BioCycle October 2006, Vol. 47, No. 10, p. 6
STUDY FINDS ADDITIVES BOOST PATHOGENS IN COMPOST TEA
Using compost to make a foliar spray or soil drench to promote plant growth and suppress plant diseases has gained popularity in the U.S., write USDA Agricultural Research Service microbiologists in the September 2006 issue of Agricultural Research magazine. The “compost teas” are made by adding small amounts of mature compost to unheated water and allowing the mixture to brew. The self-heating process of composting generally reduces pathogens, but microbiologists David Ingram and Patricia Millner found that ingredients commonly added to compost tea may promote growth of bacteria that can cause illness in humans.
Ingram and Millner, who are in the Environmental Microbial Safety Laboratory in Beltsville, Maryland, examined the potential for such bacteria to grow during both aerobic and anaerobic compost-tea production. They studied the effects of additives – such as soluble kelp, fish hydrolysates, humic acid, rock dust, and proprietary nutrient solutions – on growth of pathogenic bacteria as well as microbes that some farmers feel are beneficial and necessary to enhance soil and inhibit foliar pathogens.
Ingram found that, in general, when compost with low numbers of Salmonella and E. coli is used to make compost tea, the pathogens only grew when additives were included in the initial watery mixture; pathogens remained undetectable in all the compost teas made without commercial additives. “This debunks the view among some compost-tea producers that the aerobic bacteria in compost will inhibit growth of human pathogenic bacteria when aerobic conditions and nutrient additives are present,” says Ingram.
Such a scenario raises public-health concerns about potential contamination of treated crops, particularly those intended for fresh consumption. “Use of supplemental nutrients and other additives to produce compost tea gives even a few pathogenic bacteria a growth boost, so testing of the final tea before spraying may be necessary to ensure the absence of human pathogens,” says Ingram. Recommendations and guidelines for safe production and use of compost tea have been provided by the Compost Tea Task Force, formed by the National Organic Standards Board. The report can be found at: www.ams.usda.gov/nosb/meetings/CompostTeaTaskForceFinalReport.pdf.
NEW COALITION TO FOCUS ON “WASTE-BASED” ENERGY INITIATIVES
A coalition formed in early October – including the U.S. Conference of Mayors, the Integrated Waste Services Association, the National Solid Wastes Management Association, the Solid Waste Association of North America, and the ASME Solid Waste Processing Division – believes there should be an increased commitment to utilization of energy generated from the waste stream because of the high cost of energy. This coalition calls upon Congress, federal agencies, and states to provide additional incentives to stimulate new waste-based energy capacity. “We need more umbrella terms for focusing on biomass reuse,” stresses Ted Michaels, president of the Integrated Waste Services Association based in Washington, D.C. “Recovery of energy from waste will lessen America’s demand for foreign oil and natural gas, helping to reduce the cost of energy. Plus we need further incentives.”
Waste-based energy is a term that organizations like the U.S. Conference of Mayors, SWANA, Solid Wastes Management Association, IWSA and ASME use to refer to sources like landfill gas and biomass along with anaerobic digestion or gasificaion of organic residuals. “The energy capacity available from solid waste is largely untapped; and our commitment to grow and continually develop these waste-based energy technologies will ensure the utilization of solid waste as a clean, reliable, renewable energy source,” comments John Skinner, SWANA executive director. Projects will be described in coming issues of BioCycle.
An article in the September 2006 issue, “Building Longevity Into Composting Buildings,” reported on a variety of options to prevent structural corrosion. One option is the Stayflex System manufactured by Preferred Solutions, Inc. (PSI), which involves application of insulating foam covered with a chemical resistant polyester coat. The article incorrectly states cost information. According to Jack Stahl of PSI, for new construction, the total installed cost per square foot of floor area for the pre-engineered steel building with the Stayflex System applied to all interior surfaces of siding, roofing and structural steel is under $25. For retrofit applications, the installed cost is around $5/sq.ft. of surface area to be protected.
IMPROVING ECONOMIC RETURNS THROUGH VERMICOMPOSTING
Based in Pune, India, the BAIF Development Research Foundation is introducing sustainable systems such as vermicomposting into the region. The targeted beneficiaries are mostly marginal farmers. As reported in Leisa magazine, available biomass is limited because it’s used for other purposes such as for feeding farm animals and domestic fuel. After these priorities are met, the remaining coarse materials can be effectively processed with earthworms.
