Experiment Of Enhanced Treating Low Temperature Low Turbidity And High Chroma By Attapulgite Adsorption And Coagulant Aid

Humic acid is the main components of natural organic pollutants in the natural water. Source water undersupplies in most of Chinese areas during cold season, and icebound season can lead to water body hypoxia, resulting in degradation of animals and plants wreck in time, thus make humic acid pollution intensifies. The existing of humic acid not only results in chroma increases but also forms protective effect on the surface of colloidal particle, which makes impurities in water sedimentate difficultly, and increases the difficulty of the treatment of low temperature, low turbidity and high chroma water.This paper mainly discusses how to use attapulgite as adsorbent and coagulant aid, and the objective is to treat low temperature, low turbidity and high chroma water combined with PAC.The removal of humic acid is one of key problems in the treatment of low temperature, low turbidity and high chroma water. Therefore, this paper first experimental study on adsorbing humic acid by using attapulgite as adsorbent, then it gives a systematic discussion about the adsorption kinetics and Thermodynamics behavior of attapulgite adsorb humic acid. The results show that the adsorption equilibrium time is about 70 min.The removal rate of humic acid can reach above 90% on the optimal conditions of 15g/L attapulgite adsorb 5mg/L humic acid. And the adsorption capacity of attapulgite increased with increasing the initial concentration of humic acid. The fitting correlation coefficient of adsorption isotherm of humic acid on attapulgite from high to low are respectively: Redlich-Peterson>Freundlich>Langmuir>Temkin. The data of adsorption kinetics experiments of different initial concentration of humic acid on attapulgite showed that Lagergre first order, Lagergre second order and Elovich dynamic adsorption model describe very well the adsorption process for humic acid on attapulgite.Overnight water was used to prepare water sampleâ… which simulate practical low temperature, low turbidity and high chroma water. The coagulation and sedimentation experiment results are as follows: the optium coagulant dosage is 35mg/L by auto-adding PAC alone, however, the effluent quality is non-ideal. The dosage of PAC decrease 9mg/L after auto-adding 15mg/L attapulgite, the removal rate of chroma, UV254 and CODMn is 81.25%, 73.19% and 44% respectively, the residual turbidity and residual aluminum content in the effluent is 0.05mg/L and 1.3NTU respectively.Songhua River Water was used to prepare water sampleâ…¡which simulate low temperature, low turbidity and high chroma water for the sake of closer to actual. Study on Experimental investigation of treating low temperature, low turbidity and high chroma by using attapulgite as adsorbent and coagulant aid to high dense settling pond reactor, The results are as follows: the return of sludge to high dense settling pond reactor not only increase the degree of low turbidity and the frequency of effective collision, strengthen the treatment effect of the high dense settling pond reactor, but also more importantly to make full use of thickened sludge in the sedimentation tank. Further strengthening the superiority of high dense settling pond reactor after auto-adding attapulgite, it is believed that the cause is mainly due to multiple cyclic utilization of attapulgite by returning mud waste to mixing pool, thus make full use of efficient resources. The removal rate of chroma, UV254 and CODMn is 93.62%, 76.83% and 66.15% respectively, the residual turbidity and residual aluminum content in the effluent is below 1.5NTU and 0.061mg/L respectively, and the effluent quality is ideal on condition of 10mg/L attapulgite, 12.5mg/L PAC and sludge return ratio 4.5%.