Research On Treatment Of The Phosphorus-containing Industrial Wastewater By Modified Marble Powder And Slag

In this paper, marble powder was modified at high temperature. Modified marble powder had stronger adaptability to treat phosphorus-containing industrial wastewater.. The optimal conditions and effects of modified marble powder or slag treating wastewater sololy were studied by single factor experiments and orthogonal experiment. At last modified marble powder and slag were combined to treat the wastewater in order to find the optimal conditions. The main results were summarized as follow:(1) The results of single factor experiments in treatment of wastewater by modified marble powder were as follow: with the rise of dosage, the removal efficiency of PO₄^3- increased continuously, the residual concentration of Ca²⁺ increased rapidly and the residual concentration of Mg²⁺ decreased gradually. With the increase of reaction time, the residual concentration of PO₄^3- decreased a little, the residual concentration of Ca²⁺ and increased rapidly in 5¹0minutes and changed little after 10 minutes but the residual concentration of Mg²⁺ was just contrary to Ca²⁺. With the increase of temperature, the residual concentration of PO₄^3- decreased a little, the residual concentration of Ca²⁺ increased gradually but the residual concentration of Mg²⁺ decreased gradually. Shaking speed had little effect on the treatment effects. The optimal conditions of modified marble powder treating wastewater were dosage of 1.1g/100mL, reaction time of 10 minutes, temperature of 40℃and shaking speed of 150r/min.(2) The results of orthogonal experiment of modified marble powder treating wastewater showed that dosage was the most notable factor, next was shaking speed. The optimal reaction conditions of highest removal efficiency of PO₄^3- were dosage of 1.1g/100mL, temperature of 30℃, shaking speed of 200r/min and reaction time of 20 minutes.(3) The optimal conditions of the secondary treatment of wastewater were as follow: zeolite dosage of 3.5g /50mL and shaking speed of 60min.The wastewater could be reuse for industrial production.(4) The results of single factor experiments in treatment of wastewater by slag were as follow: with the rise of pH value, the removal efficiency of PO₄^3- increased continuously and the residual concentration of PO₄^3- kept stable when pH value achieved 9. With the increase of dosage, the removal efficiency of PO₄^3- increased continuously until the dosage achieved 2.5g, but the residual concentration of Ca²⁺ and Mg²⁺ increased. With the increase of shaking time, the residual concentration of PO₄^3-, Ca²⁺ and Mg²⁺ decreased gradually and changed little after 90 minutes. The residual concentration of PO₄^3-, Ca²⁺and Mg²⁺ decreased when temperature ranged from 20℃to 40℃, but the residual concentration of PO₄^3- and Ca²⁺ increase a little when temperatue kept increasing. The optimal conditions of slag treating wastewater were pH value of 9, slag dosage of 2.5g/100mL, shaking time of 90 minutes and temperature of 40℃.(5)The results of orthogonal experiment of slag treating wastewater showed that pH value was the most notable factor, next was slag dosage. The optimal reaction conditions of highest removal efficiency of PO₄^3- were pH value of 9, slag dosage of 2.5g/100mL, reaction temperature of 30℃and reaction time of 90 minutes.(6)The combined static experiment showed that with the increase of slag dosage, the residual concentration of PO₄^3- and Mg²⁺ decreased gradually but the residual concentration of Ca²⁺ increased. With the increase of shaking time, the residual concentration of PO₄^3- decreased very slowly, the residual concentration of Ca²⁺ increased rapidly in 10min～60min and decelerated the trend and decreased a little after 60 min, the residual concentration of Mg²⁺ changed a little in the process. The residual concentration of PO₄^3-, Ca²⁺and Mg²⁺ kept stable when the shaking speed was 150r/m. The optimal reaction condition were modified marble dosage of 0.5g/100mL, slag dosage of 0.3g/100mL, shaking time of 40 minutes and shaking speed of 150r/min.The residual concentration of PO₄^3- could meet the primary standard of GB8978-1996. The combined dynamic experiment showed that the adsorption instruments could make the wastewater meet the primary standard of GB8978-1996 from 1 to 8 hours.