부레옥잠에 의한 물의 정화효과

Purification of Water by a Wild Strain of Eichhornia crassipes

This study was performed to investigate the possibility of water purification by a wild strain of Eichhornia crassipes(water hyacinth). Three commercially available dishwashing detergents and a standard surfactant, linear alkylbenzene sulfonate(LAS), were used for this study. The experiment was done in 1.5 l transluscent aquariums. The plants were distributed into various concentrations of detergent and various kinds of detergent in the separate aquariums. The wet weight of the plants was significantly decreased(p<0.05) and the visual vitality of the plants also decreased in 2 days. The higher the concentration of detergent was, and the more time the plants were exposed to the detergents, the more decrease of growth was observed. The pH value of the culture media less than 1/2X(X = recommended use concentration) decreased in 2 days, then increased to the initial neutral level of pH in 6 days. However, the pH value of the media more than lX gradually decreased over the 6 days. The pH value of the culture media containing the LAS solution dramatically increased to a neutral pH value in 6 days(p<0.01). The chemical oxygen demand(COD) of the culture media started to decrease in 2 days and showed a 11.0-39.2% reduction that varied according to the concentration of added detergent in 6 days and showed 9.7 -39.2% reduction that varied according to the different kinds of detergent. A slight decrease of COD was observed in 12 days, but no tendency was observed between 12 and 18 days. The detergent in the culture media was highly significantly decreased in 2 days(p<0.01) and gradually decreased after this. After 6 days the remaining detergent was 12.8-23.7% from the various levels of initially added concentration, and 20.9~33.1 % from the four kinds of detergents. These results show that the reduction of COD and detergent was caused by E. crassipes and the effect was significant during the first 6 days when the plants were still growing well. These results indicate that the plant purifies contaminated water for several days and the effect could be variable according to the level of contamination and the environment in which the plant grows.