Studies On The Technology Of Mixed Thiobacillus For Sludge Biotreatment

As an environment-friendly sludge treatment technology, biological treatment will be widely used in the field of urban sewage sludge and industrial sludge treatment with its low cost, good treatment effect, few secondary pollution and less nutrient loss. This topic aimed to study the sludge treatment technology by mixed thiobacillus composed of thiobacillus ferrooxidans and thiobacillus thiooxidans. In order to optimize the sludge treatment process and improve the effect of sludge treatment, a series of process optimization tests were conducted.Primarily, to confirm the optimum formula of mixed thiobacillus and explore the influence of inoculum size, nutrient quantity, sludge moisture content, initial p H and reflux ratio on sludge treatment, a group of sequencing tests were carried out with conical flask. The results showed that sludge treatment effect displayed a marked difference under different conditions of culture compose, inoculum size, nutrient quantity, sludge moisture content, initial p H and reflux ratio. From the test results, it could be achieved that the optimal conditions of these factor were: thiobacillus ferrooxidans:thiobacillus thiooxidans = 4:1, inoculum size 15%, nutrient quantity 10g/L, sludge moisture content 98%, initial p H 6.0, reflux ratio 20%; Based on this, a dynamic amplification reaction system was designed, and anova was done on the influence of sludge moisture content, nutrient quantity, aeration rate and reactor amount on the sludge treatment. The orthogonal tests showed that: sludge moisture content made a appreciable impact on the sludge treatment effect(0.01 < p < 0.05); nutrient quantity also made a significant impact(0.05 < p < 0.1); aeration rate made a certain impact(0.5 > p > 0.1), while reactor amount made the lowest impact on the sludge treatment effect. These factors showed an affecting order of: sludge moisture content > nutrient quantity > aeration rate > reactor amount. Then optimal technological condition was obtained from the orthogonal tests, it was: sludge moisture content 97.3%,aeration rate 8 m3?h-1,nutrient quantity 9 g/L,reactor amount 10. Besides, sludge from three different wastewater treatment plants was used for testing the sludge treatment effect of the dynamic amplification reaction system under the optimal technological condition, and it could be obtained that: under the optimal technological condition, the dynamic amplification reaction system could effcetively treat different kinds of sludge. The filter cake moisture content could be less than 60%, and the amount of heavy metals were far less than limited value, while the amount of organic matters decreased less than 10%. So the treated filter cake was very fit for recycling application.