Phosphorus is one of the major nutrients that have been identified as a limited resource that would end up earlier than predicted at the rate of current consumption. Therefore, attempts to recover phosphorus from wast...Phosphorus is one of the major nutrients that have been identified as a limited resource that would end up earlier than predicted at the rate of current consumption. Therefore, attempts to recover phosphorus from waste and its subsequent use are a concern of current researchers. Nevertheless, recovery of nutrients from wastewater is cumbersome because nutrients such as phosphates () and nitrates () prefer to remain in aqueous phase rather than being adsorbed on solid matrixes. Investigation of adsorption of available - P from simulated brackish water, on granulated solid waste material, prepared by crushed autoclaved aerated concrete (CAAC), and subsequent use of the material as phosphate fertilizer would be the focus of this research. Treatment of nutrient-rich brackish water is important because such water is discharged in huge volume at the time of harvesting of shrimp aquaculture ponds. Experiments conducted in simulated brackish water confirmed non-linear adsorption association with changing distribution coefficient (KD) which attributed the maximum removal of about 98% - P from 100 mgdm-3solution at its value of 40. The non-linear adsorption supported by both the Langumuir and the Freundlich isotherm models simultaneously satisfied monolayer adsorption and multilayer adsorption depicted by the regression coefficients of greater than .99 by the linearized forms of the isotherm models. Moreover, promising phosphate uptakes characteristics are exhibited by the adsorbent at the process of repetitive adsorption which resulted in 12 g/kg uptake of phosphate at 81% efficiency. The adsorbent seems to be used as a slow-released phosphorus fertilizer at the end of its life as an adsorbent.展开更多
The water system at the Prospect Park ponds of Brooklyn, NY has been receiving chronic loads of orthophosphate from the municipal water since the mid ’90s. The ponds are currently eutrophic with degraded water qualit...The water system at the Prospect Park ponds of Brooklyn, NY has been receiving chronic loads of orthophosphate from the municipal water since the mid ’90s. The ponds are currently eutrophic with degraded water quality and high levels of P in the sediment. In this study, the distribution and speciation of P within the water column was examined. The dominant form of P in the water was found as soluble reactive phosphate (SRP) and the temporal change of SRP indicated significant internal loading from the sediment during late summer in the ponds downstream. Lake sediment was investigated for P fractionation and phosphate bound to Fe-hydroxides was the dominant form of P in the sediment. Both external and internal P pools are important and should be taken into consideration when planning for restoration.展开更多
文摘Phosphorus is one of the major nutrients that have been identified as a limited resource that would end up earlier than predicted at the rate of current consumption. Therefore, attempts to recover phosphorus from waste and its subsequent use are a concern of current researchers. Nevertheless, recovery of nutrients from wastewater is cumbersome because nutrients such as phosphates () and nitrates () prefer to remain in aqueous phase rather than being adsorbed on solid matrixes. Investigation of adsorption of available - P from simulated brackish water, on granulated solid waste material, prepared by crushed autoclaved aerated concrete (CAAC), and subsequent use of the material as phosphate fertilizer would be the focus of this research. Treatment of nutrient-rich brackish water is important because such water is discharged in huge volume at the time of harvesting of shrimp aquaculture ponds. Experiments conducted in simulated brackish water confirmed non-linear adsorption association with changing distribution coefficient (KD) which attributed the maximum removal of about 98% - P from 100 mgdm-3solution at its value of 40. The non-linear adsorption supported by both the Langumuir and the Freundlich isotherm models simultaneously satisfied monolayer adsorption and multilayer adsorption depicted by the regression coefficients of greater than .99 by the linearized forms of the isotherm models. Moreover, promising phosphate uptakes characteristics are exhibited by the adsorbent at the process of repetitive adsorption which resulted in 12 g/kg uptake of phosphate at 81% efficiency. The adsorbent seems to be used as a slow-released phosphorus fertilizer at the end of its life as an adsorbent.
文摘The water system at the Prospect Park ponds of Brooklyn, NY has been receiving chronic loads of orthophosphate from the municipal water since the mid ’90s. The ponds are currently eutrophic with degraded water quality and high levels of P in the sediment. In this study, the distribution and speciation of P within the water column was examined. The dominant form of P in the water was found as soluble reactive phosphate (SRP) and the temporal change of SRP indicated significant internal loading from the sediment during late summer in the ponds downstream. Lake sediment was investigated for P fractionation and phosphate bound to Fe-hydroxides was the dominant form of P in the sediment. Both external and internal P pools are important and should be taken into consideration when planning for restoration.
