlled and inspected.
c. Discharges that have Intermittent, dispersed flows having little or no
d. Discharges that contribute greatly to the BOD and COD and typically
come from dairies and farm related activities.
e. None of the above

7.  Non-Point Source Discharges are –

a. Discharges that have Intermittent, dispersed flows having little or no
b. Discharges that come from pipes or ditches that are monitored,
controlled and inspected.
c. Discharges that come from municipalities, or industry.
d. Discharges that are high in BOD & typically come from food
e. None of the above

8.  Facultative Bacteria require ________ in the water for their metabolism

a. Nitrogen
b. Hydrogen
c. Oxygen
d. Either aerobic or anaerobic conditions
e. Cannot live with O2 present

Legislative Update

In March 2019 the Department sent a Special Edition of the O&M News that notified you of the following pending legislation:

• L.D. 1832, An Act to Ensure Adequate Funding for the Maine Pollutant Discharge Elimination System and Waste Discharge Licensing Program.  This bill would increase the annual fee for MEPDES/WDL. 

• L.D. 1779, An Act To Establish Standards for Operation and Maintenance and Asset Management for Publicly Owned Treatment Works and Municipal Satellite Collection Systems.  This bill would establish authority for the Department to develop, via rulemaking, standards for operation and maintenance and asset management at POTWs and satellite collection systems.

These bills were printed very late in the legislative session and the Environment and Natural Resources Committee opted to carry them over to the next legislative session that begins in January of 2020.  Therefore, no action will be taken on these bills until next year.

You will be notified after the start of the next legislative session once these bills have been scheduled for a public hearing.

If you have questions on this issue please contact Brian Kavanah, Director, Bureau of Water Quality, at 287-7700.

DMR-QA Study 39 Results Due September 13

Many facilities have received their DMR-QA results from the PT providers and are beginning to send the results to DEP.  They are not officially due until September 13, but feel free to submit earlier, preferably by email.

The EPA DMR-QA Study 39 package was emailed to study participants in April.  If you don’t have a copy, it can be found at this link:


Please complete pages 10-12 of this form and send together with a copy of the DMR-QA results for all analytes tested in your lab to DEP as follows:

- Page 10:  NPDES Permittee Data Report Form – Complete and sign. This is VERY IMPORTANT- to make sure we receive your results and so we know you received and reviewed your results
- Page 11:  Identification of Laboratories – List all the labs you use. If you don’t know the lab code, let us know.
- Page 12:  Chemistry/Microbiology Analyte Checklist – Check off the analytes required on your permit, and whether you test them in-house or analyze by a state-certified lab
A copy of the lab results from the PT lab showing whether you passed each analyte tested in your lab.

Don’t worry about completing page 13 (WET Analyte Checklist) or sending WET test results to DEP. We will get the information from the WET lab directly. Also, we do not need to see the results of analytes that are tested by your contract lab, such as phosphorus or low-level mercury. These are covered under DHHS’ lab certification program and not part of this DMR-QA study.

If you fail any tests, let us know by letter or email as soon as possible.  You will need to order retest samples from the PT provider by August 30.  The retest results and a Corrective Action report must be sent to DEP by November 8.

You can always call or email if you have any questions or require further information, Brett.A.Goodrich@maine.gov, 207-287-9034.

Secondary Clarifier Washout

What Does Your Secondary Clarifier Look Like Right Now?

Copyrighted material.  Reprinted and edited with permission from Environmental Leverage, https://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.

It’s raining again. The heavy rains we are experiencing across the country can cause plant problems, including biomass washout and solids handling issues in your secondary clarifier. Many plants are designed with spare EQ tanks, holding tanks or diversion ponds to divert some of the excess flow during high rains, which are bled back into the system after the high rains have stopped. But not all plants have the extra capacity for excess flow and must try to limp through the sudden weather changes that can impact their plant, causing loss of MLSS and reduced plant efficiency.

