Environmental Science
M. Piri; E. Sepehr
Abstract
BACKGROUND AND OBJECTIVES: Phosphorus is an essential and limiting nutrient for all living organisms. Although phosphorus is a finite resource on earth, it is usually wasted today. Precipitation of struvite from waste residues is mainly carried out to recover phosphorus. This study aimed to investigate ...
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BACKGROUND AND OBJECTIVES: Phosphorus is an essential and limiting nutrient for all living organisms. Although phosphorus is a finite resource on earth, it is usually wasted today. Precipitation of struvite from waste residues is mainly carried out to recover phosphorus. This study aimed to investigate the percentage of phosphorous recovery from sewage sludge in the presence of grape-biochar via the formation of biochar/struvite precipitates. METHODS: Different amounts of grape-biochar were applied to recover nutrients (phosphorus, nitrogen, and magnesium) from sewage sludge via the formation of struvite by digestion of sewage sludge with H2SO4 and the molar ratio of magnesium/ ammonium/ phosphorus in 2:1:1 at pH=8.5. Solubility and release properties of the precipitates were determined and the equations, such as first-order, parabolic diffusion, power function, and simple Elovich models, were fitted to the kinetic data.FINDINGS: The phosphorus recovery from sewage sludge increased by application of grape biochar in the precipitation system, and the accumulation release of nutrients (phosphorus, nitrogen, and magnesium) from samples increased in the presence of grape biochar, especially in high amounts. Increasing the remove and recovery of phosphorus from sewage sludge by application of grape-biochar decreased the incidence of eutrophication, as an environmental dilemma, and provided the requirement for phosphorus-fertilizers by solid waste management. The solubility of the samples was 0.5 mole per liter hydrochloric acid > in 20 gram per liter citric acid > water. The results showed that the phosphorus - cumulative - release of composites in water good fitted the parabolic kinetic model (R2=0.97-0.99), whereas it followed the simple Elovich model (R2=0.86-0.92) in 0.5 mole per liter hydrochloric acid and first-order kinetics model (R2=0.76-0.92) in 20 gram per liter critic acid.CONCLUSION: The results indicated that the presence of grape-biochar for recovery of phosphorus from sludge as struvite had a good potential for increasing the release of nutrients for the formation of struvite, and these precipitates had a high potential to be used as a slow-release phosphorus-fertilizer.
Environmental Engineering
P. Gholamiderami; P. Lahooti; H. Darbam
Abstract
The aim of this study was to produce mulch by combining natural mineral and organic substances in order to reach soil stabilization and improve soil physical and mechanical properties in Koopal area. The effects of organic mulch (at 3 levels of O1: combination of 1% sugarcane bagasse biochar+0.5% gum ...
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The aim of this study was to produce mulch by combining natural mineral and organic substances in order to reach soil stabilization and improve soil physical and mechanical properties in Koopal area. The effects of organic mulch (at 3 levels of O1: combination of 1% sugarcane bagasse biochar+0.5% gum Arabic+0.5% gelatin; O2: combination of 3% sugarcane bagasse biochar+1% gum Arabic+1% gelatin; and O3: combination of 5% sugarcane bagasse biochar+1.5% gum Arabic+ 1.5% gelatin) and MNF organomineral mulch (at 3 levels of MNF1: 1%; MNF2: 3%; and MNF3: 5%) on soil were investigated. The soil samples were incubated for 2 and 4 months and finally placed in a wind tunnel. Some physical and chemical properties of soil were obtained as pH=7.42, O.M%=0.223, and soil texture of silty loam. The obtained results showed that compared to control, application of the mulches increased soil organic carbon percentage (1.1%), mean weight diameter (2.47 mm), geometric mean diameter (1.27 mm), penetration resistance (370), shear strength (27.38) and tensile strength (0.8) significantly and decreased soil loss (0.10 g/m2/s), fracture index, soil texture index (62.16), and crust index (1.18) significantly (p <0.01) in both incubation periods. Effects of the mulches on soil organic carbon were reduced after 4 months. In mulch treatments, soil loss rate, mean weight diameter, geometric mean diameter and tensile strength were increased significantly. In general, the organic mulch could stabilize the soil and improve the physical and mechanical properties of the soil.
