One man’s poison is another man’s meat

August 27, 2012

Click for source and interactive data map

That goes for natural habitats too.  With less rain falling in the middle of the country during the current drought, there’s less polluted runoff to the Mississippi.  That means that the river’s discharge to the Gulf of Mexico is a lot cleaner than usual.

An analysis of the Gulf from Aug. 15-21 covered more than 1,200 miles of cruise track, from Texas to Louisiana. The team found no hypoxia off the Texas coast while only finding hypoxia near the Mississippi River delta on the Louisiana coast.

Hypoxia is a condition in which the ocean waters have very low levels of dissolved oxygen present, which means that living things can’t survive there.  Fish do breathe, but through their gills.

“We had to really hunt to find any hypoxia at all and Texas had none,” says Steve DiMarco, associate professor of oceanography at Texas A&M University. “The most severe hypoxia levels were found near Terrabonne Bay and Barataria Bay off the coast of southeast Louisiana.

Basically, the dissolved fertilizer from agriculture stimulates high levels of algae growth in the waters.  When they die, they sink and decay, which uses up the oxygen in the water.  Then everything dies.  As long as the amount of chemical nutrients coming into the system is in balance with the dynamics of the waterbody, the oxygen level fluctuates within bounds that local life can tolerate.  Pollution by industry, agriculture, or local sewer systems can upset that balance.

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Where it all goes

January 13, 2010

Sometimes, when people find out about my professional work with sewage systems, they ask, “Oh, yeah, where does everything go when it goes down the drain? If you live in New York City, there’s a good chance it all goes here:

to the Newtown Creek water pollution control plant run by the NYC Department of Environmental Protection.  This is one of the largest wastewater treatment plants in the world, and I was there for a meeting this morning.  Afterwards, I took a stroll around the perimeter to get a view of the beautiful digesters, shown at the head of this post, that turn the residue of the treatment process into methane gas and inert sludge.  The shape of the tanks is quite innovative, and the DEP is very proud of them.  [In the aerial view, the digesters are on the right, under construction.]  At night, they are illuminated in their waterfront setting with blue searchlights.  These treatment plants are like ‘negative’ farms:  they use natural processes, aided by technology, to break down, rather than grow up, organic matter.

The public investment in facilities like these is enormous, and largely unremarked.  This plant is being enlarged and upgraded to the tune of about one billion dollars.  Lot’s of money is spent on sewage and drinking water, although not always wisely.

In the USA, the Clean Water Act of the 1960s was the impetus for a vast program of construction all across the nation to clean up urban waterways.  When I first came to NYC in college, it was not quite finished:  the entire west side of Manhattan dumped its raw sewage into the Hudson River, and on a  warm summer night, it stank!  A new treatment plant went on line there in the 1980s, and now all of NYC wastewater is treated, except when it’s raining (but that’s a story for another post.)

Consider this:  The waters around the city, in the Hudson and the East River, are easily cleaner than they have been in 100 years, despite the greatly increased population in the surrounding region.  In those bygone days of yore, when handsome lads would cool off in the summer with a dive off the East River docks, more likely than not they were dunking themselves in a pretty filthy brew.  Now it’s clean, although some people have a hard time believing it.

I came across this rather forlorn remnant of local national pride during my walk around the plant.