Study On Stabilization Technology Of Metal Ions In Measures Waste Residues

A large amount of solid waste was generated during the exploitation and processing of petroleum,and the heavy metals contained therein pollute water and soil and deteriorate the ecological environment.In this study,the residue of concentrated treatment of waste liquid in Changqing Oilfield were determined and analyzed by inductively coupled plasma mass spectrometry(ICP-MS).The type,morphology and leaching toxicity of metal ions in the waste residue were measured and combined with microbial toxicity experiments.The metal compound stabilizer was used,and the indoor simulation test of the compound stabilizer was carried out at the same time to further verify the practical application value of the compound stabilizer.This study provided technical means and solutions for the harmless treatment of heavy metals in the treatment and disposal of waste oil residues in oilfields,and provided reference datas for the treatment of similar wastes in Changqing Oilfield.The main results were as follows:(1)The sample Yuan 118-33 was a flocculation and sedimentation treatment process,the sample was brown wet solid,had a pungent odor,the pH value was neutral alkaline,the moisture content of the residue was as high as 46.8%,oil content was 7.0%,and the microbial number was 6.43×10~6 cfu/g.The total amount of heavy metals in the residue samples was determined,and the metal content limits of the local soil background values were compared.The results showed that the contents of Cu,Zn,Cd,Pb,Cr and Hg in the samples were higher than the local soil background values,and only the Ni content was lower than local soil background value.The leaching toxicity of heavy metals in samples was measured by sulfuric acid nitric acid method.Compared with the national standard GB 5085.3-2007 leaching toxicity limit,the leaching toxicity of Cu,Zn,Cd,Pb,Cr,Hg and Ni were higher than the standard value,and Cu was higher than 3%,Zn was about 60%higher,Cd was 9 times the standard value,Pb was about 50%higher,Cr was 0.7 mg·L~-11 higher,Hg was 0.06mg·L~-11 higher,and Ni was about 22%higher.(2)A single stabilizer containing different components in the sample Yuan118-33reacts with the heavy metal to screen the main components of the compound stabilizer according to the stabilizing efficiency.The optimal ratio of compound stabilizer was obtained by orthogonal test:the dosage of sodium sulfide was 0.015%,the dosage of potassium dihydrogen phosphate was 0.12%,and the dosage of slag was 5%.Through the experimental analysis,the optimal dosage was obtained,that was,the compound stabilizer accounts for 5%of the sample mass,and the water content was maintained at 60%.After 7 days of stabilization,the stability efficiencies of Cu,Zn,Cd,Pb,Cr,Hg and Ni were:88.5%,83.2%,86.7%,78.1%,78%,72%,50%,respectively.There was not much difference in pH value before and after the addition of the compound stabilizer,so the addition of the compound stabilizer had no obvious relationship with the pH value of the sample.(3)After the compound stabilizer treatment,the Yuan 118-33 heavy metal leaching toxicity standard GB 5085.3-2007,the leaching toxicity of Cu,Zn,Cd,Pb,Cr,Hg,Ni was lower than the standard,which was reduced by 75%,70%,92%,72%,35%,88%,55%.The results of Tessier morphology classification experiments showed that the residual states of the seven metals increased in different degrees.The five morphological changed of Zn,Cd,Hg and Cr were the most obvious,and the residual state increased by 80%,54%,69%and 31%,respectively,followed by Cu,Pb,Ni.(4)Three groups of different methods were used to analyze the toxicity of the sample Yuan 118-33 after stabilization and the microbial toxicity:there was no significant change in the microbial order before and after the addition of the compound stabilizer;after the single crystal dyeing,the strain after treatment with the stabilizer and the morphology of the strain before treatment Consistent;inhibition zone method to analyze the toxic intensity of the compound stabilizer extract on microorganisms,the results showed that the microbial growth on the plate was normal,no inhibition zone.It showed that the stabilizer had no obvious toxicity to microorganisms,and it had no obvious inhibitory effect on the growth of microorganisms while stabilizing metal ions,and provided dataes basis for microbial degradation and repair of subsequent residues.(5)Samples of the same treatment process Yuan 24-35 were selected for indoor simulation tests.The leaching toxicity of Zn,Cd,Pb and Cr in the original sample exceeded the national standard limit,which was 1.6 times,7.5 times,1.22 times and1.1 times of the standard respectively.The leaching toxicity of Cu,Hg and Ni did not exceed the standard;the compound stabilizer was added.After treatment,the leaching toxicity of the seven heavy metals decreased to 77%,67%,90%,46%,42%,73%and 54%,respectively,which were lower than the standard.The Tessier morphology classification experiment showed that the residual state of Cu,Zn,Cd,Pb and Cr in the residue was the largest,and the residual state of the residual state after the stabilization treatment exceeded 70%.Microbial toxicity experiments showed that the order of microbes before and after treatment did not change;after single staining with crystal violet,the morphology and size of the microorganisms in the materials before and after the stabilizer treatment did not change significantly.The indoor simulation test results of the measures waste liquid residue were consistent with the experimental results in chapter 4.3.There are 33 charts,16 tables and 94 references in this paper.