After protests from environmental groups, Maryland has withdrawn plans to issue a permit that would have allowed increased nutrient discharges from a wastewater treatment plant expanding in the Patuxent watershed.

Last fall, the Maryland Department of the Environment proposed a draft permit for the Little Patuxent Water Reclamation Plant that eventually could have allowed nitrogen discharges to grow by 175,000 pounds a year, and phosphorus releases by 25,000 pounds.

Now, the MDE is planning to write a new permit, which will allow the Howard County plant to expand. But in doing so, it will have to keep nutrient discharges at 2000 levels.

Welcome to the new world of the nutrient cap.

In 1992, the Bay states agreed to meet specific nutrient reductions for each major tributary, and then maintain that reduced level despite growth. That allocation has since become known as the nutrient cap. Both Maryland and Virginia recently wrote strategies to maintain their caps.

But issues with the Little Patuxent — a plant that not only has a track record of being well-run, but was also one of the first in region to implement special nutrient control technology — illustrate the complexity of maintaining caps.

“This is just the beginning,” said Tom Simpson, a professor with the University of Maryland’s College of Agriculture and Natural Resources, who co-chaired the workgroup that wrote the state cap strategy. “The Little Patuxent plant just happened to be in the wrong place at the wrong time. They were the first one to get challenged when this issue arrived.”

Indeed, the issue is sure to hit others. Last fall, former EPA Region III Administrator Bradley Campbell, citing concerns with the Little Patuxent plant, wrote a letter to all Bay states urging them to “hold the line” on nutrients. “It is surely an issue that all of you will need to confront often from now on,” he wrote.

The Little Patuxent case started in late 1999 when Howard County applied for a permit that would allow the plant to expand from a flow capacity of 18 million gallons a day to 25 mgd.

A major reason for the expansion was that the county diverted 3 million gallons a day from a treatment plant on the neighboring Patapsco River, which was removing only half as much nitrogen from effluent as the Little Patuxent plant. That switch was good for the Patapsco and the Bay, but a nutrient increase for the Patuxent River.

“If we took that 3 million gallons a day and put it back in the Patapsco, we would be introducing twice as much nitrogen into the Bay,” said Robert Beringer, chief of the Howard County Bureau of Utilities. “Now that 3 million gallons a day is being used against us, in our pound loading. How can that be anywhere near common sense?

“By doing the right thing, we put ourselves in the wrong place at the wrong time.”

The plant also serves a designated growth area. If it doesn’t expand, officials said, it could push development into other areas where homes would use septic systems — something that would generate more nutrients than the waste treated at the Little Patuxent plant.

“The last thing we want to do is, just because of the timing, clamp down on the Little Patuxent and send flow somewhere else,” said Robert Summers, director of the MDE’s Technical and Regulatory Services Administration. “In the bigger picture, we don’t want to encourage sprawl by making it too restrictive to develop in the growth areas.”

Because the Little Patuxent had already been upgraded with biological nutrient removal (BNR) technology, it seemed — at least to some — the logical place to send effluent.

Still, more effluent would mean more nutrient discharges, unless the plant found a way to achieve a greater level of reduction. The draft permit did not require that.

When the draft permit was issued last fall, the Chesapeake Bay Foundation and the state Sierra Club cried foul. Not only was the state committed to capping nutrient loads from all of its tributaries, they noted that the Patuxent River is listed as “impaired” because of nutrient pollution. As a result, it needs a cleanup plan known as a Total Maximum Daily Load.

Some interpret federal rules as not allowing increased discharges into an impaired waterway until a TMDL is developed. The Patuxent does not have a TMDL yet.

“CBF and its members intend to require Maryland to fulfill its obligations to clean up polluted waters by taking all the necessary steps to reduce excess nutrients until the water is no longer polluted,” the organization said in a letter to the MDE challenging the permit.

Faced with a potential legal challenge, the department didn’t issue the permit.

In the meantime, the state in March completed its cap strategy. The strategy said that as treatment plants expand, nutrient increases must be offset.

In the short term, the strategy set a statewide cap of 16.12 million pounds of nitrogen per year for wastewater treatment plant discharges. That’s based on an assumption that the largest 66 treatment plants upgrade to BNR technology and reduce nitrogen concentrations in effluent to 8 milligrams per liter of water. (Without BNR, effluent typically has more than twice that much nitrogen.)

Based on that, the strategy allocates a nitrogen load to each treatment plant, based on its 2000 flow. The goal is to maintain that level even as discharges increase with new growth.

For the Little Patuxent, the cap was 426,908 pounds, and is expected to be reflected in the new permit. But its estimated 2000 discharge was only 389,362 pounds because the plant was performing better than the 8 mg/l goal. That allows for some expansion.

But, as flows at Little Patuxent — and at other plants — continue to increase, they will have to improve the level of treatment to maintain the cap. “More effective BNR processes would have to be installed to achieve the lower concentrations needed to maintain the cap,” the cap strategy states.

Beringer said the MDE solution is “feasible,” although he found it ironic that the Little Patuxent was already doing better than the 8 mg/l goal — and being asked to do more — when other plants had not even reached the goal. “But in Howard County, we want to do our fair share,” he said, “even if it is more than what everyone else is doing.”

Beringer said he was concerned that any new permit have flexibility because seeking further nitrogen reductions would require treatment changes that would take time to perfect. “As you go into a new process, you have a lot of unknowns, so you want to be conservative in your estimates,” he said.

David Anderson, an attorney with the Bay Foundation, said the organization had “productive talks” with the MDE. “The CBF is encouraged that the state has heard our concerns and they may be willing to ensure that there is no increase in pollution to the Little Patuxent or the Bay,” he said.

While gradual improvements in technology will work for a while, the day may come where nutrient offsets will be needed from outside sources to make up for growth at treatment plants, Simpson said. Exactly how that will happen remains to be seen.

“We know there are some places that we would like to have growth because we have the overall infrastructure to support it, and that makes sense,” Simpson said. “What we don’t want is to get a point source strategy that encourages sprawl.”

“So we know it is not appropriate to say that no treatment plant can increase. What we haven’t figured out is the second part: How are we going to make up for those that are allowed to increase? These are really difficult issues.”