Phosphate Removal from Digested Sludge Supernatant Using Modified Fly Ash
The removal of phosphate in digested sludge supernatant by modified coal fly ash was investigated in this study. Modification of the fly ash by the addition of sulfuric acid could significantly enhance its immobilization ability. The experimental results also showed that adsorption of phosphate by the modified fly ash was rapid with the removal percentage of phosphate reaching an equilibrium of 98.62% in less than 5 minutes. The optimum pH for phosphate removal was 9 and the removal percentage increased with increasing adsorbent dosage. The effect of temperature on phosphate removal efficiency was not significant from 20 to 40 °C. X‐ray diffraction and scanning electron microscope analyses showed that phosphate formed an amorphous precipitate with water‐soluble calcium, aluminum, and iron ions in the modified fly ash.
Phosphorus-fixing ability of high ph, high calcium, coal-combustion, waste materials
A greenhouse and laboratory study was undertaken to quantify the P-sorption capacity of high pH, high calcium, coal-combustion, waste materials and determine the amount of P fertilization necessary to overcome that P-sorption ability. Three different waste materials (bottom ash, bottom ash/fly ash mixture, and bottom ash/scrubber sludge mixture) were selected based upon their handling properties and their ability to support plant growth. A steady state was apparently established within 18 hr after adding P. Phosphorus sorption behavior was typical of precipitation rather than surface adsorption for all ash materials. The combination of high pH and readily available Ca in the bottom ash and bottom/fly ash mixture favored rapid precipitation of calcium phosphates. The β-tricalcium phosphate that apparently formed in these materials would not provide adequate P for plant growth, and fertilizing with more than 1000 kg P ha−1 would be necessary to provide the needed concentrations. The calcareous bottom ash/sludge mixture would maintain a sufficient P concentration to support plant growth because of its relatively low pH. As leaching and exposure to CO2(g) proceed in the other two ash materials, equilibrium with calcite would be established and P fixing would be a smaller hindrance to plant growth.
The Law of Failure
If a broker-dealer liquidates in federal bankruptcy court, why does an insurance company liquidate in state court, and a bank outside of court altogether? Why do some businesses re-organize under state law 'assignments', rather than the more well-known Chapter 11 of the Bankruptcy Code? Why do some laws use the language of bankruptcy but without advancing policy goals of the Bankruptcy Code? In this illuminating work, Stephen J. Lubben tackles these questions and many others related to the collective law of business insolvency in the United States. In the first book of its kind, Lubben notes the broad similarities between the many insolvency systems in the United States while describing the fundamental differences lurking therein. By considering the whole sweep of these laws - running the gamut from Chapter 11 to obscure receivership provisions of the National Bank Act - readers will acquire a fundamental understanding of the 'law of failure'.