Degraded water reuse: an overview.

Communities around the world face increasingly severe fresh water supply shortages, largely due to expanding populations and associated food supply, economic development, and health issues. Intentional reuse of degraded waters (e.g., wastewater effluents, irrigation return flows, concentrated animal feeding operations [CAFO] effluents, stormwater, and graywater) as substitutes for fresh waters could be one solution to the challenge. We describe the various degraded water types and reuse options and limitations and restrictions to their use. Emphasis is given to reuse scenarios involving degraded water applications to soil. The potential for degraded water reuse is enormous, but significant barriers exist to widespread adoption. Barriers include research questions (some addressable by traditional soil science approaches, but others requiring novel techniques and advanced instrumentation), the lack of unifying national regulations, and public acceptance. Educational programs, based on hard science developed from long-term field studies, are imperative to convince the public and elected officials of the wisdom and safety of reusing degraded waters.

Radioactive materials in biosolids: dose modeling.

The Interagency Steering Committee on Radiation Standards (ISCORS) has recently completed a study of the occurrence within the United States of radioactive materials in sewage sludge and sewage incineration ash. One component of that effort was an examination of the possible transport of radioactivity from sludge into the local environment and the subsequent exposure of humans. A stochastic environmental pathway model was applied separately to seven hypothetical, generic sludge-release scenarios, leading to the creation of seven tables of Dose-to-Source Ratios (DSR), which can be used in translating from specific activity in sludge into dose to an individual. These DSR values were then combined with the results of an ISCORS survey of sludge and ash at more than 300 publicly owned treatment works, to explore the potential for radiation exposure of sludge workers and members of the public. This paper provides a brief overview of the pathway modeling methodology employed in the exposure and dose assessments and discusses technical aspects of the results obtained.

Sustainable land application: an overview.

Man has land-applied societal nonhazardous wastes for centuries as a means of disposal and to improve the soil via the recycling of nutrients and the addition of organic matter. Nonhazardous wastes include a vast array of materials, including manures, biosolids, composts, wastewater effluents, food-processing wastes, industrial by-products; these are collectively referred to herein as residuals. Because of economic restraints and environmental concerns about land-filling and incineration, interest in land application continues to grow. A major lesson that has been learned, however, is that the traditional definition of land application that emphasizes applying residuals to land in a manner that protects human and animal health, safeguards soil and water resources, and maintains long-term ecosystem quality is incomplete unless the earning of public trust in the practices is included. This overview provides an introduction to a subset of papers and posters presented at the conference, "Sustainable Land Application," held in Orlando, FL, in January 2004. The USEPA, USDA, and multiple national and state organizations with interest in, and/or responsibilities for, ensuring the sustainability of the practice sponsored the conference. The overriding conference objectives were to highlight significant developments in land treatment theory and practice, and to identify future research needs to address critical gaps in the knowledge base that must be addressed to ensure sustainable land application of residuals.

Radioactive materials in biosolids: national survey, dose modeling, and publicly owned treatment works (POTW) guidance.

The Nuclear Regulatory Commission (NRC) announced the availability of three new documents concerning radioactive materials in sewage sludge and ash from publicly owned treatment works (POTW). One of the documents is a report presenting the results of a volunteer survey of sewage sludge and ash samples provided by 313 POTWs. The second document is a dose modeling document, using multiple exposure pathway modeling focused on a series of generic scenarios, to track possible exposure of POTW workers and members of the general public to radioactivity from the sewage sludge or ash. The third document is a guidance report providing recommendations on the management of radioactivity in sewage sludge and ash for POTW owners and operators. This paper explains how radioactive materials enter POTWs, provides criteria for evaluating levels of radioactive material in sludge and ash, and gives a summary of the results of the survey and dose modeling efforts.

Surface flow (SF) treatment wetlands as a habitat for wildlife and humans.

Water quality improvement is generally the primary objective of treatment wetlands. Creation of wildlife habitat is an inevitable outcome of these projects. However, an increasing number of treatment wetland projects have been purposely designed and operated to enhance their beneficial utility to wildlife and humans. This trend to multi-purpose treatment wetlands has broadened the basis for assessing the advantages of this natural treatment alternative. There are at least 21 treatment wetlands in the U.S. that were implemented with wildlife habitat creation and/or human use as principal goals. A number of treatment wetlands outside the U.S. also share these priorities. Hundreds of other wetlands have collected and reported quantitative data on wildlife and/or human uses. The North American Treatment Wetland Database (NADB) has been expanded to include critical wildlife habitat and human use data. This paper provides a preliminary inventory of these habitat and human use treatment wetlands, summarizes lessons learned, and identifies additional data needs.