摘要
污水处理过程中产生大量剩余污泥,使得污泥脱水逐渐成为污泥处理的关键环节。本研究采用生物淋滤方法处理城市污泥,改善污泥脱水性能。通过污泥比阻、滤饼含水率和离心脱水率的变化评价生物淋滤改善剩余污泥脱水性能的效能。综合考虑污泥脱水性能改善效果和运行成本,生物淋滤优化条件为:硫粉投加量3 g/L;Fe2+投加量4 g/L;接种物投加量(接种物与供试污泥的体积比,mL/mL)0.4。在优化条件下,污泥体系被酸化至pH为2.0左右需要36～48 h,淋滤污泥的比阻由1.26×1014 m/kg降至8.14×1012 m/kg,降低了93.54%,滤饼含水率从98.39%降至73.68%,同时污泥离心脱水率从72%提高到83%。回调淋滤污泥pH至6.0,污泥比阻继续降至8.27×1011 m/kg,污泥比阻降低99.34%,污泥从难脱水状态转化为易脱水状态。通过污泥体系中铁离子和污泥絮体特征的变化,分析生物淋滤改善污泥脱水性能的机理。作为底物投加的Fe2+在微生物氧化作用下快速转化为Fe3+。生物氧化产生的Fe3+的絮凝作用可能是生物淋滤改善污泥脱水性能的主要机理。
Because of large quantities of excess sewage sludge produced from wastewater treatment plants, sludge dewatering has become one key of sludge treatment. Sewage sludge bioleaching was optimized to improve sludge dewaterability. Sludge dewaterability was evaluated with specific resistance to filtration （SRF）, water content of filter cake and ratio of water volume to total sludge volume with centrifugal separation. Considering both sludge dewaterability improvement and operation cost, the optimum conditions of sludge bioleaehing were as follows ： sulfur powder addition of 3 g/L, Fe2 ~ addition （ratio of inocula volume to sludge volume, mL/mL） of 4 g/L and inocula addition of 0.4. Under the optimum bioleaching conditions, 36 -48 hours were needed for pH value decrease to about 2.0 ; the sludge SRF decreased from 1.26 x 10TM m/kg to 8. 14 x 1012 m/kg with a SRF reduction of 93.54% , the water content of filter cakes decreased from 98.39% to 73.68% and the ratio of water volume to total sludge volume with centrifugal separation increased from 72% to 83%. After adjusting the pH of bioleaehed sludge back to 6.0, the sludge SRF further decreased to 8.27 x 1011 m/kg with a total SRF reduction of 99.34% , and the sludge can be regarded easy to be dewatered. Change of iron species in sludge system and sludge flocs properties were measured to analyze the mechanism of sludge dewaterability improvement by bi- oleaching. Fe2＋ ions added as bioleaching substrate were quickly converted to Fe3＋ through microorganism oxida- tion. Floeeulation effect of Fe3＋ may be the main mechanism of sludge dewaterability improvement.
出处
《环境工程学报》
CAS
CSCD
北大核心
2012年第8期2793-2797,共5页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(51178047)
高等学校博士学科点专项科研基金(20090014110007)
关键词
城市污泥
生物淋滤
调理
脱水
比阻
铁离子
sewage sludge
bioleaching
conditioning
dewatering
specific resistance of filtration
iron ion
