Impact assessment of an improper effluent control system: A Delphi approach

The main purpose of this paper is to identify and evaluate systematically the impacts of improper effluent control system in Jeddah, Saudi Arabia, using a Delphi approach. Impact assessment was based on the collective professional judgment of some 450 persons from Saudi Arabia and Gulf Cooperation Council (GCC) countries who are knowledgeable about the environment and about pollution. The Delphi procedure was used to aid in soliciting professional judgment and in the aggregation of results. The objective was to derive a consensus of opinion, through a structural procedure, from the selected experts (Delphi Panel) regarding the impacts of incomplete sewerage system and use of cesspools as an effluent control system in Jeddah. The Delphi approach consisted of four steps and three rounds. It started with forming a contact network (sample population) then proceeded with two iterations of a Delphi survey and finished with a consensus building workshop. Seventeen impacts were identified, interpreted, analyzed and ranked according to their magnitude, importance, probability, urgency, type, range and nature.