The tank of aerating bodily waste at the Oso Wastewater Treatment Plant in South Side Corpus Christi is strangely mesmerizing. The brown-and-tan fluid within the 181-foot-long, 25-foot-deep rectangular vat is in constant motion, its surface broken by large bubbles and foam that make the fecal brew resemble cappuccino.

The metal platforms surrounding the noxious agglomeration are free of anything that might catch a toe, but rescue ring buoys are mounted here—just in case. “This is the last place you’d want to trip and fall in,” says Sigifredo De Leon, Oso’s superintendent, as he leads me around the biggest treatment plant in a city whose wastewater-disposal shortcomings have raised the ire of the federal government for the past decade.

The EPA sued the city in 2012 for failing to properly maintain its sewers, following chronic sewage spills into Corpus Christi Bay. It took eight years for the EPA, state, and city to settle the suit in late 2020. The city must pay a $1.14 million fine and spend $725 million to improve its sewer system. Enforcement of that agreement started in January, and the work will begin at Oso.

“These upgrades were needed ten years ago,” says De Leon, a seventeen-year veteran of the city’s water department. “Other administrations just looked for ways to save money, to fix something that would work for a few years and then need to be replaced.”

Now, though, comprehensive upgrades to miles of sewer lines running under Corpus Christi, as well as improvements at Oso and five other treatment plants, are mandated by a federal court order. For the Corpus Christi Water Utilities Department, it’s a little like having a parole officer. The department must regularly file detailed reports on any sewage spills and progress reports on the slate of infrastructure improvements with state and federal regulators. The EPA will also periodically perform inspections.

With all of that, you might expect those who work with Corpus Christi’s wastewater to be feeling the pressure. But as I walk around Oso with De Leon and casually chat up workers on their smoke breaks, almost all of them tell me their jobs have improved since the EPA cracked the whip. Now, they say, what’s too long been broken can finally get fixed.

De Leon is standing on top of the thirty-foot-tall headworks at the Oso plant, the biological and chemical removal of waste from water laid out before him. Wearing a polo shirt with the top button fastened, he’s short, squat, and bespectacled. His shoulders are surprisingly broad, and his face is immaculately clean-shaven. He looks nothing like a roughneck, but he runs a grimy piece of city property.

The building below him, which houses a swirling mass of feces, is built tall to allow gravity to start the separation of solids from liquids. The plant’s ultimate job is to clean toilet and sewer water well enough that it can be safely released into Corpus Christi Bay. Yet the place where the cleaned water ends up sits on the opposite end of the plant from where it is finally released into the bay. That strange layout is likely the result of the plant’s having been expanded ad hoc over the decades. “We’re dealing with a Frankenstein of a system,” De Leon says. “The flow scheme here is not natural. But we can’t just erase what’s here and start over.” 

The Frankenstein’s monster of a plant includes a new headwaters and lift station, both of which were completed shortly before the EPA lawsuit was settled. Jiangang “Daniel” Deng, the city’s assistant director of wastewater treatment, insists their existence, and other investments made before 2020, prove that Corpus Christi has long been trying to clean its wastewater properly and keep its sewer systems working.

However, construction on the headwaters and lift station at the Oso plant wasn’t approved until after the EPA lawsuit was filed in 2012. That might suggest that those new facilities were giant bargaining chips on the road to settling the suit with terms more agreeable to the city. Corpus Christi officials predictably say that’s not the case, though they acknowledge that improvements made since 2012 may have helped their negotiating position.

Councilman Greg Smith points to the city’s progress on reducing the amount of raw sewage spilling from Corpus Christi’s wastewater system into the bay—something called a “Sanitary Sewer Overflow,” or “SSO” in utilities lingo—as one example. He says SSOs today are less than 10 percent of what they were in 2012, although the city doesn’t publish data that can corroborate that claim. Still, Smith insists that the reduction he’s seen in SSOs “was very helpful in getting a much lower cost plan from the EPA than was originally proposed.”

In 2019, the city offered to spend $655 million over fifteen years to fix its sewer problems, while the EPA sought $808 million and a ten-year timeline. The final compromise calls for $725 million spent over fifteen years. Some of the biggest projects should happen quickly; Corpus Christi officials have an $80 million capital improvement program in place for 2022—that’s close to 7 percent of the city’s $1.2 billion annual budget for the current fiscal year. Another $350 million is expected to be spent on the sewers over the next five years.  

