Study On The Deep Treatment Of Copper Containing Wastewater From Piggery With PbS Modified Membrane And Its Reuse For Cultivating Chinese Cabbage

With the improvement of the living standards of urban and rural residents,pork,as a cost-effective product,has occupied a vast market,which has also led to large-scale production and discharge of wastewater from pig farming.Due to the addition of copper in pig breeding feed and drugs,the enrichment of copper in piggery wastewater has certain potential environmental pollution problems.This experiment applies Pb S nanoparticles to the surface modification of reverse osmosis membranes,ensuring that the membrane flux is not significantly damaged.Relying on the hydrophilicity and antibacterial properties of the modified material,the membrane’s anti fouling ability is improved,and the photocatalytic performance of Pb S nanoparticles is utilized to endow the reverse osmosis membrane with self-cleaning ability,thereby extending the working cycle of the reverse osmosis membrane and reducing the cost of membrane technology water treatment.At the same time,the feasibility of using regenerated water after deep treatment with membrane technology for hydroponic cultivation of Chinese cabbage was tested.The morphological development,physiological characteristics,product quality,migration and accumulation of metal elements,and prediction and assessment of edible risks of cabbage growth process were discussed.The research conclusion show that:(1)The prepared Pb S nanoparticles modified reverse osmosis membrane has achieved relatively significant improvement in antifouling and antibacterial properties.In the antifouling test,the recovery flux rate of the photocatalytic modified membrane increased by 85.25% compared to the unmodified original membrane,the antibacterial rate of the blend increased by 94.56%,and the E.coli adhesion rate decreased by 94.47%.(2)The rejection rates of COD,nitrate nitrogen,ammonium nitrogen,total phosphorus,and copper in the secondary treatment effluent of piggery wastewater treated with modified RO membrane were 98.91%,93.77%,99.96%,100%,and 98.00%,respectively.The effluent quality met the sewage discharge standards and irrigation water quality standards.(3)The difference in copper content in the culture medium has different effects on the growth and development of Chinese cabbage at various stages.The difference in photosynthetic efficiency between the experimental groups caused by sewage stress gradually intensifies with the development of Chinese cabbage.The stress received by WW and UF treatment groups at the late growth stage causes their dry matter accumulation to significantly lag behind that of the RO group,and the fresh and dry weight of the leaves of Chinese cabbage in the RO group increased by 23.15% and 17.91% compared to BK,respectively.Compared with the BK treatment group,the soluble sugar and vitamin C in the RO group increased by 94.91% and 60.58%,while the nitrate content decreased by 22.02%,showing relatively good quality.(4)Cu stress can lead to differences in the adsorption,migration,and enrichment of different metal elements in plants.The content of the eight major metal elements in the edible part of pakchoi is basically WW>UF>RO,and both WW and UF treated pakchoi reflect potential risks in the Cu intake risk assessment system,which are represented by comprehensive risk coefficients of 2.77 and 1.97 for adults,3.19 and 2.26 for children,respectively.However,the comprehensive risk coefficient of heavy metals in RO treated reclaimed water is similar to or lower than that of BK group,meeting the safety requirements for human metal intake under the comprehensive hazard index evaluation system.