Darnell Ingram, general counsel for the Baltimore Department of Public Works, testifies before the Board of Estimates Wednesday about a consent order between the city and state for the Back River Wastewater Treatment Plant. (Christine Condon)

Baltimore’s spending board unanimously approved an agreement Wednesday with the state over the city’s troubled Back River Wastewater Treatment Plant — the state’s largest such facility.

Under the consent order agreement, which was announced earlier this month, the city pledged to repay the Maryland Environmental Service for its emergency repair work at the facility and drop its legal challenge against the state’s takeover of the plant.

The agreement spells out the role of MES at the plant going forward, including that the agency won’t leave the plant until the state issues a new order, until both parties agree it’s time or until the plant complies with its pollution limits for a three-month period.

Baltimore City agreed to “cooperate fully” with MES and reimburse the agency for its costs moving forward, though it can contest major improvements costing $2.25 million or more under certain conditions.

”This order is moving in the right direction … to ensure that the Back River Wastewater Treatment Plant is in compliance,” said Darnell Ingram, general counsel for the city’s Department of Public Works.

Public Works Director Jason Mitchell said the consent order clarifies the roles of both parties. Mitchell is a voting member of the city’s spending board, alongside Mayor Brandon Scott, City Council President Nick Mosby, Comptroller Bill Henry and City Solicitor James Shea. Mitchell said his department is “working diligently” to improve the plant, citing improving metrics from the plant’s discharge into Back River.

A state report from June 10 noted “some progress” toward the plant’s compliance, despite continuing infrastructure problems. Data from April and May indicated the average concentration of suspended solids flowing into the river was down to 9 milligrams per liter, from 21 milligrams per liter in January.

Problems have continued, meanwhile, at the city’s second wastewater treatment plant along the Patapsco River. In that plant, too, biosolids have overwhelmed the sewage treatment process, forcing workers to relocate sludge to a separate facility. Mitchell said Wednesday that the city is putting an “alternative plan” in place this week to relocate even more sludge in the hope that the treatment process will flow more smoothly.

Environmental groups such as Blue Water Baltimore, whose water quality monitoring on the Patapsco spurred state environmental regulators into action last summer, have repeatedly called for third-party oversight at the Patapsco plant, as well.

In a statement earlier this month, the Maryland Department of the Environment said it was pursuing “similar agreements” for the Patapsco plant, due to “continued noncompliance.” That plant already has exceeded its yearly limits for discharging nutrients such as phosphorous, which clog bay ecosystems with algae that robs estuarine life of oxygen.

Both Blue Water Baltimore and the state have open lawsuits against the city as a result of the pollution flowing from the two plants, which could result in additional requirements or financial penalties for the city.

Blue Water Baltimore has requested an injunction from the court to order certain immediate improvements at both of the city’s plants and more visible public notification about bacteria releases from the facilities. A response from the city is due next week, and a hearing before a judge is set for July 20.

All the while, officials like Baltimore County Executive Johnny Olszewski Jr. have raised questions about whether the city’s plants should be run under a more collaborative governance structure. The county contributes funds to the city to treat its waste but doesn’t have any say in how the plants are run, in accordance with a decades-old agreement, which Olszewski called “significantly outdated” in a recent interview.

”This is a city asset, and we respect that,” Olszewski said. “We’re not looking for ownership, but we are looking for a seat at the table.”

When asked about the possibility of such an arrangement Wednesday, Mitchell declined to comment.

”I’m not aware of that,” he said, “so I can’t comment on that.”

MES first arrived at the Back River plant in early April, bringing about a dozen staffers to work alongside city workers. This followed an unprecedented order from Maryland Environment Secretary Ben Grumbles, which called for state intervention, arguing the plant was on the brink of “catastrophic failure.”

The city challenged Grumbles’ order in court, arguing that the secretary’s two-day time frame for the city to get the plant into compliance was inadequate and the state knew as much, given that city and state officials had been discussing the facility’s problems for months.

But Grumbles’ order came after what he deemed a uniquely troubling inspection of the plant, which found extensive infrastructure problems — including nonfunctioning equipment, clogged filters and weeds growing out of sewage treatment tanks — all leading to excessive releases of nutrients and bacteria into Dundalk’s Back River.

The river was deemed unsafe for human contact in April after sampling indicated that bacteria levels were elevated beyond the state threshold. Signage was placed at Cox’s Point Park warning visitors to wash with soap and water if they came into contact with the river. That signage has since been removed, said Erica Palmisano, a spokeswoman for Olszewski, because the county determined that bacteria levels had improved.

The county is working to post informational signs at Cox’s Point and other locations warning swimmers against entering the water with open wounds and urging them to wash after contacting the water, in addition to warning of elevated bacteria levels following rainstorms, she said in an email.

In an email, Mark Shaffer, spokesman for the Maryland Department of the Environment, said the state’s advisory remains in effect.

Grumbles ordered MES to complete a report about the Back River facility, which was released in early June, just before the settlement between the city and state was announced.

That report chronicled the plant’s issues in greater detail, shedding light on various personnel issues, including a “lack of leadership” and defensive attitudes among top officials. The report said the facility was dramatically understaffed and workers received inadequate training, all while forced to deal with frequent sewage spills, animal infestations and other serious hazards.

”This staffing issue is a national issue, as you know, and Baltimore City is not immune,” Mitchell said. “We’re doing everything we can in partnership with MES and other folks to get staff on permanently or temporarily so that we can ensure compliance.”