Elmhaven Wastewater Operator: Nutrient Removal on the Night Shift

A typical shift. Rosa starts her shift by reading the plant's control screens. She checks the dissolved oxygen level in the aeration basins, because the tiny organisms that clean the water need oxygen to live. If the oxygen is low, she turns up the blowers. Next she takes a sample of the activated sludge, the brown mix of water and microbes, and looks at it under a microscope. Healthy sludge forms clumps called floc that settle well. She runs lab tests for BOD and TSS, two measures of how much waste is left in the water. She also tracks nitrogen and phosphorus, the two nutrients the plant is built to remove.

Why nutrients matter both ways. In the river, extra nitrogen and phosphorus cause heavy algae growth. When the algae die and rot, they pull oxygen out of the water, and fish can die. That is why nutrients count as a pollutant here. Yet the same nutrients are valuable on farmland. Much of the removed nitrogen leaves the plant as harmless nitrogen gas, but the phosphorus and some nitrogen can be captured in biosolids, and some plants recover a mineral called struvite, which can be used as fertilizer. So Rosa's plant treats nitrogen and phosphorus as waste in the water and as a resource once they are recovered.

Meeting the standard. Rosa's plant must keep its monthly-average effluent BOD and TSS at 30 mg/L or less before the water is released. Raw sewage coming in typically runs about 100 to 300 mg/L of BOD, so the plant removes most of the load. When a reading drifts too high, Rosa adjusts the aeration or the rate at which sludge is returned to the basins, and she logs every change.

Getting licensed. Most operators start with a high school diploma and then train on the job under a licensed operator. Every state requires passing a licensing exam. In many states, licenses run in classes such as I through IV, tied to the size and complexity of the plant. A small plant may be run by a Class I or II operator, while a large plant needs Class III or IV licensing, which takes more experience and a harder exam.

Pay and outlook. Water and wastewater treatment plant operators earned a median of $60,020 per year as of May 2025. The lower-paid tenth earned less than $39,110, and the top tenth earned over $91,060, depending on experience, license class, and location. The Bureau of Labor Statistics projects about 10,000 openings for operators each year from 2025 to 2035, and it describes operators specifically, not the whole water sector. Nearly all of those openings come from replacing workers who retire or change careers. Roughly one-third of the current water workforce becomes retirement-eligible within the next decade, and in 2016 only about 10 percent of water workers were 24 or younger, compared with 12.5 percent of all U.S. workers. On-the-job licensure is one path into water work. Others include certificate programs, four-year engineering degrees, and graduate study, and all of them are valued in the field.

Discussion questions

1. Name two specific tasks Rosa does during her shift, based on the profile.
2. Explain, in your own words, why nitrogen and phosphorus are called both a pollutant and a resource.
3. What does the profile say a plant must do before water can be released to the river, and how does Rosa fix a reading that drifts too high?
4. A trainee is deciding whether a licensing course is worth the time and cost. Using the pay figures in the profile, explain how the added pay a license makes possible compares with the cost of earning it.
5. Why does the profile say the field has steady openings even when the industry is not adding many brand-new jobs?