氧化亚铁硫杆菌对聚丙烯酰胺脱水重溶污泥的调理

Conditioning of Cationic Polyacrylamide Dehydrateded Re-dissolved Sludge by Acidithiobacillus ferrooxidans

为改善阳离子型聚丙烯酰胺(CPAM)脱水重溶污泥的脱水性能,利用嗜酸性氧化亚铁硫杆菌(简称At.f)氧化Fe^2+及产酸特性,进行了批式试验,并对菌液接种量,胞外聚合物(EPS)各层中可溶性蛋白质、多糖含量变化及泥浆颗粒表面形态进行了研究。结果表明,营养剂添加量为1.2g/L时,经At.f菌处理后pH值降到3.00以下,Fe^2+氧化率达到99.4%,污泥比阻由初始的9.49x10^12m/kg(难脱水污泥)降至最终的0.57x10^12m/kg(易脱水污泥);菌液接种量为50%时,pH值稳定在3.00以下,Fe^2+利用率达到99.7%;EPS黏液层中可溶性蛋白质、多糖含量的升幅分别较对照组下降了21.36%、26.95%,松散结合的胞外聚合物层(LB-EPS)和紧密结合的胞外聚合物层(TB-EPS)中蛋白质含量之比降低了73.02%、多糖含量之比降低了90.11%,EPS各层结构的组分向易脱水趋势改变;CPAM脱水重溶污泥由分散的絮状体变为晶型规则的块状物,在20MPa压力下进行板框压滤,泥饼含水率<60%。在营养剂添加量为1.2g/L、接种量为50%的优化条件下,At.f菌改善了CPAM脱水重溶污泥的脱水性能。

To improve the dewaterability of cationic polyacrylamide ( CPAM ) dehydrateded re-dissolved sludge, sequencing batch experiments were conducted, in which Acidithiobacillus ferrooxidans (At.f) was used to oxidize Fe^2+ and produce acid to improve the sludge dewatering performance. The effect of At. f inoculation amount, the content changes of soluble proteins and polysaccharides in different layers of extracellular polymeric substances ( EPS) and variations of sludge surface morphology were studied. The results showed that the ferrous oxidation rate reached 99. 4% when pH value of the sludge decreased to less than 3. 00 and the specific resistance to filtration ( SRF) of sludge decreased from initial 9.49 x 10^12 m/kg ( sludge hard to dewater) to the final 0.57 x 10^12 m/kg (sludge easy to dewater) with the nutrient dosage of 1. 2 g/L. When At. f inoculation amount was 50%, the pH value of the sludge decreased to less than 3. 00 and ferrous oxidation rate reached 99. 7%. Compared to the control group, the increament of soluble protein and polysaccharide in EPS slime decreased by 21. 36% and 26. 95%, respectively. Protein ratio of loosely bound EPS (LB-EPS) to tightly bound EPS (TB-EPS) dropped by 73. 02%, and polysaccharide ratio dropped by 90. 11%.EPS components of each layer tended to be easily dehydrated. Morphology of the CPAM dehydrated Tedissolved sludge changed from scattering floc to regular crystals. At the condition of 20 MPa pressure, the moisture content of the sludge decreased to less than 60%. At. f improved dewatering performance of the CPAM dehydrated re-dissolved sludge when the nutrient dosage was 1. 2 g/L and the inoculation amount of At.f was 50%.