Characteristics of Phosphorus Adsorption of Aerated Concrete in Wastewater Treatment

Abstract

Constructed wetlands are widely used throughout the world to treat a wide variety of wastewater. Numerous researches on phosphorus removal have been reported, however, in practice, phosphorus removal efficiency through the constructed wetland is still relatively lower due to various reasons. In this paper, the phosphorus adsorption capacity of aerated concrete (a building material) was investigated by using Freundlich and Langmuir adsorption isotherm equations, and then the possibility, using aerated concrete waste residues for the treatment of effluent with relatively higher concentration phosphorus at the outfall of constructed wetland end through certain engineering measures, was explored. The results showed that aerated concrete not only had a higher phosphorus adsorption capacity (6.064mg/g), but also had a higher adsorption rate, compared with some other substrate materials commonly used for constructed wetlands. Coupled with the lightweight characteristic of aerated concrete, the imagination of the secondary purification pond was likely to be formed. If the imagination turns into a reality, it will not only effectively purify sewage emissions from the constructed wetland forever, but also realize the resource utilization of large quantities of aerated concrete waste residues resulting from the construction process.

Sponge effect of aerated concrete on phosphorus adsorption-desorption from agricultural drainage water in rainfall

“…Cucarella and Renman (2009) emphasised that high solute concentrations encourage other adsorption mechanisms, such as substantial boundary concentrations; Zhang highlighted that the P adsorption of a filler is only attributed to the physical adsorption in low P concentration water, while the high P concentration of the water can sufficiently cause chemical reactions, such as complexation and precipitation, with the metals (Zhang et al 2005). In addition, some works have reported that the equilibrium adsorption capacity of aerated concrete for phosphorus reaches 300-6064 mg/kg, which is much higher than the amount of the P adsorption obtained in the present study (Fu & Li 2011;Deng & Wheatley 2018;Zhang & Zhu 2018;Castellar et al 2019). The results of the above studies were mainly due to them being based on kinetic bath studies of aerated concrete, which was crushed into a powder and then placed in extremely high P concentration water (5-60 mg/L), and the gained equilibrium adsorption capacity was nearly the theoretical maximum.…”

“…Therefore, aerated concrete is widely used in sewage treatment. The theoretical maximum adsorption amount of aerated concrete reportedly reaches 6 064 mg/kg (Fu & Li 2011). Considering the adsorption-desorption characteristics of fillers, the possibility of using aerated concrete as a filler to reduce the instantaneous P peak value of the drainage water in the initial stage of rainfall was explored by studying the adsorption and desorption properties of the aerated concrete separately.…”