Posted on 04 Jun 2013 by Neilson
Over 10 billion gallons of raw and partly treated sewage gushed into waterways and bubbled up onto streets and into homes as a result of Hurricane Sandy - enough to cover Central Park in a 41-foot-high pile of sludge, a nonprofit research group said in a report released on Tuesday.
The group, Climate Central, said about 94 percent of the sewage flowed into rivers, canals and bays in New York and New Jersey, the states hit hardest by the storm that came ashore six months ago. In New York City alone, 1.6 billion gallons spilled into area waterways.
Alyson Kenward, the principal author of the report, said in a teleconference that rising seas and strengthening storms, a result of climate change, could increase the threat of similar spills in the future. She urged an overhaul of the region's wastewater infrastructure.
"Our sewage infrastructure isn't designed to handle this type of storm surge," Dr. Kenward said.
Hurricane Sandy exposed serious shortcomings in the region's infrastructure. Dunes were breached, and subway lines and tunnels were flooded. After the storm, gasoline was often difficult to find, and electricity in some places was out for weeks.
The region's wastewater treatment facilities, almost all of which are in low-lying areas near bodies of water, proved to be particularly vulnerable.
To remain operational, treatment facilities must continuously cycle water, bringing in untreated waste and expelling cleaned water into rivers and canals. Hurricane Sandy's storm surge swamped motors and shorted out electrical equipment in some plants, halting the flow and forcing sewage to back up and leak. Other facilities were simply overwhelmed by the volume of water coming through the system.
The Climate Central report, which is accompanied by an interactive map, found that about one-third of the overflow - nearly 3.45 billion gallons - was untreated sewage. The rest was partly treated, meaning it was filtered to some extent and was perhaps chlorinated.
The group collected data provided by government agencies and plant operators from eight states affected by Hurricane Sandy, as well as from the District of Columbia.
In New York, the Bay Park Sewage Treatment Plant on Long Island was probably the hardest hit, according to the report. As much as 2.2 billion gallons of partly treated sewage poured into the Rockaway Channel until the plant was fully brought online nearly two months after the late-October storm, the report said. Over a billion gallons of untreated sewage flowed into the Hudson River from the Yonkers Joint Wastewater Treatment plant, in Westchester County.
Michael Martino, a spokesman for the Nassau County Department of Public Works, said the Bay Park plant began processing and partially treating sewage within 40 hours after it shut down and was fully compliant with regulations by mid-December. On average, Mr. Martino said, the plant processes 52 million gallons a day.
Permanent repairs to the plant are expected to cost $600 million, including the cost of raising pumps and motors and other measures to protect against future storms, he said. Officials plan to spend another $400 million to $800 million to improve defenses for wastewater facilities countywide.
In the majority of cases, the report said, storm surge was responsible for the damage. But in Washington, it was heavy rainfall that overwhelmed one treatment plant, causing 475 million gallons of contaminated runoff and untreated sewage to flow into the Anacostia River.
The damage has run into the billions of dollars. In New York, Gov.Andrew M. Cuomoinitially estimated that about $1.1 billion would be needed to repair treatment plants.
The environmental impact has been more difficult to evaluate. Currents and tides most likely flushed out much of the sewage in local waterways, experts say, though some regions imposed bans on shellfish and issued boil-water alerts in the immediate aftermath of the storm.
The report said that raising water pumps and electrical equipment and installing watertight doors and windows could bolster treatment facilities against storm surges and torrential downpours.
Any changes will be extremely expensive, and with sea levels rising and weather patterns changing, it is unclear what can be done to eliminate the dangers, Dr. Kenward said.
"These facilities do have to be close to the water," she said, "and they are inherently always going to be vulnerable to coastal flooding."