基于超声波定位技术的流化床生物滤器研发与性能分析

Design and performance of fluidized sand biofilter based on ultrasonic positioning technology

为解决流化床生物滤器在运行过程中存在床层增高影响其正常使用的问题,研发了基于超声波定位技术的滤料自清洗装置。以常规流化床生物滤器为对照组(CF),研发的自清洗流化床生物滤器为试验组(EF),比较了两组流化床生物滤器的床层增高和滤料流失程度,研究了流化床生物滤器的水处理性能。结果显示:采用超声波定位技术可有效控制流化床生物滤器的床层增高和滤料流失程度,在150%床层膨胀率下,EF组每周的床层增高和滤料流失仅为1.8±0.3 cm和28±12 g,比CF组分别降低了500%和350%。EF组的平均总氨氮(TAN)去除负荷达到了762±164.33 g/(m^(3)·d),显著高于CF组(P<0.05),在TAN快速降解的过程中,两组亚硝酸盐氮未出现明显的累积,水体中的溶氧质量浓度、碱度和COD浓度都出现一定的下降。EF组表层和底层滤料的细菌种群结构和丰度未出现明显的差异,主要优势细菌包括赭黄嗜盐囊菌属,Candidatus_Microthrix,红杆菌属和硝化螺菌属。CF组表层和底层滤料的细菌种群结构和丰度的差异较大,而优势菌群的种类较为相似,主要为罗姆布茨菌和Clostridium_sensu_stricto_1。EF组的硝化螺菌属丰度显著高于CF组,说明采用超声波技术实时控制床层高度有利于氮转化细菌的富集,进而提升了流化床生物滤器运行时的水处理性能。

To solve the problem of fluidized bed biofilter in the process of operation with the phenomenon of bed elevation which affects its normal use,a filter media self-cleaning device based on ultrasonic positioning technology was developed and the biofilter was integrated into the scortum barcoo recirculating aquaculture system.The conventional fluidized sand biofilter was used as the control group (CF) and the developed self-cleaning fluidized sand biofilter was used as the experimental group (EF).The degree of bed elevation and media loss in the two groups of fluidized sand biofilter were compared,the removal load on TAN was studied,and the differences in bacterial community structure in different areas of the fluidized sand biofilter were analyzed by high-throughput sequencing.The results showed that the bed height and media loss of the fluidized sand biofilter could be effectively controlled by ultrasonic positioning technology,and the weekly bed height and media loss of the EF group were only 1.8±0.3 cm and 28±12 g at a 150% bed expansion rate,which was 500% and 350% lower than those of the CF group,respectively.The average TAN removal load of the EF group reached 762 ± 164.33 g/(m^(3)·d),which was significantly higher than that of the CF group ( P < 0.05 ).During the rapid degradation of TAN,nitrite nitrogen did not accumulate significantly in both groups,and the dissolved oxygen concentration,alkalinity,and COD concentration in the water were all decreased to some extent.No significant differences in the structure and abundance of bacterial populations between the surface and bottom filter media of the EF group were observed,with the main dominant bacteria including Haliangium,Candidatus_Microthrix,Rhodobacter ,and Nitrospira .The differences in the structure and abundance of bacterial populations between the surface and bottom media of the CF group were greater,while the dominant species were relatively similar,with the dominant populations being Romboutsia and Clostridium_sensu_stricto_1.The abundance of Nitrospira was significantly higher in the EF group than in the CF group,suggesting that maintaining the biofilm thickness at a reasonable level may facilitate the enrichment of functional bacteria and thus enhance the nitrification performance of the fluidized sand biofilter.