摘要
超滤(UF)是沼液膜分离资源化处理的重要单元,能高效地去除悬浮物和胶体等物质,已有的研究大多关注于膜污染与膜通量的关系,缺乏对膜污染机制的分析。为进一步满足工程化需要,本研究以畜禽养殖场沼液为对象,采用截留分子量为30000、50000、100000和500000的UF膜开展浓缩试验,系统分析膜孔径对养分截留效率、膜通量变化规律及污染机理的影响。研究结果表明:不同孔径UF膜均能高效截留沼液中的COD,截留率超过80%。但对总氮、总磷和总钾截留性能整体较差,分别为24.0%~27.0%、59.0%~69.0%和9.0%~9.5%。在沼液浓缩5倍的膜浓缩过程中,水通量表现出初期速降,后保持平稳状态,最终再下降的现象,其主要污染机理为有机-无机复合滤饼层污染,占污染总阻力96%以上,吸附污染占总阻力低于3%,随孔径变大而增加。100000膜在膜处理过程中,其通量维持能力优于500000、50000、30000膜。综合稳定水通量、养分截留和膜污染情况,确定适用于沼液浓缩的UF膜的截留分子量为100000。
Ultrafiltration(UF)is a crucial unit in the resource-oriented membrane separation treatment of biogas slurry,as it can efficiently remove suspended solids,colloids and other substances.Most studies have focused on the relationship between membrane fouling and membrane flux,while there is a lack of analysis on membrane fouling mechanisms.To further meet the needs of engineering applications,this study conducted concentration experiments using UF membranes with molecular weight cut-off(MWCO)of 30000,50000,100000 and 500000,taking biogas slurry from livestock and poultry farms as the research object.The effects of membrane pore size on nutrient rejection efficiency,membrane flux variation patterns and fouling mechanisms were systematically analyzed.The results showed that UF membranes with different pore size could all efficiently retain COD in the biogas slurry,with a rejection rate exceeding 80%.However,their retention performance for total nitrogen(TN),total phosphorus(TP)and total potassium(TK)was generally poor,ranging from^(2)4.0%to 27.0%,59.0%to 69.0%,and 9.0%to 9.5%respectively.During the membrane concentration process where the volume of biogas slurry was concentrated 5 times,the water flux exhibited a pattern of a rapid initial decline,followed by a stable state,and a final decline again.The main fouling mechanism was organic-inorganic composite cake layer fouling,accounting for more than 96%of the total fouling resistance,while adsorption fouling accounted for less than 3%of the total resistance.Moreover,the adsorption fouling showed an increasing trend as the membrane pore size increased,with inter-pore adsorption being the main cause.During enhanced water recovery,the 100000 membrane demonstrated superior flux sustainability compared to 500000,50000 and 30000 membranes.Considering the integrated factors of stable water flux,nutrient retention and membrane fouling propensity,the optimal molecular weight cut-off of UF membrane determined for biogas slurry concentration was 100000.
作者
曹琦
吕晶淼
崔文静
亓传仁
李赟
韩先杰
罗文海
CAO Qi;LYU Jingmiao;CUI Wenjing;QI Chuanren;LI Yun;HAN Xianjie;LUO Wenhai(College of Resources and Environment,China Agricultural University,Beijing 100193,China;College of Resources and Environment,Qingdao Agricultural University,Qingdao 266109,China;College of Veterinary Medicine,Qingdao Agricultural University,Qingdao 266109,China)
出处
《膜科学与技术》
北大核心
2025年第5期181-190,共10页
Membrane Science and Technology
基金
“农业废弃物协同高效处理低碳资源化利用关键技术装备研发及集成示范”项目(2023YFD1701702)
山东省自然科学基金(ZR2022QD038)
山东省现代农业产业技术体系(SDAIT-08-09)。
关键词
超滤
膜污染
沼液
膜孔径
ultrafiltration
membrane fouling
biogas slurry
pore size
