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At the March 19, 2025 Manteo Board of Commissioners meeting, town manager Melissa Dickerson presented information about how the town’s wastewater system and plant work along with some of the permit parameters. She shared the 10-year capital improvement plan.

Overview

Manteo’s wastewater treatment plant was built in 1993. The system collects wastewater from households and businesses throughout the town.

Wastewater is collected and directed by gravity flow and sewage lift stations to the treatment plant off Bowsertown Road, where it is treated. In 2024, an average of 290,000 gallons of wastewater is treated and discharged each day.

The town’s Water and Sewer Department maintains more than 20 miles of various types of collection pipelines and 11 wastewater lift stations. The gravity wastewater pipes in this system range in size from 8 inches to 15 inches in diameter.

Annual sewer line inspections are conducted. The collection system has parts that are “considerably aged.” In 2022, the Waterfront Lift Station, which was underground, was replaced for $1.6 million. The replaced lift station dated from the 1940s. Some collection system pipes also date back to the ’40s.

How it works

The Wastewater Treatment Plant is a grade 3 biological plant.

At the entry to the plant, a preliminary screening and grit removal takes place. Large solid particles and inorganic materials are removed by screening and settling.

The next part of the process is secondary biological treatment and nutrient removal. So, once the wastewater goes through the auger, it goes directly to the brown tank.

The wastewater is treated biologically to remove dissolved pollutants. This means that once the wastewater reaches the “brown tank,” the wastewater in the tank is treated using microorganisms to treat the water.

The microorganisms or “bugs” are susceptible to changes in the environment. The bugs are affected by temperature. In colder temperatures they slow down.

The metabolism rate of the bugs doubles for every 10 degree increase in water temperature. This means that they require that much more dissolved oxygen to do their job.

The bugs use oxygen as an energy source to oxidize organic nitrogen and ammonia and condition the sludge in the tank for further separation in the clarifying/settling tanks, which are the round tanks downstream. Oxygen is provided by way of paddle wheel aeration in each of the three channels inside the brown tank.

Sludge inventory for the plant is calculated based on several operating characteristics and either wasted/removed and later to be hauled away or returned back to the brown tank daily to keep the bugs healthy.

After the two clarifying tanks, the water moves to the square shape tanks which house two sand filters, chlorination as a disinfectant and decolorization to remove the chlorine residual before being discharged to Shallowbag Bay.

About staff

Staff are trained and certified to manage this process. Water and Sewer director Josh O’Brien holds a grade 4 biological certification (the highest) for treatment and a grade 4 for collections. Deputy director Edward Hanisck holds a grade 2 biological and a grade 2 collections certification. Plant operator Troy Faulkner holds a grade 2 biological and grade 1 collections certification. Jonique Lee, utility maintenance worker 2, holds a grade 1 biological and grade 1 collections certifications. The town has a plant-on-call program in which staff are notified by the computers that monitor the plant. When alerted, the on-call staff member responds to the plant to troubleshoot the alert.

Stormwater

The stormwater system in Manteo, which is mostly owned by the state’s Department of Transportation, is not connected to the sanitary sewer system. During times of heavy rain or flooding, the town’s collection and treatment systems do experience inflow and infiltration of rainwater into the system.

Regulation and Testing

“The Wastewater Treatment process is highly regulated,” states the report. The federal Environmental Protection Agency sets the standards and the North Carolina Department of Environmental Quality permits the plant and has regulatory authority to enforce the town’s National Pollutant Discharge Elimination System permit. Every five year, the town applies for a permit extension which gives the town limits for operating. The town pays an annual permit fee based on compliance. The fees can be increased due to plant violations and non-compliance.

Some of these limits and measurements change each time the town’s permit is renewed or new parameters can be added. With each permit, the town must react to new standards which sometimes requires plant adjustments.

Effluent is tested five days a week to confirm that operations are within permitted limits. The town also tests five sample sites in Shallowbag Bay. Some 13 samples are gathered at each site. A wastewater laboratory contractor processes the samples. Results can take one to four weeks.

