標題: Expression dewatering of alum-coagulated clay slurries
作者: Chang, IL
Chu, CP
Lee, DJ
Huang, CP
環境工程研究所
Institute of Environmental Engineering
公開日期: 1-五月-1997
摘要: Filtration followed by expression characteristics of the alum-coagulated clay slurries are first reported in this paper. A strong correlation between alum chemistry and the dewatering efficiency exists. At pH 3, where the positively charged ions are the dominating species, the alum addition has only a minor improvement on dewatering efficiency. At pH 7 and pH 10, where sweep flocs enmeshment play the major role, dewatering performance improves continuously as alum dose increases. At pH 5.2, where a charge reversal regime exists, the dewatering efficiency exhibits a reversal phenomenon as well. The overall dewaterability follows: pH 5.2 > pH 3 > pH 7 > pH 10. A complete test consists of the filtration and expression stages, which are discussed separately. The filtration stage is discussed based on the average specific resistance and the residual moisture in the filtration cake. The expression stage is discussed based on the combined Terzaghi-Voigt rheological model, from which the fraction contributed by the secondary consolidation (B) and the particle creeping factor (eta) are evaluated. For the dewatering sake, a lower B and a higher eta are desired. Both parameters B and eta increase at elevated alum dose and/or lower pH value, while exhibiting a local minimum in charge reversal regime at pH 5.2. The optimal alum dose considering sludge dewaterability is discussed.
URI: http://dx.doi.org/10.1021/es9605329
http://hdl.handle.net/11536/565
ISSN: 0013-936X
DOI: 10.1021/es9605329
期刊: ENVIRONMENTAL SCIENCE & TECHNOLOGY
Volume: 31
Issue: 5
起始頁: 1313
結束頁: 1319
顯示於類別:期刊論文


文件中的檔案:

  1. A1997WW94800026.pdf