Thermophilic anaerobic digester with ultrafilter for solids stabilization

A thermophilic anaerobic digester with ultrafilter (TADU) for solids separation offers potential advantages of higher VS destruction, biomass retention, and pathogen removal. However, potential disadvantages include ultrafilter fouling, decreasing flux, and high VFA concentrations. In this study, a thermophilic anaerobic digester coupled to a sintered titanium, cross-flow ultrafilter was operated for over five months. Dairy manure was digested (HRT of 23 days). The filtrate VFA concentration was low (220 mg/L as HAc), average VS destruction was 49%, and a low average effluent fecal coliform concentration of 10(2) MPN/100 mL was observed. The low coliform value may be beneficial if dewatered biosolids are used for livestock bedding since low pathogen counts help prevent mastitis. Ultrafilter fluxes of 40-80 L/m2-hr were maintained by cleaning using caustic (3.5% NaOH) followed by water and acid (3% phosphoric acid). Sand from livestock bedding was found to damage the pump and ultrafilter. If TADU were implemented at full scale, then replacing sand bedding with dewatered biosolids should be considered.

Immunodetection of 3-nitrotyrosine in the liver of zymosan-treated rats with a new monoclonal antibody: comparison to analysis by HPLC

Zymosan-induced peritonitis is associated with an increased production of reactive nitrogen oxides that may contribute to the often-observed failure of multiple organ systems in this model of acute inflammation. Quantitative biochemical evidence is provided for a marked 13-fold increase in protein-bound 3-nitrotyrosine (NTyr), a biomarker of reactive nitrogen oxides, in liver tissue of zymosan-treated rats. In order to investigate the localization of NTyr in this affected tissue, a monoclonal antibody, designated 39B6, was raised against 3-(4-hydroxy-3-nitrophenylacetamido) propionic acid-bovine serum albumin conjugate and its performance characterized. 39B6 was judged by competition ELISA to be approximately 2 orders of magnitude more sensitive than a commercial anti-NTyr monoclonal antibody. Binding characteristics of 39B6 were similar, but not identical, to that of a commercial affinity-purified polyclonal antibody in ELISA and immunohistochemical analyses. Western blot experiments revealed high specificity of 39B6 against NTyr and increased immunoreactivity of specific proteins from liver tissue homogenates of zymosan-treated rats. Immunohistochemical analysis of liver sections indicated a marked zymosan-induced increase in immunofluorescent staining, which was particularly intense in or adjacent to nonparenchymal cells, but not in the parenchymal cells of this tissue. Quantitative analysis of fractions enriched in these cell populations corroborated the immunofluorescent data, although the relative amounts detected in response to zymosan treatment was greatly reduced compared to whole liver tissue. These results demonstrate the high specificity of the newly developed antibody and its usefulness in Western blot and immunohistochemical analysis for NTyr, confirm the presence of NTyr by complementary methods, and suggest the possible involvement of reactive nitrogen oxides in hepatic vascular dysfunction.