基于正渗透技术的沼液浓缩工艺优化  

Optimization of forward osmosis process for concentration of biogas slurry

作　　者：许美兰[1] 叶茜[1] 李元高[1] 宋燕清 肖芬 

机构地区：[1]厦门理工学院厦门市膜技术研发及应用重点实验室,厦门361024 [2]武汉市博天环境集团股份有限公司,武汉430000

出　　处：《农业工程学报》2016年第2期193-198,共6页Transactions of the Chinese Society of Agricultural Engineering

基　　金：福建省科技计划重点项目(2013N0035);福建省资助省属高校科研专项课题(2014JK0035)

摘　　要：为解决沼液体积过大,难以实际应用的问题,采用正渗透技术对沼液进行浓缩。通过对不同条件下沼液正渗透浓缩工艺运行性能的研究,发现较优的膜朝向为活性层朝向沼液;错流速度宜采用20.5 cm/s;汲取液宜选择浓度为2 mol/L的MgCl_2溶液。在上述优化条件下将沼液浓缩至5倍。浓缩后的沼液中溶解性有机物、总磷、总氮、氨氮和总钾浓度均显著提高。正渗透膜对上述物质的截留率均达到80%以上。该研究为沼液正渗透浓缩技术的广泛应用提供了一定的技术基础。Biogas slurry is one of the products of anaerobic fermentation of livestock wastewater, which contains substantial quantities of organic matter, nitrogen, phosphorus, potassium and other nutrients. For environmental protection and resources recycling, the biogas slurry could be used as a fertilizer. However, the biogas slurry could not be completely used for nearby farmland and it is difficult to transport such large volume of biogas slurry. Therefore, concentration becomes important for economic transportation and practical application of the biogas slurry as a fertilizer. In recent years, forward osmosis（FO） concentration technology has attracted growing interest. However, there were few researches concerning concentration of the biogas slurry with FO technology. To facilitate the extensive application of FO process for concentration of biogas slurry, further and comprehensive works should be carried out. In this study, a forward osmosis process was built for concentration of the biogas slurry and the performance of this process under different conditions was investigated. The results indicated that the membrane orientation should be set as FO model when the active layer was facing the feed solution. When the support layer was facing the feed solution（pressure retarded osmosis, PRO model）, although the initial water flux was higher, the water flux declined quickly. Under the FO model, the hydraulic shear caused by the cross flow could prevent the deposition of the solutes of the biogas slurry over the active layer of the membrane, thereby alleviating the membrane fouling. By comparing the performance of the FO process under different cross flow velocities of 10.2, 15.4, 20.5, 25.6 and 30.7 cm/s, the cross flow velocity of 20.5 cm/s was considered to be preferred for this process. When the cross flow velocity was increased to be 25.6 and 30.7 cm/s, the water flux decline quickly, which was possibly due to the severer internal concentration polarization and membrane fouling caused by the higher initial wa

关 键 词：浓缩 优化 渗透 沼液 膜朝向 错流速度 汲取液 

分 类 号：X71[环境科学与工程—环境工程] S19[农业科学—农业基础科学]