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

The recycling of waste paper and the circulation of water effectively reduce the operation cost of the enterprise, however, they inevitably lead to the entrance, reproduction and growth of the microbes, so that there may be corrodible machines and harmful deposits which may affect the quality of the paper.In this thesis, we used the beef extract-peptone medium and the potato medium in which we cultured the bacterium and fungus in the paper pulp added by different amount of two kinds of thiamethoxam antibacterial agents as well as its white water, and we observe and analyze the effect. Also, we analyze the influencing factors to the remanent bacteriostatic agent in the post process of treating wastewater.The results prove that if 1# and 2# thiamethoxam kind of antibacterial agents effect independently and in the case of little dosage, the inhibitory action to the bacterium and fungus in the paper pulp and the water reaches better. When the dosage of 1# antibacterial agent is 10 ppm, the antibacterial efficiency against the bacterium and fungus in the paper pulp whose concentration is 0.8% reached 62% and 86% respectively, and the efficiency reached both about 75% in the white water whose concentration is 0.15%. When the dosage of 2# antibacterial agent is 10 ppm, the efficiency reached 66% and 84% respectively in the paper pulp whose concentration is 0.8%, and it reached about 80% in the white water whose concentration is 0.15%. The antibacterial effect of 2# antibacterial agent is better than that of1#.In the same conditions, the antibacterial efficiency of compound antibacterial agent is higher than that of using either exclusively. When the dosage of 1# antibacterial agent is 12 ppm and the dosage of 2# antibacterial agent is 4 ppm, the antibacterial efficiency against the bacterium and fungus in the paper pulp reached 95% and 98%, and it reached 98% and 96%in the white water. When we analyzed the compound antibacterial agent, we found that in 48 h, the removal rate of bacterium and fungus remain more than 95%. Therefore, it has chronicity.When we treated the waste water, we screened out the 2# as the dominant bacterium.The best condition for it to degrade COD is that the primary concentration of wastewater is60%, and the pH is 8, the temperature should be 35 ℃ as well. As we culture it for 8 hours,the removal rate of COD in the waste water could reach about 85%. Experiencing by thiamethoxam antibacterial agents to influence on the dominant bacteria, the results show that the antibacterial agents will have an inhibiting effect on the dominant bacteria in the activated sludge, and also it will affect the effect of the after-treatment of the waste water.