| 摘要 |
<p>A process for the purification of waste waters accumulating from pulp production, particularly from chlorine bleaching of pulp. Solid particles from the waste water are released in a series-connected, mechanical cleaning stage and the cleaned waste water is introduced into an electrolysis installation, wherein the waste water is subjected to anodic oxidation under constant movement, and an electric potential differential is plotted between the electrodes, and the pH of the waste water is set and maintained in a suitable manner at ca. 1 to 6.5. The waste water which is thus treated is transferred into a flocculation zone, in which an aqueous solution of a powerful cationic polyelectrolyte is added to the waste water under constant movement, and the pH is set and maintained at 1 to 6.5, and a flocculation of colloids and suspended components occurs. The treated waste water together with the flocculated products is transferred into another zone, in which the flocculated products are separated out. Neutralization of the waste water freed of the flocculated products then takes place and the neutralized waste water is transferred into an activated sludge installation, for biological decomposition of the organic products still present in the waste water by suitable microorganisms, with addition of additive nutritive materials, whereupon the waste water which is so clarified is discharged into a receiving stream.</p> |
