Membrane fouling can be a problem in water purification systems. Researchers studied how pre-coagulation and sedimentation can help reduce this fouling. They used a special membrane in a pilot-scale water purification plant. The pre-treatment helped reduce reversible fouling, but did not decrease irreversible fouling. This type of fouling was mainly caused by organic substances that were not effectively removed by pre-coagulation. The use of aluminum as a coagulant did not significantly contribute to irreversible fouling in this study.