A contribution to the development of a process to valorize the wastewater of wet phosphate fertilizer production

This paper tackles the issue of water intensity of phosphate fertilizer (P-fertilizer) production. Our study focuses the acidic effluent from the wet P-fertilizer production process, containing phosphates, fluorides, silicates, sulfates, and hardness-forming compounds. A novel wastewater treatment approach, encompassing both water and salt recovery, has been developed. The methodology involves laboratory experiments utilizing authentic effluent from a production site in Jordan. Furthermore, a thermodynamic simulation model was formulated to aid in the understanding and scale-up of the examined treatment process. The outcomes of the study revealed that a two-step neutralization of the P-fertilizer wastewater using NaOH, followed by the separation of precipitates, could lead to a reduction of approximately 94 % in fluoride content and nearly complete removal of water hardness components. Remarkably, this process retained the majority of phosphates in solution. The treated effluent becomes well-suited for subsequent conventional reverse osmosis (RO), yielding about 50 % treated water, with the potential to recycle the brine back into the production process. An initial economic evaluation suggests a favorable business proposition, with projected revenues ranging from $ 0.48 to $ 9.95 per cubic meter of treated feedwater, depending on average or optimistic boundary conditions. In summary, this research offers an innovative and economically viable solution for addressing the water-intensive challenges in phosphate fertilizer production, emphasizing sustainable resource management and the potential for substantial environmental and economic benefits.