An incubation study was conducted in laboratory to determine the effect of lime (L) as CaCO3 and phosphorus (P) as TSP on soil pH and available soil P in an acid soil. Four rates of L equivalent to 0, 1, 2 and 3 ton C...An incubation study was conducted in laboratory to determine the effect of lime (L) as CaCO3 and phosphorus (P) as TSP on soil pH and available soil P in an acid soil. Four rates of L equivalent to 0, 1, 2 and 3 ton CaCO3 ha-1 and four rates of P equivalent to 0, 25, 50 and 75 mg P kg-1 were applied in combinations as treatments. The soil was incubated at field capacity for 8 weeks (wk) after which they were extracted using NaHCO3 (Olsen), Mehlich-3, Kelowna and Bray & Kurtz-1 extractants and soil pH was determined. Lime significantly (P < 0.001) increased soil pH. Phosphorus decreased it, though not significantly. Both L and P had significant effects (P < 0.001) on P availability irrespective of extractants used. Two ton CaCO3 plus 75 mg P kg-1 gave the highest available phosphorus. Mehlich-3 method extracted the largest amount of P (14.54 - 67.35 mg·kg-1) while Olsen extracted the smallest amount (3.25 - 32.77 mg·kg-1). The mean extractable P in soils was found to be in the order of Olsen 2 = 0.87 to 0.95).展开更多
[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dos...[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.展开更多
文摘An incubation study was conducted in laboratory to determine the effect of lime (L) as CaCO3 and phosphorus (P) as TSP on soil pH and available soil P in an acid soil. Four rates of L equivalent to 0, 1, 2 and 3 ton CaCO3 ha-1 and four rates of P equivalent to 0, 25, 50 and 75 mg P kg-1 were applied in combinations as treatments. The soil was incubated at field capacity for 8 weeks (wk) after which they were extracted using NaHCO3 (Olsen), Mehlich-3, Kelowna and Bray & Kurtz-1 extractants and soil pH was determined. Lime significantly (P < 0.001) increased soil pH. Phosphorus decreased it, though not significantly. Both L and P had significant effects (P < 0.001) on P availability irrespective of extractants used. Two ton CaCO3 plus 75 mg P kg-1 gave the highest available phosphorus. Mehlich-3 method extracted the largest amount of P (14.54 - 67.35 mg·kg-1) while Olsen extracted the smallest amount (3.25 - 32.77 mg·kg-1). The mean extractable P in soils was found to be in the order of Olsen 2 = 0.87 to 0.95).
文摘[Objective] The research aimed to study influence factors of phosphorus removal by chemical method in sewage treatment system. [ Method] In different reaction systems, removal effect of the phosphorus in sewage by dosing lime and influence of the constraint factor were stud- ied. [ Result] Lime precipitation method treating high-concentration phosphorus wastewater could not only decline cost of phosphorus removal by chemical method, but also reach better treatment effect under suitable stirring and precipitation conditions by controlling alkalinity and pH. Phosphor- us content of chemical sludge after treatment could reach 9% -12%, with higher recyclable value. E Conclusion] Lime method treating phosphorus- rich sewage was more economic than low-concentration phosphorus sewage, and had very great potential for recycling phosphorus.
