本文選題：海水 + 生物膜�。� 參考：《浙江大學(xué)》2016年博士論文

【摘要】：高效、環(huán)保的循環(huán)水養(yǎng)殖模式是未來水產(chǎn)養(yǎng)殖的必然發(fā)展選擇,在海水循環(huán)水養(yǎng)殖系統(tǒng)中生物濾池實(shí)際運(yùn)行時(shí)常出現(xiàn)啟動(dòng)慢、耗時(shí)長等問題,影響循環(huán)水養(yǎng)殖系統(tǒng)的可靠性和穩(wěn)定性。循環(huán)水養(yǎng)殖系統(tǒng)平均化負(fù)荷設(shè)計(jì)忽略了魚類污染物排放變化規(guī)律,導(dǎo)致養(yǎng)殖水體存在氨氮和亞硝酸鹽氮超標(biāo)的風(fēng)險(xiǎn)。針對(duì)以上問題,本文從海水淡水環(huán)境中生物膜生長、填料表面修飾、成熟填料接種和變速流調(diào)控等方面研究了硝化生物生長特征和關(guān)鍵作用因子以及水體循環(huán)優(yōu)化和調(diào)控措施。論文主要結(jié)果如下：(1)海水環(huán)境中當(dāng)亞硝酸鹽氮濃度分別不小于100mg/L和12mg/L時(shí)氨氧化菌(AOB)和亞硝酸鹽氧化菌(NOB)活性分別受到抑制,淡水環(huán)境中AOB沒有受到明顯抑制,而NOB抑制濃度不小于50mg/L；游離亞硝酸(FNA)對(duì)海水和淡水環(huán)境中NOB活性的完全抑制濃度分別不小于0.05mg/L和0.21mg/L。海水環(huán)境中NOB以Nitrobacter為主而淡水環(huán)境則以Nitrospira為主,鹽度可能降低了Nitrospira對(duì)基質(zhì)的競爭能力。然而海水生物膜生物量和胞外聚合物(EPS)蛋白質(zhì)組成含量明顯高于淡水生物膜含量,此點(diǎn)與總有機(jī)碳(TOC)和熒光光譜檢測(3D-EEM)結(jié)果一致,這種現(xiàn)象源于硝化生物膜對(duì)鹽度環(huán)境的適應(yīng)機(jī)制。(2)表面修飾填料可在25d內(nèi)建立完全硝化能力,早于普通空白填料(35d)；修飾填料能夠明顯地促進(jìn)NOB在生物膜生長早期定殖過程,避免亞硝酸鹽氮積累,減輕游離亞硝酸(FNA)對(duì)AOB和NOB的生長抑制。修飾填料表面物質(zhì)組分變化研究發(fā)現(xiàn)修飾填料表面作用物質(zhì)為蛋白質(zhì)和多糖,這些大分子物質(zhì)為生物膜生長提供潛在的有機(jī)物源和空間結(jié)構(gòu)。(3)利用成熟填料接種生物濾池,接種量越大(如10～15%接種比例)生物濾池啟動(dòng)越快,越早形成完全硝化能力。然而新生物膜生長(如硝化能力、胞外聚合物(EPS)組分、細(xì)菌豐度等)更易被成熟生物膜抑制,這是由兩者之間基質(zhì)競爭引起的。硝化生物膜生長過程主要產(chǎn)生3種高絲氨酸內(nèi)脂(AHL) (C4-HSL C8-HSL和3OC8-HSL),后兩者可能促進(jìn)硝化生物膜生長,因此在充足基質(zhì)的基礎(chǔ)上投加人工AHL是促進(jìn)生物膜快速生長的途徑之一。(4)羅非魚攝食后12h內(nèi)0～4h和8～12h為氨氮排放低谷期(4.2～4.7mg/(h*kg)),4～8h為氨氮排放高峰期(11～12mg/(h*kg));低循環(huán)率下無機(jī)氮濃度高于高循環(huán)率對(duì)應(yīng)濃度,排放高峰期總氨氮(TAN)為3.26-3.37mg/L,亞硝酸鹽氮(NO2-N)為1.32～1.45mg/L,超出羅非魚健康生長限制濃度(TAN≤3mg/L,N02--N≤1 mg/L)。變速流通過增加氨氮排放高峰期內(nèi)循環(huán)流量明顯地降低了高峰期氨氮和亞硝酸鹽濃度(TAN:2.03～2.24mg/L,NO2--N:0.56～0.62mg/L),方法易于實(shí)現(xiàn)、成本低,為系統(tǒng)水質(zhì)調(diào)控和低成本養(yǎng)殖技術(shù)提供參考。
[Abstract]:Efficient and environmentally friendly recycling water culture model is the inevitable choice of aquaculture in the future. In the seawater circulating water culture system, the actual operation of biofilter often has some problems such as slow start-up, long time consuming and so on. The reliability and stability of circulating water culture system are affected. The design of average load of circulating water culture system neglects the change rule of fish pollutant emission, which leads to the risk of ammonia nitrogen and nitrite nitrogen exceeding the standard in culture water body. In order to solve the above problems, the characteristics and key factors of nitrification were studied from the aspects of biofilm growth in seawater and fresh water environment, surface modification of fillers, inoculation of mature fillers and regulation of variable velocity flow, as well as optimization and control measures of water circulation. The main results are as follows: (1) the activities