本研究使用傳統與倒錐(倒錐角度= 5o)厭氣流體化床生物反應器(AFBBRs)並安裝壓差調控迴流量之儀控裝置，嘗試由操控床壓差之方式操作AFBBRs，俟每一組AFBBR達穩定狀態(steady state)後，除了測得出流水質(乙酸、COD及VSS)及生物膜特性參數(生物顆粒粒徑dp、生物膜厚δ及生物顆粒濕密度ρp)外，亦將穩態之操作條件、化學/生物參數及生物膜剝落速率(rd)代入涵蓋有比生物膜剝落速率與比生長速率之經驗式，以釐清傳統或倒錐AFBBRs對生物膜之生長較為有利。接著將傳統與倒錐AFBBRs調控不同床壓差(Pt)使液相表流速(ul)改變，並進行生物膜剝落之動態實驗，除了探討在不同ul下傳統與倒錐AFBBRs之水動力學特性(包含Pt及膨脹床高度Hb)與rd間之關係外，並以實驗數據驗證傳統與倒錐AFBBRs床總壓差及膨脹床高度模式之適用性。此外，本研究亦另安裝與上述相同槽規格之傳統與倒錐AFBBRs進行非穩態(unsteady state)操作(固定迴流量)，並藉床壓差之量測以探討非穩態操作下AFBBRs之生物膜剝落情形及床膨脹情形，並釐清δ、Hb與Pt間之關係。
　　穩態之傳統與倒錐AFBBRs在體積負荷率(乙酸合成廢水) 3.0 ~ 12.1 g COD/L-day之操作條件下，皆隨著體積負荷率之倍數增加，生物產氣量(Qg)亦呈現倍數增加；在流體化床區下層之較上層者為小，惟下層之ρp則較上層者為大，顯示流體化床區之生物顆粒有分層現象；傳統AFBBR之比生物膜剝落速率(σ)較倒錐AFBBR者為大，且傳統AFBBR之與生物膜生長無關之剝落係數( bd = –2.16 )及與生長速率有關之剝落係數( bd' =1.66 )皆較倒錐AFBBR者( bd = –5.95；bd' =1.57 )為大，意謂著倒錐AFBBR對生物膜之生長較傳統者有利。事實上，本研究在相同體積負荷率下，倒錐AFBBR之生物膜厚度及生物質量皆較傳統AFBBR者為大。
　　穩態之傳統與倒錐AFBBRs，在藉床壓差調控不同ul ( = 1.0 ~ 3.7 cm/s)之生物膜剝落動態實驗中，Hb與rd二者皆隨著ul之增加而增加。在傳統AFBBR中，Pt隨ul之增加而微幅增加，但在倒錐AFBBR中，Pt隨ul之增加而明顯降低；不同ul下造成之生物膜表面剪功率(ω)介於0.60 ~ 2.24 μW/cm2，在該ω範圍內，傳統與倒錐AFBBRs之σ皆與ω呈正相關，且在相同之ω下，傳統AFBBR之σ較倒錐AFBBR者為大。將傳統與倒錐AFBBRs之穩態操作及生物膜剝落動態實驗之ul、Qg等物理操作條件及實驗數據，依氣/液/固空隙率模式可求得三相之空隙率(g 、l及 p)。傳統與倒錐AFBBRs之l皆隨ul之增加而增大，p皆隨ul之增加而減小，g則隨ul之增加而差異不大。傳統與倒錐AFBBRs之床壓差(Pt)和床膨脹高度(Hb)之模式模擬值與實驗值之偏差介於(+28%) ~ (–15%)間。
　　非穩態之傳統與倒錐AFBBRs在體積負荷率(乙酸合成廢水) 6.1 g COD/L-day (固定迴流量)下操作，於連續操作55天後傳統與倒錐AFBBRs兩者之COD去除率即達90%，Qg隨COD去除率之增加而增加；COD去除率及Qg在非穩操作之最初期即達穩定，但AFBBRs內之生物質量則是在操作後期趨於穩定。隨著活性碳擔體附著生物量之增加，rd逐漸增加，當AFBBRs內生物質量趨於穩定時，rd即變化不大，惟傳統AFBBR之rd較倒錐AFBBR者為大；隨著擔體附著生物膜厚度之增加，生物顆粒之比重隨之變小，Hb和Pt皆隨之增加，顯示δ、Hb皆與Pt呈正相關。

　　Both conventional (taper angle = 0o) and tapered (= 5o) anaerobic fluidized-bed bioreactors (AFBBRs) used in this work were equipped with pressure transmitters and automated devices to control recycle-flow rate. When the two AFBBRs (with this operating mode) reached steady state, effluent quality (acetate, COD, and VSS) and bioparticle characteristic parameters (bioparticle diameter dp, biofilm thickness , and wet density of bioparticle p) were determined. Additionally, by inserting operational conditions, chemical and biological parameter values, and biofilm detachment rate (rd) into an empirical equation incorporating specific biofilm detachment rate (σ) and specific growth rate (μ), one can determine whether the tapered AFBBR is superior to the conventional AFBBR for effective attached-growth of biofilm or not. Thereafter, by varying different pressure drops (ΔPt) in the two AFBBRs to incur the changes of ul, dynamic biofilm detachment experiments were conducted. The experiments aimed to determine the relationship between the hydrodynamic characteristics (ΔPt and expanded-bed height Hb) and rd in the two AFBBRs operated at different ul. Meanwhile, the proposed pressure-drop and expanded-bed height models were also validated by these experimental results. Moreover, another conventional and tapered ( = 5o) AFBBRs with the same dimensions as the previous two AFBBRs were used and operated at a designated recycle-flow rate to proceed with the unsteady state study. This study aimed to correlate ΔPt with  and Hb in the two AFBBRs.
