Recovering Phosphorus and Nitrogen from Leachate Collected from Chidaya Sanitary Landfill Dodoma Tanzania for Fertilizer Production

Abstract

The demand for fertilizer is a global issue that poses a significant threat to future food security. Tanzania is among the countries which rely on agriculture for food production and contribute largely to the economy of the nation. However, farmers incur high production costs due to the utilization of expensive and environmentally insecure fertilizers. The present study investigated the potential of recovering nitrogen and phosphorus nutrients from leachate to produce fertilizer. Hanna pH meter (HI-98121) was used to determine the pH of leachate which was found to be 8.29 ± 0.33. The concentration of phosphorus and nitrogen was determined by using DR 4000 spectrophotometer and was found to be 305.24 ± 16.20 and 189.80 ± 0.165mg/L, respectively. Atomic Absorption Spectrophotometer was used in the determination of magnesium (13.13 ± 0.22 mg/L), potassium (3377 ± 123.4 mg/L), calcium (336 ± 3.65mg/L) and sodium (1270.6 ± 156.90 mg/L). The recovery of the nutrients was done through struvite precipitation, in which 74.01% of phosphorus and 57.27% of nitrogen were recovered under an optimal pH of 9.0 and magnesium-phosphorus molar ratio of 5:1. XRD patterns were analyzed by XRD Rietveld refinement method, for phase quantitative and qualitative analysis. Results show that the precipitates formed were struvite and hydroxyapatite. The elemental composition of struvite was examined by using XRF in which plant nutrients including K, P, Mg, Na and Ca were identified. Production of fertilizer is feasible by using leachate from landfills, thus, to reduce the cost of production, alternative sources of magnesium from locally available materials should be explored.