Building on the successful results of previous studies of flotation of Waste Activated Sludge (hereafter WAS) using the new technique utilizing CO2 gas as well as using model-gas (80%N2+20%CO2), this study aims to develop a simple model for dewatering WAS for easier re-use and safer disposal. It introduces a simple laboratory model for dewatering WAS in two stages, flotation followed by centrifugation. The first stage enables recycling a mixture of greenhouse gases containing 20%of CO2 and 80%of N2 gases by volume while the second stage uses a centrifuge model for dewatering WAS. Using the experimental dewatering model, promising results were obtained for dewatering WAS. It is hoped that the results of this study will lead to more study for efficient reuse of greenhouse gases to decrease global warming by collecting and recycling emissions of the gases from burning the fossil fuels then reuse them in wastewater and sludge treatment.