What’s the Status of Point Source Nitrogen Reduction

 in the Chesapeake Bay Watershed?

January 2004

What reductions have been achieved?

As of 2001, point sources represent 21% of the total nitrogen load (or 59 million pounds per year)

delivered to the Chesapeake Bay from all sources in the 64,000 square mile Chesapeake Bay

watershed. There are 368 point source municipal and industrial wastewater treatment facilities

that contribute significant amounts of nutrients to the Chesapeake Bay (58 are industrial and 310

are municipal). Since 1985, these point sources achieved a 32% reduction (26 million pounds per

year) in total nitrogen being delivered to the Bay. 

How were these reductions achieved?

These reductions were accomplished by the voluntary implementation of nutrient reduction

technology (NRT) and/or pollution prevention measures at approximately one third of the 368

facilities. Industrial reductions have been primarily due to pollution prevention although some

end-of-pipe technology has been employed. For municipal facilities, which contribute the bulk of

the point source nitrogen load, the percentage of flow currently operating under NRT from all

facilities is approximately 55%. Several of the Bay jurisdictions have instituted a variety of

innovative incentive-based programs to implement NRT at municipal wastewater treatment plants

generally via 50% state cost share grants. To date, Maryland has spent approximately $190

million, and VA approximately $99 million in capital cost share funding for NRT design,

construction and installation. PA has allocated funds both under their Growing Greener initiative

for NRT upgrades as well as by providing creative opportunities through their SRFs and Sewage

Act Planning Program. A handful of these facilities were required to implement NRT or have

nitrogen limits under a state NPDES permit. However, facilities were accountable for the

performance of the technology generally through cost share contractual agreements. For the few

facilities that do have nitrogen limits in their permits, this is primarily a result of the recent

institutions of local TMDLs for many Bay sub-basins.

How much does it cost?

NRT technology is advancing at an exponential rate: Less than 10 years ago reductions to 8 mg/l

were state-of-the-art for this region and it cost about $35/lb of nitrogen removed. Now, reductions

down to 3 mg/l are entirely feasible, and the costs are less than $10/lb for facilities that have no

NRT in place, and an average of $4/lb for the many facilities that have some form of nutrient

removal operating now. In 2002, the Chesapeake Bay Program assembled a broad stakeholder task

force including academia, state agencies, and municipal experts to estimate the cost of

implementing NRT to 3 mg/l for all 368 point sources in the watershed. They estimated that $4.7

billion in capital expenditures would be required for all facilities to go beyond their current

operating conditions, or plans, to get to discharge levels of 3 mg/l TN ($4.5 of this would be to

upgrade the 310 municipal facilities). However, this was a conservative estimate. A recent

engineering study of Maryland=s 66 major municipal facilities, concluded that the cost of

implementing NRT to 3 mg/l would be 32% less than the previous Chesapeake Bay Program study. 

Additionally, a recent study by Virginia=s Hampton Roads Sanitation District developed revised
costs for NRT to 3 mg/l for their 8 facilities which resulted in estimates that were 23% less than the

Bay Program estimated for those same plants. 

What contributions can point sources make toward 

restoring the Chesapeake Bay?

In March 2003, the Bay Program adopted new nutrient reduction goals, calling for Bay watershed

jurisdictions to reduce the amount of nitrogen entering the Bay from the current 285 million

pounds to no m ore than 175 million pounds per year (or a 110 million pound per year reduction). 

Estimates have been made of the potential for point source reduction at various levels of treatment. 

Results of this analysis were that point sources could conceivably contribute either 13, 26, or 37%

of the total reductions needed for the Bay if all facilities reduced their discharges to total nitrogen

concentrations of 8, 5, or 3 mg/l respectively by 2010. But rather than a one size fits all approach,

Bay jurisdictions will determine the required reduction levels on a facility-by-facility basis during

implementation of their respective tributary strategies and water quality standards. 

What is in store for the future?

Nutrient removal continues to advance for the Bay=s point sources. By 2010, current plans are that

the total flow from municipal facilities treated by NRT will rise from 55% to 81% which equates to

an additional reduction of 3.1 million pounds per year from 2001 levels. Industries, through

pollution prevention or end-of-pipe treatment are expected to also contribute an additional 500,000

pound reduction by 2010. Each of the Bay jurisdictions are in the process of developing tributary

strategies to achieve their respective nutrient allocations. These strategies will include a facility-byfacility assessment of what additional actions will be required for point sources. Virginia has

announced a Notice of Intent for Regulatory Action (NOIRA) to develop technology based limits

and all states are also in the process of developing their nutrient related water quality standards. 

These standards together with the tributary strategies will form the basis for decisions on NPDES

permitting requirements for point source facilities. It has been agreed that annual average limits

for nitrogen are appropriate as the Bay=s response is linked not to monthly discharges, but to long

term loads. Additionally, innovative approaches to permitting such as watershed-based permitting

and trading are being considered by the Bay partners. At the same time, technology regarding

both performance and affordability continues to advance. 

Table 1: Chesapeake Bay Point Source Profile 

Point

Source

Category

# Facilities

in Bay

Watershed

Cumulative M illions of Pounds Reduction from 2001 levels

of Total Nitrogen Delivered by 2010

(% reductions of total watershed load contribution)

Costs to go to 3

mg/l (billions of

dollars)**

As

Planned*

All to 8

mg/l

All to 5

mg/l

All to 3 mg/l

Municipal 310 2.6 12.9 26.9 36.8 $4.5

Industrial 58 0.5 1.0 1.7 3.8 $0.2

Total 368 3.1(3%) 13.9(13%) 28.6 (26%) 40.6(37%) $4.7

* For the municipal facilities to increase flow under NRT from 55% to 81%, and additional reductions known

as planned for industries.

** According to conservative Bay Program 2002 estimates although recent studies in MD and VA show that

these costs could be 23% - 32% lower. 

Contact: Allison Wiedeman, Technology Coordinator, (410) 267-5733