WS Atkins plc, appointed as lead designer for Phase 1 of the project, contracted VBTM Associates Ltd to provide detailed engineering designs for potable water storage, wastewater handling, including prevention of septicity, and advanced treatment of greywater. VBTM designed facilities to treat up to 137,000 cubic metres/day of wastewater from the airport including surface water run-off prior to discharge into the Red Sea. VBTM also designed new water storage and distribution systems, which involved a secondary disinfection stage of capacity 36,000 cubic metres/day. VBTM provided designs for part of the treated wastewater (approximately 86,000 cubic metres/day) to be recovered, treated and reused within the airport as process water for ventilation and air conditioning systems, generators etc., and water for irrigation of the tree nurseries and lawns.