Using Enhanced Coagulation Technology To Improve The Treatment Effect

Enhanced coagulation has been identified as a best available technology for removing natural organic matter (NOM) and reducing disinfection by-products (DBPs), the study and application in drinking water of enhanced coagulation has been carried out for years, and enhanced coagulation has been used in waste water or sewage water treatment in recent years. Based on the current state of enhanced coagulation study and application, the author studied enhanced coagulation using in waste water treatment, and prepared, characterized an environmental friendly, multifunctional agent, potassium ferrate, and its efficiency in water treatment was also studied.Jar tests were carried out to solve the problems about the choice of coagulants, the optimization of coagulation conditions (such as pH, coagulation dose) to treat two types of waste water, which were produced in wood processing. The results indicated, that using polyferric sulphate (PFS) can enhanced the efficiency of eliminating COD and color, and powdered activated carbon filtration, Fenton oxidation are unfit to combine PFS enhanced coagulation to treat those two types of waste water, that biological process can enhanced the later PFS coagulation process, further more, biological and PFS enhanced coagulation combined processes can be a primary flow in those two types of waste water treatment system, and the correlative study still remains to be carried out.High pure solid potassium ferrate was prepared by chemical synthesis, and was characterized by FTIR and UV. The result of the tests that carried out to measure the aqueous decomposition of potassium ferrate indicated that the stability of ferrate depends on pH, and under alkaline conditions (pH=9~11), the ferrate has high chemical stability, and under acidic conditions (pH<6), the. ferrate is highly unstable and decomposes rapidly.The effect and impacts of removal aniline from water by potassium ferrate were studied. The pH of raw water, potassium ferrate dose, reacting time and theinitial concentration of aniline impact the removal of aniline. The oxidation of ferrate is the chief mechanism to removal aniline by potassium ferrate. And the tests of treating simulated aniline water sample indicated, that potassium preoxidation can enhanced the ability of PAC coagulation to remove organic matter.The removal of particles and resolvable organic matter in the treatment of low temperature raw water by potassium ferrate combined PAC coagulation was studied at the first time. The result showed that the optimized coagulation conditions can enhanced the removal of particles, but has little effect on the removal of resolvable organic matter. Potassium ferrate can easily remove resolvable organic matter through its high oxidation and coagulation ability, and potassium ferrate preoxidation combined PAC coagulation can realize the removal of particles and resolvable organic matter at the same coagulation process. The result has good reference to improve the coagulation efficiency at low temperature condition.