The conversion of municipal sludge and poultry manure to activated carbon results in a significant ash fraction that contains several different anions and cations. The objectives of this study were to determine whether the select ions are released or leached from virgin carbon into the sorption medium at different pH values. Activated carbon was placed in solutions of pH 1, 5, or 7, and the leaching of six cations (cadmium, chromium, copper, nickel, lead, and zinc) and two anions (arsenate and selenate) was recorded. Considerable quantities of zinc and copper were removed at pH 1 from all carbon sources. However, the amounts leached at pH 5 and 7 were small or undetectable. Our results indicate that leaching or desorption from carbons made from municipal sludge or poultry manure is pHdependent and occurs readily under highly acidic conditions but minimally under pH conditions typically seen in contaminated water or wastewater. Water Environ. Res., 78, 2324Res., 78, (2006.

This review section covers journal articles and conference papers related to biosolids and sludge management that were published in 2008. The literature review has been divided into the following sections:
 •Biosolids regulation and management issues,
 •Biosolids characteristics and measurement,
 •Sludge treatment technologies,
 •Disposal and reuse,
 •Odor and air emission, energy issues,
 •Risk Analysis
 The sludge treatment technologies include: pretreatment and sludge minimization, anaerobic digestion, aerobic digestion, alkaline stabilization, composting, dewatering, drying and innovative technologies. The disposal and reuse section covers combustion/incineration, pyrolysis, and land application that reviews issues pertaining to nutrients, heavy metals, synthetic organics, and pathogens. Biosolids have sometimes been used for the reclamation of marginal or contaminated lands ‐ such applications have been classified under non‐agricultural uses.

From field studies conducted by Tulane University (New Orleans, Louisiana), efficiency of advanced alkaline disinfection in closed systems was found to depend on ammonia concentration, pH, exposure time, temperature, total solids content, pretreatment storage time, and mixing effectiveness. In this study of a closed alkaline system, an additional pathogen stressor pressure was tested. The effect of the alkaline dosing has been assessed for dewatered raw and aerobically and anaerobically digested municipal sludge cake that produce un‐ionized ammonia at concentrations of 0.05 to 2% on a dry‐weight basis. Inactivation of Ascaris suum eggs increased from 50 to 99% as the temperature was increased from 40 to 55°C, thus achieving Class A levels. The systems studied were compared with an alkaline process operated under open conditions, which limited the concentrations of ammonia available because of Henry's Law. Under a closed pressurized system, the effect of un‐ionized ammonia was greatly increased, and the resulting time required for inactivation was reduced from hours or days to minutes. In the next few years, it is expected that alkaline disinfection of biosolids will be optimized in relation to the factors stated above, at much lower doses of the alkaline agents. The closed‐system alkaline processes that will be developed will be more energy‐efficient, cost‐effective, and have full control of potential odorous emissions.

No abstract

Surrogate indicator organisms are needed to assess the presence of pathogenic agents in the waste matrices, to monitor the fate of potential pathogens during processing and land application and to provide a risk assessment for human health based on the presence of these indicators. Surrogate indicator organisms are indigenous to sludge, relatively inexpensive to analyze and can measured within days. These organisms have the potential to be used in place of Ascaris or poliovirus as a screening device during bench-scale or pilot-scale testing of proposed sludge disinfection processes. Additionally, they can be used for continued performance monitoring of the disinfection process prior to land application. In several studies, a variety of surrogate indicators have been assessed with various sludge disinfection processes. These disinfection processes include the Bioset Advanced Alkaline Stabilization Process, J-Vap ® Heat Drying Process, Synox Process and BioChem Resources Neutralizer™ Process. For the Bioset Process, the results showed that a 3-log reduction was achieved in the aerobic endospores when the Ascaris eggs were completely eliminated. The somatic bacteriophages actually appeared to be more resistant than poliovirus. Thus, aerobic endospores could be used as a surrogate indicator of the reduction of Ascaris eggs in the advanced alkaline stabilization process. In the J-Vap Process, at 55 o C or greater the somatic bacteriophage and Ascaris eggs are nearly completely inactivated. The time that the temperature was equal to or greater then 50 o C was significant in the log reduction of somatic bacteriophage and Helminth egg inactivation (p < 0.05 for both). However, time at or above 50 o C was not significant for Enteric Virus inactivation (p = 0.266). In the Synox Process, when the density of Clostridium spores were less than 100 CFUs per gram of solids, 80 to 90 percent of the time no viable Ascaris eggs could be detected (< 1 viable egg per 25 grams of dry solids). However, the results from the acidic treatment process did not show a linear relationship between log reduction in eggs and spores. Thus, C. perfringens showed potential to be an appropriate surrogate indicator for Ascaris for acidic treatment processes, but more research is needed. For the BioChem Process, in preliminary testing, aerobic endospores were shown to be poor indicators for inactivation of Ascaris suum eggs. Results from Clostridium perfringens and somatic bacteriophage analysis will be available in March. In conclusion, it is apparent that each disinfection process has a different surrogate indicator, rather than being able to use a universal surrogate indicator organism for all sludge disinfection processes.