PASTEURIZATION, FLOCCULATION AND PRECIPITATION OF LIMNETIC OR SALTWATER PLANKTON

摘要

PURPOSE:To remove plankton and to collect floating pumice stones without contamination of water, by spreading the pumice stones having a deposited salt thereon, which is dissolved in water to form aluminium hydroxide, on the water surface. CONSTITUTION:A conc. solution of Al(OH)3, Al2(SO4)3 or the like is adsorbed and stuck to the porous part of pumice stones crushed into a proper particle size, and then the pumice stones are dried to prepare a product. When the product is spread onto the water surface, Al(OH)3 as such and the Al salt after hydrolysis liberate Al(OH)3. The liberated AlOH)3 impedes the physiological action of limnetic or saltwater plankton by adsorption, flocculation or surface-coating thereof. Thereafter, the pumice stones are floated without being precipitated. The floated pumice stones are easily recovered by an oil fence, nit or the like. The flocculated plankton sticking to the surface of the recovered pumice stones can be almost removed by washing them with water and then nearly completely removed by simple heating.