Remediation Of Petroleum Hydrocarbon Soil In Shenfu Wastewater Irrigation Area By Dairy Dung Biochar

The Shenfu Irrigation District was established in 1960 and is one of the largest oil-sewage irrigation areas in China.Clear water irrigation was completed in 2000,but petroleum hydrocarbon residues and pollution still exist in the area.It is a very necessary and urgent problem to carry out practical restoration of residual petroleum hydrocarbon contaminated soil in Shenfu sewage irrigation area.In this paper,the petroleum hydrocarbon contaminated soil in the Shenfu Sewage Irrigation District of Shenyang City was taken as the research object.The biochar was prepared by using cow dung as raw material,the preparation conditions,application conditions and the degradation effect of petroleum hydrocarbons and the bioavailability of petroleum hydrocarbon degradation were carried out.Correlation study to explore the principle and mechanism of cattle manure biochar to repair petroleum hydrocarbon contaminated soil in sewage irrigation area.In this way,it provides a green and efficient environmentally-friendly soil new material for the oil-carbon contaminated soil in the sewage irrigation area and develops low-cost in-situ remediation technology,and expands the utilization of cow dung resources.The main results are as follows:?1?Degradation of petroleum hydrocarbon pollution in soil by cow dung biocharAs the pyrolysis temperature of cow manure biochar increases,the degradation rate of petroleum hydrocarbons increases.When the pyrolysis temperature of cow manure biochar is 700°C,the degradation rate of petroleum hydrocarbons in soil is the highest,which is 63.58%.As the amount of biochar applied to cattle manure increases,the rate of degradation of petroleum hydrocarbons in the soil increases.Considering the comprehensive factors,the cow manure biochar 50g·kg^-1_soiloil was determined,and the degradation rate was 63.58%.The effect of soil application conditions on the degradation of petroleum hydrocarbons in soil showed that the degradation rate of petroleum hydrocarbons in soil was the best when the soil pH was 7,which was 16.12%.When the soil pH is greater than 7 or less than 7,the degradation rate decreases.When the soil temperature is 30?,the degradation rate is preferably about 19.6%.When the degradation time increases from 30d to 150d,the degradation rate tends to be flat.At 180d,the petroleum hydrocarbon degradation rate was 65.33%.?2?Study on Bioavailability of Petroleum Hydrocarbons in Soil by Cow Manure BiocharFor the treatment of wheat soil,under different treatment conditions of control soil?CK?,nitrogen and phosphate?NP?soil,cow manure biochar?C5?soil,cow manure biochar nitrogen fertilizer and phosphate fertilizer?CNP?,The effect of cow manure biochar on soil physical and chemical properties indicates that the addition of cow manure biochar reduces the acidity of the soil by more than 0.25 unit values.The change of soil N,C,S,TOC percentage and pH is CK<NP<CNP<C5.The effect of cow manure biochar on the migration and transformation of soil-plant petroleum hydrocarbons showed that the concentration of petroleum hydrocarbons in wheat seedlings showed leaf>roots,and the ratio was about 5times.The petroleum hydrocarbon content in the roots of wheat seedlings is:NP>CK>C5>CNP,while the leaf parts are:NP>CK>CNP>C5.After 45 days,the soil petroleum hydrocarbon residue CK>NP>C5>CNP,CK16.32%,NP 19.64%,C5 52.62%and CNP 56.88%.The addition of cow dung biochar to the soil has no passivation effect on petroleum hydrocarbons in the soil.With the increase of the amount of cow charcoal biochar,the absorption of petroleum hydrocarbons in the roots and leaves of wheat seedlings showed a downwardtrend.Petroleumhydrocarboncontentinwheatseedlingroots CK?0g/kg?>C1?10g/kg?>C2?20g/kg?>C3?30g/kg?>C4?40g/kg?>C5?50g/kg?,and leaves CK>C1>C2>C3>C4>C5,With the increase of the amount of biochar applied to the cow dung,the removal rate of petroleum hydrocarbons in the soil increased,which promoted the removal of petroleum hydrocarbons in the wheat soil.Under different conditions of adding cow manurebiochar,thepetroleumhydrocarbonremovalrateswere16.33%?CK?,22.68%?C1?,29.94%?C2?,39.79%?C3?,46.77%?C4?,52.62%?C5?.The biotransfer coefficient?BTC?is CK 1.90 at the maximum and the minimum is CN1 1.81,indicating that the addition of biochar inhibits the transport of petroleum hydrocarbons to the leaves of roots,root enrichment factor?RCF?and stem and leaf enrichment factors?SCF?is greater than 1,indicating that the concentration in plant roots and leaves is greater than the concentration of petroleum hydrocarbons in the soil.As the amount of biochar added increased,the RCF and SCF coefficients increased,CNP>C5>NP>CK;C5>C4>C3>C2>C1>CK.?3?Cow manure biochar has long-term repair effect on petroleum hydrocarbon contaminated soil in Shenfu sewage irrigation area.