Study On The Start-up Of Split-feed Anaerobic Baffled Reactor

The Split-feed Anaerobic Baffled Reactor (SABR) is a sort of efficient biological sewage treatment reactor. For its unique structure and flow characteristic, the flow filed in SABR is very complex. Then the wastewater can intimately contact with a large amount of activated sludge when it passes through the SABR.The reactor's flow characteristic was studied by computer and experiment. The reactor's start-up and anaerobic granular sludge cultivating method were studied based on a series of testing using carbamide and glucose wastewater. In this work, the most parameter and suitable operating condition of SABR was studied. The result could be summarized as follows:l.The velocity, pressure and turbulence performance in the reactor were investigated at inlet flow rate of 0.276L/h,0.420L/h,0.840L/h, 1.680L/h. The inlet flow rate of 1.680L/h was best for this reactor. The results of the RTD studies and the RTD curves showed that both of the effluent recycling ratio and the inlet proportion had influence on the hydraulic characteristics of SABR. In this experimentation, the best effluent recycling ratio is 100%.2.The start-up of four lab-scale SABRs inoculated with sewage,aerobic activated sludge,sludge from a conventional sewage sludge digester and mixed sludge, respectively, was investigated. When the four reactors were started using low loading start-up, COD were controlled at 300～450mg/L and an HRT was 72h. The result of the test showed that, the COD removal efficiency of the reactor which inoculated with mixed sludge exceeded 80% after running 9 days. It was shortened 3～10 days compared with the other reactors. The COD removal efficiency of the reactor which inoculated with aerobic activated sludge was higher than 92% after running 15 days. The pH,VFA and Alkalinity of these reactors were studied.3.1.00mg/L of Fe²⁺ and Mg²⁺,0.06 mg/L of Co²⁺ and Ni²⁺were added into the reactors. The supplement of Fe²⁺, Mg²⁺, Co²⁺and Ni²⁺ can promoted the start-up of SABR. The COD removal efficiency of the reactor which was operated with adding nutritive salt was up to 90% after running 9 days. In the process of start-up, the reactor had a higher removal rate of organics, more than 5%～15% and has a lower VFA value than reactor without adding nutritive salt. Meanwhile the alkalinity was higher and the ability of resistance for organic load shock was much stronger.4.The supplement of flocculant (PAC,0.5mg/L) can promoted the start-up of SABR. Compared with reactor without floccules, the start-up time of reactor with flocculant was shortened 6 days. In the process of start-up, the reactor which was operated with adding flocculant had a higher removal rate of organics more than 5%～12% and has a lower VFA value than reactor without adding flocculant. Meanwhile the alkalinity was higher and the ability of resistance for organic load shock was much stronger. It was similar with the reactor which was operated with adding nutritive salt.