Effect of Silica Sand Addition in Fluidized Bed Reactor on Productivity and Efficiency of Struvite Crystal Formation

English

Abstract

Introduction: This research is motivated by liquid waste containing phosphate and ammonium, which can pollute waters. Struvite crystallization in a fluidized bed reactor is a solution because it can reduce pollutants and produce fertilizer, but still needs to increase efficiency and productivity. Struvite itself is an environmentally friendly slow-release fertilizer. This study aims to examine the effect of the addition of silica sand on the efficiency and productivity of struvite formation.

Methods: Uniform the size of silica sand using a ball mill operated for 30 minutes at 80 rpm, then sieved using mesh 50. Na2HPO4 as a phosphate source, NH₄Cl as an ammonium source, and MgCl₂ as a Magnesium source. NaOH or HCL as acid base solution. There are two factors, namely the addition of silica and fluid flow velocity. The analysis carried out is the productivity and efficiency of struvite crystal formation.

Results: The diameter of silica sand is 2,97 x 10^-4 m. The maximum and minimum velocities of fluid flow with the addition of silica sand are 0.0034 m/s and 0.0102 m/s. The highest productivity and efficiency were 121.9 g/L and 88.15% with the combination of silica sand addition factor and flow velocity of 0.0034 m/s.

Conclusions: The addition of silica sand and using minimum speed in the struvite crystal formation process can increase the productivity and efficiency of struvite crystals. Flow velocity determines the transportation of ions to the crystal surface, the maximum speed allows the newly formed crystal nucleus to break