TREATMENT OF WASTEWATER WITH CONSTRUCTED WETLANDS SYSTEMS AND PLANTS USED IN THIS TECHNOLOGY - A REVIEW

Water issues are still here, urbanization and industries generate different types of wastes which then affect water. Many technologies have been introduced for water treatment and efforts are being made to improve and maintain water quality, while also providing easily available and low-cost technologies. Several methods which are easily available but due to high cost, they cannot be introduced everywhere, especially rural areas. Recently, constructed wetlands have been proven to be an efficient technology to treat water. With its biological, physical and chemical treatment, constructed wetland technology becomes the best choice by many countries around the world. Existing research shows that COD (Chemical Oxygen Demand), BOD5 (Biological Oxygen Demand), TKN (Total Kjeldahl Nitrogen), TSS (Total suspended solids) etc. have been removed to a significant degree by using constructed wetlands. This technology is a system of different materials, such as gravel, vegetation and recently introduced tool knows as biochar. The combination of these makes the system efficient for water treatment but some factors such as area, weather conditions, type of wastes do matter. Selection of constructed wetland type and suitable plants is very important. In this paper, efficiency of constructed wetland system, its mechanism, the types of plants used in the system and role of plants to enhance the efficiency of the wetland system from all over the world are widely reviewed and discussed.