of AOB and NOB in seawater environment were inhibited when nitrite nitrogen concentrations were not less than 100 mg / L and 12 mg / L, respectively, but AOB was not significantly inhibited in fresh water environment. The total inhibitory concentration of free nitrite (FNA) on NOB activity in seawater and fresh water was not less than 0.05 mg / L and 0.21 mg / L, respectively. In seawater environment, Nitrobacter is the main component of NOB, while in freshwater environment Nitrospira is dominant. Salinity may reduce the competitive ability of Nitrospira to matrix. However, the biomass of seawater biofilm and the content of extracellular polymer (EPS) protein composition were significantly higher than that of fresh water biofilm, which was consistent with the results of total organic carbon (TOC) and fluorescence spectroscopy (3D-EEM). This phenomenon originates from the adaptation mechanism of nitrification biofilm to salinity environment. (2) Surface modified fillers can establish complete nitrification ability within 25 days, which is earlier than normal blank fillers (35 days), and modified fillers can obviously promote the colonization process of NOB in the early stage of biofilm growth. Nitrite nitrogen accumulation was avoided and free nitrite (FNA) inhibited the growth of AOB and NOB. The changes of the composition of the surface matter of the modified packing were found to be proteins and polysaccharides, which provided potential organic source and spatial structure for the growth of biofilm. (3) the biofilter was inoculated with mature fillers. The larger the inoculation amount (such as 10 ~ 15% inoculation ratio), the faster the biofilter started, and the earlier the complete nitrification ability was formed. However, the growth of new biofilms (such as nitrification ability, extracellular polymer (EPS) components, bacterial abundance, etc.) is more easily inhibited by mature biofilms, which is caused by the competition of matrix between the two biofilms. Three kinds of high serine internal lipids (AHL) (C4-HSL C8-HSL and 3OC8-HSL) were produced during the growth of nitrifying biofilm, which may promote the growth of nitrifying biofilm. Therefore, adding artificial 4.2~4.7mg/ on the basis of sufficient substrate is one of the ways to promote the rapid growth of biofilm. (4) the peak of ammonia nitrogen emission (11 ~ 11 ~ 8 h) is observed in 0 ~ 4 h and 812 h within 12 h after feeding in tilapia (4.2~4.7mg/ (h*kg). The concentration of inorganic nitrogen at low cycling rate of h*kg); (12mg/) was higher than that at high cycling rate. Total ammonia nitrogen (Tan) and nitrite nitrogen (no _ 2-N) were 3.26-3.37 mg / L and 1.32 鹵1.45 mg / L respectively, which exceeded the healthy growth limit (Tan 鈮，

本文編號(hào)：2072640