Analysis,Investigation And Treatment Of Soil Pollutants After The Closure Of Oil Enterprises

In recent years,with the gradual enhancement of people's awareness of environmental protection,the efforts of pollution prevention and control and industrial structure adjustment in various places have been continuously intensified,and a large number of backward chemical enterprises have been regulated and closed down.Since the special action of 'two reduction,six treatment and three promotion' was launched in Jiangsu Province in 2016,many printings,electroplating,powder coating,chemical industry and other enterprises have been 'suspended'rectification,and a large number of industrial enterprises along the Qingshui Corridor are also included in the scope of this shutdown.Due to the poor pollution prevention and control measures of early industrial enterprises and the long production and operation time,the production equipment in the workshop is often accompanied by leakage phenomenon.Once there is negligence in the stacking of raw materials,solid waste storage and production links,pollutants will penetrate into the ground,leaving behind the 'suspected contaminated land'.If the soil through the self-purification can't timely treatment of pollutants,so will not only harm the growth of plants,also pose a threat to human survival,Therefore,it is necessary to eliminate the hidden danger of environmental pollution through soil management.In this study,the soil remediation case of Starfish Oil Plant was selected,and the effect of remediation was analyzed by comparing the concentration of target pollutants before and after treatment and the change of soil agrochemical properties.Haixing Oil Factory is located in the west of Luting River,the water supply channel of Tongyu River,within 1000 meters.It is mainly engaged in the disposal and utilization of waste mineral oil.The main raw and auxiliary materials are waste mineral oil(the main composition and rough content of waste mineral oil are:waste mineral oil 93%,water 5%,impurities 0.8%),and the product is fuel oil.In this study,soil sampling and analysis were conducted on the site after the enterprise was closed,characteristic pollutants:semi-volatile organic pollutants and petroleum hydrocarbons were targeted,and the combined biological remediation of soil in the contaminated site for 2 years was carried out by adopting the combined remediation technology of petroleum hydrocarbon degrading bacteria and rice planting.The characteristic pollution factors(polycyclic aromatic hydrocarbons,petroleum hydrocarbons)and part of fertility factors detected before and after treatment were compared,and the following conclusions were drawn:(1)After two years of treatment,in the same area,the petroleum hydrocarbon degrading bacteria-rice remediation method has a better degradation effect on the pollutants in the 0-50cm depth of the surface soil,with the highest degradation rate of 75%,but the degradation of petroleum hydrocarbons in the lower soil is not obvious,with the degradation rate of only 9.48%.(The rice root system is shallow and cannot penetrate deeper soil layer,so it has little promotion effect on deep microbial activities.)This method has obvious effect on surface soil treatment,and poor degradation efficiency on deep soil.(2)According to the Classification Standard for Cultivated Land Quality Inspection Indicators in Jiangsu Province,the soil surface layer thickness,organic matter,available potassium,total nitrogen and available phosphorus in this plot have been improved to a certain extent after remediation,and the soil pH value tends to be neutral.Among them,surface layer thickness,organic matter and available potassium are in the range of Grade 2(higher)in the soil classification standard.Total N and available P reached the range of Grade 3(middle)in the soil classification standard.The pH value is in the level 1(high)range on the soil classification scale.Therefore;the agricultural properties of the land have been improved and promoted to a certain extent.(3)Adding an appropriate amount of nitrogen,phosphorus and potassium sources to the site soil(nitrogen,phosphorus and potassium)can create soil conditions conducive to the growth of rice roots,improve soil agricultural properties,promote the growth of rice and microorganisms,and improve soil remediation efficiency.