Even if a plant does not have combined sewers, heavy rainfall can still impact their plant if no covers are in place. Rain can add hydraulic loading to primaries, aeration basins, and clarifiers. We have seen plants that typically have a flow of 3 MGD jump up to 11 MGD during a very high rainy season. This drastically changes the hydraulic retention time in the basin, washing out some of the sludge and reducing settling times in the clarifier. Hydraulic overloading leaves you with significantly less time and less numbers to treat the excess flow.

Remember, it always is a time and numbers game in wastewater. Time is limited by your equipment’s hydraulic loading and the only thing you can sometimes control is the numbers, or bacteria. Equalization can help with high loadings. An EQ tank can help even out the flow to minimize the roller coaster effect on the plant. Sometimes bioaugmentation can help balance out the high swings of loading.

Overloaded systems cannot handle the incoming inorganic flow, as weirs may be submerged. All sorts of debris, rags, garbage or even large chunks of grease can dislodge in sewer lines and lift stations and can make their way down to the primaries of a wastewater treatment plant. This can cause excessive wear and tear on screening, pumps and tanks and make solids handling nearly impossible. Moving parts should be adjusted! Don’t just maintain the speeds or levels that were set when the plant was built! The system needs to be tweaked! Your influent changes daily, with regular flow as well as heavy rains, so make changes to your equipment to optimize your plant! Little changes can help make big improvements!

Heavy rain can wash oils off of streets and industrial sites. And where does the storm water go, loaded with oils, dirt and debris? Many times it can wind up in the wastewater treatment plant either directly or through infiltration. High levels of grease at the treatment plant can impact solids handling in the clarifier. High levels of grease can also cause foaming due to the growth of Nocardia and Microthrix, which are hard to dewater. Municipalities should check for excessive levels of grease or oils in the influent. Bioaugmentation products may be useful to help reseed and degrade the oils and greases.

Hydraulic overload can also cause significant temperature and Dissolved Oxygen (DO) swings. Heavy rains can lower water temperature. Since colder water can hold more oxygen than warmer water, this can affect the types of biology present, which can make a huge difference in the way your biomass reacts, settles, dewaters, as well as how much you spend on solids handling costs.

High flows that cause MLSS loss from the aeration basin and clarifiers can shift the sludge age, leading to a younger biomass younger. Look under the microscope for an increase in amoebae or flagellates in your system. This shift in sludge age might give you difficulties in solids handling capabilities as well as loss of treatment efficiency. Adjust your MLSS and sludge age according to the loading so that you can again beat the time and numbers game. Adjusting your wasting rates and returning more sludge to the system to increase biomass concentration can help. It may be possible to return some of the biosolids from the digester to reseed the plant. Make sure you do are not introducing septic sludge or high levels of filaments that can harm your system.

Be extremely critical of nutrient levels during wet weather events. This is often overlooked during crisis periods. The bacteria do not care what is going on in the outside world; they still sufficient N and P. If a spill or heavy rains come in, make sure to "spill" extra nutrients if your plant typically adds them. Or decant from your digester if you need more nutrients instead of adding extra nutrients from a bag. You have your own source on hand. If you typically add ferric or alum to remove nutrients, you may need to cut back slightly after a heavy rain to make sure you are not actually causing nutrient deficiency.

Nitrification is the hardest to recover quickly when nitrifiers are lost from washout conditions. While the carbonaceous bacteria can recover relatively quickly from washout, when nitrifiers are washed out it can take quite a while to rebuild the numbers capable of handling the plant’s influent. Check nutrient levels and add bioaugmentation if necessary.

Hydraulic washout can cause final effluent problems. Disinfection can be significantly impacted by high rains and hydraulic overload. If the flows are too high and run too fast through the systems, detention times are decreased and disinfection may not be thoroughly effective. Chemical additions may need to be adjusted. And finally, flooded lakes and rivers may put a limitation on the discharge points.

Monthly Problem Set / For Practice Answers, July

1. a.
2. e.
3. e.(5,000 gal/200 gal/hr = 25hrs)
4. b.(60 ft X 30 ft X 20 ft X 7.48 = 269,800 gal)
5. a. (2,600,000 gal/day X day/1440 min = 1,805 gpm)
6. b.
7. a.
8. d.