Another biomass source is cattle dung. As taught by BAIF, material on weight basis for vermicomposting is three parts of dry biomass (chopped into pieces of less than 10 cm) and two parts of wet dung. Mixed well and wetted to 30 to 40 percent, the substrate is covered with a wet gunny (loose canvas). After two weeks, 200 earthworms are introduced for every 100 kg of substrate. After stirring and watering for about 45 days, the vermicompost is ready for use.
Many projects grow fruit trees on marginal land. The surface-feeding species of Eisenia foetida was effective. Vermicompost has become established as a successful income generation activity, reports Leisa. In one project, more than 250 groups produced nearly 2,000 tons of vermicompost in a year. Value is about $8,500 (U.S.). Concludes the report: “Vermicompost making through self-help groups is a good example of BAIF’s strategy. By combining technical interventions with community mobilization, BAIF tries to enable the rural poor to come out of poverty.”
FIVE CITIES HAVE “BRIGHT IDEAS” ABOUT SUSTAINABILITY
A summer issue of Sierra has a special report on “Green Streets” – cities that have bright ideas about transit, recycling, energy and food. They particularly cite the following cities:
Chicago (pop. 2,862,244) – A rain garden atop City Hall, bike-commuter station downtown, and a green roofs program with more than 2.5 million sq. ft. Chicago is the the first city to charge higher vehicle-registration fees for SUVs and requires all new city-owned buildings to meet green design standards.
New York City (pop. 8,104,079) – Two-thirds of New Yorkers get to work without cars. The city has one of the largest hybrid-bus fleets in the nation. Eighteen percent of NYC’s land area is devoted to parks.
Portland, Oregon (pop. 533,492) – Protected surrounding farms and open space fitting new developments onto half the usual land area. First major city to tackle global warming, Portland saves $2 million annually on city energy bills, has strict green building standards, and creates less greenhouse gases than it did 15 years ago.
San Francisco (pop. 744,230) – Purchasing policies phase out toxic products; studies potential for renewable energy from waves off its shores; has acclaimed recycling program and sends compost from food scraps to region’s vineyards and farms.
Seattle (pop. 571,480) – Launched Climate Protection Agreement, mandatory recycling, retrofits diesel vehicles that cut particulate pollution in half, invests in renewable energy while reducing net greenhouse gas emissions to zero.
PROTECTING HARVESTED FRUITS AND VEGETABLES FROM PESTS
A method for ridding harvested fruits and vegetables of insect pests and microorganisms – without use of ozone-depleting chemicals like methyl bromide – has been developed by researchers at the University of California, Davis. According to Resource, published by the American Society of Agricultural and Biological Engineers (ASAB), a technique called metabolic stress disinfection and disinfestations suffocates insects. Ethanol gas is also applied briefly to accelerate killing of fungi and bacteria and to damage insect eggs.
The process, explains Resource, would be applied to pallets of fruits and vegetables to prevent both damage during storage and shipping, and transporting potentially invasive insects globally. A patent is pending on the technology.
Researchers at UC Davis Crocker Nuclear Laboratory hope the technique will allow for the complete phase-out of methyl bromide. An added benefit is that the carbon dioxide and ethanol used during treatment are recovered and recycled. Researcher Manuel Lagunas-Solar anticipates that commercial processing units could be available in two to three years. He can be contacted at: email@example.com.
GAS PRICES VS. ECOFRIENDLY, COST-EFFECTIVE MASS TRANSIT
The U.S. Federal Highway Administration has awarded The American Institute of Architects (AIA) a contract of as much as $2 million to study benefits that well-designed community transportation projects bring. To be completed by July 2007, the study will measure how transportation projects promote economic development, protect public health, safety and the environment, while enhancing architectural design and planning.
“Transportation design is shifting in the United States with increased emphasis being placed on people rather than just automobiles. Transportation is an investment in the community and placing a greater focus on walkable, mixed use urban development around transportation options is something that architects have been advocating for many years,” said David T. Downey, managing director of the AIA Center for Communities by Design. “This study will measure the value of well-designed transportation projects and the degree to which the transportation investment extends beyond the basic infrastructure and enhances the neighborhood and community as a whole.”
The AIA is partnering with the University of Minnesota’s Center for Transportation Studies (CTS) to complete the research portion of the study. CTS is a nationally known transportation research body that draws upon experts from a wide variety of disciplines, including architecture, landscape architecture, civil engineering, economics, public policy and environmental studies.
October 25, 2006 | General
BioCycle October 2006, Vol. 47, No. 10, p. 6