The Effect Of Temperature And Co-metabolic Substrates On The Treatment Of Ethanol Wastewater By Aerobic Granular Sludge

With the rapid growth in demand for fuel ethanol,energy issues become the world's increasingly prominent key issues.the development of ethanol for food as fuel has been greatly limited.Although the fuel ethanol can bring good social and economic benefits,but its waste water treatment problems are particularly prominent.Cellulose ethanol wastewater?CEW?is a more difficult to deal with high concentrations of organic wastewater,such as untreated direct emissions will cause serious pollution to the environment cellulose ethanol wastewater is a more difficult to deal with high concentrations of organic wastewater,such as untreated direct emissions will cause serious pollution of the environment.In this study,the effects of aerobic granular sludge based on cellulose ethanol wastewater and the effects of temperature and co-metabolism on the denitrification efficiency of aerobic granular sludge were studied.First,the aerobic granular sludge system was started by simulating the IC anaerobic effluent of cellulose ethanol wastewater to achieve good denitrification and COD removal.The study found that the use of simulated cellulose ethanol wastewater can successfully start the aerobic granular sludge system,the successful operation of aerobic granular sludge has good performance.Sludge particle size in the range of?0.4⁰.8?mm dominance,the proportion of89.8%.And the complete coefficient is 99.5%.the removal rate of COD was 97.6%⁹9.8%,and the average removal rate of ammonia nitrogen was increased to 74.5%.Nitrate and nitrite did not accumulate during the typical period,indicating that the system was carried out by simultaneous nitrification and denitrification.The experiments were conducted at 10?,20?,and 30?.The results showed that the COD removal at the stable phase under three different temperatures were 10.3%,12.7%,13.7%when the raw cellulosic ethanol wastewater was feeding as influent.The total inorganic nitrogen removal were 42.8%,53.6%,70.5%respectively,indicating that higher temperature was able to improve the activity and growth rate of ammonia oxidizing bacteria and nitrite oxidizing bacteria,and further to promote nitrogen removal.However,the COD removals at three different temperatures were almost same when the effluent from an anaerobic reactor?IC?was feeding as influent,and were less than 15%.the main reason caused low COD removal is that he organic matters in effluent of IC were hard biodegradable.But there is a big impact of temperature on nitrogen removal,and the removal of NH₄⁺-N was 60.9%at 30?,which was2.0 and 1.3 times at 10?and 20?,respectively.The total inorganic nitrogen removal was improved with the temperature increasing,and the amount of removed NO₃^--N was enhanced.Due to the biodegradable organic matters insufficient in the reactor,the denitrification via endogenous carbon source may play a key role in nitrogen removal,and the denitrification via endogenous carbon source was enhanced by the increasing temperature.The nitrogen balance analysis showed that the nitrogen losses were 37.6%?45.0%?53.6%at different temperature which indicate rising temperature not only enhance the activity of microorganisms but also enhanced the denitrification via endogenous carbon source,furthermore improved the nitrogen removal.The experiments were conducted with three co-metabolic substrates?glucose,acetic acid and ethanol?.The removal efficiencies of COD in the wastewater were respectively 18.9%,28.9%and 28.0%,all of which were remarkably higher than the blank,indicating that all three can promote the degradation of the refractory substances.When acetic acid was used as co-metabolism substrate,the removal amount of NH₄⁺-N and NO₃^--N was higher than those of glucose and ethanol.The removal efficiency of TN with glucose,acetic acid,ethanol were respectively 1.4,1.8,and 1.6 times that of the blank,which was 41.1%.The nitrogen loss of the three co-metabolic substrates were 53.2%,72.2%,69.4%.Co-metabolism promoted the increase of organic matter in aerobic granular sludge.The addition of acetic acid to the reactor has the highest organic content.The proportion of AOB in the granular sludge was more than that of NOB after adding three kinds of co-metabolic substrates.The proportion of AOB in the total metabolites was:acetic acid>ethanol>glucose.The TN degradation rate was the highest after adding acetic acid,the highest rate of N₂ was produced and the internal channel was the highest.