Microwave treatment and struvite recovery potential of dairy manure.

Microwave digestion of liquid dairy manure was tested for the release of nutrients, such as orthophosphates, ammonia-nitrogen, magnesium, calcium and potassium, both with and without the aid of an oxidizing agent (hydrogen peroxide). The orthophosphate to total phosphorus ratio of the manure increased from 21% to greater than 80% with 5 minutes of microwave treatment. More than 36% of total chemical oxygen demand (t-COD) of the manure was reduced when microwave digestion was assisted with peroxide addition. In addition, the volatile fatty acids (VFAs) distribution shifted to simpler chain acids (acetic acid in particular) with an increase in operating temperature. In the second part of the study, digested manure with increased soluble phosphate was tested for the recovery of struvite (magnesium ammonium phosphate) at different pH. It was found that up to 90% of orthophosphate can be removed from the solution. Overall, it was concluded that the oxidizing agent-assisted microwave digestion process can be used upstream of anaerobic digestion, following which the anaerobically digested manure can be used for struvite recovery. Thus, this microwave digestion process presents the potential for enhanced efficiencies in both manure digestion and struvite recovery.

Sewage sludge nutrient solubilization using a single-stage microwave treatment.

The effects of an advanced oxidation process combining microwave, hydrogen peroxide and acid hydrolysis in a single stage (MW/H2O2/H+ -AOP) on the process efficiency of sewage sludge treatment and nutrient recovery were investigated. At lower temperature regimes (60-80 degrees C), the soluble phosphate was substantially higher in a two-stage process than in a single stage MW/H2O2/H+ -AOP process. However, higher soluble phosphate concentration was obtained for single-stage treatment at the higher operating temperature regimes (100-120 degrees C). With the addition of an inorganic acid, a very high yield of soluble phosphate was obtained in the solution at 120 degrees C. In tests with acid addition, soluble ammonia increased as temperature increased. For single stage MW/H2O2/H+ -AOP, maximum soluble ammonia was obtained at 120 degrees C. Significant concentrations of soluble COD were also obtained in this treatment. A threshold temperature of 80 degrees C was observed, at which all of the COD could be solubilized. However, at higher temperatures (100-120 degrees C), further oxidation processes occurred to form carbon dioxide, resulting in decreased amounts of soluble COD in the solution.

Photoabsorption study of Bacillus megaterium, DNA and related biological materials in the phosphorus K-shell edge region.

We measured the X-ray transmission spectra of several biologically related samples in the phosphorus K-shell edge absorption region. These include red phosphorus, hydrated sodium phosphate (Na(3)PO(4).12 H(2)O), deoxyribonucleic acid (DNA), adenosine triphosphate (ATP), diolylphosphatidyl choline (DOPC), and Bacillus megaterium spores. Red phosphorus essentially displays an edge-jump. All other spectra are similar in form and energy position: Each is dominated by a narrower, more intense first peak and a broader but less intense second peak. The corresponding K-shell edge absorption thresholds are shifted toward higher energy relative to that for red phosphorus, as expected for increasing degrees of phosphorus oxidation. The B. megaterium spectrum has aspects common to both the phosphate and DNA spectra and is therefore interpreted as a composite of spectra arising from DNA, ribonucleic acid (RNA) and phosphates within the spore. The B. megaterium spore spectrum provides information for resonant radiation damage studies in the phosphorus K-shell edge absorption region by identifying candidate photoexcitations. In addition, the absorption spectra will be useful in X-ray microscopy and macromolecular crystallography studies at the phosphorus K-shell edge.

[Disorders of energy metabolism in the rat brain under extreme exposures: a new method for assessing the energy state of the brain]. / Issledovanie narushenii énergeticheskogo metabolizma mozga krys pri ékstremal'nykh vozdeistviiakh: novyi metod otsenki énergeticheskogo statusa mozga.

We propose a new method to evaluate energy state of the brain based on vital assay for phosphate metabolites and intracellular pH in the brain. A proposed Z-index describes a set of correlations between phosphates involved in brain energy metabolism assayed in vivo by magnetic resonance spectroscopy on 31P nuclei. We tried to use Z-index as a quantitative test for disturbed energy metabolism. Potentialities of Z-index for evaluating rat brain energy state after extreme influences (gamma [correction of X-] irradiation and postoperative shock of the brain cortex) have been demonstrated.