| Molasses alcohol wastewater(MAW)is a typical acid(pH 3.7-5.8)industrial organic waste produced after alcohol distillation.Its chemical oxygen demand(COD,?50000 mg/L),biochemical oxygen demand(BOD,? 30000 mg/L)and suspended solids(SS,?10000 mg/L),etc.contents are high,therefore it is very difficult to deal with.This experiment employed a full-scale internal circulation(IC)reactor and a pilot-scale IC reactor as the subject,and explored the feasibility and treatment efficiency of the two reactors in anaerobic treatment of MAW,in addition,a preliminary exploration of ecological purification was carried out after anaerobic treatment.The working volume of the full-scale IC reactor and the pilot-scale IC reactor used in this experiment are 500 m~3 and 2 m~3,respectively.Both pig manure and anaerobic sludge were added as substrate before operation.The feeding pattern during the experiment was continuous daily feeding,during which no nutrients,catalysts,additives and buffers were added,and both reactors were set to operate under natural conditions.The whole process adopted a strategy of gradually increasing the organic loading rate(OLR).The main results are summarized as follows:1.The treatment efficiency of the pilot-scale IC reactor was considerable.During the entire experiment,the average elimination rate of COD reached76.91%,the total biochemical gas production reached 465.56 m~3,and the average daily gas production was 3.88 m~3.The average content of methane in biogas was54.83%.The ammonia nitrogen content of the effluent did not fluctuate greatly,the average ammonia nitrogen content was 1687.40 mg/L,while the sulfide content somewhat increased,with an average sulfide content of 133.47 mg/L.High-throughput sequencing of the 16 S r RNA gene in V3 and V4 regions of microbials in granular sludge at different stages showed that the top five dominant bacteria at the family level were Bacteroidetes?vadin HA17,Propionibacteriaceae,Spirochaetaceae,Anaerolineaceae,Ruminococcaceae respectively;the top five dominant archaea at the family level were Methanosaetaceae,uncultured?bacterium?c?Bathyarchaeia,Methanobacteriaceae,Methanomassiliicoccaceae,uncultured?bacterium?o?Methanomicrobiales.2.It is difficult to reach the discharging standard by relying only on the anaerobic digestion.In daily applications,a combination of anaerobic and other pathways is often utilized.In this experiment,the anaerobic effluent of MAW was ecologically purified by constructing a micro-ecosystem.The micro-ecosystem had a good effect on the elimination of 5 parameters such as COD.It can be maintained at a high level at the early stage.Although the concentration of pollutants in the influent water increased and the treatment cycle was shortened in the later stage of the experiment,the elimination rate of the five parameters such as COD by the micro-ecosystem was relatively stable,and the purification effect was achieved in a relatively short period of time.After a hydraulic retention time(30 feedings),the effluent Chemical oxygen demand,Ammonia nitrogen,Total nitrogen,Total phosphorus,and Biochemical oxygen demand concentrations of the micro-ecosystem reached 211.30,4.85,24.45,3.27,and 42.2mg/L,respectively.Through the combination of anaerobic and aerobic methods,the treatment of molasses alcohol wastewater could be integrated into an organic entirety,overcoming the difficulties,mastering the main points,and providing certain theoretical guidance and a practical reference for daily productions.3.The full-scale IC reactor had a good overall effect in treating MAW.During the entire experimental cycle including start-up period and the stabilized phase,the average elimination rate of COD reached 76.35%,and the total biochemical gas production reached 71,000 m~3.The average daily gas production was 1019.18 m~3 within stabilized phase,the average methane content in the gas samples during the whole experiment was 55.18%.The content of ammonia nitrogen of effluent remained relatively stable,the average ammonia nitrogen content was 1597.67 mg/L,while the sulfide content was significantly reduced,and the average sulfide content was 51.07 mg/L.The analysis of the microbial community structure showed that the top five dominant bacteria at the family level were Bacteroidetes?vadin HA17,Anaerolineaceae,Syntrophaceae,Ruminococcaceae and Syntrophobacteraceae respectively;and the top five dominant archaea at the family level were Methanosaetaceae,Methanomassiliccaceae,Methanobacteriaceae,uncultured?bacterium?p?Aegiribacteria,uncultured?bacterium?o?Methanomicrobiales respectively. |
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