摘要
利用复合嗜酸性硫杆菌(氧化硫硫杆菌和氧化亚铁硫杆菌)在不同接种量下(5%,10%,20%)对城市污泥进行生物沥浸,探讨了沥浸过程中不同重金属的浸出效果及其与pH值和氧化还原电位(ORP)的相关关系.结果表明,该方法能有效地浸出污泥中的重金属,生物沥浸处理10d后,污泥中Cu、Zn和Ni的浸出率可分别达到98%、99%和90%,硫杆菌接种量越大,沥浸反应速率越快,20%接种处理>10%接种处理>5%接种处理>未接种处理.污泥生物沥浸过程中pH的下降和ORP的上升,是促进污泥重金属溶出的主要驱动力,但其中Cu的浸出同时受pH下降和ORP上升的双重影响,而Zn和Ni的浸出则主要受pH影响.污泥中Cu、Zn和Ni开始大幅度浸出的pH阈值大约为4、5和5左右.研究还发现,生物沥浸处理虽可使污泥中有机质、全氮、全磷和全钾含量有所下降,但并不影响其农业利用价值.
The effect of the co-inoculation of two acidophilic Thiobacillus （Acidithiobacillusferrooxidans LX5 and Acidithiobacillus thiooxidans TS6） on the solubilization efficiency of sludge-born heavy metals by bioleaching was studied in batch experiments. The correlation between sludge-born metal solubilization and pH and/or oxidation-reduction potential （ORP） arising from bioleaching is also discussed. The results show that bioleaching with the two acidophilic Thiobacillus greatly improved the heavy metal solubilization efficiency from a sludge matrix. Removal efficiencies of 98% for Cu, 99% for Zn, and 90% for Ni were obtained after 10 days of bioleaching. The greater the inoculum percentage, the shorter the bioleaching time. For example, the bioleaching reaction time for different inoculum treatments were in the order 20% inoculum 〈 10% 〈 5% 〈 0% （control）. The decrease of pH and the increase of ORP from bioleaching were two important factors resulting in metal solubilization, especially for sludge-born Cu. However, the solubilization of Zn and Ni derived from sludge was attributed to the pH decrease only. The effect of ORP on Zn and Ni solubilization was not observed. It was found that the threshold values of pH for metal solubilization were about pH 4 for Cu, pH 5 for Zn, and pH 5 for Ni. In addition, the contents of organic matter, nitrogen, phosphorus, and potassium in bioleached sludge were, to a certain extent, decreased due to bioleaching treatment, but this did not affect the application of bioleached sludge to farmland.
出处
《环境科学学报》
CAS
CSCD
北大核心
2008年第6期1155-1160,共6页
Acta Scientiae Circumstantiae
基金
国家高技术研究发展计划(863)项目(No.2006AA06Z314)
教育部新世纪优秀人才支持计划(No.NCET-04-0505)~~
关键词
城市污泥
生物沥浸
嗜酸性硫杆菌
重金属
municipal sludge
bioleaching
acidophilic Thiobacilli
heavy metal
