【導(dǎo)讀】碳來源和特性污染物，從屬于膨脹的顆粒狀污泥床過程。EGSB過程的穩(wěn)定由實。驗室實驗首先研究了。TA電離是影響系統(tǒng)的酸基度平衡的優(yōu)勢的因素。而能生活強的系統(tǒng)揮發(fā)性基礎(chǔ)抵抗pH減少到低于。揮發(fā)性脂肪和不飽和脂肪酸除。每小時次于積極從事它的極大值以外幾乎沒有抑制上去沼氣生產(chǎn)。酸堿度污泥顆粒化的,適當(dāng)?shù)牧魅胛锖脱b載使EGSB過程穩(wěn)定。應(yīng)器是穩(wěn)定的為TPD廢水處理。處理,NaOH以某一溫度和壓力滌綸纖維被水解在某種程度上。然而廣泛應(yīng)用的曝氣過程已經(jīng)妨害由缺乏了解到相關(guān)。存在于進水形成分子或離子狀態(tài)。率和有害的阻力的厭氧控制處理方法。未來的egsb技術(shù)發(fā)展的由于噸/日廢水處理依賴。處理的穩(wěn)定性是論述、酸堿平衡是強調(diào)和實驗室實驗是傳導(dǎo)。在實驗室厭氧的反應(yīng)器和egsb反應(yīng)器到保持高濃度的生物資源的情況一樣。發(fā)生和沼氣生產(chǎn)的地方。當(dāng)做混合溶液穿過氣體液體固體分離器、那污泥穿過分離器的

　　

【正文】 r maximum turnover rates of COD averaged 60 % , the system was switched to a load shocking with higher hydraulic load as much as 200 % of the normal load at the day 16. The depression of biogas production was in the wake of the shocking load. The COD removal efficiency decreased with a lag of several days after the anaerobic system received the shocking load. The results illustrated that the 19 performance of EGSB reactor could be unstable when the operation parameter changed greatly. The removal of COD recovered to a normal level of 55 %62 % in a week , while the biogas production recovered to the normal level of m3/(kgCOD) in 10 d. 3 Theoretical calculation and discussions Acidbase balance and buffering capability of TPDWastewater The pH is one of the most important parameters indicating the stability of anaerobic system. The best pH for methanogenic bacteria is from to ( Souza , 1986) . While VFA accumulating leads to a decrease of pH , the efficiency of the anaerobic treatment has already declined markedly ( Gu , 1993) . Therefore , it is more important to control VFA than to control pH in anaerobic system. The alkalinity is regarded as an important role to resist the VFA accumulation so as to increase pH in an anaerobic system (Kroeker , 1979 。 Gu , 1993) . Alkalinity of the wastewater is defined as the gross substance which can react rationally with strong acids. Alkalinity includes many kinds of alkali ponents such as carbonates , bicarbonates , hydrates and anic base. They are called as total alkalinity in the wastewater (Editorial Board of Environment Protection Bureau of China , 1997) . The TPD wastewater has plex ponents and the concentration of carbonates , bicarbonates and hydrates cannot be obtained expediently. So the total alkalinity was used as a significant indicator for the basic ponents in the wastewater. Commonly , acidbase balance of the mixed liquor in anaerobic reactor is dominated by ionization balance of ammonia , VFA and carbonates (Kroeker E J , 1979 。 Zhang , 1997) . Ammonia ionization equilibrium as Equation (2) : NH3H2O=NH++ OH. (2) As the [ H+ ] increases , pH decreases and equilibrium shifts to the right . At 35 ℃ , the ionization constant is 605 VFA is usually posed by acetic acid and propionic acid. As two kinds of VFA have close ionization constants , the ionization equilibrium can be simplified as the acetic acid 20 ionization illustrated in Equation (3) : CH3COOH=CH3COO + H+ . (3) As the [ H+ ] increases , equilibrium shifts to the left and the unionized volatile acid ( UVA ) concentration increases. At 35 ℃ , the ionization constant is 605 As the UVA concentration increases above 10 mg/L , a digester trends towards failure (Kroeker , 1979) . The ionization equilibrium of carbonates is illuminated as Equation (4) . H2CO3=HCO+ H+=CO + 2H+. (4) The acidbase equilibrium in an anaerobic system also include the dissolve balance of CO2 between liquidgas phase , the balance of carbonate and phosphate between liquidsolid phase , the balance of other salt ionization. It was explained that sulfhydrate and orthophosphoric acid only provide limited buffering capacity monly as a result of low conce ntration ( Capri , 1975) . The buffering capacity of ammonia and VFA can be neglected when pH varied from to , and the buffering capacity of the anaerobic system unexceptionably resulted from the ionization of carbonic acid. So the pH and the acidbasic balance are controlled by carbonic acid and the ionization of a kind of alkali . The latter is collaborated by VFA , ammonia and the other strong acid and alkali . It is tested that the range of concentration of P and sulfideS are mg/L , Mg/L and mg/L correspondingly , the average values are , and mg/L , respectively. According to the previous work mentioned above , the buffering capacity of ammonia , phosphate and hydrosulphuric acid can be neglected in TPD wastewater. Then , which one is responsible for the buffering of the acidbase balance when EGSB process is applied to treat the TPD wastewater 6 How to obtain a stable pH with the range of in such a carbonic acid Pbicarbonate system 6 TA is dualanic acid , which exists in water with two states of molecule or ion state. Further more , its solubility connected closely with pH. The ionization equilibrium is shown as follows (Editorial Board of Encyclopedia of Chemical Industry , 1990) : VFA and UFA in the mixed liquor It is known that the anaerobic process involves two major groups of bacteria that degrade 21 anic substrate in two major ways. In the first stage ,揳 cidform攂 acteria hydrolyze and degrade the plex anic substrates to volatile fatty acids (VFA ) . In the second stage , VFAs are utilized by methanogenic bacterial and methane gas is produced. The two processes occur simultaneously and process stability depends on maintenance of a delicate biochemical balance between the two major phases for anic substrates. Anaerobic process instability is usually indicated by a rapid increase in the concentration of VFAs with a subsequent decrease in methane gas production. There are many factors associated with instability or process failure , for example , insufficient acclimation of the methane formers to new substrates , rapid temperature or pH fluctuations. From the results by Kroeker et al . (Andrews , 1969 。 Kroeker , 1979) , anaerobic digestion toxicities related more directly to excessive concentration of un2ionized volatile acids (UFAs) , although they probably indirectly related to excessive free ammonia concentrations. What is more , the toxicities have a close correlation with pH due to the reason that UFA is easier than other pounds to perate through cell membrane. As soon as microbe assimilates the UFA , pH in the cell depresses rapidly and metabolic rate of