Performance Evaluation of Sand-based Surface flow Constructed wetland in Domestic Wastewater Treatment using Typha Orientalis as Macrophyte

Abstract

A laboratory-scale free water surface-flow constructed wetland was set up at the Department of Civil Engineering; Ladoke Akintola University of Technology (LAUTECH) Ogbomoso, Nigeria in May 2013 to demonstrate the performance of sand- based constructed wetland, using Typha Orientalis as a viable low-cost efficient treatment option for domestic wastewater from kitchen. The nutrient removal and performance evaluation of the constructed wetland in treatment of kitchen wastewater against retention period of ten days was investigated.

During the 10-day retention period, the sand- based constructed wetland set up with Typha Orientalis had improved the wastewater quality significantly as it had reduced 94.9% of Turbidity, BOD₅ by 79.0%, NO^-₃ by 66.7%, 87.9% of SO^-₄ , 70.24% of Cl^-, Conductivity by 70.8% and Magnesium by 80.62%. The pH value and Dissolve Oxygen increased by 28.3% and 64.01% respectively and the initial offensive odour of the raw water was no more noticeable. The final effluent was found to be suitable for non-drinking purposes like crop irrigation and keeping aquatic animals. However, it was noted that a 7- day detention time was optimal for the treatment of domestic wastewater from kitchen.

The treatment system was found to be economical, as the cost of construction only was involved and maintenance cost very minimal. It was environmentally friendly as it was free from offensive odour and insect invasion. The prototype scale is recommended for in-situ use, especially for wastewater from kitchen.

Keywords: Constructed wetland, Domestic wastewater, Nutrient removal, Retention period, Typha Orientalis