　　In the steady-state conventional and tapered AFBBRs with volumetric loading rates (VLRs) of 3.0 – 12.1 g COD/L-day, the biogas production rate (Qg) increased doubly with a double increase in VLR. The  in the lower-part of the fluidized-bed zone was thinner than that of the upper-part, whereas the p in the lower-part of the fluidized-bed zone was larger than that of the upper-part. This implied that bioparticles’ stratification occurred in the two steady-state AFBBRs. In addition, the specific biofilm detachment rate (σ) of the conventional AFBBR was greater than that of the tapered AFBBR; both the non-growth-associated detachment coefficient (bd = –2.16) and the growth-associated detachment coefficient (bd' = 1.66) of the conventional AFBBR were larger than bd (= –5.95) and bd' (= 1.57) of the tapered AFBBR. This implied that the tapered AFBBR was superior to the conventional AFBBR for biofilm growth. In fact, at the same VLR in this study, δ and biomass in the tapered AFBBR were larger those of the conventional AFBBR.
　　From the dynamic biofilm detachment experiments (using steady-sate conventional and tapered AFBBRs), Hb and rd increased with an increase in ul (=1.0－3.7 cm/s). In the conventional AFBBR, ∆Pt increased slightly with increasing ul, whereas ∆Pt declined markedly with increasing ul. At ul ranging from 1.0 to 3.7 cm/s, the calculated shearing power on the biofilm (ω) were 0.60－2.24 μW/cm2. Within this range, σ of the two AFBBRs positively correlated with ω. At the same ω, the σ of the conventional AFBBR was larger than that of the tapered AFBBR. By placing physical operating conditions and experimental results (ul, Qg, etc.) of the two steady-state AFBBRs and dynamic biofilm detachment experiments into the gas-liquid-solid hold-up model, the hold-up of gas, liquid, and solid (εg, εl, and εp) can be calculated. With an increase in ul, εl increased, εp decreased, and εg changed slightly. The simulated ∆Pt and Hb were (+28%)－(–15%) deviated from the experimental results.
　　In the unsteady-state conventional and tapered AFBBRs with a VLR of 6.1 g COD/L-day (a designate recycle-flow rate), the COD removal efficiencies reached 90% at the 55-th operating day and, meanwhile, Qg increased with an increase in COD removal efficiency. During the unsteady-state operation period, the COD removal efficiency and Qg reached stable level at the early stage, whereas biofilm/biomass reached stable level at the final stage. In addition, rd gradually increased with increasing amount of biomass (attached onto activated carbon). When biomass in the conventional and tapered AFBBRs reached stable level, rd changed slightly but rd of the former was larger than that of the latter. With an increase in δ, the specific gravity of bioparticle decreased and Hb and ∆Pt increased, indicating that ∆Pt was positively correlated with δ and Hb .

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