Interpreting science in the real world for sustainable land application.

Today's land application practices are designed to effectively treat wastes, and have evolved from earlier practices that centered on cheap disposal with less regard for environmental protection. The major objectives of this paper are to (i) review how current land application practices, and our understanding of them, have evolved over time and (ii) explore how science is used (and sometimes misused or ignored) in the development of design, regulation, and management of sustainable land application. Land treatment technologies have been used effectively for the treatment and recycling of many types of wastewaters and organic residuals for many years. Extensive research and demonstration efforts, as well as experience with pilot- and field-scale projects, have provided the information about soil reactions with contaminants in wastewater and organic residuals needed to design and operate sustainable land application projects. Still, systematic research programs are as important today as ever to support studies aimed at producing information on how soil-based treatment and recycling systems work, to address new areas of concerns as they arise, and continue to improve the overall design, performance, and reliability of land application systems as sustainable soil treatment and recycling systems.