水热+厌氧消化对污泥碳、氮、磷溶出的影响

研究了水热预处理和厌氧消化联合作用时温度对污泥中碳、氮、磷溶出的影响。结果表明:水热处理温度越高越有利于污泥中碳氮磷的溶出,当水热温度为200 ℃时,SCODCr的溶出率较原泥提高了5.9倍;氨氮和总氮的溶出率分别提高了7.2和8.7倍;磷酸根和总磷的溶出率分别提高了0.2和6.1倍。厌氧消化后污泥中碳磷浓度下降,而氮浓度上升。厌氧消化后累积产气量与水热温度有关:当温度为160 ℃时,最大累积产甲烷量为12 223 L/mg-CO D C H 4 (以每mg COD的产甲烷量计),较原泥提高了14.5倍。根据试验结果,提出了从水热和厌氧消化污泥中回收氮磷的策略,即水热处理污泥后可在污泥清液中投加镁源进行磷的回收,厌氧消化中溶出的氮可通过加入吸附材料进行吸附回收。在污泥中氮磷资源回收的同时,可通过水热过程提高污泥厌氧过程中累积产甲烷量。

Effect of hydrothermal and anaerobic digestion on dissolution of carbon,nitrogen and phosphorus in sludge

The influence of hydrothermal pretreatment temperature and anaerobic digestion on the dissolution of carbon, nitrogen and phosphorus in sludge was studied. The results showed that the higher the hydrothermal pretreatment temperature was more favorable to the dissolution of carbon, nitrogen and phosphorus. When the hydrothermal pretreatment temperature was 200 ℃, the dissolution rate of SCODCr improved by 5.9 times compared with the raw sludge, the rate of NH3-N and TN improved by 7.2 and 8.7 times, and the rate of P O 4 3 - and TP improved by 0.2 and 6.1 times, respectively. After the anaerobic digestion, the carbon and phosphorus content in sludge decreased, while the nitrogen content increased. The cumulative methane production was related to the hydrothermal treatment temperature; when the hydrothermal temperature was 160 ℃, the cumulative methane production was up to 12 223 L/mg-CO D C H 4 , increased by 14.5 times than that of the raw sludge. According to the experimental results, strategy for recovering nitrogen and phosphorus from the hydrothermal and anaerobic digestion sludge was proposed, including adding some magnesium source after hydrothermal pretreatment so as to recover phosphorus, and adding some adsorbent to adsorb the nitrogen during the dissolution of anaerobic digestion. It was also proposed that while recycling the nitrogen and phosphorus in sludge, the cumulative methane production in anaerobic digestion should be improved through water and thermal process.