Removal of COD and total nitrogen in constructed wetlands with intermittent aeration in relation to hydraulic detention time

Abstract

Increased pollution caused by inadequate sewage disposal makes it increasingly necessary to seek efficient wastewater treatment techniques, but at a relatively low cost, especially for applications in rural areas or in deprived areas in order to improve not only the environmental quality but also the quality of life of the population. Wetlands or wetland systems constructed are simple, efficient and cost-effective systems using aquatic macrophytes grown on substrates where the effluent is treated under appropriate physical, chemical and biological conditions. The hydrology and feeding mode of the system are important parameters to achieve satisfactory results in the removal of contaminants in built floods, and although there has been a growing use of this technology in the last decades, there is still a great gap in the understanding of this system, which limits improving treatment and reaching more sustainable levels. Thus, the present project has as objective to evaluate the effect of hydraulic detention time on the removal of COD and Total Nitrogen in floodwaters constructed with intermittent aeration. Two flooded floodwaters will be evaluated, where each will receive a daily flow of 5 liters of synthetic domestic wastewater, resulting in a 5-day detention time. It will be installed perforated pipes along the longitudinal section of each built-up flood that will allow to evaluate the following parameters: COD, dissolved oxygen, redox potential, pH, total nitrogen, nitrate, nitrite, total phosphorus, electrical conductivity, temperature and flow. The data collected will be evaluated and compared qualitatively. (AU)