Based on the filtration of sand filter bed, a solid and nitrification biofilter of floating plastic bead was designed and tested. In the biofilter, the bead was layered automatically in water according to the size and...Based on the filtration of sand filter bed, a solid and nitrification biofilter of floating plastic bead was designed and tested. In the biofilter, the bead was layered automatically in water according to the size and gravity of plastic bead. With two types of diameter 5 mm gravity 0.94 and diameter 2 mm gravity 0.5 beads, the biofilter performed well in solid separation and ammonia nitrification. The bead filter performances were tested in a recirculating aquaculture system. When pump power was 0.75 kW and flow quantity was 20 m^3·h~ -1, the recirculating culture system could support 10 m^3 water in culture density of 16 kg·m~ -3 Amur sturgeon. Suspended solid filtering rate was 90% and ammonia nitrification capacity was 149 g·m~ -3·d~ -1. Within water exchanged period of two weeks, the water quality was as following, SS≤100 mg·L~ -1, Ammonia≤1.0 mg·L~ -1, Nitrite≤0.18 mg·L~ -1 and Nitrate 24≤mg·L~ -1. After 15 days’ culture, fish survival rate was 99% and growth rate was 50%. The experiment result showed that the bead biofilter could meet the need of recirculating aquaculture system in solid separation and ammonia nitrification.展开更多
文摘Based on the filtration of sand filter bed, a solid and nitrification biofilter of floating plastic bead was designed and tested. In the biofilter, the bead was layered automatically in water according to the size and gravity of plastic bead. With two types of diameter 5 mm gravity 0.94 and diameter 2 mm gravity 0.5 beads, the biofilter performed well in solid separation and ammonia nitrification. The bead filter performances were tested in a recirculating aquaculture system. When pump power was 0.75 kW and flow quantity was 20 m^3·h~ -1, the recirculating culture system could support 10 m^3 water in culture density of 16 kg·m~ -3 Amur sturgeon. Suspended solid filtering rate was 90% and ammonia nitrification capacity was 149 g·m~ -3·d~ -1. Within water exchanged period of two weeks, the water quality was as following, SS≤100 mg·L~ -1, Ammonia≤1.0 mg·L~ -1, Nitrite≤0.18 mg·L~ -1 and Nitrate 24≤mg·L~ -1. After 15 days’ culture, fish survival rate was 99% and growth rate was 50%. The experiment result showed that the bead biofilter could meet the need of recirculating aquaculture system in solid separation and ammonia nitrification.
文摘为了解凡纳滨对虾(Litopenaeus vannamei)养殖过程中挂膜式生物滤器内不同位置间微生物群落结构多样性的差异,采集已运行46 d的挂膜式生物滤器内挂膜上部外侧和内侧、下部内侧和外侧及收集盘5个不同位置的微生物,采用分子生物学手段,通过16S r RNA基因高通量测序法对生物滤器内微生物进行多样性分析,并对不同位置间功能性微生物进行对比。结果显示,在门水平上,5个不同位置共鉴定出10个主要类群,其中,变形菌门(Proteobacteria)所占丰度比例较大,为主要优势类群,硝化螺旋菌门(Nitrospirae)在挂膜内外两侧检出比例均较高(平均4.3%),收集盘内则较低(0.33%),存在显著性差异。共鉴定出41种优势属,其中地杆菌属(Pedobacter)为绝对优势种属,短小盒菌属(Parvularcula)为次优势属,二者丰度比例均在10%以上,硝化螺旋菌属(Nitrospira)为第三优势属,挂膜不同位置丰度比例(平均4.31%)显著高于收集盘内比例(0.28%)。挂膜上氨氧化细菌(AOB)平均丰度比例为1.70%,硝化细菌(NOB)平均比例为6.99%,是系统中主要去除氨氮和亚硝酸氮的微生物。生物滤器各部位微生物物种多样性丰富,微生态系统稳定,可有效维持循环水系统的水质。生物滤器硝化作用主要在上部进行,下部净化能力较弱,收集盘内基本没有硝化能力。生产中应合理配置挂膜数量,科学设计挂膜长度以提高生物滤器的净化效率。
