This paper addresses an innovative constructed wetland system designed to treat edible oil refinery wastewater. The main aim is to intensify the performance of the horizontal sub surface flow constructed wetland (HSSFCW) technology through the integration of adsorption mechanism by means of appropriate adsorbents. Characterization of the wastewater showed that it was highly loaded in (1) chemical oxygen demand (COD) which ranged from 2091-3612 mg/l and averaged 2725 ± 505 mg/l (N=6) as well as (2) phosphate ranging from 4410 – 9779 mg/L and averaging 7989 ± 1914 mg/l (N=6). A conventional constructed wetland technology alone may not be effectively applied to remove such high COD and phosphate loadings. Consequently, it is of strategic importance that adsorption process, as an additional COD and phosphate removal mechanism, be incorporated in the reed beds to intensify its overall treatment efficiency. Coal ash and alum sludge were found to be good adsorbent of COD and phosphate, respectively. This was evidenced by their good adsorption capacity index (1<n<10), as found by batch adsorption tests. An innovative constructed wetland system comprising of seven HSSFCWs (each one of dimensions 10.0 m x 1.5 m x 0.6 m) connected in series was designed to be operated under a plug flow regime. In this paper, the design procedures are detailed and the setup of the innovative constructed wetland system is presented.