587 / 2019-01-19 18:32:47

The Experimental Study on the Dewatering of Digested Sludge with the Pre-treatment by Freezing and Thawing at Different Temperatures

sludge treatment, freezing and thawing technology, drying conditions

全体主题 > 燃料利用与化学循环技术

The production of sewage sludge is increasing with the development of residential, institutional, commercial, and industrial establishments. As it contains a wide range of harmful substances such as heavy metal, pathogenic bacteria and parasite and so on, it must be disposed harmlessly. One of the best ways is to burn with industrial burners. However, its high water content, even up to 99%, restricts its disposal in practice. It is necessary to dewater before burning it. An investigation was conducted on the drying process of digested sludge from a meat processing factory of in Anshan. Two kinds of samples were collected on site at different water content levels from its own sewage treatment plant which includes physical, chemical, and biological processes to remove contaminants and produce environmentally safe treated wastewater. This study on the sewage sludge was performed in the lab to investigate the characteristics when drying at several temperatures compared with those pre-treated under freezing and thawing. The dewatering rate was applied to distinguish the drying process and the change of appearance was detailed observed to illustrate their effect. It is found that the higher the drying temperature, the greater the dewatering rate is. The results also suggest that it is beneficial to dewater with a 10% increase through the method of freezing and thawing in removing the free water between micro gaps. Therefore, freezing and thawing method has the great potential of application in the drying process with the benefit of remove bacteria from sludge at the same time.