冻融对碱性发酵污泥脱水性能的影响

摘要

In order to study the effects of freezing -thawing on the alkline fermentation sludge dewater ability , experiments were carried out to the alkline sludge pH adjusted by Ca ( OH) 2 and NaOH respectively by measuring the capillary sunction time ( CST ) , particle , 70 minSV, soluble COD, proteins, carbohydrates, ammonia and orthophosphate .The results showed freezing-thawing conditioning can improve the dewater ability of alkline fermentation sludge well.The CST of sludge pH adjusted by Ca (OH)2 decreased to 21.4 s under -19~-13 ℃after 6 h and 18.5 s under -8 ℃after 24 h from 101.5 s.For the sludge pH ad-justed by NaOH the CST decreased from 1 058.6 s to 33.9 s at the end of freezing-thawing conditioning under natural conditioning , but remained at 300 s above under -8℃.It dem-onstrated that the SCOD , soluble proteins , carbohydrates , ammonia , and orthophosphate de-clined in different degrees for sludge pH adjusted by NaOH , but unchanged for sludge pH adjusted by Ca ( OH ) 2 during freezing -thawing conditioning .The SCFAs ( shorty chain acids) increased slightly for both of them .In total, the freezing-thawing is a possible way to improve the alkline fermentation sludge dewater ability and to obtain high organics recover -y efficiency .%为了考察冻融对碱性发酵污泥脱水性能的影响，在自然条件（-19～-13℃）和恒温条件（-8℃）分别对Ca（ OH）2和NaOH作为碱试剂的发酵污泥进行了冻融处理，测定了冻融过程中毛细吸水时间（CST）、粒径、70 minSV以及各物质的变化情况．结果表明，冻融对碱性发酵污泥能起到较好的调理效果：对Ca（OH）2作为碱试剂的发酵污泥，CST在自然条件下经6 h冰冻由101．5 s下降到了21．4 s，在-8℃条件下经24 h冰冻可以下降到18．5 s．对NaOH作为碱试剂的发酵污泥在自然条件下冻融72 h，CST由1058．6 s下降到了33．9 s，而-8℃条件下仍然在300 s以上．通过对冻融过程各溶出物的分析，得出NaOH作为碱试剂的发酵污泥在冻融过程中SCOD（溶解性有机物）、蛋白、多糖、氨氮和磷均有不同程度的下降，而Ca（ OH）2作为碱试剂发酵污泥的变化则不大，两种过程中有机酸的均有小幅度上升．试验表明冻融是一种较好的改善碱性污泥脱水性能并且获得较高有机物回收率的方法．