Experimental Research On Resourceful Treatment Of Distillers’ Grains

According to the data of2013, the annual output of distillers’ grains is37million tons in our country. They are in a large amount and concentrated, If nothandled in time, they will be rotten, not only waste the precious resources, and willcause serious pollution to environment.In this paper, taking the distillers’ grains of aliquor company in Luzhou Sichuan as the research object, with the method ofelutriation soaking out the soluble organic matter of distillers’ grains for anaerobicfermentation to produce biogas. The treated washing water continue to wash thedistillers’ grains, achieve a circular without outside pattern, also can treat liquorproduction wastewater at the same time, the remaining residue can be mixed with airstripped ammonia nitrogen for the production of feed, or for other uses.This test taking the fresh distillers’ grains elutriation process in the first place,to determine the best elutriation process conditions, experiments show that: in35℃,stirring, elutriation time for three days, the soluble organic matter of distillers’ grainscan be better leached, COD, ammonia nitrogen and SS of washing water is12115mg/L,287.3mg/L and2831mg/L respectively. Due to in the process of elutriationhydrolysis acidification occurred, washing water pH is about4.6; the remainingresidue for secondary elutriation, the amount of organic matter leaching is far lessthan the first time.Following the best temperature and inoculation quantity of anaerobicfermentation were studied, test showed that the temperature of35℃,40%inoculated quantity, by a day of anaerobic fermentation pH restore neutral, the gasproduction rate and COD removal rate, methane content of biogas can be in a ideallevel. In amplification research shows that: under the condition of the optimumtemperature and inoculation quantity, after a day of anaerobic fermentation pH canrestore and maintain at about6.8, the pH is suitable for the growth of anaerobicfermentation bacteria; the biogas production in the first eight days maintained at ahigh level, remained above550mL/d, gas production peak is at the seventh day, the cumulative gas production is as high as1340mL,in the whole fermentation periodthe gas production rate was107.75mL/g, COD removal rate was83.1%, had a bettereffect on COD removal; SS removal efficiency was not high, about47%, andunstable; Anaerobic fermentation had no removal efficiency on ammonia nitrogen,at the end of the fermentation period the ammonia nitrogen would be increased,increment is12.7%.In the early stage of the fermentation fermented, ammonianitrogen content changed greatly in the whole gas production cycle, the averagemethane content of biogas was65.60%.The test of COD and ammonia nitrogen accumulation showed that, throughmany elutriation-anaerobic cycles treatment, COD didn’t accumulate; but the contentof ammonia nitrogen had an obvious accumulation. Each cycle, the content ofammonia nitrogen increased about250mg/L.Every Five cycles, when theconcentration of ammonia nitrogen to anaerobic microorganism lethal concentrationof1600mg/L, ammonia nitrogen in the fermentation liquor need to be removed.Experiment shows that: in the conditions of pH=10, gas liquid ratio is3000, thetemperature is35℃, had high removal efficiency for the content of ammonianitrogen in cycles distillers’ grains washing water, removal rate of95.1%, thecontent of ammonia nitrogen could reach about60mg/L, satisfied with followingelutriation.