The Study On Startup Of Pilot-Scale UASB Reactors Treating Wastewater From Natural Gas Purification

The Wastewater from natural gas purification is comprised of normal purifying Wastewater, and examining and repairing Wastewater. The concentration of organics in normal purifying Wastewater is low and this Wastewater is easy to dispose; while the concentration of organics in examining and repairing Wastewater is high, which is hard to deal with. Anaerobic technologies are broadly used in dealing with high organic concentration Wastewater. As successful one of anaerobic technologies, up-flow anaerobic sludge blanket (UASB) is used not just in easily degraded high organic concentration Wastewater but also in hardly degraded high organic concentration Wastewater. The star-up of UASB reactors dealing with examining and repairing Wastewater is studied in the paper. The reactors are run on the condition of mesophilic anaerobic digestion.Two pilot-scale UASB reactors are seeded with sludge from acidification pond and other UASB reactors. The influent is mixed with examining and repairing Wastewater and fresh water, and is mixed with the demand of experimentation. The examining and repairing Wastewater is from Yinjin Department. As the examining and repairing Wastewater is abundant in nitrogen and alkalinity, there is no addition of them. While, there is a lack of phosphorus in the examining and repairing Wastewater. To meet the demand of bacteria and accelerate the speed of startup, phosphate fertilizer and microelements are added. The temperature of two pilot-scale reactors is increased from room temperature to 36℃, and 2℃is increased every day to prevent the bad reaction of quick temperature advance. The concentration of COD in influent is increased from 1000mg/L to 6000mg/L. When bad reaction appears, the concentration of COD in influent is reduced to the instance. The pH of effluent is steady which indicates the digestion system gets a good counteract on acid and alkali. To avoid the accumulation of VFA and acidification of reactor system, the concentration of VFA in effluent is analyzed. The star-up of pilot-scale UASB reactors continues 133d and then get into steady state. The COD removal is about 40%.