Research On Demulsification And Biodegradation Of Emulsified Oil Wastewater Used For Hydraulic Supports In Mines

In recent years,mining,steel,petrochemical and other industries have been involved in the discharge of emulsified oil wastewater.The composition of this type of wastewater is complex,and at the same time,due to the presence of a large amount of emulsifiers,it is difficult to separate the oil and water phases and is easy to accumulate in the water body.Based on this,this thesis takes the emulsified oil used in mine hydraulic supports as the target pollutant,respectively explores the effects of different pretreatment effects and influencing factors,and then combines them with biodegradation technology.Explore the influence of emulsified oil on the microbial community and the changes in the main components of emulsified oil during different treatments.This paper uses inorganic salt electrolyte treatment method,ultrasonic treatment method,and Fenton oxidation method to treat emulsified oil wastewater.It is found that the effect of inorganic salt cations is Mg²⁺>Ca²⁺>Na⁺;when the ultrasonic intensity is 150W/m²,the action time is 10min When the temperature is 20℃,ultrasonic treatment can obtain a good oil removal rate;in Fenton oxidation reaction,n(H₂O₂:Fe²⁺)=4:1、m（H₂O₂:COD）=1:1.349,and the effect is best when the reaction is 120 minutes.Comprehensive analysis The treatment effect of Fenton oxidation method is better than that of inorganic salt electrolyte treatment method and ultrasonic treatment method.Under the best conditions,the COD removal rate and oil removal rate of Fenton oxidation method reach about 90%at the maximum value,and the turbidity can be reduced to below 80NTU.Through the ladder acclimation method to screen and enrich the high-efficiency degradation bacteria,the optimal degradation conditions are 30-35℃,p H6-7,and aeration time of 10h;under the optimal conditions,the content of polysaccharide and protein in the extracellular polymer（EPS）is all Significant increase,helps the emulsified oil to be adsorbed by microorganisms.In addition,glucose,sodium acetate,and sodium lauroyl glutamate also promote the biodegradation process,and sodium acetate has the most obvious effect when the concentration is about 500mg/L;and the water is discharged under the best working conditions.COD 39.52±3.84mg/L,oil content 7.05±1.76mg/L,turbidity 5.99±1.49NTU,meeting the mine water discharge standard in the coal industry pollutant discharge standard（GB20426-2006）.Through high-throughput sequencing,it was found that the flora EMU＿21 was reduced from17 phyla to 13 phyla.After domestication,it was mainly composed of Proteobacteria（92.75%）,Planctomycetota（1.92%）,Actinobacteriota（1.52%）.The species diversity is significantly reduced,and the proportion of bacteria with hydrocarbon degradation function is significantly increased.The emulsified oil used in this test is mainly mixed with additives such as dispersant and antioxidant,extreme pressure antiwear agent,oily agent,biocide,defoaming agent,etc.The main components are oleic acid,stearic acid,palmitic acid,hexamethyl Cyclotrisiloxane（D3）,EDTA,2,2’-methylenebis-（4-methyl-6-tert-butylphenol）（antioxidant MBP）,nonylphenol polyoxyethylene ether（NPEO）,dodecylbenzene sulfonic acid,octadecadienoic acid dimer,etc.After pretreatment,oleic acid,antioxidant MBP,and dispersant D3 mainly remain in the effluent;long-chain alkanes in the effluent of biological treatment are reduced,and a small amount of antioxidants MBP and D3 are not completely degraded,while nonylphenol ethoxylates（NPEOs）,oleic acid,stearic acid,palmitic acid,stearyl alcohol,and sodium lauryl sulfonate are all degraded to varying degrees during the treatment process.From the perspective of bacterial community diversity,the changes in the above components are related to the obviously enriched bacterial groups Comamonadaceae,Pseudomonadaceae,Sphingomonadaceae,Rhizobiaceae,Alcaligenaceae,Burkholderiaceae,Phyllobacteriaceae.The paper has 46 figures,14 tables,and 102 references.