Experimental And Research On Lampshade Polishing Wastewater Treatment

The most important characteristics of high boron-silicon glass lampshade polishingwastewater are low CODCr, high concentration of the turbidity and the suspending solids,and pH value is in the range of 7.7～8.2. The coagulation sedimentation is one of the mosteffective ways to treat this kind of wastewater. Chemical analysis was used to determinethe characteristics of polishing wastewater. Based on this, the removal efficiencies ofinorganic coagulant Al₂（SO₄）₃·18H₂O, FeC_l3·6H₂O and inorganic polymer coagulantpolyaluminum chloride （PAC） were studied through the orthogonal experiments, and thenthe main influencing factors as well as the optimum reaction conditions were optimized.Considering the removal efficiency of the turbidity and the cost of each kind of treatmentprocess, the process flow for treating polishing wastewater was given.In this research, the effects of coagulant dosage, pH, temperature, mixing time,mixing speed for stirring, reaction time and reaction speed for stirring on the orthogonalexperiment with seven factors and three levels are inspected．The turbidity of wastewateras the standard is used to judge the coagulation treatment effect.Through the experiments, the main three influence factors are pH, temperature andthe reaction time for stirring.When the coagulant is PAC, the best reaction condition is: the optimal dosage is 40mg/L, pH value is 8, water temperature is 45℃, mixing time is 60 s, mixing speed forstirring is 500 r/min, reaction time is 30 min, and the reaction speed for stirring is 100r/min.When the coagulant is Al₂（SO₄）₃·18H₂O, the best reaction condition is: the optimaldosage is 180 mg/L, pH value is 8, water temperature is 30℃, mixing time is 120 s,mixing speed for stirring is 300 r/min, reaction time is 30 min, and the reaction speed forstirring is 60 r/min.When the coagulant is FeCl₃·6H₂O, the best reaction condition is: the optimal dosage60 mg/L, pH value is 8, water temperature is 45℃, mixing time is 120 s, mixing speed forstirring is 300 r/min, reaction time is 30 min, and the reaction speed for stirring is 60r/min. Under the optimum reaction conditions, the removal rate of turbidity of the threekinds of coagulants is more than 99.5%. The quality of the effluent water can meet therequirement of national discharge standard （The reuse of urban recycling water–Waterquality standard for industrial uses） and there is no water mark left if used it to clean theglass lampshade. If using the PAC or Al₂（SO₄）₃·18H₂O as the coagulant, the treatment costis 0.06 Yuan/ton, and the pharmaceutical consumption is low. Corporation will getconsiderable economic benefits, if the wastewater treated can be reused.