The Sand Island 82-mgd Wastewater Treatment Plant (WWTP) is a primary treatment facility serving metropolitan Honolulu (the largest WWTP facility in the State of Hawaii).  The facility began its operations in 1978 and services an area stretching from Kuliouou Valley on the East side of Honolulu to Aliamanu on the West side of Honolulu.  RMTC provided professional services for the expansion / modification of the Sand Island WWTP.  The scope of work for this project included capacity expansion of the facility from 82 mgd to 90 mgd and various modernizations / modifications to the plant including changing the plant to a chemically enhanced primary treatment plant.