TECHNOLOGY FOCUS - ENVIRONMENT - Preferred Method: The step of collecting the wastewater further comprises a step of separately collecting acid wastewater and alkaline wastewater, and setting the water residence time for greater than or equal to 8 hours. The step of removing fluorine further comprises: removing fluorine at the first grade comprising adding calcium salt into the wastewater with pH value regulated, setting the ratio of the added amount of the calcium salt to the mass of the fluorine ion to 4:1-5:1, stirring and reacting for 20-30 minutes, and precipitating for 1-2 hours and then removing the precipitated chemical sludge; removing fluorine at second grade comprising adding calcium salt into the wastewater treated by removing fluorine at the first grade, setting the added amount of the calcium salt to 500-1000 mg/l, stirring and reacting for 20-30 minutes, precipitating for 2 hour and removing the precipitated chemical sludge; and concentrating the chemical sludge produced during removing the fluorine, then conveying the sludge after dehydrating the concentrated sludge and filling, or deeply treating the recycled fluorine, returning the concentrated filtrate to the step of regulating the pH value and then continuously treating. In the step of removing fluorine at the second grade further comprises adding 100-200 mg/l of flocculating agent and 3-8 mg/l of coagulant aid, when adding calcium salt. The step of treating by aerobic organisms further comprises: recycling the chemical sludge discharged during treating by aerobic organisms into the treating process of aerobic organisms, concentrating the remained sludge, then dehydrating, then conveying and piling, returning the concentrated filtrate to the step of incomplete anaerobic reaction, and continuously treating. The step of removing COD, and the incomplete anaerobic reaction time is 8-12 hours. The step of removing COD, and the water residence time during treating by aerobic organisms is greater than or equal to 20 hours. The concentration of the sludge is 3000-4000 mg/l, and the precipitating time is 1-2 hours after the reaction.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The calcium salt is calcium chloride. The flocculating agent is aluminum sulfate or poly aluminum sulfate. The coagulant aid is polyacrylamide.    TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: The wastewater treating system further comprises two units for removing fluorine connected in sequence. The first unit for removing fluorine is composed of a first reaction pool and a first precipitating pool for finishing removing fluorine at the first grade. The second unit for removing fluorine is composed of a second reaction pool and a second precipitating pool for finishing removing fluorine at the second grade, and the second reaction pool is connected with the water outlet of the first precipitating pool. The first reaction pool in the first unit for removing fluorine is connected with the pH value regulating pool, and the water outlet of the second precipitating pool of the second unit for removing fluorine is connected with the incomplete anaerobic reaction pool. The system additionally comprises a sludge concentrating pool comprising a chemical sludge concentrating pool for concentrating the chemical sludge produced in the unit for removing fluorine, and the chemical sludge concentrating pool is connected with the chemical sludge discharging port of the precipitating pool in the unit for removing fluorine. A biochemical sludge concentrating pool for concentrating the biochemical sludge discharged during aerobic organism treatment, and the biochemical sludge concentrating pool is connected with the biochemical sludge concentrating pool biochemical sludge discharging port of the precipitating pool in the unit for removing fluorine. The pH value regulating pool and the precipitating pool in the unit for removing fluorine are provided with stirring devices. The pH value regulating pool is provided with an online pH value monitoring instrument for measuring the pH value in the pool.