水热预处理对污泥厌氧产气性能的影响

发布时间：2018-05-13 10:13

  本文选题：污泥 + 水热预处理　； 参考：《青岛科技大学》2017年硕士论文

【摘要】：城市污泥是一种非常复杂的非均质胶团,如果不进行合理处置,不仅会对环境造成严重的污染,同时会造成资源浪费。厌氧消化是国内应用较多的一种污泥处理技术。而传统厌氧消化技术停留时间长,厌氧速率及产气效率低,限制了该技术的发展。水热预处理技术可以破坏污泥细胞结构,促进污泥中有机质溶出从而可以有效的提高污泥厌氧消化速率,提高厌氧产气率。本研究中,利用水热技术对污泥进行预处理,考察了水热过程中污泥固液比、水热时间及温度对污泥中碳氮磷溶出的影响,然后进行厌氧消化,根据累积产气量确定了最佳的水热预处理条件,同时探究了厌氧消化对污泥中碳氮磷溶出的影响,通过研究污泥中氮磷资源的回收及污泥预处理后固液相分别产气,优化了污泥厌氧产气条件,最终确定了整套污泥资源化处理方案。主要实验结果如下:(1)水热预处理可以促进污泥中碳氮磷的溶出,VFAs、COD和总氮的溶出率随着污泥固液比的增大而增大,而氨氮的溶出率逐渐降低,固液比10%时,污泥总磷溶出率最大为95.37%;随着水热时间及温度的增加,污泥中COD及总氮的浓度逐渐增加,VFAs、总磷及磷酸根呈先增大后减小的趋势,氨氮浓度随水热时间的增加先升高后降低,而随着水热温度的升高逐渐升高。(2)污泥水热后,厌氧消化效率提高,累积产气量增大,随着污泥固液比的增大,污泥累积产气量逐渐下降,产气效率降低;随着预处理时间的增长,污泥累积产气量及产气效率降低,而随着水热温度的升高,呈先升高后降低的趋势。根据污泥厌氧产气情况,选择最佳水热条件为污泥固液比在5%,在水热温度为160℃下,处理0.5h。水热预处理后会提高污泥厌氧消化过程中VS和TS去除率,同时会提高沼气中的甲烷含量。(3)厌氧消化后,不同预处理条件下污泥中碳磷浓度下降,氮浓度升高。固液比10%时,TCOD和SCOD降解率最大,分别为23.40和81.55%,总氮和氨氮的浓度升高最多,固液比5%时,总磷和磷酸根降低最多;水热时间为1.0h时TCOD和SCOD降解率最大,分别为17.42%和48.43%,总氮和氨氮浓度升高最多,磷酸根和总磷分别在水热时间为1.5h和0.5h时降低最大;水热温度200℃和160℃时SCOD和TCOD降解率最大,分别为60.24%和39.86%,氨氮和总氮浓度在160℃水热温度下提升最大,水热温度在200℃时,磷酸根和总磷的降低程度最大。(4)水热预处理后回收污泥中的氮磷再进行厌氧消化,会提高污泥厌氧消化性能,同时会提高厌氧消化过程中总氮及磷酸根的溶出率,脱氮磷后污泥累积产气量可提高11.25%,同时日产气效率提高。污泥水热后,将污泥进行固液分离,固液相分别进行产气,会提高污泥厌氧产气效率和产气量,厌氧消化周期可缩短10-15天,其中液相累积产气量是未进行固液分离污泥产气量的1.3倍。
[Abstract]:Urban sludge is a very complex heterogeneous micelle. If it is not disposed properly, it will not only cause serious pollution to the environment, but also cause waste of resources. Anaerobic digestion is a kind of sludge treatment technology which is widely used in China. However, the development of traditional anaerobic digestion technology is limited by its long residence time, low anaerobic rate and gas production efficiency. Hydrothermal pretreatment technology can destroy the cell structure of sludge, promote the dissolution of organic matter in sludge, which can effectively improve the anaerobic digestion rate of sludge and increase the anaerobic gas production rate. In this study, the sludge was pretreated by hydrothermal technique. The effects of the ratio of solid to liquid, the time of water and heat and the temperature on the dissolution of carbon, nitrogen and phosphorus in the sludge were investigated, and then anaerobic digestion was carried out. According to the cumulative gas production, the optimum conditions of hydrothermal pretreatment were determined, and the effects of anaerobic digestion on the dissolution of carbon, nitrogen and phosphorus in sludge were investigated. The recovery of nitrogen and phosphorus resources in sludge and the production of gas in solid and liquid phase after pretreatment were studied. The anaerobic gas production conditions of sludge were optimized, and the whole treatment plan of sludge reuse was finally determined. The main results are as follows: (1) hydrothermal pretreatment can promote the dissolution of carbon, nitrogen and phosphorus in sludge, and the dissolution rate of COD and total nitrogen increases with the increase of solid / liquid ratio of sludge, but the dissolution rate of ammonia nitrogen decreases gradually, when the ratio of solid to liquid is 10, With the increase of hydrothermal time and temperature, the concentration of COD and total nitrogen in sludge increased gradually, the total phosphorus and phosphate radical increased first and then decreased, and the concentration of ammonia nitrogen increased first and then decreased with the increase of hydrothermal time. However, with the increase of hydrothermal temperature, the anaerobic digestibility and cumulative gas production increased. With the increase of the ratio of solid to liquid, the cumulative gas production of sludge decreased gradually and the efficiency of gas production decreased. With the increase of pretreatment time, the cumulative gas production and gas production efficiency of sludge decreased, but with the increase of hydrothermal temperature, the sludge increased first and then decreased. According to the condition of anaerobic gas production of sludge, the optimum water-heat condition is that the ratio of solid to liquid of sludge is 5, the temperature of water and heat is 160 鈩，

本文编号：1882727