Factors impacting design and performance of upflow anaerobic hybrid reactors

In this study, effect of supporting media type, height ratio of the supporting media among factors impacting the design of Upflow Anaerobic Hybrid Reactors and effect of organic load, pH, sulfate and chlorine parameters among factors impacting the system performance have been investigated. For this purpose, upflow hybrid reactors have been supported with three different ratios employing various natural supporting media like perlite, basalt and quartz. During the investigations with synthetic wastewater, it has been determined that ideal supporting ratio is 1/4 and ideal supporting media is perlite. In conditions where hydrolic retention time (HRT) is 24 hours and organic load is 10 kg. COD/m3, anaerobic hybrid reactors with perlite presented a COD removal efficiency of 96.3-96.47 % and TOC removal efficiency of 78.00-79.30%. In these conditions, COD conversion ratio into methane changed between 0.36-0.44 L CH4/g COD(r). Various reactors presented a nitrogen removal in the range of 16.16-28.95% and phosphorus efficiency in the range of 22.62-25.13 %. During investigations to determine the impact of pH in the wastewater, it has been found out that optimum performance is obtained with pH in the range of 6.3 and 8.45. Out of this interval, COD removal efficiency and gas production decreased considerably. It has been determined that, optimum pH value is 7.2. During the investigations of the impact of sulfate, optimum performance is achieved with COD/ SO4= higher than 50%. Gas production almost stopped with a wastewater sulphate concentration of 2130 mg/L and COD/ SO4= ratio less than 5. COD efficiency decreased 30-35% with organic shock load increase to 20 kg COD/m3 day from 5 kg COD/m3 day. During our investigation, we have seen that the reactors with perlite ratio of 1/4 presented the strongest resistance. During all our investigations, TVA/Alkalinity ratio was under 0.1 for all organic loads. Our investigations for the impact of NaCl showed that a NaCl concentration of 4 g/L presented considerable improvements in the reactor efficiencies and increased the gas production. A NaCl concentration of 8 g/L in the wastewater presented the first inhibition effect, a NaCl concentration of 24 g/L in the wastewater presented a toxic effect and decreased the reactor performances.