| With the vigorous development of China's economy,living standards of residents have greatly improved and people's tendency of choosing a healthier dietary structure is stronger.In particular,the demand for livestock and poultry products will gradually increase and it will accelerate the livestock and poultry breeding industry at the same time.At present,livestock and poultry farming is the industrial pillar of agriculture and peasant economy in China's rural areas,which will benefit the improvement of China's rural economy.However,the excrement discharge of livestock and poultry manure is large.If it is not effectively treated and utilized,it will cause environmental pollution and cause harm to health of livestock and humans..Objective:This study aims to initially explore the use of plant materials to treat pig manure contamination.Through the extraction process of mucilage of Seriphidium transiliense seeds and the use of extracting mucilage as flocculant to study the treatment effect of pig manure sewage.The potted test?plant?was used to absorb heavy metal elements in the soil of the pig manure sewage.This research will provide a reference for the purification of soil for the application of livestock manure and for the selection of plants in the field of phytoremediation.Methods:Firstly,single factor experiments were carried out on three factors affecting the extraction rate of mucus.On this basis,response surface methodology?Box Behnken design?was used to optimize the extraction.Taking the extracted mucus as flocculant and flocculation rate and COD as the measurement index,the concentration,pH value and flocculant dosage of pig manure wastewater were tested.Based on the characteristics of heavy metals enrichment in soil by plants,different concentrations of pig manure sewage were designed to treat plants.The enrichment coefficient,transfer coefficient and total amount of migration were taken as indicators to test the heavy metals enrichment ability of plants.Results:The results of response surface methodology showed that the highest extraction rate of Artemisia scoparia seed mucilage under the experimental conditions was 16.8%.The extraction conditions were:extraction time 3 h,liquid-to-liquid ratio 60:1,extraction temperature 64?.When the mucus dose was 2 mg·L-1,mixed alum(40 mg·L-1)was used at pH 7 value.The flocculation rate and COD removal rate of pig feces were 62.6%and 68.3%respectively.Odontox odorata had the strongest enrichment ability of heavy metal Cr and Cu in A3 treatment,and the content of heavy metal Cr was 28.24 mg·kg-1?above ground?.The content of heavy metal Cu was 6.23 mg·kg-1?above ground?and 16.99 mg·kg-1?below ground?in part?above ground?and 107.3 mg·kg-1?below ground?.The content of Cr was 20.24 mg·kg-1?above ground?and 90.71 mg·kg-1?below ground?in Sargassum vulgaris the highest in A2 treatment,and the content of heavy metal Cu was 2.55 mg·kg-1?above ground?and 9.26 mg·kg-1?below ground?.The maximum total migration of cadmium was 0.45 mg and 0.83 mg,while those of Cr was 141.2 mg and 346.13 mg,and those of Cu was 30.15 mg and 47.2 mg,respectively.The results showed that the sage and odor grass had strong absorption capacity for heavy metals?Cr,Cu?in the soil,but the absorption capacity of heavy metal Cd was weak.The roots of plants have strong ability to accumulate heavy metals?enrichment factor>1?,but they are not conducive to the migration of heavy metals?earth?,but the transfer coefficients are less than 1.Conclusion:In the process of pig manure treatment,flocculation rate and COD removal rate increase with the increase of mucus content;pH has no obvious change trend on the treatment effect;the combination of alum and mucus can significantly improve the flocculation rate and COD removal rate.The results showed that the soil pH and conductivity of the two plants increased with the increase of pig manure wastewater concentration,but the transfer coefficients are less than 1. |
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