Submitted to: American Society for Microbiology
Publication Type: Popular Publication
Publication Acceptance Date: 4/15/2011
Publication Date: 7/1/2011
Citation: King, G.M., Brooks, J.P., Brown, S., Gerba, C., O'Connor, G.A., Pepper, I.L. 2011. Land application of organic residuals: Public health threat or environmental benefit. American Society for Microbiology. Policy Booklet. 21 pp. Interpretive Summary: All living organisms produce wastes that are unwanted and need to be disposed of in a proper fashion. This document reviews the diverse types of organic residuals; how such residuals are produced, used and regulated; and the associated microbiological concerns from both a public and occupational health perspective. Organic residuals are produced from concentrated animal feeding operations and from waste water treatment plants; in total greater than 100 million tons of waste residuals are produced on a yearly basis, all requiring proper disposal. Currently, disposal consists of use on lands as an agronomic fertilizer. Regulatory decisions are based on hard scientific facts and data collected over a number of years which can be concisely summarized to yield potential risks associated with these practices. Overall, it appears that the use of these residuals can be conducted properly and that proper use yields low risks. Still, much remains to be solved and the science of residual wastes in the field remains an area poorly understood from a microbiological perspective.
Technical Abstract: Waste residuals consist of manure and biosolids produced by concentrated animal feeding operations and municipal waste water treatment plants. All wastes need to be disposed of in a proper manner, protecting public and environmental health, but also in a sustainable fashion to ensure that no system is overburdened. The benefits of waste recycling, however, are not always obvious and can be accompanied by considerable concern and controversy. This report investigates the benefit and potential issues associated with waste disposal. Historically, wastes have been applied to land to recapture nutrients, but the over application of wastes can lead to nutrient runoff, severely impairing our nation’s waterways. In addition, the generation of greenhouse gases and emissions is an area needing further research. The presence of organic chemicals is a new area of concern and the presence of endocrine disruptors is an area which requires far more research. Biological risks tend to drive media exposure, but the presence of a small number of highly infectious pathogens still leads to concern for waste reuse, particularly on any food crop. Risk assessments suggest that safe reuse of wastes can be accomplished, with overall risks below 1:10,000 for long-term exposures; however short-term or accidental exposures can still lead to high risk. This policy report highlights what we know, but also gives guidance for future research directions.