『Abstract
　Nitrogen removal in wetlands is achieved through two pathways: (a) N cycling and (b) storage. N cycling is a permanent removal pathway. There has been an increasing interest in the development of technologies to alleviate permanent nitrogen removal limitation in constructed wetlands by ensuring prevalence of conditions enhancing N cycling. The purpose of this study is to review an emerging technology of vegetated submerged bed constructed wetland system aimed at improving nitrogen removal in wetlands through rational system design. The design and performance of this system type is evaluated. The oxygen transfer capacity and nitrogen removal mechanisms on system performance are evaluated. Constructed wetland combinations most commonly consist of vertical flow (VF) and horizontal flow (HF) beds where VF and HF are aimed at nitrification and denitrification, respectively. Nitrate nitrogen accumulation is the most limiting factor in typical VF based systems.

Keywords: Nitrogen removal; Constructed wetland; N cycling; Oxygen transfer』

1. Introduction
　1.1. Vegetated bed constructed wetlands
　1.2. Oxygen transfer
2. Technologies based on principles of conventional VSB
　2.1. Vertical and horizontal flow VSB hybrid system
　2.2. Vertical and horizontal flow VSB hybrid design proposal
3. Conclusions and recommendations
References