A statistical and kinetic approach to develop a Floating Bed for the treatment of wastewater

Abstract

Abstract Pollution of fresh water bodies is a global threat today and its the right time to take necessary steps to restore those contaminated lakes without disturbing the food web. Floating Bed (FB) is a green and sustainable technology, which can be used in treatment process. The present study aims to design a floating bed and assessing its performance for the treatment of domestic wastewater. Pistia stratiotes is considered as the plant of interest as it contains a plenty of aerenchyma tissues, which keep it in floating condition without any supporting material. Box-Behnken Design (BBD) was applied to develop the system and to study the effect of various parameters and their interaction effect on performance. The system was able to remove 96 % COD at an optimum condition : initial COD of 321.3 mg L-1, vegetation coverage ratio of 0.43 and wastewater depth of 29.4 cm. The plant also uptake significant amount of nutrient as effluents of the most experimental runs were contained below 2 mg L-1 of NH4+-N and 4 mg L-1 of and PO43--P. A maximum Relative Growth Rate (RGR) of 0.0847 g g-1day-1 was obtained for Pistia stratiotes, when the vegetation coverage ratio was 0.25. In the kinetic analysis study, it was concluded that biodegradation followed the zero-order and first-order model with R2 value of 0.9765 and 0.9171, respectively. Overall, the system was working well and since it is one of the most eco-friendly technology, can be used in treatment of polluted water body.