Once low-flow systems are in wide use, as they are in this region and the West generally, the garbage grinder comes into focus as a machine that adds to water usage for the benefit of a dubious disposal destiny. During our region's drought in the late 1970s, water agencies specifically asked us to avoid using the disposals. We reluctantly devoted water about once a week to keeping the grinder clear of detritus. My household's kitchen prep doesn't use all that much water, and anyway, de minimus additions at the level of any one household can still add up to an urban area sending a lot of filtered and chemically sanitized water down the drain just to carry garbage to the sludge system.
Regarding "beneficial reuse," land application of sewage sludge is good conceptually IF the sludges can first be minimized and then be kept free of toxics. But real practices and regulatory structures are seriously flawed. Problems are discussed by the Sierra Club in its just-updated sludge policy, which is in the final few days of review and will then replace the old one now shown at www.sierraclub.org/policy/conservation/solidwaste.asp
From the introduction: "Although the Sierra Club supports the use of pathogen- and pollutant-free treated human waste as fertilizer, such a practice is only possible by separating the industrial waste stream from human waste. Sewage treatment plants are not designed to separate wastes and to produce fertilizer. They were designed to remove pollutants from the wastewater. Many of these pollutants concentrate in the resultant sludges. As a result the exact composition of any sludge is unknown. Urban sludges are a highly complex, unpredictable biologically active mixture of organic material and human pathogens, SOME OF WHICH ARE RESISTENT TO ANTIBIOTICS OR CANNOT BE DESTROYED THROUGH COMPOSTING. SLUDGE can contain thousands of industrial CHEMICALS, including dozens of carcinogens, hormone disrupting chemicals, toxic metals, dioxins, radionuclides and other persistent bioaccumulative poisons. The Federal Clean Water Act defines sewage sludge as a pollutant."
The Club reports: "In 1997 the Cornell Waste Management Institute concluded that current regulations governing land application do not protect human health, agricultural productivity, and the environment (http://cwmi.css.cornell.edu/Sludge.html). In 2002, the National Research Council of the National Academy of Sciences (NAS) warned that the scientific underpinning of the 503s was based on outdated or nonexistent science. The NAS panel also warned that even if all of the contaminants of this complex and unpredictable waste mixture were known, single agent risk assessment, and using standard risk management strategies, would not be protective of human health. (www.epa.gov/waterscience/biosolids/nas/complete.pdf ) In 2002, University of Georgia scientists published groundbreaking research that documents and explains how deaths and illnesses reported by sludge-exposed rural residents are linked to land application (www.biomedcentral.com/1471-2458/2/11 )" [Emphasis in the original.] "On July 13, 2000, the US House Science Committee held a hearing on the 199
9 National Research Council report entitled "Strengthening Science at the US EPA". The 503s were singled out as an example of regulation that is being driven by politics,rather than by sound science. In 2000 the CDC/NIOSH identified Class B sewage sludge as a potential hazard to workers who handle this material, and the same year the EPA Office of Inspector General also concluded that due to lack of data and lack of oversight the EPA cannot assure the public that current land application practices are protective of human health and the environment. A September 6, 2002, Memo from the EPA Inspector General to EPA stated that the agency has not conducted the basic research needed to determine the risks associated with [the land application of sewage sludges]. A 2005 paper, published in the International Journal of Occupational and Environmental Health- www.IJOEH.com/pfds/IJOEH_1104_Snyder.pdf - documents how EPA, working with municipalities, state agencies, and industry-friendly scientists, covers up reported illnesses and deaths linked to land application. Public opposition to land application is increasing. The National Farmers Union opposes applying sludges to agricultural land. In 2003, 73 health, environmental, and farm organizations petitioned EPA to place a moratorium on land application of sewage sludges. EPA turned down the petition, citing fraudulent studies it had funded that alleged that land application was safe."
[Emphasis in the original.]
Here's the conclusion: "The European Union, aware of the need to protect soils in perpetuity, has based its land application policies on the principle of non-degradation and sustainability with much more protective regulations. And the European community has plans for even stricter regulations in the future. In fact, several European countries are following Switzerland?s example of phasing out land application altogether.
"In contrast, the US EPA appears to be headed in the opposite direction. Instead of tightening the regulations that would improve sludge quality and sludge management, EPA no longer regulates dioxins and dioxin-like compounds, no longer requires post-storage pathogen testing, no longer requires certification that pathogen reduction and vector attraction reduction requirements for Class B sludge have been met, significantly weakened the Class B pathogen sampling requirements, and allows radionuclides, including plutonium and radium, in sludges that are used for growing food and feed crops. In addition, the metal products industry and AMSA are successfully resisting EPA's proposed tighter pretreatment standards for metals. Meanwhile the amount of toxic material being discharged into sewage treatment plants has increased every year since 1996.
"Finally, there is increasing evidence of risks from unregulated and unmonitored organic compounds concentrating in land applied sludges (http://cwmi.css.cornell.edu/Sludge.html
and Kinney Chad et al. Survey of Organic Wastewater Contaminants in Biosolids Destined for Land Application (2006). Environ. Sci. Technol." [Emphasis in the original.]
One wouldn't have much incentive to add food to this badly broken system unless one were selling InSinkErators.
Mary Lou Van Deventer
Urban Ore, Berkeley, CA
To End the Age of Waste
On Feb 29, 2008, at 11:57 AM, Kendall Christiansen wrote:
Perhaps, but that?s not what the empirical research suggests: no surprises here; numerous studies find that water usage associated with disposer is generally regarded as de minimis, even unmeasurable, in terms of typical household consumption, and entirely subject to existing patterns of use related to meal prep and clean-up. Probably ten things to do to reduce household consumption of water (surprising percentage actually devoted to external use) before thinking about a disposer, e.g., low-flow/dual-flush toilets, low-flow showerheads, front-loading/EnergyStar washing machines, etc.
In NYC, the progressive/pioneering Battery Park City development has required disposers in its last nine or so residential towers, and found them fully compatible with the onsite blackwater treatment systems they also require. And when they asked the City what to do with the screened solids, the response was to ?flush ?em down the sewer?, because Manhattan?s wastewater is too ?light? for the WWTP to function effectively.
And if you read the recent Harper?s ?Wasteland? article (or the City?s recent Solid Waste Management Plan), you?ll note that effectively 100% of NYC?s biosolids are beneficially reused, with over half processed into fertilizer pellets and successfully marketed. Kate Ascher?s wonderful ?The Works? contains an annotated illustration of that process.
When we consider kitchen garbage grinders and the sewage system, we need to plan with expected water shortages in mind. Here's an update from the Environmental News Service.