Arab J Sci Eng (2014) 39:3571–3578 DOI 10.1007/s13369-014-1029-3 RESEARCH ARTICLE - CIVIL ENGINEERING Pollutant Removal Efficiency of Vertical Sub-surface Upward Flow Constructed Wetlands for Highway Runoff Treatment Rajendra Prasad Singh · DaFang Fu · DaNeng Fu · Huang Juan Received: 24 April 2012 / Accepted: 15 March 2013 / Published online: 18 March 2014 © King Fahd University of Petroleum and Minerals 2014 Abstract Four small-scale cylindrical, vertical upward flow constructed wetland units were installed and evaluated to determine the effectiveness of these units to treat highway runoff. The highway runoff was collected during various rainfall events in the year 2009 from Lukou Viaduct sec- tion of Nanjing airport express highway. The natural zeolite and gravel were used as filter substrates and all four units were planted with common reed (Phragmites spp.). These four units were subjected to similar hydraulic retention time (6 h HRT) with different hydraulic loads. Water samples were collected from the influent and effluent of vertical flow con- structed wetlands, and were analyzed for determination of total suspended solids, COD, ammoniacal nitrogen, total ni- trogen and total phosphorus. The results show that vertical flow constructed wetlands with zeolite–gravel substrate com- bination achieved the best performance between all systems with mean removal efficiency of 57 % TSS, 45 % COD and 78 % ammoniacal nitrogen. The average ammoniacal nitro- gen decreased by approximately 65 % in all wetland units, suggesting that this design had the highest nitrification rate. The study also revealed that the use of substrate materials with specific characteristics, such as zeolite and gravel, can enhance the removal of nutrients. However, the overall per- formance of vertical upward flow constructed wetlands was not effective. R. P. Singh (B ) · DaFang Fu · DaNeng Fu · H. Juan Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 210096, China e-mail: rajupsc@seu.edu.cn; fdf@seu.edu.cn Keywords Highway runoff · Vertical upward flow constructed wetland · Substrates · HRT · Pollutants removal efficiency · Adsorption · Zeolite 1 Introduction In recent years, many countries have been paying great attention to environmental protection. However, as economic development has increased, water pollution has become a prominent environmental issue. In particular, highway runoff has become a major pollution source to the surrounding environment [1]. Highway runoff consists of different types 123