April 2009, Vol. 21, No.4


New Applicator May Reduce Runoff From Poultry Litter

With the help of colleges at the U.S. Agricultural Research Service (ARS) National Soil Dynamics Laboratory (Auburn, Ala.), engineer Thomas Way has developed a new field tool that reduces runoff from the land application of poultry litter.

The tool digs shallow trenches that are about 50 to 75 mm (2 to 3 in.) deep, places the poultry litter in the trenches, then covers it with soil. The applicator is designed to be attached to a tractor and can dig four trenches as it is pulled through a field, according to an ARS press release.

Burying the poultry litter “significantly reduces the risk of runoff,” the release says.

Collaborators in six states have used the applicator in their research. One study found that when litter was applied with the new applicator, phosphorus and nitrogen runoff was 80% to 95% lower than when litter was applied conventionally, according to the press release.

Way also collaborated with ARS scientists throughout the country to examine the applicator’s effectiveness with different crops, such as corn in Alabama, Kentucky, and Maryland; cotton fields in Mississippi and Georgia; and Bermuda grass and tall fescue stands in Alabama. Results show that the new tool has the potential to reduce water pollution when used to apply poultry litter on a variety of crops. ARS is pursuing a patent and seeking companies to manufacture and market the litter applicator.

U.S. EPA Reports on Cruise-Ship Wastes

The U.S. Environmental Protection Agency (EPA) released the Cruise Ship Discharge Assessment Report on Dec. 29. The report was created in response to a March 2000 petition by the environmental group Bluewater Network (San Francisco) for more information and regulatory action on cruise-ship pollution. It assesses five cruise-ship wastestreams: wastewater, graywater, oily bilge water, solid waste, and hazardous waste.

For each wastestream, the report identifies the volume and type of waste, laws applying to the waste, waste management, potential environmental impacts, the federal government’s actions to address the waste, and options and alternatives to address waste from cruise ships in the future.

With amenities on a par with those of luxury hotels, cruise ships have the potential to generate similar types and volumes of wastes, according to EPA.

On one ship, EPA measured a wastewater generation rate of 64 L (17 gal) per day per person. According to the report, most cruise ships’ wastewater undergoes biological treatment followed by disinfection, and some ships have installed advanced wastewater treatment systems with higher levels of biological treatment, solids removal, and disinfection.

Graywater includes wastewater from sinks, baths, showers, laundry, and galleys. EPA’s research found that the average graywater generation rate is about 643,450 L/d (170,000 gal/d) per vessel and 254 L/d (67 gal/d) per person. According to the report, ships with advanced wastewater treatment systems usually treat one or more graywater sources along with their wastewater, but on some ships, graywater is not treated. Some ships have graywater holding tanks that are either treated on land or sent to larger holding tanks for controlled discharge, the report says.

Oily bilge water also is a concern. For instance, the report says a vessel with only six small 3-mm (0.125-in.) leaks and four 6-mm (0.25-in.) leaks without substantial pressure behind them can produce more than 5.41 million L/yr (1.43 million gal/yr), or 14 Mg/d (15 ton/d), of oily bilge water. Total accumulations and discharge can vary across a fleet.

Possible solutions cited in the report include setting general standards or best management practices to decrease or eliminate the contaminants or volume of untreated water discharged; increasing the use and range of onboard handling and treatment technologies; requiring full accounting for the disposal of wastes; improving enforcement of and compliance with laws through inspections, rewards to passengers who report illegal activities, and instruction on the proper operation of waste management equipment; charging a passenger fee for a marine engineer on-board ships; and establishing an interagency Cruise Ship Pollution Prevention and Enforcement Program. Read the full report at www.epa.gov/owow/oceans/cruise_ships/pdf/0812cruiseshipdischargeassess.pdf

Ocean Absorption Study Will Measure Effects of Carbon Dioxide

The U.S. National Oceanic and Atmospheric Administration (NOAA) and the U.S. National Science Foundation have commissioned a study of how carbon dioxide absorbed by the ocean can alter fisheries, marine mammals, coral reefs, and other natural resources, according to a NOAA press release. This will be the first comprehensive national study of the issue.

Since the beginning of the Industrial Revolution, oceans have absorbed about a third of all man-made carbon dioxide emissions released into the air. This has reduced some of the harmful effects that greenhouse gases trapped near Earth’s surface would have had in the atmosphere and on land, but scientists are finding that increased absorption is altering the biology and chemistry of oceans, the press release says.

“Carbon dioxide released into the atmosphere through the burning of fossil fuels is … being absorbed into the oceans with potentially catastrophic effects on life in our oceans,” said Steven A. Murawski, director of scientific programs and chief science advisor for NOAA’s Fisheries Service. “Some of the most vulnerable species — clams, crabs, lobsters, mussels, shrimp, and scallops — are also some of the most important economically to the United States.” These species represent about half of the total annual value of fish harvested in U.S. water, he added. 

Ocean absorption of large amounts of carbon dioxide reduces the pH of the water. Acidification of the ocean could affect coral reefs and marine plankton, as well as other animals and plants, according to the press release.

A panel of 10 to 12 scientists is being formed to conduct the 18-month national study of how carbon dioxide emissions absorbed into the oceans may be altering fisheries, marine mammals, coral reefs, and other natural resources. The committee will include scientists with expertise in chemical oceanography, paleoceanography, biological oceanography, physiology, marine ecology, resource economics, geochemistry, resource management, and ocean-climate modeling.

The need for this study, to be conducted by the National Academy of Sciences, was outlined by the U.S. Congress in the reauthorization of the Magnuson–Stevens Fishery Conservation and Management Act in 2007.  For more information see www.noaa.gov, www.nmfs.noaa.gov, and www.pmel.noaa.gov