Nutrient Removal at Kettleford: A Wastewater Operator Career Profile

A typical shift. At the fictional Kettleford facility, the operator starts by reviewing overnight readings on the plant's SCADA system, the computer network that tracks flows, tank levels, and equipment across the facility. Next comes a walk through the plant. The operator checks the aeration basins, where billions of microorganisms feed on the waste in the water. A small sample of that mixture goes under a microscope, because the health of those microorganisms tells the operator how well the process is working. Bench tests then measure ammonia, nitrate, and phosphorus in the water. Based on those numbers, the operator adjusts how much air and chemical the process receives so the plant stays inside its discharge permit.

Nitrogen and phosphorus: resource and pollutant. Nitrogen and phosphorus are nutrients that plants need to grow. In a river, too much of either one feeds heavy algae growth. When the algae die and break down, they pull dissolved oxygen out of the water, and most fish need dissolved oxygen above 5 milligrams per liter to stay healthy. The operator's job is to remove most of the nitrogen and phosphorus before the water leaves the plant. Secondary treatment standards require the monthly average of oxygen-demanding waste and suspended solids in the discharge to stay at 30 milligrams per liter or lower. The same nutrients that are a problem in the river are a resource on a farm, which is why some plants recover them for fertilizer.

Getting licensed. The path usually starts with a high school diploma, followed by on-the-job training as an operator-in-training. Every state requires passing a certification exam, and each state sets its own license levels. Texas, for example, uses Class D through Class A. Kettleford's fictional state numbers its wastewater licenses Class I through Class IV. A Class I license covers a small, simple plant. A Class IV license is required for the largest, most complex systems and takes more experience and a harder exam to earn. Many operators move up the classes over a full career.

Pay and outlook. Water and wastewater treatment plant operators earned a median of $60,020 per year as of May 2025. The lowest-paid 10 percent earned less than $39,110 and the highest-paid 10 percent earned more than $91,060, depending on experience, license class, and location. The Bureau of Labor Statistics projects about 10,000 openings for operators each year, on average, from 2025 to 2035, and that figure describes operators specifically, not the whole sector. The country employed about 131,000 operators in 2025. Total employment is projected to decline slightly, so the openings come from replacing workers who retire or change occupations, and EPA estimates that roughly one-third of the water workforce is eligible to retire within 10 years.

Discussion questions:

1. Name two specific tasks the Kettleford operator performs during a shift, based on the Career Profile.
2. In Kettleford's fictional state, explain the difference between a Class I wastewater license and a Class IV wastewater license.
3. The profile says nitrogen and phosphorus are both a resource and a pollutant. Explain that idea using details from the Kettleford plant.
4. Suppose a state requires a wastewater operator to pass a $300 certification exam and finish a $1,500 training course before reaching the median pay of $60,020 per year. Explain why that upfront cost is small compared with the career's pay over time.