| Anaerobic sewage treatment process itself has the peculiarity of savinginvestment, the ability of treating high concentration organic wastewater effectively,and the operation is stable. Which is suitable for China’s national conditions. As thethird generation of anaerobic reactor, EGSB（Expanded Granular Sludge Bed）hashigher rising velocity inside by using effluent recirculation. Which promotes the masstransfer effect between the slurry mixture, and improves the efficiency of reactor fortreating high concentration wastewater.The role of the three-phase separator is very important in EGSB reactor. Witcheffects the effluent water greatly, and its requirements of designing is very high. In theview of this, I imagine simplifying off the three-phase separator in the EGSB reactor,expanding the diameter of the top of the reactor, and having the ratio of its height inthe entire height of the reactor increased appropriately. So, by increasing thecross-sectional area suddenly, the flow-rate of the mixture within the reactor reduced,to achieve the purpose of the three-phase separator. In that case, the structure ofEGSB was simplified, and it is good for promoting the using.This paper examines the performance of wastewater treatment of the EGSBreactor designed independently. During the experiment, the temperature inside thereactor is controlled at35±1°C. After45days of the start to run, the influent CODconcentration achieved to about5480mg/L, the removal rate stabilized at around70%, the reactor started successfully. After that, the water quality appears minorfluctuation phenomena after each time the organic load increased. But, only in arelatively short period, the operation was stable. During improving the load phase,COD removal efficiency reached to87.7%when the influent organic load wasincreased to22500mg/L or so, and the average of COD removal rate reached to80.75%.When NH3-N concentration, in the EGSB operating environment, within therange of502~570mg/L, would cause a greater influence to the activity of theanaerobic micro-organisms, inhibit the proceeds of biochemical reaction. Anaerobicmicro-organisms, after a short-term, could be domesticated in the survival conditions,will be able to adapt to the operating environment of higher concentrations of NH3-Ngradually. This inhibition will be lifted. A linear relationship between the influentCOD load (x) and the required dosage of alkali(y) is: y=0.7917x-26.295. The pH ofthe influent was controlled within the range from6.65to7.59, gradually, theconcentration of the reactor influent was increased from5300mgCOD/L to10987mgCOD/L, the average of COD removal rate was79.8%in this period. The sludge VSS in the reactor dropped to18.5g/L at the40th day from24.5g/L at theforties day. At the110s day, sludge VSS was about22.5g/L. At the80s and130s day,the granular sludge proportion of particle size in the range of1.0-1.2mm were16.7%and21%. The settling performance of the granular sludge, within the same particlesize range of the particles, at the bottom of the sludge bed, is better than that in the topof the sludge bed. In the case of without three-phase separator,and the hydraulic loadof reactor was Improved in the way of increasing reflux ratio, the removal rateachieved to87.7%,when the influent organic load was22500mg/L and the hydraulicload was4.56m3/m2h. |
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