Corpus Christi isn’t alone among Texas cities in contending with EPA orders. The agency also successfully sued Houston in 2018, resulting in a $4.4 million fine and $2 billion in promised spending on upgrades. That’s a bigger bill than Corpus Christi’s, but the necessary fixes in Corpus Christi are in some ways more challenging. Sewer systems often rely on gravity to push waste through their pipes—lift stations raise wastewater and then drop it down through sewer lines. In Houston, whose average elevation above sea level is about fifty feet, that process gets a natural, well, lift that it doesn’t in Corpus Christi, where the average elevation is just seven feet.

Corpus Christi relies on more than a hundred lift stations to pump waste through its sewer lines, and many of these are five decades old, making them prone to failures that can cause sewage spills. And those old lift stations are relatively new compared to other parts of Corpus Christi’s system. Some of the city’s underground sewer lines were laid ninety years ago, and the EPA found that 450 miles of the city’s sewage pipes were prone to crack or clog, which also contributes to raw sewage running underground during rainstorms and eventually ending up in the bay. The wastewater treatment plants have old bones too. (Oso, the largest, was built in 1941.) And the EPA found the city’s six facilities violated federal law numerous times by allowing enough rainwater into their systems to flush out excrement before it could be treated.

Corpus Christi residents and businesses will pay to fix all of those problems, largely in the form of wastewater fees that are set to increase annually through 2029.

The Oso plant sees a lot of action. More than half of the city’s population lives in South Side, and the plant discharges an average of 12 million gallons of water a day into the bay. On rainy days, it can discharge three times that much.

Oso has six bubbling tanks to do that work. Each propagates bacteria that feed on filth. At the bottom of the tanks, jets blow out oxygen, which gives the vats their hot tub–like appearance and encourages the growth of that bacteria, which arrived at the plant with the human waste, as well as small entourages of protozoa, rotifers, viruses, fungi, and algae.

This colony of microorganisms feasts on the waste from toilet water before it’s sluiced to what’s called a clarifier tank, where the remaining solids drift to the bottom. That sludge is dried and shipped to landfills. The still-tainted water, meanwhile, is given a chlorine bath that kills the bacteria, and is then subjected to another chemical bath of sodium bisulfite to neutralize the chlorine. The resultant water isn’t drinkable, but it’s clean enough to be released into Corpus Christi Bay. Two nearby country clubs also use the cleansed discharge, which is piped directly from the wastewater treatment plant to their golf course fairways.

Thanks to the court-ordered investments, one of the oldest tanks, along with other equipment, are scheduled to be replaced at a cost of $56 million. That work is expected to begin late this year and finish in 2025. Other improvements have already been made. For instance, De Leon tells me that his crews no longer have to head outside onto the roof when the system that separates raw sewage from debris such as toilet paper fails, a process that used to require a giant rake to be hand-cranked across water tanks. A more reliable mechanical rake has been installed.

The job website lists the average salary of a wastewater treatment operator in Texas at $24.28 an hour, plus around $6,700 a year in overtime. For the moment, that’s not enough to fill all the available jobs at Oso. The city has budgeted for 25 workers, but today the plant only employs 15. This short staffing is felt most keenly when crews need to be trained on new equipment, which takes personnel out of their rotations. That makes any new upgrade a scheduling headache.

The Oso staff’s jobs will become more hectic when upgrades resume later this year. Because the footprint of the city’s wastewater treatment plants has not expanded over the decades, new equipment typically gets built on top of older equipment, forming layers of ruins under these plants. The ground at Oso is undercut with both active and retired underground sewer pipes, making any construction more difficult.

Still, De Leon welcomes these disturbances. During his nearly twenty years in the department, he’s witnessed neglect while working at four of the city’s six wastewater treatment plants. He describes unwanted equipment unexpectedly showing up at facilities, ready to be installed without the managers even knowing it was coming. These days, city engineers call operators for advice before purchasing anything. “Things are better now,” he says.

Perhaps as proof, he insists on taking all visitors to the Oso plant to the outfall, where a steady gush of processed water is being released into the bay after treatment at the plant. There, De Leon points below him. “You can look through the water,” he says, sunlight glinting off his glasses. “You can see clear to the bottom. A lot of times there are turtles swimming in here.”