Study On Extraction Method And Acute Toxicity Of Semi-volatile Organic Pollutants From Sludge

With the rapid development of urban sewage treatment plants in China,sewage treatment capacity is increasing,sludge production is increasing,sludge residual toxic and harmful substances have potential harm to the ecological environment and human health.therefore,it is particularly important to analyze the types of toxic and harmful substances in sludge and their comprehensive biological toxicity for further sludge disposal.In this study,gas chromatography-mass spectrometry(GC-MS),inductively coupled plasma emission spectrometry and cold atomic absorption spectrometry were used to analyze semi-volatile organic pollutants and heavy metals in sludge.four types of 20semi-volatile organic pollutants(SVOCs)were detected,including aniline and p-diaminobiphenyl,phenol,phthalate and polycyclic aromatic hydrocarbons.The content of only nickel in heavy metals is much higher than the sludge sludge related standards in China,and much higher than the reported average of nickel in China.the content of other heavy metals is lower than the limit of relevant standards in China and the average level of sludge in China.In this study,four extraction methods were used to extract semi-volatile organic pollutants from sludge.the single factor experiment was used to optimize the extraction methods,and the extraction conditions with the highest acute toxicity were obtained.The experimental results show that ultrasonic extraction and qu ech ers method are simple,but the extraction efficiency is not high.Soxhlet extraction efficiency is high,but time-consuming and labor-consuming,and more organic solvents are needed,which is easy to pollute the environment;The extraction efficiency of matrix solid phase extraction was the highest among the four methods,and the operation was simple and rapid.Response surface methodology(RSM)was used to optimize the dosage of dispersant and eluent in matrix solid-phase dispersion extraction.The mathematical model Y=90.00+4.17A+0.86B+3.75AB-6.44A~2-2.94B~2 for the relationship between the response value(luminescence inhibitory rate of luminescent bacteria Y)and the respective variables(dispersant dose A,eluent dose B).The distribution of residual points is almost on a straight line,which shows that the model has good fitting effect.The dosage of dispersant was 2 g,eluent was 30 mL,and the acute toxicity of the extract was 90%.The effect of dispersant dosage on biotoxicity was more obvious.