Research On The Water Treatment Of The Organic Matter In The Pearl River Water With Pre-oxidation,Coagulation And Adsorption

Dissolved organic matter(DOM)in water has complex structure and diversity of physical and chemical properties.DOM is not only the main material that can cause color and odor,but also can be transformed into disinfection by-products in the chlorination process.These substances cause hazard to human health.Coagulation,as an important part of water treatment,is one of the most effective convenient and economical process technologies to remove DOM,but the effect of DOM removal is not good,adsorption is a better way to remove organic matter in water.Pre-oxidation can change the configuration of organic matter in water and promote the removal of organic matter by subsequent processes,it is more efficiency to removal organic pollutants by combination of different processes.In this study,expect to obtain an advanced treatment to the Pearl River through to used combined technology,the ozone pre-oxidation and permanganate pre-oxidation,coagulation by polyaluminium chloride(PAC)and adsorption by powdered activated carbon were used solely on treatment to study the effect and getting suitable dosage of coagulat and adsorbents,and then selectivity to remove the organic matter in the water of the those craft was discussed.Physical and chemical fractionations were utilized to characterize the DOM in the Pearl River raw water and after pre-oxidation,enhanced coagulation and adsorption.The main contents and results are as follows:The fractions with molecular weight(MW)<3 kDa of DOM was predominant component in the Pearl River,more than 50%,the fractions with molecular diameter <0.45?m of organic matter was less than it.Other fractions with MW of DOM was less.Chemical fraction showed that the hydrophilic matter(HiM)are richer than others,more than 50%,the hydrophobic neutral(Ho N)?hydrophobic base(HoB)and hydrophobic acids(HoA)are 13.3%?11.1%?9.6% respectively in DOM.The effect of coagulation was best when the dosage of PAC was 12.5 mg/L,but the effect of organic matter removal was not good by coagulation alone,the rate of TOC removal just 28%.And the effect of organic matter removal was better when put into powder activated carbon during coagulation,the rate of TOC removal could improve to 39.3%.Powder activated carbon can improve the effect of organic matter removal by adsorb small MW organic matter and HiM.The optimal dosage of powder activated carbon is 0.12 g/L.Pre-oxidation by ozone and permanganate can remove part of the organic matter and change the characteristics of water and the composition of organic matter in water.The potential of zeta point in water was lower and the stability of colloid was decline after Pre-oxidation by ozone and permanganate.Pre-oxidation can oxidize macromolecular organic matter into small molecule hydrophilic substances,the organic matter with MW less than 3 kDa was increased.The effect of organic matter removal by permanganate pre-oxidation was better than pre-ozone.Compare the effect of organic matter removal to the Pearl River water by coagulation and adsorption under same conditions after pre-oxidation by ozone and permanganate.The results of organic matter removal and physical and chemical fractionations showed that the combined coagulation and adsorption after pre-oxidation could better remove the DOM of the Pearl River water.