Honolulu is restoring power to a major sewage treatment plant that was overwhelmed by storm water and sludge during Hurricane Ana.

The city said Wednesday crews installed new motors at Sand Island Wastewater Treatment Plant that are allowing rotating arms to move solids out of tanks for processing.

Storm water overwhelmed the plant on Sunday, sending 20 million gallons of untreated sludge into below-ground rooms. This left the plant without power.

An estimated 5,000 gallons of sewage also flowed out of manholes into Honolulu Harbor.

The city says power will be restored to more parts of the plant by Friday and afterward.