Study On Anaerobic Treatment Efficiency Of Fur Wastewater And Operation Of IC Reactor

The composition of fur wastewater is complex,and the additives in processing makes it more difficult to degrade and more toxic.Therefore,the traditional aerobic biochemical treatment methods require complex technological process and high energy consumption,and also produce large amount of sludge.As an efficient and economical treatment method,anaerobic biological treatment has not been widely used in the treatment of fur wastewater,and there was no systematic study on the anaerobic process so far.This research was based on fur wastewater with high concentration volatile fatty acids?VFA?from a sheep shearing wastewater treatment plant in Hebei province.On the laboratory test,we examined the removal rate of COD_Cr,BOD₅/COD_Cr,the content and composition of VFA,pH and ORP,and determined the sludge activity in different temperature groups.We further examined IC reactor performance on fur processing wastewater and explored the optimum operation parameters in pilot-scale study.The removal rate of COD_Cr,NH₃-N,VFA,ALK,grease and so on were tested continuously.At the same time,we used high throughput sequencing platform to track microbial community dynamics in granular sludge.The anaerobic experiments under two groups of different concentrations of fur wastewater were carried out at 20?and 35?,respectively,and the adaptability of the wastewater to anaerobic treatment was investigated.The results showed that B/C of the wastewater was 0.7,and the acetic acid content in VFA of wastewater was higher than 40%,which was more favorable in anaerobic methanogenic process.The percentage of CH₄ in biogas detected by gas chromatography was 53.34%and the potential of methane production was360 mL/g COD_Cr.GPC spectra showed that macromolecules were degraded effectively after anaerobic biological treatment at different temperatures.The results of granular sludge activity after anaerobic treatment showed that low temperature had a certain inhibitory effect on the sludge MLVSS/MLSS,formation of sludge EPS and the activity of methane production.The MLVSS/MLSS of sludge,the content of protein and polysaccharide in EPS was higher than that at low temperature,and the content of coenzyme F₄₂₀20 in sludge was mainly affected by temperature.Under the condition of medium temperature,we examined the IC reactor performance on fur processing wastewater and explored the optimum operation parameters of IC reactor by a 60 d scale test.The results showed that the wastewater can adaptto the IC reactor and start normal operation rapidly in 5days.In steady operation stage,when the influent COD_Crr concentration stabilises at under 3000 mg·L^-11 and the acidibility was at around 45%,there was no apparent VFA accumulation and the effluent COD_Crr removal rate remained stable at about 55%.When the concentration of influent COD_Crr exceeds 3000mg·L^-11 and fluctuations obviously,the average removal rate of COD_Crr was about50%.The average removal rate of grease was 61.3%,and the best residence time was 6 h.Compared with the existing hydrolysis acidification and aerobic treatment,IC reactor treatment has improved the efficiency of VFA degradation significantly,which indicates that IC reactor has great engineering applicability for treating fur processing wastewater.We used high throughput sequencing method to track microbial community dynamics in granular sludge.The results showed that there was a certain proportion of Euryarchaeota in the granular sludge of the IC reactor,and methanogenic bacteria were active,and the proportion of Bacteroidetes and Firmicutes were stable in the process of operation,which was propitious to the reaction.In addition,the complexity of fur wastewater stimulated the growth of new microflora in granular sludge.The abundance and diversity of the flora decreased increased to be stable.The cluster analysis showed that the microbial community was divided into two goups.CCA showed that the significant environmental factors affecting microbial community structure were temperature,pH and MLVSS/MLSS respectively.The results showed that the treatment efficiency of IC reactor applied to fur wastewater could meet our expectation;the rapid adaptation and stable activity of the anaerobic microbial system can ensure the stable operation of the IC reactor.The condition of medium-temperature is the key factor to ensure a high efficiency in practical engineering.