EVALUATION OF REHABILITATION PROCEDURES IN THE ARABIAN GULF FOCUSSING ON THE MAFRAQ WTW IN ABU DHABI

Rehabilitation of concrete structures in the Arabian Gulf States is a common practice due to several factors including high chlorides in the ground water, high septicity in the sewers, less than adequate quality control in routine maintenance.An excellent case study is provided by the recently completed 30-month contract carried out by the Abu Dhabi Municipality to rehabilitate the whole of Phase I of the Mafraq Wastewater Treatment Works. Designed to treat 104,000 m3/d sewage on average, the unit was in need of replacement after barely 12 years of operation. Completed at a cost US23.6 million, rehabilitation proved to be a more cost-effective solution than a whole new unit, which was estimated to cost US 51 millionOverriding all this is the problems associated in dealing with Contractors who are struggling with new and innovative ways to rehabilitate concrete.This paper reviews the trials and tribulations of completing this demanding project.