Managers for big sewage treatment plants that spew tons of nitrogen into the ocean have a nifty saying that has been dredged up regularly in the arguments to divert our sewage to one of the county plants, Cedar Creek. The mantra is, "The solution to pollution is dilution." In other words, the vastness of ocean waters is so great that we can dump whatever we like with abandon and there will be no consequences.

This assumption is being challenged by a study reported in the May 16 issue of Science, done by an international team led by Peter Liss of the University of Anglia in England and Texas A&M University entitled "Impacts of Atmospheric Anthropogenic Nitrogen on the Open Ocean." Anthropogenic means "caused by humans." The study delves into the complicated relationship that nitrogen plays in the global carbon cycle. While on the one hand, nitrogen fuels the growth of microscopic plants that absorb carbon dioxide, the primary gas that is blamed for global warming, the study points out unintended consequences. Researcher Peter Liss says, "The bad news is that two-thirds (of the carbon absorbed) is offset by another greenhouse gas, nitrous oxide." He cautions against added levels of nitrogen input into the oceans.

Against this global backdrop, Great Neck decision makers are struggling with a local issue of sewage treatment.

Engineering consultants for the Water Pollution Control District met with Nassau County engineers last week to take a closer look at their widely contradictory cost estimates for diversion. The county estimate for diversion is between $25 million to 30 million; Nautilus, the district's estimating firm, arrived at a much higher number, $65 million. According to a source who attended the meeting, Nautilus presented a detailed cost estimate enumerating current prices for the considerable piping and roadwork that would be needed. For example, they anticipated future growth and figured on using 30-inch force mains for the project. The county estimators figured on a less expensive 24-inch force mains.

County estimators used a parametric system of estimating that takes into account a database of average costs over the last 15 months to arrive at their calculations.

None of the estimates take into consideration what the legal fees would be if communities along the path of diversion construction attempted to block the project that would create traffic disruptions, an inconvenience with no benefits to them.

A diversion project would mean laying pipes on East Shore Road, up Northern Boulevard, turning right on Shelter Rock Road, a left turn on the south service road of the LIE and continuing to the intersection of Glen Cove Road where it would meet up with existing piping to Cedar Creek. The estimated time of completing such a project is 18 months.

The engineers will be meeting again this week on May 29 to continue honing the numbers. These meetings are not open to the press.

With the renewed emergence of the diversion option, the discussions and details of combining the two plants have been muted.

The future governance of a combined plant has been raised as an issue. An idea that is under consideration is the formation of a sewer and stormwater authority, similar in structure to the Water Authority of Great Neck North. Currently, sewage treatment is billed as a tax. It is deductible for federal tax filing purposes. If an authority were established, the cost for sewage treatment would be billed as a usage fee. Tax-exempt institutions would pay their share.

How would usage be determined? It would be based on the inflow of water to a home. Both Manhasset-Lakeville Water District and WAGNN measure the amount of water coming into your home; that same amount of water flows out of your home with the exception of sprinkler systems, some of which is absorbed into the ground and some of which runs off.

Currently, a family of two pays the same rate for wastewater treatment as a family of five even though the volume would be considerably greater for the larger family.

Stormwater management is a serious issue that needs attention as well. Some policy makers believe that an authority that would address both sewage treatment and stormwater management might increase the effectiveness of both.

The creation of an authority requires an act of the New York State legislature.

(Editor's note: For background information on this issue, go to the May 6 and May 22 issues in the archives of the Great Neck Record at www.antonnews.com.)