| Upflow Anaerobic Sludge Bed(UASB),being successfully developed by Lettinga Professor Lettinga from Holland in 1970 s,has been used for over 4 decades;it is one of the most promoted anaerobic reactor,which could be attributed to less investment,low operative costs and maintenance costs,less residual sludge in the operation,high Processing Load and other features of Upflow Anaerobic Sludge Bed,corresponding to the objectives of sustainable development proposed currently.UASB has have made great progress development in theoretical research at lab scale and in practice.The climate in Northern China resulted in low temperature of wastewater in municipal pipe network,if Middle,if thermophilic UASB technique is about to be adopted to treat wastewater,an additional secondary thermoelectric device was required to raise the wastewater temperature to the desired temperature range,which consumed a lot of energy.It will not only increase economic input of wastewater,but also not correspond to requirements of Energy Saving and Pollution Reduction.The Yingkou is located in northeast China and its municipal wastewater contains a certain amount of salt.Consequently,Study of performance of Upflow Anaerobic Sludge Bed initiated at different temperature for treating wastewater in Yingkou area is of great practical importance.Experiments of UASB reactors are mainly divided into domestication and cultivation of anaerobic sludge,UASB reactors operated under the load increasing and high load stage,the water temperature varies with the season.Domestication and cultivation of anaerobic sludge.Inoculation Sludge was just entered into reactor,anaerobic microorganisms must adapt to waste water environment,species and amount of anaerobes are relatively low,so in this stage,COD concentration of inflow remained at 644~1396mg/L,with an average COD removal rate of 34.7%,water temperature of reactors varied from 6℃ to 19℃.It is normal for the reactors to have a relatively low efficiency in the initial stage.UASB reactors operated under the load increasing.In this stage,fine anaerobic granular sludge appeared in the reactor,increasing loads is advantageous for accelerating granulation of sludge,by adjusting input COD concentration,input flow,HRT to change loads of reactor.Input COD concentration varied from959 to 3900 mg/L with an average COD removal rate of 59.3%,water temperature of reactors varied from 18℃ to 26℃,HRT is 19.8h,15.8h,13.8h,11.8h respectively.The removal effect of reactor increased with increasing temperature.High load stage.This stage is used to test the capability of resisting shock loading,Input COD concentration varied from 3264 to 4680mg/L with an average COD removal rate of 75.8%,water temperature of reactors varied from 24℃ to 27℃,HRT is 13.2h,UASB reactor is of relatively strong resistance to shock loading.From perspective of CASS technique,low-temperature UASB technique,investment,operation fees,COD removal fees,we reached the conclusion that UASB is of economic advantage and is capable of deeply promoted and developed. |
