水产养殖微生物絮团形成过程的初步研究

发布时间：2018-12-30 11:28

【摘要】：生物絮凝技术是通过控制水体中C/N(15)使异养细菌利用水中氮素同化为微生物蛋白,形成可被滤食性养殖对象摄食的生物絮体,生物絮体即净化了养殖水质又能够被养殖对象摄食,这与中国传统高产养殖池塘中存在着始于草食性鱼类粪便的食物链有相似之处。因此本论文研究了在异位、原位中粪便向生物絮体的转化的过程,并研究了在序批式反应器(SBR)中利用养殖废水中的无机氮转化成生物絮体进而形成颗粒污泥的过程。第一部分:罗非鱼粪便在分解过程中形态和营养成分变化实验采用新吉富罗非鱼(Oreochromis niloticus)粪便在反应器中转化为生物絮体并观察形成过程中结构、粗蛋白、氨基酸、胞外聚合物变化。粪便在转化过程中结构变疏松,直至最终发展成以丝状菌为骨架的生物絮体。随着粪便的分解,自第4天开始,反应器中氨氮浓度开始缓慢上升,第7天达到峰值7.46 mg/L,亚硝态氮也随之升高至7.81 mg/L,并且硝态氮也开始快速增至21.6 mg/L。絮体粗蛋白含量在第九天达到最高值26.37%,总氨基酸在第7天达到最高值20.44%。絮体中的总氨基酸含量虽比粪便高,但比饲料中总氨基酸33.16%低。絮体疏松结合的胞外聚合物(LB-EPS)的主要成分是多糖,而紧密结合的胞外聚合物(TB-EPS)中蛋白质是其主要成分。第二部分:生物絮凝养殖罗非鱼中絮体性质变化的过程在封闭养殖缸内,养殖新吉富罗非鱼并添加葡萄糖作为碳源,观察生物絮体形成过程。养殖缸内硝态氮逐渐积累到77.09 mg/L,最终氨氮和亚硝态氮分别为1.55 mg/L、2.81 mg/L。絮体中粗蛋白和总氨基酸逐渐增加到37.55%和35.79%,且生物絮体的生物量逐渐升高到495.02 mg/L。絮体的SVI30先升高至74.97 ml/g后又降低至27.66 ml/g。絮体中松散结合的胞外聚合物以多糖为主,不利于絮体间凝聚,LB-EPS在起初含量较高为37.70 mg/g之后降低至12.05 mg/g。在紧密结合的胞外聚合物则以蛋白质为主,TB-EPS含量先升高至403.86 mg/g,后又降低至116.17 mg/g。絮体在p H=6.0时硝化效果差,而在p H=7.5时硝化效果好。第三部分:好氧颗粒污泥处理水产养殖废水在序批式反应器(SBR)处理养殖废水,并培养出好氧颗粒污泥(AGS)。絮体由起初的松散状,渐渐发展成结构紧密的颗粒污泥,其平均粒径为150μm。当总悬浮固体颗粒物在17.39 mg/L左右,SBR反应器稳定。SBR反应器对硝态氮、活性磷、溶解性有机碳的有较高的去除率分别在96.10%、91.37%、92.79%以上,但对氨氮、亚硝态氮去除率有较大波动。在一个典型SBR反应周期内好氧颗粒污泥在30 min内快速吸收水中硝态氮、氨氮、溶解性有机碳。加热法提取AGS的疏松结合的胞外聚合物较超声波提取法多,而紧密结合的胞外聚合物较少。超声波法提取的颗粒污泥内TB-EPS含量较絮体中高,而絮体中LB-EPS含量较高。以上表明好氧颗粒污泥对水产养殖废水有较好的净化效果。
[Abstract]:Biological flocculation technology is to control C / N _ (15) in water to assimilate heterotrophic bacteria to microbial protein from nitrogen in water to form biological flocs that can be fed by filter feeding objects. Biological floc not only purifies the water quality but also can be fed by the culturing object, which is similar to the food chain which started from herbivorous fish dung in the traditional high yield culture pond of China. In this paper, the process of transformation from feces to biological flocs in ectopic and in situ was studied, and the process of transforming inorganic nitrogen from culture wastewater into biological flocs in sequencing batch reactor (SBR) was studied. The first part: the changes of morphology and nutritional composition of tilapia feces during the decomposition process. The (Oreochromis niloticus) feces of New Giff Tilapia were transformed into biological flocs in the reactor, and the structure, crude protein, amino acids were observed during the process of formation. Changes of extracellular polymers. The feces were loosened in structure during transformation, and eventually developed into biological flocs with filamentous skeleton. With the decomposition of feces, the concentration of ammonia nitrogen in the reactor began to rise slowly from the 4th day, and reached a peak value of 7.46 mg/L, on the 7th day, and the nitrite nitrogen increased to 7.81 mg/L,. Nitrate nitrogen also increased rapidly to 21.6 mg/L.. The crude protein content of floc reached the highest value 26.37 on the ninth day, and the highest value of 20.44 on the 7th day. The content of total amino acid in floc was higher than that in feces, but lower than that in feed (33.16%). Polysaccharide is the main component of loose bound extracellular polymer (LB-EPS), and protein is the main component in tightly bound extracellular polymer (TB-EPS). The second part: the process of changing the properties of flocs in biological flocculation culture tilapia is in the closed aquiculture tank, and the formation process of biological flocs is observed by adding glucose as carbon source. Nitrate nitrogen accumulated gradually to 77.09 mg/L, in aquiculture tank. The final ammonia nitrogen and nitrite nitrogen were 1.55 mg/L,2.81 mg/L., respectively. The crude protein and total amino acids in the flocs increased to 37.55% and 35.79% respectively, and the biomass of the biological flocs increased to 495.02 mg/L.. The SVI30 of floc increased to 74.97 ml/g and then decreased to 27.66 ml/g.. The loosely bound extracellular polymers in the flocs were mainly polysaccharides, which were not conducive to flocs aggregation. The LB-EPS content decreased to 12.05 mg/g. after the initial content was 37.70 mg/g. In the tightly bound extracellular polymers, the protein was the main one, and the TB-EPS content increased to 403.86 mg/g, and then decreased to 116.17 mg/g.. The nitrification effect of flocs at pH 6.0 was poor, while that at pH 7.5 was better. The third part: aerobic granular sludge treatment of aquaculture wastewater in sequence batch reactor (SBR) treatment of aquaculture wastewater, and cultivate aerobic granular sludge (AGS). From the initial loose shape, the floc gradually developed into a compact granular sludge with an average particle size of 150 渭 m. When the total suspended solid particulate matter was about 17.39 mg/L, the SBR reactor was stable. The removal rates of nitrate nitrogen, active phosphorus and dissolved organic carbon in the SBR reactor were above 96.101.37% and 92.79%, respectively. However, the removal rate of ammonia nitrogen and nitrite nitrogen fluctuated greatly. During a typical SBR reaction cycle, aerobic granular sludge rapidly absorbs nitrate nitrogen, ammonia nitrogen and dissolved organic carbon in water within 30 min. The loose bound extracellular polymer extracted by heating method is more than ultrasonic extraction method, but the tightly bound extracellular polymer is less. The content of TB-EPS in granular sludge extracted by ultrasonic method was higher than that in flocs, and the content of LB-EPS in flocs was higher. The above results indicate that aerobic granular sludge has good purification effect on aquaculture wastewater.
【学位授予单位】：上海海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X714

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