Study On Membrane Coupling Process And Photocatalytic Technology For Treatment Of Livestock And Poultry Manure Water

With the expansion of the scale of breeding,livestock manure and water with complex composition and huge volume are produced.In addition to traditional pollutants such as COD,SS,TN,NH₃-N,and TP,livestock and poultry manure also adds antibiotics,heavy metals(Cu²⁺,Zn²⁺)and other difficult-to-treat pollutants.Therefore,a new environmentally-friendly and cost-effective new technology for the treatment of livestock and poultry manure water has been developed,which mainly deals with antibiotics,Cu²⁺,Zn²⁺and other issues to meet the increasingly stringent discharge requirements of livestock and poultry manure water.?1?A modified peach wood-based biomass activated carbon?PAC?was prepared by using peach wood as raw material,microwave heating carbonization and K₂CO₃ activation.The composite photocatalyst?ZnS@PAC?was obtained by ultrasonic-assisted co-precipitation method.After optimized by the response surface method?RSM?,the optimal preparation conditions of ZnS@PAC were determined as 800 W microwave power,3 h activation time,and 0.5 mol/L.ZnS@PAC was analyzed and characterized by SEM,XRD,EDS,PL and DRS.80 mg ZnS@PAC was added to 50 mL of enrofloxacin?ENR?solution?10 mg/mL?,and the degradation rate was 97.35%when exposed to a xenon light source for 45 min.The RSM prediction value?97.81%?is compared with the actual measurement value,and the standard deviation is 0.325%.The photocatalytic degradation process of ZnS@PAC complies with the quasi-first-order kinetic equation,and its reaction rate constant is 0.021min^-1.?2?Grille pond,primary sedimentation tank,conditioning tank,flocculation sedimentation tank,and sand filter are used as pretreatment processes.The optimal operating conditions are:the residence time of the primary sedimentation tank is 4 hours,and the polyaluminum chloride is a flocculation sedimentation agent.The dosage is 5 g/L;the filtration speed of the sand filter is 30 L/h,and the running time of the pretreatment process is 45 min.The effluent SS concentration is 50 mg/L,and the removal rate is about 85.71%;the EC concentration is10.4 ms/cm,and the removal rate is about-9.47%;the COD concentration is 2802 mg/L,and the removal rate is about 14.36%;NH₃-N The concentration is 541.49 mg/L,the removal rate is about 9.09%;the TP concentration is 71.09 mg/L,the removal rate is about 8.87%;the TN concentration is 387.39 mg/L,the removal rate is about 18.54%;the Cu²⁺concentration is 5.10 mg/L,the removal rate is about-4.29%;Zn²⁺concentration is 20.81mg/L,and the removal rate is about-4.36%.?3?After treatment of livestock and poultry manure water through membrane coupling process,the COD concentration in the permeate is 329 mg/L,and the removal rate is about88.08%;the TN concentration is 66.40 mg/L,and the removal rate is about 82.70%;The concentration of NH₃-N was 77.58 mg/L,and the removal rate was about 84.77%.All three indicators met the relevant requirements in the“Emission Standards for Pollutants in Livestock and Poultry Industry"?GB18596-2001?.Four indicators including pH,Cu²⁺,Zn²⁺,and SS all meet the relevant requirements in?GB18596-?"Emission Standards for Pollutants from Livestock and Poultry Farming Industry"?revised draft?.The permeate Cu²⁺concentration is 0.35 mg/L The removal rate was about 93.53%;the concentration of Zn²⁺was 1.70 mg/L,and the removal rate was about 89.67%;the concentration of SS was 0.6mg/L,and the removal rate was about 98.80%.The membrane coupling process has a desalination rate of about 88.75%,a concentration ratio of about 1:3.49,and a processing cost of about 3.00 yuan/ton.