Research On Treatment Of Phenol Wastewater In Coal Gasification By Completely Mixed Anaerobic Biofilm Process

Coal gasification wastewater has complex water quality components,is difficult to degrade and is toxic and harmful,which has become the biggest obstacle to the development of coal gas industry.When the phenolic compounds in coal gasification wastewater are high,the anaerobic process can reduce the content of difficult-to-degrade organic matter in the wastewater,but the traditional anaerobic process has problems such as high energy consumption and poor removal efficiency.Therefore,this experiment mainly uses a new completely mixed anaerobic biofilm reactor to degrade phenolic compounds in coal gasification wastewater,which overcomes the problem of the short flow of traditional anaerobic biofilm method,and its biomass is not easy to lose.Enhanced the biological mass delivery course between filler and phenol wastewater.This study explored the factors affecting the treatment of COD and phenolic compounds in a fully mixed anaerobic biofilm reactor.The box-Benhnken experimental design using response surface methodology was used to determine the removal effect under optimal conditions;The effect of adding Fe₃O₄ nano-particles on the treatment of COD and phenolic compounds and the loss and occurrence status of Fe₃O₄ nano-particles in the system.Finally,the high-throughput biosequencing technology was used to study the microbial archaea and bacterial communities in the inoculated sludge and domesticated sludge stage reactors,thereby providing new ideas and theories for improving the anaerobic treatment process for the degradation of phenolic pollutants in coal gasification wastewater.Factor influence experiments were used to determine the response surface design test.The reactor HRT was centered at 48 h,the rotation speed of the stirring blade was centered at 80 rpm,and the inlet water basicity was centered at 30 mmol / L.Box-Benhnken experimental design using response surface method.Model analysis and optimization can be used to obtain the optimal parameters of the reactor during operation: when the reactor HRT is 60 h,the stirring blade speed is 83 rpm,and the inlet water basicity is 32 mmol / L.At the same time,the total phenol removal rate can reach 82.41%.After adding Fe₃O₄ nano-particles,the best process parameters: HRT is 48 hours,feed water alkalinity is 30 mmol / L,mixing propeller speed is 80 rpm,the total phenol removal rate is finally stabilized at about 85%,which is increased by 8 percentage points;COD removal rate is finally Stable at 89%,an increase of 6 percentage points.After the addition of Fe₃O₄ nano-particles,when the other conditions are unchanged,the effluent alkalinity,effluent p H,and gas production are reduced,while the OPR and organic acid content are increased.It is believed that Fe₃O₄ nano-particles has not achieved the expected effect.Increasing the phenol loading had little effect on the removal rate of total phenol and COD,the effluent alkalinity of the reactor,and the system ORP,but it reduced the effluent p H and increased VFA.Through high-throughput sequencing analysis,it was found that Methanothrix and Methanobacterium became dominant archaea in the domestication stage.And with the progress of experiments,the relative abundance of acetic acid-type methanogens increased,and the relative abundance of hydrogen-type methanogens decreased.Compared with inoculated sludge,the phenol-degrading bacteria Methylocystis and Commamonas became dominant bacteria during the stable operation of the reactor,and the sludge on the biofilm could effectively increase the content of the bacterial community that degrades phenolic compounds after phenol acclimation.