城市污水处理厂污泥制取生物柴油的试验研究

Biodiesel Production from Sludge of Municipal Wastewater Treatment Plants by In-situ Transesterification

以某污水处理厂的二沉污泥为研究对象，在不同温度条件下通过原位酯化试验制取生物柴油，并实现污泥的减量化和稳定化，同时对制取生物柴油过程中产生的有机溶剂进行回收和利用。结果表明，二沉污泥在酸催化条件下通过原位酯化可以使其中的脂质转化为生物柴油，污泥减量率平均为71.6％，减量后的污泥VSS／SS平均值为0.30，十分稳定。气相色谱分析表明，生物柴油的最大产量为1.93％，脂肪酸甲酯主要为棕榈油酸甲酯、棕榈酸甲酯、油酸甲酯、硬脂酸甲酯和亚油酸甲酯，且在55～75℃范围下温度对生物柴油产量及脂肪酸甲酯类型的影响不大。此外，用于酯化的甲醇回收后可以用作污水处理中反硝化的有机碳源。

The biodiesel production from secondary sludge of a municipal wastewater treatment plant was studied by in-situ transesterification under different temperatures to achieve sludge reduction and stabilization. The organic solvent from the production process was recovered and utilized subsequently. The results showed that the lipid in the secondary sludge could be converted into biodiesel by in-situ transesterification in the presence of acid catalyst. Meanwhile, the sludge reduction rate attained an average of 71.6% and the VSS/SS ratio was very stable at approximately 0.30. Gas chromatography analysis of fatty acid methyl esters （FAMEs） revealed that the maximum yield of biodiesel from the secondary sludge by in-situ transesterification was 1.93% and FAMEs produced from the sludge mainly contained methyl esters of palmitoleic acid, palmatic acid, oleie acid, stearic acid and linoleic acid. Temperatures between 55℃ and 75 ℃ had little effect on the biodiesel yield and types of FAMEs. Moreover, the recovered methanol during transesterification could be used as a carbon source for denitrification in wastewater treatment plants.