To explore the feasibility of the green water purification process of ultrafiltration with short process and low chemical dosage

continuous filtration was used as the pretreatment process

and a pilot study of continuous filtration-ultrafiltration process for Songhua River water treatment was performed in terms of treatment efficiency and membrane fouling. In addition

a comparison experiment with direct ultrafiltration was performed to investigate the role of continuous filtration in the combination process. The results showed that the continuous filtration-ultrafiltration process had excellent removal efficiency for turbidity and ammonia nitrogen. The removal rates were 99.75% and 70.77%

respectively. But the removal of organic matter was inefficient. The removal rates of CODMn and UV254 were 32.21% and 17.12%

respectively. In the early stage

the rate of membrane fouling was slow

and it became faster after the 15th day. The transmembrane pressure increased to the superior limit of 50.3 kPa on the 50th day. Continuous filtration showed a good removal effect on tryptophan protein

and ultrafiltration showed different degrees of removal of soluble biometabolites

tryptophan proteins

fulvic acid organics

and humic acids. Humic acids and tryptophan proteins were the main irreversible contaminants of ultrafiltration membranes. The removal rate of CODMn

UV254

and ammonia nitrogen by the combination process were 9.97%

7.02%

and 33.84% higher than that of direct filtration

respectively. Moreover

the membrane fouling rate of the combination process was much less than that of direct ultrafiltration. Continuous filtration pretreatment cannot only improve the removal efficiency of organic matter and ammonia nitrogen

but also alleviate ultrafiltration membrane fouling effectively.