Abstract Biofloc systems rely on suspended solids in the water to house microbes that can remove or cycle nitrogenous wastes; however, nitrogen cycling can be inconsistent. In contrast, external biofilters are used in many recirculating systems to provide a more consistent environment for microbes to process nitrogen. Regardless of the biofiltration approach, solids levels must be controlled to prevent issues in shrimp such as gill fouling, low dissolved oxygen levels, and other negative impacts. The purpose of this study was to examine the effects of settling chambers versus foam fractionators for solids filtration and to compare external biofilters to the biofloc approach as biofiltration strategies. Sixteen 1-m3 round, polyethylene tanks were randomly assigned to four treatments, each of which had four replicate tanks. Eight biofloc systems were established: four using settling chambers for solids control (BF-S) and four using foam fractionators (BF-F). The other eight tanks used external biofilters; four had settling chambers (EB-S) and the other four had foam fractionators (EB-F). All 16 systems were stocked with 250 shrimp at an average size of 4.3 g which were grown for 85 days. There were no significant differences in shrimp production between treatments; however, variability was high in biofloc systems. Nitrite levels were significantly lower in systems with fractionators compared to systems with settling chambers. The concentrations of dissolved Na, Mg, Ca, Sr and Ba in the water were significantly reduced in treatments with settling chambers. The results of this study show that filtration choices significantly impact short- and long-term water quality and reusability but may not have much effect on shrimp production in the short-term.

中文翻译：

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不同固体和生物过滤器对太平洋白虾（Litopenaeus vannamei）集约化生产系统的影响

摘要 生物絮团系统依靠水中的悬浮固体来容纳可以去除或循环含氮废物的微生物；然而，氮循环可能不一致。相比之下，外部生物过滤器用于许多再循环系统，以为微生物提供更一致的环境来处理氮。无论采用何种生物过滤方法，都必须控制固体含量以防止对虾的问题，例如鳃污染、低溶解氧含量和其他负面影响。本研究的目的是检查沉降室与泡沫分馏器对固体过滤的影响，并将外部生物过滤器与生物絮凝方法作为生物过滤策略进行比较。16 个 1 立方米圆形聚乙烯罐被随机分配到四个处理中，每个处理有四个重复罐。建立了八个生物絮团系统：四个使用沉降室进行固体控制 (BF-S)，四个使用泡沫分馏器 (BF-F)。其他八个水箱使用外部生物过滤器；四个有沉降室（EB-S），另外四个有泡沫分馏器（EB-F）。所有 16 个系统都放养了 250 只虾，平均大小为 4.3 克，生长了 85 天。处理间虾产量无显着差异；然而，生物絮团系统的可变性很高。与带有沉降室的系统相比，带有分馏器的系统中的亚硝酸盐水平显着降低。在沉降室处理中，水中溶解的 Na、Mg、Ca、Sr 和 Ba 的浓度显着降低。