Every month, the town submits a discharge monitoring report to the state’s Department of Environmental Quality. All sample results are submitted. The town’s current budget calls for spending around $55,000 a year on testing for compliance sampling. If the town has violations, O’Brien as the operator-in-responsible charge is required to report it to the town manager, as the plant permittee, within 24 hours of receiving lab results of non-compliance. Later, the town must report by sending a letter addressing the violation and how the town will address the issue causing the violation.

Once upon time, the town spent upwards of $30,000 per year on wastewater treatment plant violations. The town was also on the EPA watchlist for the high amount of violations the plant received, reported Dickerson.

“Today, the town has a very strong commitment to making sure that the effluent not only meets the standards of the permit but exceeds expectations to make sure that we are doing what we can do to reduce pollutants and protect water quality in Shallowbag Bay. One example of that commitment is the UV Disinfection Project that is currently underway at the plant. This will change our current disinfection process from using chlorine to UV light,” Dickerson reported.

Capital Improvement Plan

The UV disinfection project was included in the 10-year capital improvement plan that was approved by the Board of Commissioners on July 19, 2023. This plan set into motion a number of priorities for projects related to water, wastewater collection system and wastewater treatment system.

For this fiscal year, the 10-year Water and Sewer Capital Improvement Plan shows replacing the terracotta sewer main and brick manhole replacement on John Borden Street at $247,185 and Devon Street phase I for $268,286.

Additional terracotta sewer replacements are scheduled for Ananias Dare Street, Budleigh Street, Sir Walter Raleigh Street, Agona Street, Fernando Street and Devon Street in phase II: Wingina (old) and Wano Lane. The 10-year plan is projected to cost $15,497,299.

Wastewater Treatment Plant capacity.

A limit or “capacity” is based on the design of the plant of 600,000 gallons per day per year, which is called a “quagmire” in the script.

When the average of 480,000 gallons per day or 80% of the permitted daily flow for a calendar year is reached, the town is required to consult an engineer and start the design process for a plant expansion to handle additional capacity.

At 90% capacity, or 540,000 gallons per day, the town would be required to begin the construction of expanded treatment facility.

Development Coordination

Development permit approvals are now coordinated with the Planning and the Water and Sewer departments.

States the Dickerson script, “early in my career with the Town of Manteo, Director O’Brien noted for me concerns that he had regarding development approvals and we have continuously worked to make process improvements along the way. One of those process improvements is that when we receive a building permit application, I request that the water and sewer department conduct an ‘existing conditions’ survey. This means that staff go to the site and look at the water and sewer connections that would have been stubbed out when the subdivision was built to ensure that the connection is up to the Town’s standards as required by the Town’s ordinance and other applicable laws. If there is no connection and a connection needs to be made, that work is done under the supervision of Town staff so that we know the connection meets those standards.”

The explanation continues, “When staff receive notice of new connection or uses, we notify and coordinate with Director O’Brien to make sure that new development is within design standards.

“As such, we contacted Director O’Brien once we heard there was an interest to add ‘craft brewery’ to the Town’s zoning ordinance as a special use. Director O’Brien shared that the plant was not designed to treat high levels of industrial waste. One risk is that the wastewater goes directly through the headworks into the ‘brown tank’ where the bugs live and work. The most frequently used parameter to determine pollutant strength in wastewater treatment is BOD. BOD is biochemical oxygen demand. Higher levels of BOD are one of the many risk factors (like temperature noted before) that can impact the health of the bugs in the brown tank.”

The report continued: “Wastewater Treatment comes with a diverse set of challenges. Currently, the majority of the wastewater that we treat is residential, commercial or institutional. Proposed uses with potential high levels of pollutants need to be scrutinized. We take pride in the work we do by being proactive in maintaining and operating the collection system and plant. We make every effort to keep violations at bay and to be responsible in managing publicly owned infrastructure.”

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