Abstract:

In order to ensure the rapid, timely, and effective treatment of water pollution, based on the excellent coagulation effect of poly-Si-Fe(PSF) and the rapid precipitation performance of flocculation, and with simulated domestic sewage as the experimental water sample, we studied the flocculation and precipitation time parameters of the shortened coagulation precipitation process (shortened process) and their impacts on filtration through beaker experiments, compared the removal effects of PSF and polyaluminum chloride (PAC) under the shortened and conventional processes of coagulation filtration, and analyzed the flocs by scanning electron microscopy (SEM). Finally, we observed the treatment effect of the shortened process on actual domestic sewage. The results show that in the coagulation sedimentation experiment, the PSF shortened process with 2 min of flocculation and 3 min of precipitation can reach the pollutant removal level close to that of the conventional process. With a dosage of 0.162 mmol/L, the turbidity and average COD_Cr removal rate are 0.59% and 11.5%, respectively. In the actual water treatment experiment, when the dosage reaches 0.162 mmol/L, the removal efficiencies of turbidity and COD_Cr by the PSF shortened process are 27.88% and 11.11% higher than that by PAC shortened process respectively. In the filtration experiment, the filtered water quality of the PSF shortened process was stable, and the average COD_Cr removal rate reached about 85%, 7% higher than the PAC shortened process. The SEM picture shows that the flocculation of PSF in the shortened process has a more compact structure and larger particle size than PAC catkins, thus better flocculation and precipitation effect.

Key words: poly-Si-Fe, domestic sewage, shortened coagulation filtration, filtering effect