Research On Inhibitory Effect Of The Bromine Antimicrobial Agents For Waste Paperboard Papermaking System

In recent years, with the increasing number of paper-making enterprises which use waste paperboard as raw materials and the reusing of white water in papermaking systems, all above lead to that microbial inflows machine system and make microbes breeding, so as to produce slime pulp and generate paper defects under certain conditions.In this experiment, I design the test conditions of bacteriostatic effect on waste paperboard pulp and microorganisms in white water using bromine-based antibacterial agent. I selected beef extract peptone medium and potato medium as culture media in which different amount of bacteriostatic agents were adding to the pulp and the white water respectively containing bacteria and fungi, then coated and observed. And in late wastewater treatment process, the effect of residual bacteriostatic agent for wastewater treatment process factors were analyzed.The results showed that the two selected brominated antimicrobial agents both had good antibacterial effect. When the amount of antimicrobial agent is less than 10ppm, the inhibitory effect of bacteriostatic agents 2# is generally better than agents 1#. The highest inhibitory efficiency of antimicrobial agents 1# on bacteria and fungi in pulp were 69.4%, 91.1% respectively while the maximum inhibition of bacteria and fungi efficiency in white water were 84.7% 91.1% respectively; the antibacterial efficiency of antibacterial agent #2 on bacteria and fungi in pulp were 73.4%,90.7% respectively as the highest inhibitory efficiency on bacteria and fungi in white water were 89.8%,90.6% respectively. Since both bacteriostatic agents for pulp and whitewater inhibitory effect is different, the two antimicrobial agents can be proportionally compounded. When the dosage of both were same, compounded antibacterial agents generally were superior to single antimicrobial agent in the inhibiting effect to the bacteria. With the increase of the amount of antimicrobial agents, the rising rate of bactericidal efficiency of the compounded antibacterial agents was significantly higher than the single antibacterial agent. After that considering the cost and the requirements of the inhibiting effect to the bacteria, the compounded antibacterial agents is compounded at the ratio of 3:1 to bacteriostatic agent 1 # 2 # respectively, i.e., the amount of each is 12ppm and 4ppm. And at this ratio the fungicidal efficiency to the bacteria and fungi were 95.0%,97.4%,97.9%,96.0%. And the timeliness analysis of the compounded antibacterial agents showed that the fungicidal efficiency can maintain about 95% in 48h so that the compounded antibacterial agents had a long-term nature.In the latter part of the wastewater treatment process, the best advantage dominant bacteria strains were screened for wastewater treatment as No.1 advantage bacterium and after analysis, the optimum conditions for its wastewater treatment were as follows: incubation time 8h, pH 8, temperature 35℃, wastewater concentration 60%. Then the effect of the compounded antibacterial agents on the best advantage bacteria basis were observed and analyzed. The results showed that bacteriostatic agent 1# would affect the wastewater treatment of No.1 advantage bacterium but it was not enough to lead to death and can be maintained at level of less 50%. And in the waste water treatment process, antimicrobial agents can reduce the removal rate of ammonium and COD. At the dosage of antibacterial agents was 0-120 ppm, the removal rate of ammonium was reduced to 26.9% as the removal rate of COD was reduced to 34.3%.