Septic tanks stink for bay



That's the word that came to mind this week, reading how federal and state environmental agencies are demanding Baltimore spend $900 million during the next decade to fix its creaky, leaky sewer system.

Not unfair to Baltimore, mind you, whose residents pay among the lowest sewer bills on the East Coast.

Without this long-overdue crackdown, the city would keep polluting the Chesapeake Bay with overflows of raw sewage. Besides, the city can spread the cleanup costs among more affluent metro counties that are hooked into the city's treatment plants.

What's unfair is this:

Maryland and its neighboring bay-watershed states of Pennsylvania and Virginia continue to let millions of citizens who are not connected to centralized sewage treatment plants act as if their stuff doesn't stink.

I'm talking about all the places, from mobile homes to McMansions (to my own house), that use septic tanks, a 50-year-old, grossly polluting technology that is little more than an out-of-sight version of the old outhouse.

A fifth of Maryland's 5.3 million citizens -- and about one third of the six-state bay watershed's 15 million people -- are on septic systems.

These are concrete tanks buried in the back yard, collecting wastewater from the home's plumbing. The solids settle to the bottom of the tank and are gradually liquefied by bacteria.

Liquid waste flows out the top part of the tank into an underground drain field, where the soil filters and detoxifies bacteria and viruses harmful to human health.

From the human health standpoint, septic systems are superior to the outhouse. But they are just as harmful, if not more so, to the health of the bay.

That's because the soil, while it removes bacteria, doesn't do much to remove the nitrogen from the septic tank. Excess nitrogen is the main culprit in the bay's losses of seagrass and oxygen.

An urban resident hooked to a state-of-the-art sewage treatment plant sends about 2 pounds of nitrogen into bay waterways a year.

A rural-suburban resident using a septic tank produces about 9 pounds a year.

Because not all sewage treatment is state of the art, and because fewer people use septic tanks, the tanks are about 6 percent of the bay's nitrogen problem -- vs. 20 percent for sewage plants.

This was one reason why Maryland's legislature refused two years ago to require proven technologies that can make septic tanks 60 percent to 90 percent less polluting.

They caved in to opposition from real estate agents, homebuilders, developers and farmers (the same farmers who whine we should crack down on development, not them).

But look at the trends. Sewage treatment plants are rapidly being forced to upgrade, and soon may be able to reduce nitrogen to less than 1 pound per person per year.

Septic tanks are proliferating and not getting one whit cleaner. In Anne Arundel County, about half of all new houses use septic tanks.

In another decade or two, septic tanks could be a bigger polluter than sewage treatment. Now is the time to do something about it, because retrofitting existing tanks is harder than doing the right thing whenever a house is built.

The other knock on less polluting septic tanks is cost -- $5,000 to $7,000 extra, nearly double that of traditional systems.

But in Texas and Louisiana, states where hundreds of thousands of less polluting systems are installed, those costs quickly came down to about $1,000 extra.

There are also real questions of equity here. We pay, on average, $28,000 per person for modern sewage treatment plants, including the costs of hooking homes into the system.

Expensive? Well, cleaner water and a healthy environment cost money. Why should those who CHOOSE to live outside sewered areas get off cheap, at the expense of the bay?

It's also unfair competition for Smart Growth programs, which try to save the state's remaining open space by steering growth into sewered areas that are planned for development.

Requiring less than the cleanest septic systems while forcing cities to spend on sewage treatment is an unfair subsidy to sprawl.

In the Maryland legislative session, House Bill 8 and Senate Bill 77 would take a small but important step toward upgrading septic tanks. The bills have the backing of legislative leaders.

They would provide a state income tax credit up to about $5,000 per person, and up to a total of $1.5 million in tax credits annually, for people who voluntarily replace septic tanks with less polluting ones.

What we really need is to require that all new houses not hooked to sewers have cleaner septic tanks or alternatives such as composting toilets -- ditto for septic tanks in need of replacing.

To restore the bay, nitrogen must be reduced two or three times as much in the next decade as in the past couple of decades -- by as much as 150 million pounds a year.

Doing that will take the best technology from a variety of pollution sources -- agriculture, sewage plants, automobiles, power plants.

It's unconscionable to keep building modern houses, costing hundreds of thousands of dollars, that pollution-wise are barely removed from the days of the outhouse.

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