Enhanced Coagulation: A Case Study On Typical Micro-Polluted South-China Source Water

In this thesis,two sorts of coagulants have been tested for the study of enhanced coagulation with the typical micro-polluted source water in South-China , which are inorganic coagulants( aluminum chloride(AlCl3 ),ferric chloride(FeCl3), industrial PACl and other PACl of different basicity),and organic polymer coagulant-aids (PAM,C1596,organic Si), respectively.The types of coagulants ,dose,pH of source water have been explored with the turbidity,organics and aluminum/iron concentration selected as the investigated targets for finished water.It has been shown that both the dose and the pH of source water greatly influence the coagulation.It can increase the removal ratio of turbidity, organics and control the concentration of aluminum/iron to different extent by adding the dose of the coagulants or changing the pH of water while the optimum dose and pH are different for each target.So it is necessary to consider overall to determine the optimum dose and pH. (Aluminum chloride,ferric chloride,industrial PACl)display different characteristics and rules in enhanced coagulation and industrial PACl has advantage in water treatment in comparison.As for the PACl,it has been found that the effect of coagulation improve regularly with the increase of basicity.It can not only improve water quality,but also cut down the dose of coagulants through the cooperation of coagulants with coagulant-aids (PAM ,C1596,or Organic Si). The molecular-weight and electric-charge of coagulant-aids are important factors influencing the coagulation.It is found that (Organic Si) is better in the water treatment with the low dose of coagulant and PAM is more effective for that with higher dose of coagulant.