Application of a novel coagulant in reservoir water treatment in Qingdao

Epichlorohydrin-dimethylamine (DAM-ECHs) of different viscosity were acquired by adjusting the mass fraction of cross-linker and applied as assistant of polyferric chloride (PFC, basicity = 1.0) on treatment of humic acid polluted reservoir water in a hybrid coagulation-ultrafiltration process (C-UF). The coagulation effects of PFC combined with DAM-ECHs was compared and the ideal dosing methods were selected to conduct the ultrafiltration treatment. Thus, the impacts of DAM-ECHs co-operate with PFC on membrane fouling of regenerated cellulose (RC) membrane in C-UF were evaluated. Experimental outcome disclosed that application of DAM-ECH3 was more effective on turbidity and HA elimination than the other two DAM-ECHs, especially at low PFC dosage. This phenomenon was owing to highest cationic degree (viscosity) among three DAM-ECHs. The enhance effect of DAM-ECHs became obsolete when the dosage exceeded 1.0 mg/L. Besides floc strength, increase of DAM-ECHs dosage in certain range relatively increased floc size, structure (compactness) and recovery ability, which was proved to be crucial for control of membrane fouling. Specifically, when the mass fraction of ethanediamine was 3.0%, coagulation process formed floc possess largest size, most open structure, and superior recoverability, which resulted in lowest membrane fouling resistance.

Automated summary

Epichlorohydrin-dimethylamine (DAM-ECHs) with different viscosities were used as assistants for polyferric chloride (PFC) in the treatment of humic acid polluted reservoir water. The effects of DAM-ECHs combined with PFC on membrane fouling were evaluated. The application of DAM-ECH3 was found to be more effective in turbidity and humic acid removal compared to the other two DAM-ECHs, especially at low PFC dosage. However, the enhancement effect of DAM-ECHs became obsolete when the dosage exceeded 1.0 mg/L.