Ki-Woon Chang

Estimation of Phosphorus Adsorption Capacity of Alum-amended and Composted Paper Mill Sludge

Excess application of paper mill sludge (PMS) in field can limit phosphorus uptake by crops because aluminum presented in the sludge can fix or adsorb available phosphorus which is necessary for crop growth. To investigate phosphorus (P) adsorption characteristics of PMS, we examined P adsorption maximum using Langmuir isotherm and P adsorption energy constant using Freundlich isotherm for PMS without alum, PMS with alum, and composted PMS with alum through a laboratory incubation test. The maximum P adsorption capacities were 800 in soil, 47 in PMS without alum and 61 in PMS with alum. P adsorption capacity with alum treatment for PMS increased by 30%. That of PMS compost was 68 and showed that composting increases 11% of P adsorption. Freundlich constant was 22 in check soil, while values in PMS without alum and in PMS with alum were 398 and 426, respectively. After composting, value of PMS compost significantly increased as 1,819. In conclusions, p adsorption capacity for PMS were increased by alum treatment or composting and therefore excess or continuous land application of alum-amended or composted PMS can limit P uptake for crops by reducing available P in sell.

Effect of Water Treatment Sludge on Growth of Rice Seedling

To know the effect of water treatment sludge (WTS) as a rice seedling culture soil, rice seeds are sown, germinated and grown on the culture soils mixed with different ratios of WTS to sand (100:0, 50:50, 30:70, respectively), and their growth effects was compared to that of control, commercial culture soil. When WTS is used as a culture soil for rice, the length and weight of the top part of rice seedling somewhat decreased than those of control treatment while their root length and weight in all WTS treatments significantly increased. Although phosphorus and potassium uptake of rice seedling in WTS treatments was slightly decreased, WTS treatment showed to develop root growth which is necessary in the seedling stage of all plane. Such a stimulatory effect on root growth of rice seedling was significant in the mixture ratio of 50% WTS to 50% sand.