![[logo] US EPA](https://webarchive.library.unt.edu/web/20090513113704im_/http://www.epa.gov/epafiles/images/logo_epaseal.gif){kind=logo}
A Comparison of Measures to Assess Sludge Stability after Anaerobic Digestion
The vector attractiveness (frequently associated with odors and unsightliness) of sludge is an important parameter in protecting public health and the public’s acceptance of biosolids land application. Odor is the most common complaint. Currently accepted methods for assessing vector attractiveness of anaerobically digested sludge are either highly variable depending on the influent sludge characteristics or require an exorbitant amount of time to complete. Therefore, a need exists for establishing a more efficient and reliable method to assess the vector attractiveness of sludges treated with anaerobic digestion.
A local WWTP with a staged approach to anaerobic digestion (four anaerobic digesters in series) has been targeted as a prime location to take sludge samples. Samples of raw and digested sludges after each of the four digesters, as well as finished sludges from an aged stockpile kept on-site will allow the assessment of several different stages of vector attractiveness of the same sludge source. Currently accepted methods for assessing vector attractiveness of anaerobically digested sludge (percent removal of volatile solids and the additional volatile solids loss test) will be tested against non-conventional methods which include, but are not limited to, biochemical oxygen demand, pathogen/indicator levels, and enzymatic parameters which gauge metabolic activity. All sampling will be performed by EPA personnel and laboratory analyses will be performed in-house.
Contact: Bethany AnnMadge Acquisto, 513/569-7690, (EIMS #117991)