| BaiYin Fluoride L.T.D is the factory that produced all kinds of fluoride with fluorite, Alot of the fluoride-laden wastewater discharged from the plan every year Which seriouslypolluted the environment. The simple one-stage wastewater treatment facilities wereconstructed for the preliminary treatment of fluoride wastewater. As a result theconcentration of fluoride in the wastewater was about l00 mg/L. which didn't meet thenational standard of the discharge. Therefore, they decide to construct wastewater treatmentfacilities to make treated wastewater reuse or discharge.During the experiment, studies four kinds of the concentration fluoric wastewater.Mainly analysis of the primary concentration,pH value and the content of coagulant effecton the fluoride removal. Compared with lime-direct-sadimentation treatment, Al2(SO4)3(orPAC)+Ca(OH)2 treatment and Ca(OH)2+ Al2(SO4)3 (or PAC) treatment,the test resultsdemonstrated that (l)primary fluoride concentration and pH value mainly affected,pH valueis the key of fluoride removal. (2)For l00mg/L fluoric wastewater bylime-direct-sadimentation treatment the results is not good. The fluoride concentraion ofeffluents can be reduced about 30mg/L. (3)Al2(SO4)3 (or PAC)+Ca(OH)2 treatment caneffectively defluoridate for the concentration of fluoride in wastewater below 50mg/L and isinvalid for above 50mg/L. (4) Ca(OH)2+ Al2(SO4)3 (or PAC )treatment is the effectivelymethod for the level about l00mg/L. Among this process PAC is better than Al2(SO4)3, whenpH value is the rang of 6.0 to 7.0 and PAC concentration is 500mg/L,the fluorideconcentration of effluents can be reduced lower than 10mg/L. Therefore, depending upon theexperimental result, the thesis provide first-stage lime- sadimentationan and second-stage-chemical coagulation precipitation.wastewater technological process for BaiYinfluoride L.T.D.The effluent from this treatment can be reused or discharge. (5) the paperstated the mechanism which chemical coagulation precipitation can improvelime-sadimentation treatment. |
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