Symposium no. 06 Paper no. 77 Presentation: poster 77-1

On the basis of knowledge about P-adsorption by soils, we succeeded to synthesize very effective P adsorbent (high performance P adsorbent: HPA) which can effectively remove P from water for avoiding eutrification of water bodies such as ponds and rivers. The materials of the HPA were the soil, especially the volcanic ash soil with high P-adsorbing ability, and the various sludges. Generally, these materials were added with ferrous sulfate, pelletized and baked at 500 C for 15 min. The HPA had much higher abilities to adsorb P and to resist against mechanical disintegration in water than the volcanic ash soil. These abilities are prerequisite for cheap and simple removal of P from flowing water by percolation through the column of the P-adsorbent. The used and P-saturated HPA could be utilized as an amendment of P-deficient soils or could be regenerated with dilute sulfuric acid for further use as a P-adsorbent. Consequently, various users in Japan have welcomed the HPA. In addition, the HPA and its derivatives could strongly adsorb As (III), As (V), F and some toxic heavy metals as well and could be used for removing these pollutants from our environments