Optimization and Kinetic Study of Phosphorus Dissolution from Primary Settled-Nightsoil Sludge

In this study, chemical extraction using different acid concentrations, solids concentrations, and reaction time with subsequent interactions mechanism were carried out to evaluate the potential of phosphorus (P) recovery from primary settled-nightsoil sludge (PSNS). The response surface methodology (RSM) with Box-Behnken experimental design and one-way ANOVA analysis were also employed to establish optimal P leaching conditions. The extraction efficiency relied mainly on acid and solids concentration. The second-order polynomial model was successfully developed for extracting process designs. Approximately 93% of P could effectively be extracted from PSNS of 20,000 mg/L with 0.5 M of H2SO4 at reaction time of 45 min (optimum condition). Kinetic studies showed that the pseudo-second order was fit to describe leaching of P and metals. Moreover, the rate of kinetic constants (k2) of the P, Fe, Mg, and Ca under optimum condition were found to be 0.1607, 0.1099, 0.0317, and 0.0053 g/mg·min, respectively. The 99% leaching of maximum extracted P concentration at the equilibrium (9.6673 mg/g) took place in less than one hour. The findings of a suitable simple and low-cost method P dissolution from PSNS not only provides understanding of leaching kinetics, but also helps to pave a way of recovering P from a renewable resource in the field of waste utilization

Phosphorus Recovery from Anaerobic Co-Digestion of Waste Activated Sludge and Food Waste: Effect on Molar Ratio of Mg/Ca and Mg, Ca, Fe/P

The aim of the study was to evaluate the effect of mixing ratios and Hydraulic Reaction Time (HRT) on Phosphorus (P) recovery from waste activated sludge through pretreatment of anaerobic co-digestion to chemical precipitation processes. P recovery efficiency was improved in association with an increase of HRT. Molar ratios were carried out using Anaerobic Co-Digestion. The results showed that the molar ratios, improvement of recoverably were simultaneously achieved. Compared with anaerobic digestion pretreatment system, the molar ratios of Mg/Ca, Mg/P, Ca/P and Fe/P were observed in the anaerobic co-digestion pretreatment system. At 7, 10, 15 and 20, P was recovered into solid precipitates at 2-8%, 19-29%, 39-52%, and 40-72%, respectively with a P content in solid of about 0.8-1.4%, 0.9-2%, 1-7%, and 7-11%, P dry weight which is superior to commercial fertilizer (8.80% P). Results therefore indicate that recoverable P from urinal wastewater can be effectively used to produce fertilizer for agricultural cultivation by common ion precipitation and adsorption processes

Phosphorus Extraction from Waste Activated Sludge using Sulfuric Acid Leaching: Recovery P and Reduction P Leakage

Better understand the extractability of phosphorus (P) recoverable made from sustainable activated sludge in order to drastically lessen reliance on non-renewable phosphorus sources. Sulfuric acid (H2SO4) concentration enhanced P-extraction efficiency. The experimental research design on acid leaching of was defined using the effect of time and concentration. The effect of H2SO4 concentrations upon P extraction was shown to be significant within that investigation. The best possible leach condition was waste activated sludge with 0.1 M H2SO4 in 30 mins, which also extracted 98% of a P and was employed for P precipitation. In the connection of pH 9 value and Mg/Ca=2, the efficiency of P recovery 93% substantially improved. The findings of this research are obligated to generate a comprehensive information on the acceptability of P-composite matter recovered from waste activated sludge in order to urge decision-makers to use it. This will also aid in attempting to close the P loop in the human environmental for food cultivation, as well as benefit of reducing P leakage of WAS to landfills

Congenital afibrinogenaemia caused by uniparental isodisomy of chromosome 4 containing a novel 15-kb deletion involving fibrinogen Aalpha-chain gene

Among rare inherited deficiencies of coagulation factors, congenital afibrinogenaemia is characterised by the lack of fibrinogen in plasma. In the last few years, several genetic defects underlying afibrinogenaemia (mostly point mutations) have been described in the fibrinogen gene cluster. In this study, the molecular basis responsible for afibrinogenaemia in a Thai proband was defined. Point mutation screening was accomplished by directly sequencing the three fibrinogen genes. The impossibility to amplify fibrinogen Aalpha-chain gene (FGA) exons 5 and 6 suggested the presence of a homozygous deletion. A specific long-range PCR assay enabled the identification of a novel 15-kb deletion, representing the largest afibrinogenaemia-causing deletion described so far. Direct sequencing of the deletion junction allowed mapping of the breakpoints in FGA intron 4 and in the intergenic region between Aalpha- and Bbeta-chain genes. Since the mutation was inherited only from the mother and nonpaternity was ruled out, a maternal uniparental disomy (UPD) was hypothesised. UPD test, carried out with markers covering the whole chromosome 4, revealed that maternal isodisomy was responsible for homozygosity of the 15-kb deletion in the proband. The apparently normal phenotype of the proband, except for afibrinogenaemia, suggests that UPD for chromosome 4 is clinically silent. This represents the first case of a documented complete isodisomy of chromosome 4 causing the phenotypic expression of a recessive disorder. In silico analyses of the regions surrounding the breakpoints suggested that the 15-kb deletion might have originated from an inappropriate repair of a double-strand break by the nonhomologous end joining mechanism