Effect of aeration and urease enzyme on struvite crystallization from synthetic wastewater of complex fertilizer industry

• Main Author: Zulfikar Luthfi, Muhammad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/35974
• Institution: Institut Teknologi Bandung

The complex fertilizer industry produces wastewater which contributes to pollution of water bodies because it contains high levels of phosphate and ammonium concentrations and contains high TKN (Total Kjeldahl Nitrogen) containing organic nitrogen. Organic nitrogen found in complex fertilizer wastewater is urea so it is necessary to hydrolyze urea to ammonium. Ammonium formed from the hydrolysis process of urea will then react with magnesium and phosphate to form struvite, a crystal from Magnesium Ammonium Phosphate (MAP). The aim of this study was to determine the effect of aeration and hydrolysis of urea with urease enzymes in reducing ammonium and phosphate in synthetic fertilizer complex wastewater through struvite precipitation. Struvite precipitation was carried out in a batch (reactor) reactor which had a working volume of 0.5 L with variations in aeration rate, duration of aeration, and the addition of the urease enzyme derived from jack beans (Canavalia ensiformis). The remaining ammonium and phosphate levels analyzed in this study and struvite crystal formation (MAP) were determined using a Scanning Electron Microscope (SEM) and X-ray diffraction (XRD). The results showed that the aerated reactor partitions could form struvite crystals and set aside the content of ammonium and phosphate in complex fertilizer synthetic wastewater. The addition of magnesium MgCl2 is better in forming struvite crystals compared to MgO. Ammonium removal with molar ratio [Mg2 +]: [NH4 +]: [PO43-] 1: 2: 1 reaches 61-77% at high aeration rates because a lot of ammonium is released into the air. The phosphate allowance reaches 99%. The urease enzyme from jack beans is proven to hydrolyze urea to ammonium and increase the pH value. The sediment products obtained were struvite crystals which were confirmed through analysis using SEM-EDX and XRD.