The Enhanced Pretreatment Research Of High Chlorine Oily Wastewater From A Company Of Sinopec

In this thesis,the high chlorine oily wastewater from a company of Sinopec is mainly from the ballast water of the tanker,ship tank cleaning seawater,crude oil pipeline jacking seawater and the clean water of the crude oil settling tank.This thesis mainly researches the methods of reducing the concentration of main pollutants in wastewater and improving its biodegradability because the wastewater could not be discharged into the refinery high concentration refining wastewater treatment system.Then the technology of pilot test is designed to provide the basis for industrial application.Water quality analysis shows that the high content of petroleum,SS,COD and ammonia-nitrogen are main causes of bad biodegradability.The contents are 36.25mg/L,466.7mg/L,4140mg/L and 142.5mg/L respectively.So the enhanced pretreatment takes removing COD,ammonia-nitrogen,petroleum and SS as the main targets.The flocculation precipitation method is used to remove the petroleum and SS,it is found that using inorganic flocculant FeCl₃200mg/L,and organic flocculant PAM?61328?2mg/L could get the best treatment result when the pH value is 9.The petroleum and SS content are reduced to 3.35mg/L and 20.9mg/L,the removal rate could be up to 90.8%and 95.5%respectively.In order to reduce more COD for improving the biodegradability of wastewater,laboratory investigates COD removal efficiency of some oxidation technologies and their combination using,the result shows that the best operating is to oxygen-enriched aerate first,then,to flocculate,and to Fenton oxidate at last.Researching the influence of reaction time,dosing quantity of Fenton reagent and the pH value conditions on COD removal efficiency could find the best experimental condition which is to oxygen-enriched aerate for 10 minutes before flocculation,to dose H₂O₂ for 8ml/L with the molar ratio of Fe²⁺and H₂O₂ is 1?5,to adjust pH value to 3.5,and to control the reaction time for 90 minutes.The COD content is reduced to 1590mg/L and the removal rate could be up to 61.6%,the B/C value increases from 0.124 to 0.252 and the biodegradability improves significantly.In order to remove ammonia-nitrogen for improving the biodegradability of wastewater again,it is found that the struvite precipitation has good treatment effect.The best experimental condition is screened by orthogonal experiment.While the molar ratio of N,P,Mg is 1?0.4?1 and the pH value is 9.5.The ammonia-nitrogen content is reduced to 46mg/L and the removal rate could be up to 67.7%.The COD content is reduced to 1260mg/L and the removal rate could be up to 69.6%.After oxygen-enriched aerating,flocculating,Fenton oxidating and struvite precipitating,the biodegradability of wastewater could be significantly improved.After be diluted 5 times and be biodegraded by the activated sludge from the refinery high concentration refining wastewater treatment system,the COD of wastewater could be reduced to less than 50mg/L after 24 hours.It is up to the standard of sewage discharged.The technological route of pretreatment of high chlorine oily wastewater is designed based on the above results,the pilot equipment has been set up,and the daily capacity is 200m³.Through the daily monitoring data,it is found that the effect of this equipment is very good,the removal rate of petroleum,SS,COD and ammonia-nitrogen reach 88.9%,93.8%,65.3%and 93.8%respectively,and the wastewater could discharge into the refinery high concentration refining wastewater treatment system.It is proved that the technology has significant economic benefit,environmental benefit and social benefit,so it could provide relevant evidence for industrial application.