Prevention of starch degradation in pulp, paper or board making processes using zinc ions and an oxidizing biocide
The invention relates to biocidal systems comprising zinc ions and an oxidizing or non-oxidizing biocide, their use, and methods for preventing or decreasing starch degradation in starch-containing process waters from pulp, paper or board production processes.
1. A method of controlling starch degradation in starch-containing process water from pulp, paper or board production, comprising:
treating the process water with zinc ions and a biocide, wherein the zinc ions and the biocide is an oxidizing biocide.
2. The method of claim 1 , wherein the zinc ions and the biocide are continuously, intermittently or alternately added to the starch-containing process water.
3. The method of claim 1 , wherein the zinc ions and the biocide are added simultaneously to the starch-containing process water.
4. The method of claim 1 , wherein the biocide is added prior to the addition of the zinc ions.
5. The method of claim 1 , wherein the zinc ions are added prior to the addition of the biocide.