Abstract
Removal of nutrient is important in water purification. Different purification methods have already been developed and in practice. However, problems derived from the use of artificial materials in purification system such as cost, recycling and disposal remain unsolved. Nitrate removal ability of paddy straw has also been reported by the researchers. Considering its effect on environment and to find out the most suitable way of application, the authors carried out a series of experiments using paddy straw mixed with charcoal, pumice stone and zeolite, and investigated their abilities as water purifiers. From the results, all of the items had showed the removal of nitrate and ammonium to some extent. In specific, the removal ratios of total nitrogen were increased from 67% to 92%, -6% to 51%, and 41% to 94% for charcoal, pumice stone, and zeolite, respectively.
