Study On Depth Treatment For Chemical Industry Wastewater By Using Many Flocculants

Following the rapid development of economics,chemical products are playing a significant role in people's production and life.However,on the other hand,the production process has gradually become a common and serious problem on environmental pollution and also human health as the increasing of chemical products. Especially some organic substances which are produced under the production process of fine chemical products such as pharmaceuticals,dyes,chemical products of day life and so on because a large part of these substances are in complex structure, poisonous or hard to degradation.Therefore,it is really hard to process chemical waste water.That is why the research on how to remove organic pollutants in chemical waste water has become an important task of current environmental pollution controlling.Chemical flocculation method is better than other methods because it is simply, easy to operate,economic and effective.It can make the complex procession become much easier by adding flocculant into waste water to remove tiny suspended solid and colloidal particles that can not be taken by using natural precipitation.The main purpose of this experiment is doing research on the depth effect of working on chemical waster water by using three common inorganic flocculants and one organic ploymer flocculant.They are aluminum sulfate(Al₂(SO₄)₃),Ferric trichloride(FeCl₃), polymeric aluminum chloride(PAC) and polyacrylamide(PAM) respectively. Through this experiment,it can be determined the dosage,the best pH value and the best water condition of these four flocculants.And also after testing in different arrangement of inorganic flocculants and organic flocculants,the results are as following:1.When the flocculant working alone,the removal of pollutants from high to low is PAC>FeCl₃>Al₂(SO₄)₃>PAM.PAC has the best effect in 40mg/L dosage. And the removal rates for turbidity,COD,aniline and nitrobenzene are 89.9%, 36%,30.7%and 27%respectively.The best pH value for Al₂(SO₄)₃,FeCl₃ and PAC are 7.5 and 8.It can be concluded that FeCl₃ has the best effect of flocculation in the condition of weak acid,Al₂(SO₄)₃ can achieve the best processing effect in neutral condition and PAC,on the other hand,can achieve the best processing effect in the condition of weak alkaline.2.When the inorganic and organic flocculants in different arrangement,the removal of pollutants from high to low is PAC+PAM>FeCl₃+PAM>Al₂(SO₄)₃+PAM. While PAC and PAM has the best processing effect with 40 Plus 2mg/L dosage.At the same time,the removal rates for turbidity,COD,aniline and nitrobenzene are 94.1%,57.5%,42.2%,38.9%respectively.3.Stirring slowly for 15 minutes is the best stirring time of depth processing on chemical waste water.