Phosphorus Recovery from Wastewater Treatment Plants by Using Waste Concrete

We evaluated a reaction process in which waste concrete was used to recover phosphorus from wastewater.We conducted experiments using various actual wastewater samples obtained by the sludge dewatering process at a sludge disposal plant. The removal ratios of orthophosphate ions from actual wastewater samples were higher than those in the case of model wastewater for which the initial concentrations of orthophosphate ions (131-161 mgPL^-1) were equal to those for the actual wastewater sample and the Ca/P ratio (approx. 5 g g^-1). This result indicates that the high concentration of calcium ions originally contained in the wastewater samples promotes the reaction of HAP. The novel phosphorus recovery process developed in this study, which is based on the use of waste concrete, has the potential to contribute to the inexpensive recycling of phosphorus resources.