Despite occasional claims to the contrary, the local governments that own or oversee wastewater plants in the Washington metropolitan region are doing a great deal to help clean up the Bay.

These plants, which account for roughly one-third of all of the wastewater treated in the Bay watershed as a whole, have spent or are spending more than $100 million in local dollars on an initial round of nitrogen removal technology. (In almost all cases, these capital expenditures have been matched on a 50-50 cost-share basis with state and federal agencies, but the tens of millions of dollars in annual operating costs generated by running these extra treatment processes are borne entirely at the local level.)

The effort is now beginning to bear fruit in the form of lower nitrogen discharges to the Potomac River and other Bay tributaries.

Both nitrogen and another common element, phosphorus, are essential nutrients in aquatic ecosystems, but their overabundance in the Bay has contributed to many of the problems we’re now trying to fix.

Reducing the amount of these nutrients that wash off farms and urban landscapes and are discharged in wastewater effluent has been the major focus of the Bay restoration effort.

By the year 2000, the Blue Plains Wastewater Treatment Plant in the District of Columbia, the nation’s largest wastewater facility, had voluntarily reduced its annual discharge of nitrogen 38 percent from the levels it released in 1985, which is the Chesapeake Bay Program’s baseline year for measuring progress.

The equivalent reduction number for all of the major plants in the region, taken as a whole, is somewhat less — 21 percent — a reflection of the fact that a number of the plants are still installing the necessary equipment and operating systems.

By 2003, though, when all of these upgrades are completed, the region’s treatment plants will have achieved a 55 percent reduction from the 1985 baseline.

The achievements of area wastewater plants are even more impressive when you take into account the region’s rising population. The total volume of wastewater treated at area facilities rose 10 percent from 1985 to 2000. It will continue to increase propo‘tionally to population growth in the region, which the Metropolitan Council of Governments forecasts will rise 33 percent in the next 25 years.

Continued improvements in wastewater treatment performance are necessary just to maintain current levels of progress, let alone to reach the more ambitious nutrient reduction goals now being formulated by the Bay Program.

The fact is that every source of nutrients in the watershed, from treatment plants to factories, from farmers to homeowners who fertilize their lawns, will have to do more. Determining how to equitably share that burden will be the major challenge of the next few years.

As plans are made for further nutrient reductions, it is crucial to recognize the significant progress that local governments in the Washington region have already made.

We will continue our efforts to reduce nutrients flowing to the Chesapeake Bay and look forward to doing our fair share to ensure the success of the ongoing restoration efforts of this invaluable resource.