EMBRACING SUSTAINABILITY PRINCIPLES IN DESIGNING INNOVATIONS IN BIOSOLIDS

Principles of sustainability can be reduced to a paraphrase of the Golden Rule: “Do unto the Earth beyond your fence as you would have others do to the Earth around you.” A vision of sustainability for Philadelphia, and for many other cities, is a program that creates no odor nuisances, that poses no risk from biosolids-borne pathogens, and that is a dependable, affordable, year-round recycling program. Philadelphia's cake applications to farmlands may prove unsustainable for phosphorus build-up; its composting system creates unacceptable odors in the city; its conventional anaerobic digesters provide uncertain pathogen reductions; and its mine reclamation program has caused unacceptable community odor nuisances. And, none of these programs operate dependably across all seasons. To accomplish a vision of sustainability requires innovation in treatment practices and uses, which is uncommon in the biosolids profession. This paper looks at various opportunities for injecting more innovation into biosolids practices, including: multiple stage digestion (both thermophilic and mesophilic); “productification” for maximum biosolids value; re-examination of enzymes and nutrients for enhanced biosolids stability; and, energy extraction from the entire treatment system, including biosolids processing. The paper argues, too, for an aggressive research agenda into odor, pathogen and persistent pollutants, because a failure to have sound answers to public concerns in these areas undermines sustainability. Further, the paper calls for initiatives within the profession to collaborate on reporting the performance of new equipment and technologies.