A membrane combined process to cope with algae blooms in water

• Combined membrane process was investigated to cope with algae bloom water.
• Algae bloom in this study did not affect membrane filtration operation.
• PAC and KMnO4 prolonged the cycle of filtration.
• Medium and small MW of HPO and N-HPI caused irreversible fouling.

Algae blooms seriously threaten water quality and the supply of drinking water. A membrane process combined with coagulation, powdered activated carbon, and potassium permanganate was used as a treatment and investigated for its ability to cope with algae blooms in water bodies. The experimental results demonstrated that algae blooms can cause greater organic matter concentrations with large increases in the small neutral hydrophilic fraction (molecular weight (MW) lower than 1000 Da). This organic matter was effectively removed by pretreatment; therefore, no serious impacts on membrane filtration operation were found. Powdered activated carbon and potassium permanganate prolonged the filtration cycle. By investigating the fouled membranes during microfiltration (MF), we determined that the organics responsible for irreversible membrane fouling included strong hydrophobic and neutral hydrophilic organics with medium and small MWs, especially protein and carbohydrate in the neutral hydrophilic fraction. Alkaline cleaning was more efficient for organic elution than acidic cleaning; however, the acidic agent desorbed protein more effective than the alkaline agent.