• 关键词：制革污泥  生物淋滤  铬  调理  沉降  脱水

• 基金项目：国家自然科学基金(20377023);江苏省自然科学基金重点项目(BK2004213);浙江省重大科技攻关项目(2004C10004)

• 周立祥
• 南京农业大学资源环境学院,南京210095

• 周顺桂
• 南京农业大学资源环境学院,南京210095

• 王世梅
• 南京农业大学资源环境学院,南京210095

• 方迪
• 南京农业大学资源环境学院,南京210095

• 王电站
• 南京农业大学资源环境学院,南京210095

• 摘要：构建了一个以70L生物淋滤反应器为主体的制革污泥生物除铬的工艺。 实际运行结果表明, 采用特异的硫杆菌TS6, 反应6d, 制革污泥中Cr溶出率可达到87.4%。 随后进行的污泥沉降与离心脱水试验表明, 生物淋滤具有显著的污泥调理功效, 显著提高污泥沉降与机械脱水性能。 生物淋滤处理的污泥, 经12h的静置沉降, 污泥体积可减少57.2%, 并且无需添加任何絮凝剂, 即可取得良好的机械脱水效果。 生物淋滤处理导致的污泥体系pH的下降与Fe³⁺浓度的上升可能是污泥沉降与脱水性能得以改善

• Abstract：In China, about 300,000 tons of Cr(Ⅲ)-containing tannery sludge are annually produced. The Cr(Ⅲ) removal and recovery from the tannery sludge will greatly reduce the environmental risk when the decontaminated sludge is applied as organic manure or soil conditioner. The first step of Cr recovery is the extraction from tannery sludge. The Cr(Ⅲ)and other metals chemical leaching from tannery sludge by mineral acids has been studied. However, this process has never been applied because of high cost, operational difficulties and large consumption of chemical agents. A bioleaching process based on 70L bioreactor was developed for extracting Cr(Ⅲ) from tannery sludge. The results showed that the inoculation of the adapted Acidithiobacilli (Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans) and 3.0g·L^-1 S⁰ addition as their substrates could accelerate Cr solubilization from tannery sludge. After 6 days of hydraulic residence time, pH of the sludge decreased from initial 6.0 to 1.82, and the Cr removal efficiency reached 87.4%. Chromium solubilization occurred through acidification of the sludge media derived from the bacterial oxidation of added sulfur and native ferrous sulfide in tannery sludge. The valence of chromium extracted from the sludge during the bioleaching process predominate as Cr(Ⅲ), indicating that Acidithiobacilli and the chemical oxidant (Fe³⁺) could not transform low toxicity Cr(Ⅲ) into high level Cr(Ⅵ) in the bioleaching process. Tannery sludge is difficult to be dewatered. Generally, it is required to add inorganic or organic flocculating agent in sludge prior to dewatering sludge. However, the experiment showed that the bioleaching process improved markedly the ability of the settlement and dehydration for the bioleached sludge. The volume of the bioleached sludge decreased 57.2% after 12h settling, meanwhile the untreated sludge only reduced 33.2%. The bioleached sludge was easier to dewater than untreated sludge as well as the sludge with 30mg/L PAM. As a result, the inorganic or organic flocculating agent was not required for dewatering the bioleached sludge. Low pH and high Fe³⁺ concentration resulted from the sulfur element and native ferrous sulfide oxidation in tannery sludge seems to be responsible for enhancing the ability of the settlement and dehydration.

• Key words：tannery sludge  bioleaching  Cr  conditioning  settlement  dehydration

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