生物海绵铁复合填料曝气生物滤器处理养殖海水脱氮条件优化研究

为了提高海水循环养殖系统(RAS)中曝气生物滤器(BAF)系统脱氮效率,减少亚硝态氮(NO^2--N)积累和曝气量,将铁基复合生物填料引入BAF系统,以间歇式曝气营造BAF系统好氧、缺氧和厌氧的循环环境,采用扫描电子显微镜考察了填料表面形态,研究了不同复合填料配比及曝气运行方式下的氮污染物的处理效果,并利用单因素实验对生物滤器的各重要运行参数进行优化。结果显示,添加铁基填料可以提高约10%的脱氮效率,降低25%的NO^2--N积累并节省50%的曝气量;海水BAF系统在如下运行参数条件下有更优的去除性能,间歇曝气时长为12 h,聚碳酸亚丙酯(PPC)凝胶亲水填料与海绵铁复合配比为3∶1,温度为30℃,水力负荷率(HLR)为1.2 m^3/(m^2·d),进水氨氮(NH4^+-N)负荷为1 mg/L。研究表明,在RAS中引入铁基填料并以间歇曝气方式运行,能提高BAF系统处理氮污染物效率,明显降低NO^2--N积累和运行耗电量,为BAF在RAS中的生产应用提供理论依据。

Condition optimization of aquaculture seawater treated by biological aerated filter with biological sponge iron composite filler

To improve the removal efficiency of nitrogen pollutants by the biological aerated filter(BAF)system in a recirculating aquaculture system(RAS)and reduce the accumulation of nitrates and the amount of aeration,a type of iron-based composite biological filler was introduced into the BAF system.The environment of aerobic,anoxic,and anaerobic cycling,in turn,was built with intermittent aeration in this BAF system.The surface morphology characteristics of the fillers were investigated using a scanning electron microscope.The treatment performance of nitrogen pollutants under different proportions of the two substances in the composite filler and different aeration operation modes were investigated.Then,single-factor tests were used to optimize the important operating parameters(including temperature,hydraulic loading rate,and influent ammonia nitrogen load)of the BAF with the iron-based composite biological filler.The results showed that the denitrification efficiency improved by approximately 10%,the accumulation of nitrous nitrogen was reduced by 25%,and 50% of the amount of aeration was saved after adding iron-based packing in the BAF system.The BAF system with the iron-based composite biological filler exhibited the best removal performance under the following operating conditions:Intermittent aeration time of 12 h,composite proportion of the polypropylene carbonate gel hydrophilic filler and sponge iron in the composite filler of 3∶1,the temperature of 30℃,hydraulic loading rate of 1.2 m^3/(m^2·d),and the influent ammonia nitrogen load of 1 mg/L.The introduction of the biological sponge iron composite filler and intermittent aeration could improve the removal efficiency of nitrogen pollutants in the BAF system.It significantly reduced the accumulation of nitrite nitrogen and reduced the power consumption of the operation.The results of this study will be useful in understanding how aerobic and anaerobic environments promote nitrogen transformation.This study also optimized the operating parameters for the actual application of the BAF system with the iron-based composite biological filler in RAS.