Difference in immobilization effect of heavy metal-contaminated soil between two different amendment methods was evaluated; 1) both of steel slag (i.e., consisted in solid phase) and soluble phosphate (i.e., consisted in liquid phase) were simultaneously applied to contaminated soil (i.e., simultaneous amendment methods) and 2) soluble phosphate and steel slag was applied sequentially to the contaminated soil (i.e., sequentially amendment methods). The application rate of stabilizers to soils was determinated based on weight/weight ratio of 5% for steel slag and PO4/Pb molar ratio of 2.0 for phosphates, respectively. To identify difference of immobilization effect to test soil, three different soluble phosphates, such as Na2HPO4·12H2O, Ca(H2PO4)2·H2O and (NH4)2HPO4 were used. The sequential amendment was 6 ~ 27% more effective than the simultaneous amendment in terms of the immobilization efficiency for Pb, Cu, and Cd in the contaminated soil. There was little difference in case of Zn. Among the three phosphates tested, (NH4)2HPO4 was clearly the most effective. Residual form of heavy metals concentration in sequentially methods is higher than those in simultaneously methods. At the same time, more exchangeable and carbonate-bound forms of heavy metals in simultaneously methods were observed than in sequentially case. These result implies that the sequential amendment method was more effective than the simultaneous amendment method in terms of heavy metal immobilization in the contaminated soil.

The objectives of this study were to evaluate the effects of chemical additives on total phosphorus (TP), soluble reactive phosphorus (SRP), and total volatile fatty acids (total VFAs) in hanwoo slurry. The treatments in this study were ferrous sulfate, alum, and aluminum chloride, and applied at the rate of 0, 0.5, and 1.0 g/25 g of hanwoo slurry. All of the chemical treatments significantly lowered TP (11 to 53% of the untreated control), SRP (41 to 99.9% of the untreated control), and total VFAs (22 to 48.5% of the untreated control) by reducing hanwoo slurry pH (3.42 to 6.86). Among these chemical amendments, addition of 0.5 g ferrous sulfate, alum, and aluminum chloride to hanwoo slurry were the best results evaluated on farms with respect to reducing negative environmental impacts. In conclusion, the results of this study indicate that the use of chemical amendments should be considered in the development of best management practices (BMPs) for the hanwoo industries.

The goals of this study were conducted to investigate the effects of applying liquid aluminum chloride (AlCl3) to rice hulls on pH and soluble reactive P (SRP). A total of 800 broiler chicks (4 treatments × 4 replicates × 50 birds) were housed into 16 floor pens in a single house for 5 weeks. The treatments were divided into 4 groups: control, 100 g of liquid AlCl3/kg of rice hulls, 200 g of liquid AlCl3/kg of rice hulls, and 300 g of liquid AlCl3/kg of rice hulls. Liquid AlCl3 was sprayed on the rice hulls surface at a rate of 100 g, 200 g, and 300 g liquid AlCl3 per kg rice hull. pH values and SRP contents were significantly decreased (P<0.05) with the increased liquid AlCl3 levels in comparison with control. However, no significant differences in SRP contents were observed among all treatments at 3 and 4 weeks. Applying 100 g, 200 g, and 300 g liquid AlCl3 to rice hulls reduced SRP contents by 18, 25, and 52% for 5 weeks, respectively, compared with the controls. In conclusion, these results suggest that using liquid AlCl3 on rice hulls should be promising for reducing water contamination and resulted in a reduction in SRP contents, which reduced pH.

The objective of this study was conducted to evaluate the effects of poultry litter amendments on pH and soluble reactive phosphorus (SRP) in poultry litter. Two laboratory studies were conducted for 42 d in Exp. 1 and for 10 d in Exp. 2, respectively. The poultry litter was treated with various amendments which included 4 g fly ash and 4 g AlCl3 (AlCl₃.6H₂O)/100 g litter in Exp. 1 and 4 g alum(Al₂(SO₄)₃.14H₂O), 8 g alum, 8.66 g liquid alum, and 17.3 g liquid alum/100 g litter in Exp. 2; untreated litter served as controls. There were no differences in pH between control and T1(4 g fly ash) and SRP contents between T1(4 g fly ash) and T2(4 g AlCl₃) in Exp. 1. A significant difference in pH and SRP contents in Exp. 2 was observed among all treatments(P< 0.05). In experiment 1, T1(4 g fly ash) and T2(4 g AlCl₃) at 42 d decreased SRP in litter by 47.1% and 62.6% of that from litter alone, repectively. In experiment 2, T1(4 g alum), T2(8.66 g liquid alum), T3(8 g alum), and T4(17.3 g liquid alum) treatments at 10 days reduced SRP contents by up to 36.2%, 62.9%, 87.0%, and 83.9%, respectively, when compared with the controls. Decrease in SRP contents was chiefly associated with reduction in litter pH. These results indicate that use of various litter amendments to limit P solubility has potential and should be pursued as a means of reducing soluble reative phosphorus during short term.